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Question for dzlpwr
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Power Wagon got to the root of the problem and nascar mark backed it up with the 100% stock pump statement. The VE pump is capable of flowing more fuel than the gen 1 engine can burn and generating the fuel flow for around 400 engine HP. According to the shop the rebuilt my pump, verified by another shop, the same VE pump on my 92 is used on stationary engines rated at 390 to 400 HP. Tight lipped is about right. It took me a year and a little over a $1000 in parts to get them to talk but I finally got some explanations that I mostly verified thru a friend of mine and the shop he deals with.
The main reason for differences in ratings is the CPL. This list denotes fuel delivery volume, fuel delivery timing, pump timing, valve lift, etc. I found out the hard way that because a pump is rated at 230 hp doesn't mean it will work on any application. The fuel delivery time and rates on the pumps have to match valve timing and air delivery on the engine for the ratings to mean anything. The pump I had built runs much better than the wrong one even though on paper it is rated much less. Power Wagon hit it exactly when he mentioned cam, exhaust and intake manifold changes to make the horsepower. Given the cubic inches of the motor and the restrictions to air flow in and out there is a practical limit to the amount of power that can be made. Fuel amount plays a part but the combination of air in and air out play a larger part and that cannot be remedied by turning up the fuel. The same principal applies to the air system as applies to the fuel system; turning up the pressure doesn't always result in power gains. There is a limit to volume that can be shoved thru a given area and the curve of diminishing returns gets steep fast. The stationary engines I have seen have much larger turbos and air intake systems on them, on the order of 2x, and the fuel consumption rates are not exponentialy larger than the motor in my truck.
I think Piers is on the right track with the cam grinds he is testing. In addition, head porting and some high flow intake and exhaust manifolds should result in some better hp gains without decreasing reliability.
According to Cummins the main reason the P pump was used starting in 94 was the need to meet emissions standards. The P pump generates higher lines pressures which translates to better fuel atomization and combustion. A by-product of this was increased HP but it also necessitated a redesign of the heads and pistons to change flame travel and combustion characteristics. Just raising line pressures doesn't guarantee more fuel, only a better use of the delivered fuel. Changing injector size is the way to deliver more fuel but it also changes spray patterns. While the POD's seem to work fine there seems to be room for improvement by changing washers to help with the smoke problem. This seems to indicate that injector size, spray patterns and piston shape all work together to make the higher HP ratings possible. Cummins also clearly states that deviating from the CPL for a particular motor may produce adverse results. That statement along with number of gen 2 motors with injector and fueling enhancements that are scuffing pistons leads me to think there are some unknowns here that can have a large impact. It would really annoy me to drop $6000 on a rebuild because of a $400 set of injectors.
The governor spring issue was also an interesting conversation. While the shop that built my pump would have put it in they would not warranty the pump or any subsequent problems. The explanation I got was my pump was rated for a certain rpm and increasing that increased the chances of pump failure. The specific failure they were worried about was the tendency of the pump to lock into over-fuel and cause a runaway engine. He maintained that there was more than enough fuel to take the engine way beyond the design specs for rpm which leads me back to the conclusion the VE pump can deliver enough fuel without major modifications. The chance of a detonated 6bt was not worth a $12 part to me.
One last thing on hp ratings, if DC runs true to form then the advertised hp ratings should be at the rear wheels on my truck. Figuring a 30% drive train loss that would mean the engine hp would be 160/. 70 = 228. That would seem to indicate a stock pump is 230 hp.
The main reason for differences in ratings is the CPL. This list denotes fuel delivery volume, fuel delivery timing, pump timing, valve lift, etc. I found out the hard way that because a pump is rated at 230 hp doesn't mean it will work on any application. The fuel delivery time and rates on the pumps have to match valve timing and air delivery on the engine for the ratings to mean anything. The pump I had built runs much better than the wrong one even though on paper it is rated much less. Power Wagon hit it exactly when he mentioned cam, exhaust and intake manifold changes to make the horsepower. Given the cubic inches of the motor and the restrictions to air flow in and out there is a practical limit to the amount of power that can be made. Fuel amount plays a part but the combination of air in and air out play a larger part and that cannot be remedied by turning up the fuel. The same principal applies to the air system as applies to the fuel system; turning up the pressure doesn't always result in power gains. There is a limit to volume that can be shoved thru a given area and the curve of diminishing returns gets steep fast. The stationary engines I have seen have much larger turbos and air intake systems on them, on the order of 2x, and the fuel consumption rates are not exponentialy larger than the motor in my truck.
I think Piers is on the right track with the cam grinds he is testing. In addition, head porting and some high flow intake and exhaust manifolds should result in some better hp gains without decreasing reliability.
According to Cummins the main reason the P pump was used starting in 94 was the need to meet emissions standards. The P pump generates higher lines pressures which translates to better fuel atomization and combustion. A by-product of this was increased HP but it also necessitated a redesign of the heads and pistons to change flame travel and combustion characteristics. Just raising line pressures doesn't guarantee more fuel, only a better use of the delivered fuel. Changing injector size is the way to deliver more fuel but it also changes spray patterns. While the POD's seem to work fine there seems to be room for improvement by changing washers to help with the smoke problem. This seems to indicate that injector size, spray patterns and piston shape all work together to make the higher HP ratings possible. Cummins also clearly states that deviating from the CPL for a particular motor may produce adverse results. That statement along with number of gen 2 motors with injector and fueling enhancements that are scuffing pistons leads me to think there are some unknowns here that can have a large impact. It would really annoy me to drop $6000 on a rebuild because of a $400 set of injectors.
The governor spring issue was also an interesting conversation. While the shop that built my pump would have put it in they would not warranty the pump or any subsequent problems. The explanation I got was my pump was rated for a certain rpm and increasing that increased the chances of pump failure. The specific failure they were worried about was the tendency of the pump to lock into over-fuel and cause a runaway engine. He maintained that there was more than enough fuel to take the engine way beyond the design specs for rpm which leads me back to the conclusion the VE pump can deliver enough fuel without major modifications. The chance of a detonated 6bt was not worth a $12 part to me.
One last thing on hp ratings, if DC runs true to form then the advertised hp ratings should be at the rear wheels on my truck. Figuring a 30% drive train loss that would mean the engine hp would be 160/. 70 = 228. That would seem to indicate a stock pump is 230 hp.
Fletch',
In the table it shows 1200/350... . now 350 bar = approx 5,150 psi based on 1 bar = 1 atmosphere= 14. 7 psi.
I can't imagine the other figure being a measure of 'bar(s)' since that takes up into the kind of pressures that are in the 2nd/3rd gens. 17-18K psi.
I also agree with the air in/air out item that has been mentioned before and noted by cerberusiam.
The thing with the intake manifold "air in", is that on a normally aspirated engine (gas) you do need to remove all restrictions etc. since the engine is basically 'sucking' air. In our application though, it is a charged or, pressurized system, so I'm not entirely sure if the issue of "roughness" is a major deal.
Yes, porting helps by removing the significant obstructions to flow in the head/ports/ etc... but the fact that there is a 'grain' or texture shouldn't be a contributing factor.
As I understand it the 1st Gens got off pretty lucky in terms of "stock" camshaft profiles... . the 1st gen has a "better" cam than the 2nd Gens do, perhaps to compensate (if only a bit) for the generally poorer flow characteristics of the head.
So we start out with a somewhat better cam, have poor air/flow in the head, and limitations on the VE operating pressures and volume (to a lesser degree), based, if nothing else, on the inability to move enough air volume at low drive pressures to burn the fuel from the VE.
The VE can have the fill timing tweaked, I think, but darned if I'm far enough along to spec that...
Pump RPM is largely limited by the plunger return springs, (as well as cam plate, rollers,) which are very precisely matched to prevent the cam plate from jumping off the rollers (floating) during heavy/harsh acceleration and, to assure the plunger is not displaced from a perfectly centered position. Basically to prevent the plunger from "cocking" to one side.
BTW what is the actual max pump RPM in relation to crankshaft RPM??? The table says 4500 min-1.
The plunger, distributor head bushing, and control collar (which is affected by governor spring/gov. screw/full fuel screw choices) are fitted so extremely precisely (they are "lap fitted" and require no seals/gaskets") that they seal even at very high pressures. The small losses are utilized to aid in plunger lubrication believe it or not. .
The cam plate and its cam contour influence the fuel-injection duration. Cam stroke and plunger-lift velocity are the decisive criteria.
Due to wide variations in applications a special cam-plate surface is constructed for each specific engine type/application.
These cam plates are not interchangeable between different VE pumps.
So, we are left with very few options in terms of "internal" modifications. We can't for example do like the 2nd gens, and just do a 'cam plate', or plunger/barrel mod. NOPE... .
The gov. spring is something that can be done... I'm still honestly uncertain of this, though.....
If you use the gov spring change to raise the defuel point ( I assume without need to touch the gov screw),,, is that similar in effect to, using the gov. screw to raise the overall RPM limit higher which also seems to "drag" the fueling limits higher????
OK, I know that is long winded, but hang in... .
There is no way around the fact (that I can see right now) that we are left with: camshaft change(s), turbo changes, porting or outright head changes, and a new more effective injector design/configuration.
Well, that's it, I know it's long but it's real late, I'm tired and if it confusing... sorry. .
Now, did I miss something that would change the conclusion/options?????
bob.
In the table it shows 1200/350... . now 350 bar = approx 5,150 psi based on 1 bar = 1 atmosphere= 14. 7 psi.
I can't imagine the other figure being a measure of 'bar(s)' since that takes up into the kind of pressures that are in the 2nd/3rd gens. 17-18K psi.
I also agree with the air in/air out item that has been mentioned before and noted by cerberusiam.
The thing with the intake manifold "air in", is that on a normally aspirated engine (gas) you do need to remove all restrictions etc. since the engine is basically 'sucking' air. In our application though, it is a charged or, pressurized system, so I'm not entirely sure if the issue of "roughness" is a major deal.
Yes, porting helps by removing the significant obstructions to flow in the head/ports/ etc... but the fact that there is a 'grain' or texture shouldn't be a contributing factor.
As I understand it the 1st Gens got off pretty lucky in terms of "stock" camshaft profiles... . the 1st gen has a "better" cam than the 2nd Gens do, perhaps to compensate (if only a bit) for the generally poorer flow characteristics of the head.
So we start out with a somewhat better cam, have poor air/flow in the head, and limitations on the VE operating pressures and volume (to a lesser degree), based, if nothing else, on the inability to move enough air volume at low drive pressures to burn the fuel from the VE.
The VE can have the fill timing tweaked, I think, but darned if I'm far enough along to spec that...
Pump RPM is largely limited by the plunger return springs, (as well as cam plate, rollers,) which are very precisely matched to prevent the cam plate from jumping off the rollers (floating) during heavy/harsh acceleration and, to assure the plunger is not displaced from a perfectly centered position. Basically to prevent the plunger from "cocking" to one side.
BTW what is the actual max pump RPM in relation to crankshaft RPM??? The table says 4500 min-1.
The plunger, distributor head bushing, and control collar (which is affected by governor spring/gov. screw/full fuel screw choices) are fitted so extremely precisely (they are "lap fitted" and require no seals/gaskets") that they seal even at very high pressures. The small losses are utilized to aid in plunger lubrication believe it or not. .
The cam plate and its cam contour influence the fuel-injection duration. Cam stroke and plunger-lift velocity are the decisive criteria.
Due to wide variations in applications a special cam-plate surface is constructed for each specific engine type/application.
These cam plates are not interchangeable between different VE pumps.
So, we are left with very few options in terms of "internal" modifications. We can't for example do like the 2nd gens, and just do a 'cam plate', or plunger/barrel mod. NOPE... .
The gov. spring is something that can be done... I'm still honestly uncertain of this, though.....
If you use the gov spring change to raise the defuel point ( I assume without need to touch the gov screw),,, is that similar in effect to, using the gov. screw to raise the overall RPM limit higher which also seems to "drag" the fueling limits higher????
OK, I know that is long winded, but hang in... .
There is no way around the fact (that I can see right now) that we are left with: camshaft change(s), turbo changes, porting or outright head changes, and a new more effective injector design/configuration.
Well, that's it, I know it's long but it's real late, I'm tired and if it confusing... sorry. .
Now, did I miss something that would change the conclusion/options?????
bob.
Great thread!! Everyone agrees upgrades to air/exhaust flow are super important, and now some suggest intake manifold improvements. How do you propose accomplishing that. Last time I had the intake manifold cover off I guess I should have examined the interior more closely. Are we talking ablut porting the intake manifold? Is there sufficient access to accomplish that. Or, better yet, has anyone done it? Henry
Bush, I'm not ready to agree with you on this point... I've seen some test data with water flow and it can make a significant difference... water and air are both fluids so the same priciples would apply.
"Corrugated" hoses (like the one from the air box to the turbo intake) are a big restriction to air flow. And you know 90* elbows are not good either.
Just hate to see everone overlook the obvious.
This thread has gotten good. Lots of good ideas here.
Jay
Bush,
The governor screw controls how much spring pressure is applied to the fueling advance plate which overcomes the flyweights starting the defueling process. Changing the screw settings changes the characteristics of the defuel point and curve from what was calibrated on the test stand. Turning in the full power screw does the same thing by advancing the fueling plate starting point in addition to changing the amount of fuel that is delivered on each stroke. Defuel point goes up, max rpm point goes up. Changing the tension of the spring allows more fuel at more advance to perpetuate rpm increase. The problem is Bosch doesn't list the springs by application, only by CPL. Since the VE pump is used in applications that run up to 5000 rpms that spring is pretty important in limiting top rpm by CPL. The point the pump builder was making is changing the governor spring without changing other pieces in the pump could result in a over-fuel lockup. The VE pump's timing is dynamic by rpm. The faster you spin it the more injection advance is used so rpm increase is perpetuated till design limits are hit. I would guess that at 2900 rpms the pump has only used 60-70 percent of available advance and with no other safety measures increasing that is dangerous.
The corrugated tube and 90 degree elbows could impact performance if the limits of flow have been hit. Banks advertises a 10% increase in power by using their aftercooler. That would indicate that the aftercooler is probably a larger source of restriction, along with the air filter, than the intake tube or path the compressed air takes to the manifold. The dual horn air intakes do not advertise increased air flow, instead they justify themselves by increasing air distribution to all cylinders. Once again you don't get anymore volume thru a fixed area but what does come thru is distributed better among competing resources thereby increasing efficiency which is reflected in a power increase. I don't know how to prove it scientifically but it seems a logical assumption that there are large gains to made in air flow efficiencies before designs limits intrude.
It seems to me if we compared diesel technolgy to gas technology it would be like comparing a Model A to Viper. To date there has not been a lot of research and engineering done to improve the diesel engine, as compared to the gas engine, but I think that will change as the EPA starts looking for ways to further justify their existence.
The governor screw controls how much spring pressure is applied to the fueling advance plate which overcomes the flyweights starting the defueling process. Changing the screw settings changes the characteristics of the defuel point and curve from what was calibrated on the test stand. Turning in the full power screw does the same thing by advancing the fueling plate starting point in addition to changing the amount of fuel that is delivered on each stroke. Defuel point goes up, max rpm point goes up. Changing the tension of the spring allows more fuel at more advance to perpetuate rpm increase. The problem is Bosch doesn't list the springs by application, only by CPL. Since the VE pump is used in applications that run up to 5000 rpms that spring is pretty important in limiting top rpm by CPL. The point the pump builder was making is changing the governor spring without changing other pieces in the pump could result in a over-fuel lockup. The VE pump's timing is dynamic by rpm. The faster you spin it the more injection advance is used so rpm increase is perpetuated till design limits are hit. I would guess that at 2900 rpms the pump has only used 60-70 percent of available advance and with no other safety measures increasing that is dangerous.
The corrugated tube and 90 degree elbows could impact performance if the limits of flow have been hit. Banks advertises a 10% increase in power by using their aftercooler. That would indicate that the aftercooler is probably a larger source of restriction, along with the air filter, than the intake tube or path the compressed air takes to the manifold. The dual horn air intakes do not advertise increased air flow, instead they justify themselves by increasing air distribution to all cylinders. Once again you don't get anymore volume thru a fixed area but what does come thru is distributed better among competing resources thereby increasing efficiency which is reflected in a power increase. I don't know how to prove it scientifically but it seems a logical assumption that there are large gains to made in air flow efficiencies before designs limits intrude.
It seems to me if we compared diesel technolgy to gas technology it would be like comparing a Model A to Viper. To date there has not been a lot of research and engineering done to improve the diesel engine, as compared to the gas engine, but I think that will change as the EPA starts looking for ways to further justify their existence.
cerberusiam,
Can we go a bit further here, if you're inclined... .
You mention "... The governor screw controls how much spring pressure is applied to the fueling advance plate ... "
I'm not certain what your phrase "advance plate" describes??
In the thread "detailed VE pump info" I have posted some pics of pump internals. Maybe if you have a minute you might have a look and see if you can relate that 'advance plate' to one of the pics in there and tell me. Is the "advance plate" synonomis with control collar???
I am intrigued by something in your next bit of the post...
"... ... Changing the screw settings changes the characteristics of the defuel point and curve from what was calibrated on the test stand. Turning in the full power screw does the same thing by advancing the fueling plate starting point in addition to changing the amount of fuel that is delivered on each stroke. Defuel point goes up, max rpm point goes up. Changing the tension of the spring allows more fuel at more advance to perpetuate rpm increase..... "
I noticed that the first adjustement, the gov screw, seems to have an impact on defuel characteristics, while the full power screw changes two things. One is advancing the fuel plate starting point AND in addition the amount of fuel that is delivered on each stroke.
Am I reading or interpreting this right... . the full fuel screw is likely to have a higher chance of run-away or "over-fuel" condition than just the gov. screw?????
If in fact we are looking at a potential runaway condition, I wonder, as an aside, if this is similar to the 'recall' that happened on the earlier VE pumps, were a spring or check valve could fail and cause run-away condition... if so, there may be a direct link to what you are saying as well... .
I'm not being critical, just trying to follow the train of thought here... (good luck bob)
Let me repeat, I SUCK at formula's, maybe formual himself
could translate the max RPM of the pump as a reading from engine tach speed too... how far, in terms of engine RPM can the pump be pushed?? At least 3600 going by nascar's experience...
On the intake/air flow item... I fully agree that the system starting with the air filter needs improvement since we start with an air flow deficiency to begin with. Cleaning up the air supply pipe innner surface would possibly help a bit, (every bit counts) but I don't know if the slightly "mottled" texture of the intake manifold is critical. I refer to the area immediately under the intake horn.
The head intake ports, yes, they need work, as does the area's around the valves etc, as shown on PDR's site re: porting.
(If you put on a 94+ head you'd be ahead of the game just in that. I'm also betting it is less costly than a full porting/polishing job too... yes/no???
The intake horn's 90*'s is less than desirable that's for sure. I wonder how the 2nd Gen horn would work in terms of advantages???
Certainly widening the radius of the 90* would help in terms of redirection of air being more gentle, as would splitting the horn like the dual ram intake horn.
JLEONARD,
I'll have a go at your thoughts too... I realize that fluids can be significantly affected by the inner surface of what it's passing thru, turbulence is certainly an issue.
Air however, is not a fluid, but a gas. It's surface tension/adhesion is similar in function but much less an issue.
Anything that would cause a measureable turbulence/restriction to water would be less of a factor for air, I would think. By that I mean modest surface contours, 'mottling' such as seen in castings.
Since the air itself is being forced thru the system, it has the 'energy' to overcome most low level restrictions like surface texture(s) and, will not see any major 'turbulence' created in it's flow due to those textures.
Large casting lumps etc, yes, they will cause poor air flow. That is why heads are ported and polished, to rid them of the significant casting irregularities and lumps which interfere and redirect airflow.
Does any of this track or am I off base here..... ?? jump in you guys...
Ask questions, contribute, whatever... . this is an open discussion here... . besides, I need help... .
hdm48 you have experience in porting polishing, dzlpwr, philip, nascar mark, formula, cerberusiam (were did that nick come from by the way???)
Bob.
Can we go a bit further here, if you're inclined... .
You mention "... The governor screw controls how much spring pressure is applied to the fueling advance plate ... "
I'm not certain what your phrase "advance plate" describes??
In the thread "detailed VE pump info" I have posted some pics of pump internals. Maybe if you have a minute you might have a look and see if you can relate that 'advance plate' to one of the pics in there and tell me. Is the "advance plate" synonomis with control collar???
I am intrigued by something in your next bit of the post...
"... ... Changing the screw settings changes the characteristics of the defuel point and curve from what was calibrated on the test stand. Turning in the full power screw does the same thing by advancing the fueling plate starting point in addition to changing the amount of fuel that is delivered on each stroke. Defuel point goes up, max rpm point goes up. Changing the tension of the spring allows more fuel at more advance to perpetuate rpm increase..... "
I noticed that the first adjustement, the gov screw, seems to have an impact on defuel characteristics, while the full power screw changes two things. One is advancing the fuel plate starting point AND in addition the amount of fuel that is delivered on each stroke.
Am I reading or interpreting this right... . the full fuel screw is likely to have a higher chance of run-away or "over-fuel" condition than just the gov. screw?????
If in fact we are looking at a potential runaway condition, I wonder, as an aside, if this is similar to the 'recall' that happened on the earlier VE pumps, were a spring or check valve could fail and cause run-away condition... if so, there may be a direct link to what you are saying as well... .
I'm not being critical, just trying to follow the train of thought here... (good luck bob)
Let me repeat, I SUCK at formula's, maybe formual himself
could translate the max RPM of the pump as a reading from engine tach speed too... how far, in terms of engine RPM can the pump be pushed?? At least 3600 going by nascar's experience...
On the intake/air flow item... I fully agree that the system starting with the air filter needs improvement since we start with an air flow deficiency to begin with. Cleaning up the air supply pipe innner surface would possibly help a bit, (every bit counts) but I don't know if the slightly "mottled" texture of the intake manifold is critical. I refer to the area immediately under the intake horn.
The head intake ports, yes, they need work, as does the area's around the valves etc, as shown on PDR's site re: porting.
(If you put on a 94+ head you'd be ahead of the game just in that. I'm also betting it is less costly than a full porting/polishing job too... yes/no???
The intake horn's 90*'s is less than desirable that's for sure. I wonder how the 2nd Gen horn would work in terms of advantages???
Certainly widening the radius of the 90* would help in terms of redirection of air being more gentle, as would splitting the horn like the dual ram intake horn.
JLEONARD,
I'll have a go at your thoughts too... I realize that fluids can be significantly affected by the inner surface of what it's passing thru, turbulence is certainly an issue.
Air however, is not a fluid, but a gas. It's surface tension/adhesion is similar in function but much less an issue.
Anything that would cause a measureable turbulence/restriction to water would be less of a factor for air, I would think. By that I mean modest surface contours, 'mottling' such as seen in castings.
Since the air itself is being forced thru the system, it has the 'energy' to overcome most low level restrictions like surface texture(s) and, will not see any major 'turbulence' created in it's flow due to those textures.
Large casting lumps etc, yes, they will cause poor air flow. That is why heads are ported and polished, to rid them of the significant casting irregularities and lumps which interfere and redirect airflow.
Does any of this track or am I off base here..... ?? jump in you guys...
Ask questions, contribute, whatever... . this is an open discussion here... . besides, I need help... .
hdm48 you have experience in porting polishing, dzlpwr, philip, nascar mark, formula, cerberusiam (were did that nick come from by the way???)
Bob.
The fueling advance plate overcomes the flyweights starting the defuel???????????????????? Doesn't the governor spring pulling the governor lever assembly oppose the flyweights? Can't be the control collar, Bush, I don't think, its a reactive device. Adjusting lever, maybe? Humor, maybe? There I did it - had to show my ignorance!
Hey Fletch',
Don't ever feel your asking dumb questions bud... . there are no such things around here..... trust me...
In fact all questions result in the rest of us going back, re-reading, and maybe 'seeing the light'... so ask on...
I admit I need to clarify in my own mind what cerberusiam was referring to when he mentioned 'fueling advance plate'.
As I look at those pics I posted I see the gov spring pulling on the following: the idle spring, which pulls the Tensioning lever, which in turn pushes against the Start lever and in doing this it hits the Tensioning Lever Stop. After all these components make full contact, the effect is to push against the Sliding Sleeve, now, as that is pushed back it in turn, presses harder on the base(s) of the Flyweights.
Ok, follow me here and see if I'm seeing/interpreting this right.....
After all that, right up to pushing on the Flyweights, the Flyweights are held in (prevented from expanding outward) and this ends up holding the control collar forward and prevents the Distributor-Plunger Cutoff Bore from being exposed.
THAT, results in more fuel delivery, longer. As that happens the RPM climbs and if the load does not continue to increase, the Flyweights again, start to expand outward and pull the control collar back, eventually opening the Cutoff Bore, and reducing/ending the fuel delivery cycle.
Go to the link and scroll down to the pics, then look at pics 1,2,3. to see what I'm thinking...
http://turbodieselregister.com/forums/showthread.php?s=&threadid=65478
Bob.
Don't ever feel your asking dumb questions bud... . there are no such things around here..... trust me...
In fact all questions result in the rest of us going back, re-reading, and maybe 'seeing the light'... so ask on...
I admit I need to clarify in my own mind what cerberusiam was referring to when he mentioned 'fueling advance plate'.
As I look at those pics I posted I see the gov spring pulling on the following: the idle spring, which pulls the Tensioning lever, which in turn pushes against the Start lever and in doing this it hits the Tensioning Lever Stop. After all these components make full contact, the effect is to push against the Sliding Sleeve, now, as that is pushed back it in turn, presses harder on the base(s) of the Flyweights.
Ok, follow me here and see if I'm seeing/interpreting this right.....
After all that, right up to pushing on the Flyweights, the Flyweights are held in (prevented from expanding outward) and this ends up holding the control collar forward and prevents the Distributor-Plunger Cutoff Bore from being exposed.
THAT, results in more fuel delivery, longer. As that happens the RPM climbs and if the load does not continue to increase, the Flyweights again, start to expand outward and pull the control collar back, eventually opening the Cutoff Bore, and reducing/ending the fuel delivery cycle.
Go to the link and scroll down to the pics, then look at pics 1,2,3. to see what I'm thinking...
http://turbodieselregister.com/forums/showthread.php?s=&threadid=65478
Bob.
I agree with you, Bob, but... ... ... fuel advance plate???????????? Only one lever isn't shown in the diagrams but is referenced: adjusting lever. It is shown in one picture. Full fuel screw impinges upon it, as I see it. That's the only thing I can come up with that might be the "mysterious" fuel advance plate. I get this feel'in, tho, someone's pull'in someone's leg. Remember the peanut gallery on another forum laughing at this thread earlier. Don't recon they might have joined us, do ya?
Bush,
I agree that the 'mottled' as you call them surfaces of the castings are not very significant in restricting air flow, but the 90* bends are and especially the corrugated style hoses... . these cause turbulence or "eddys" , disturbing the flow.
Have any of us reached the point where these are significant? Probably some have... . I'm sure I have not since I have stock injectors and no intercooler... . just a very short piece of connecting hose and the intake 'tunnel'.
Hey what about the grid heater???? Anybody think that's significant? Think it's worth taking it out and experimenting?
Just some more thoughts. Now my head hurts.
Jay
I agree that the 'mottled' as you call them surfaces of the castings are not very significant in restricting air flow, but the 90* bends are and especially the corrugated style hoses... . these cause turbulence or "eddys" , disturbing the flow.
Have any of us reached the point where these are significant? Probably some have... . I'm sure I have not since I have stock injectors and no intercooler... . just a very short piece of connecting hose and the intake 'tunnel'.
Hey what about the grid heater???? Anybody think that's significant? Think it's worth taking it out and experimenting?
Just some more thoughts. Now my head hurts.
Jay
http://www.diesel-central.com/forums/thread.asp?ForumID=15&TopicID=686
Last post on the page is directed right at you guys, by name even.
Last post on the page is directed right at you guys, by name even.
Last edited by a moderator:
Post from KTA-Cummins
I hope I'm not overstepping my bounds here but this post by KTA-Cummins is directed at this thread. It's nice to see a productive exchange of information. Hopefully it will continue.
KTA-Cummins wrote-
Wow that thread is really getting technical now, but there are a few things I am confused on, maybe someone can help.
The pump and injector system is pretty basic really. If you increase fuel delivery at the pump without changing the injector the peak injection pressure goes up. If you increase injector flow the pressure goes down. You can not raise injection pressures with the pump by not changing fueling rates, they go hand in hand. The needle in the injector is set to begin injection between 3200 and 3800psi depending on the injector number, the needle shuts again when the pressure drops below 32-3800psi. What the pressure peaks at in-between depends on injectors and fuel delivery rate.
Cerberusiam-- I would like to know who made these 390+hp ve powered engines as I have never heard or seen of one, Cummins certainly never did, so who else has, possibly there may be some better parts out there afterall?
Also the scuffed pistons are a direct result of excessive egt's for too long, not of bad injectors, they burn holes through the tops of pistons, not swell them. Also DC's ratings have never been at the rear wheels 160hp=160fwhp sorry.
Bushy--- 17-18KPSI IS Probably not an unreal PEAK injection pressure, the P can just, get to an maintain that pressure much quicker and longer. The first gen head is a different number than the second gen because it is not notched to clear the p-pump and the early heads had big injector holes, but the passageways in the head and the valves are the same size, so why would they flow soo much worse than the later heads??? Cummins subs them to the later heads if you replace one anyways?? The same is true of the cams a 160hp 1stgen and a 215hp second gen have virtually identical cams and again the later 215 cam replaces the old cam so again why are these engines soo much more restrictive???
Oh yeah If you guys are scared to change governer springs then DON'T!!!! LOL
I hope I'm not overstepping my bounds here but this post by KTA-Cummins is directed at this thread. It's nice to see a productive exchange of information. Hopefully it will continue.
KTA-Cummins wrote-
Wow that thread is really getting technical now, but there are a few things I am confused on, maybe someone can help.
The pump and injector system is pretty basic really. If you increase fuel delivery at the pump without changing the injector the peak injection pressure goes up. If you increase injector flow the pressure goes down. You can not raise injection pressures with the pump by not changing fueling rates, they go hand in hand. The needle in the injector is set to begin injection between 3200 and 3800psi depending on the injector number, the needle shuts again when the pressure drops below 32-3800psi. What the pressure peaks at in-between depends on injectors and fuel delivery rate.
Cerberusiam-- I would like to know who made these 390+hp ve powered engines as I have never heard or seen of one, Cummins certainly never did, so who else has, possibly there may be some better parts out there afterall?
Also the scuffed pistons are a direct result of excessive egt's for too long, not of bad injectors, they burn holes through the tops of pistons, not swell them. Also DC's ratings have never been at the rear wheels 160hp=160fwhp sorry.
Bushy--- 17-18KPSI IS Probably not an unreal PEAK injection pressure, the P can just, get to an maintain that pressure much quicker and longer. The first gen head is a different number than the second gen because it is not notched to clear the p-pump and the early heads had big injector holes, but the passageways in the head and the valves are the same size, so why would they flow soo much worse than the later heads??? Cummins subs them to the later heads if you replace one anyways?? The same is true of the cams a 160hp 1stgen and a 215hp second gen have virtually identical cams and again the later 215 cam replaces the old cam so again why are these engines soo much more restrictive???
Oh yeah If you guys are scared to change governer springs then DON'T!!!! LOL
jbolt et al, it kind of gripes me that because some of us still learning and asking one another questions, that some others feel privileged to smirk and tease. Examine the above post you quoted and discover how knowledgeable are the teasers. Claims are made that the first and second heads are basically identical except the later is notched to accomodate the P-pump. If that were true and the internal passages etc were the same, as claimed, they'd flow the same. They don't - early heads flow roughly forty percent less - or maybe PDR is mistaken.
Secondly, the early cams and the later cams are identical. Well I can only say that poor, lost little PDR has a diferent grind for the two and actually believes there is good reason for it. Hopefully Piers and will read this so he can realize how much R&D he wasted.
Finally, the grand conclusion that increasing the fueling rate goes hand in hand with . . . Whoever doubted that - is this supposed to be instructive of something - I'm missing it.
I see nothing in this post that moves us forward.
Fair is fair, men! I suggest we don't laugh at one another if we live in a glass house. Hope this isn't callous, Bush. if so edit it at will. Henry
Secondly, the early cams and the later cams are identical. Well I can only say that poor, lost little PDR has a diferent grind for the two and actually believes there is good reason for it. Hopefully Piers and will read this so he can realize how much R&D he wasted.
Finally, the grand conclusion that increasing the fueling rate goes hand in hand with . . . Whoever doubted that - is this supposed to be instructive of something - I'm missing it.
I see nothing in this post that moves us forward.
Fair is fair, men! I suggest we don't laugh at one another if we live in a glass house. Hope this isn't callous, Bush. if so edit it at will. Henry
:-laf
The relationship between crankshaft speed and injector pump speed is fixed at a 2:1 ratio. This is because a 4 cycle engine fires once every other stroke.
Now, for some fun examples... ... ...
For each revolution of the injector pump, the distributor plunger moves back and forth 6 times. This means that the reciprocating frequency of distributor plunger is 3 x engine rpm.
Assume engine crankshaft speed of 3000rpm
Injector pump rotational speed will be 1500rpm
Distributor plunger is reciprocating at 9000 strokes / min. (150 strokes / sec)
Sean
Sorry guys, looks like I brought down the house with laughter with some of the inferences I made. Let me just say some of the ideas are inferences, chasmic at times, due to a lack of practical experience and knowledge. If anyone feels the need to laugh at my expense I sure don't want to deprive them of a little humor to lighten their life. I chose to post my ideas in an attempt to validate, clarify, or change them as needed. Pursuit of knowledge is supposed to be a good thing, unfortunately there are those that will laugh at the ignorance rather than share their knowledge without reserve. If my ideas are off base anyone has the right to shed some illumination on my ignorance, but please keep the derogatory laughter to a minimum. Even dumb rednecks have a limit.
Nuff said.
Bob - Thank you for catching my screw up. When I start calling things thingamabob and dohickey its time switch to decaf. Here is the link I am using for reference, http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html, and after rereading it for the nth time its starting to make sense so here is another stab at it.
The governor spring pulls the tension lever attached to the goervernor lever assembly which advances which advances the control sleeve. This moves the sleeve in relation to the spill port. The fill port takes a max charge of fuel on every cycle and the spill port controls the amount of fuel delivered on each stroke. By allowing the control lever to move farther more tension is exerted on the tension lever which allows the control sleeve to move farther. The flyweights then pull the control sleeve back when they overcome the tension of governor spring.
Turning the full power screw moves the starting point of the control sleeve forward which increase fuel delivered on each stroke. Looking at the physical pump on my bench the attachment point of the governor spring does not have the same leverage as the fuel power screw attachment point. This would indicate the defueling curve changes as the control sleeve is moved from the test stand postion.
The reference to a fuel advance plate is the inference the timing rollers sit on a plate that is turned as pressure in the feed pump rises. This would effectively increase injection timing.
At WOT max fuel is be delivered on each stroke and as RPMs rise injection timing is advanced. The problem I see, and was detailed to me, is what would happen if the control sleeve jammed in a wide open postion that was beyond design specs for the engine.
Is there a 'over center' position on the governor assembly that could possibly be reached? The clearances in all the pieces are fairly close so it would not take much contamination to cause problems. A drop of water, a speck of dirt, a piece of scale could effectively cause a runaway. In a perfect world all the fuel we buy is perfectly clean and the highest grade possible, all maintenance is done exactly on time, and age never effects the components in the fuel system so this scenario will never happen.
On either Piers, TST, or Dave Fritz's site are the instructions for increasing max RPM using the high idle screw. This is the 'accepted' way to increase max RPM but changing the governor spring is also addressed if more RPM is wanted/needed.
There are several posts of individuals turning the full power screw in to far and having the engine immediately jump to 2000 rpms and not idle down.
Taking all the above together, doesn't it seem logical that:
1. Adjustments to full power screw could lead to problems
2. Changing governor spring could lead to problems
3. Moving away from pump specs could have unknown results
Agree? Disagree? Clarify?
For the record I am not 'scared' to change the governor spring. I don't have enough information yet to decide one way or another if that is what I want or need. I thought the idea of these forums was to share ideas, experiences, and opinions so everyone could make their own decisions based on the best information possible. If that makes me 'scared' so be it.
Clarification on 390+ HP VE applications. If I inferred it was a Cummins engine that was not the case. The conversation I had was about the ability of the VE pump to generate HP in excess of 300. The statement was 'seen specs for the VE pump in applications up to 400 HP'. The engine was not specified. The reference was to Bosch specs for building a certain version of the VE pump. Doesn't nascar mark's numbers indicate this is logical or did I misread the dyno numbers he posted?
The instance of scuffing the piston I referred to was not related to holes burnt in the piston. The piston and cylinder was 'scuffed' and the compression was down. The suggestion was made there was too much fuel present to burn and the cylinder walls were washed down causing the problem. Whether this was a bad injector, overfueling at the wrong time, wrong injection timing, or something else was never determined. My point was changing fueling specs could have some unknown results such as the above. If somebody can prove beyond a reasonable doubt that putting too much fuel into a cylinder at the wrong time will NOT cause a problem I will happily concede the point.
If the 'peanut gallery' wants to laugh at my ignorance thats fine. I am NOT professing to know it all, just looking for some answers that make sense.
Nuff said.
Bob - Thank you for catching my screw up. When I start calling things thingamabob and dohickey its time switch to decaf. Here is the link I am using for reference, http://www.cs.rochester.edu/u/jag/vw/engine/fi/injpump.html, and after rereading it for the nth time its starting to make sense so here is another stab at it.
The governor spring pulls the tension lever attached to the goervernor lever assembly which advances which advances the control sleeve. This moves the sleeve in relation to the spill port. The fill port takes a max charge of fuel on every cycle and the spill port controls the amount of fuel delivered on each stroke. By allowing the control lever to move farther more tension is exerted on the tension lever which allows the control sleeve to move farther. The flyweights then pull the control sleeve back when they overcome the tension of governor spring.
Turning the full power screw moves the starting point of the control sleeve forward which increase fuel delivered on each stroke. Looking at the physical pump on my bench the attachment point of the governor spring does not have the same leverage as the fuel power screw attachment point. This would indicate the defueling curve changes as the control sleeve is moved from the test stand postion.
The reference to a fuel advance plate is the inference the timing rollers sit on a plate that is turned as pressure in the feed pump rises. This would effectively increase injection timing.
At WOT max fuel is be delivered on each stroke and as RPMs rise injection timing is advanced. The problem I see, and was detailed to me, is what would happen if the control sleeve jammed in a wide open postion that was beyond design specs for the engine.
Is there a 'over center' position on the governor assembly that could possibly be reached? The clearances in all the pieces are fairly close so it would not take much contamination to cause problems. A drop of water, a speck of dirt, a piece of scale could effectively cause a runaway. In a perfect world all the fuel we buy is perfectly clean and the highest grade possible, all maintenance is done exactly on time, and age never effects the components in the fuel system so this scenario will never happen.
On either Piers, TST, or Dave Fritz's site are the instructions for increasing max RPM using the high idle screw. This is the 'accepted' way to increase max RPM but changing the governor spring is also addressed if more RPM is wanted/needed.
There are several posts of individuals turning the full power screw in to far and having the engine immediately jump to 2000 rpms and not idle down.
Taking all the above together, doesn't it seem logical that:
1. Adjustments to full power screw could lead to problems
2. Changing governor spring could lead to problems
3. Moving away from pump specs could have unknown results
Agree? Disagree? Clarify?
For the record I am not 'scared' to change the governor spring. I don't have enough information yet to decide one way or another if that is what I want or need. I thought the idea of these forums was to share ideas, experiences, and opinions so everyone could make their own decisions based on the best information possible. If that makes me 'scared' so be it.
Clarification on 390+ HP VE applications. If I inferred it was a Cummins engine that was not the case. The conversation I had was about the ability of the VE pump to generate HP in excess of 300. The statement was 'seen specs for the VE pump in applications up to 400 HP'. The engine was not specified. The reference was to Bosch specs for building a certain version of the VE pump. Doesn't nascar mark's numbers indicate this is logical or did I misread the dyno numbers he posted?
The instance of scuffing the piston I referred to was not related to holes burnt in the piston. The piston and cylinder was 'scuffed' and the compression was down. The suggestion was made there was too much fuel present to burn and the cylinder walls were washed down causing the problem. Whether this was a bad injector, overfueling at the wrong time, wrong injection timing, or something else was never determined. My point was changing fueling specs could have some unknown results such as the above. If somebody can prove beyond a reasonable doubt that putting too much fuel into a cylinder at the wrong time will NOT cause a problem I will happily concede the point.
If the 'peanut gallery' wants to laugh at my ignorance thats fine. I am NOT professing to know it all, just looking for some answers that make sense.
Last edited by a moderator:
It seems to me that biggr lines would also help. I'm also no expert but everytime tractor pulling is discussed the boys tell me to get the injectors lasered and get bigger lines. I think with the bigger lines it would take pressure off of the pump and get more fuel to the injectors quicker, wouldn't it? So it seems it would obviously make a difference and get more fuel just by adding them, similar to replacing injectors.
I also wonder about those 230 horse pumps. Is there anything done to them besides after being rebuilt, being put on the test stand and flowing a certain amount of cc's which is equivelent to horsepower? I wouldn't see how they were too different than the stock ones unless you can install different fuel leaf springs like the old roosa master pumps, which gave them more fuel flowing after the rebuild and allowed you to make quite a bit higher horsepower. As I say, I'm definately no expert. We might have to get Piers involved in this discussion. There's got to be more potential in the VE pumps than 300.
I'll probably end up BOMBING more now after this discussion.
John
I also wonder about those 230 horse pumps. Is there anything done to them besides after being rebuilt, being put on the test stand and flowing a certain amount of cc's which is equivelent to horsepower? I wouldn't see how they were too different than the stock ones unless you can install different fuel leaf springs like the old roosa master pumps, which gave them more fuel flowing after the rebuild and allowed you to make quite a bit higher horsepower. As I say, I'm definately no expert. We might have to get Piers involved in this discussion. There's got to be more potential in the VE pumps than 300.
I'll probably end up BOMBING more now after this discussion. John
Fletch', cerberusiam,
The day people on this forum start laughing at, and ridiculing one another for trying to learn, or even just throwing out some thoughts is the day I walk away from here, and don't look back.
I have NO problem ZERO, ZIP, if someone wants to jump in...
I am dissapointed that someone would want to deliberately turn a thread or discussion away from being productive for ANY reason... be it sales $$$, or whatever...
cerberusiam,
I mentioned earlier, I think to fletch(?) that many times a post will result in alot of us going back to re-think or look again at things, usually with good results.
Thank you for the last post, and I mean that with no sarcasm.
I personally have had to go back and look at, and think about the internals, their function(s), affects on other downsteam components etc. THAT is a GOOD thing...
Post on bud... .
Hey Sled',
Thanks for point out that item... . I'll leave my personal opinion of that out of here since it has no place in here. .
Whether to change out the gov spring or, just use the high idle screw was one of the thoughts being discussed. . it had nothing to do with safety, or anything other than is it necessary/advantageous or will the simple method do just as well.
That has resulted in some good back and forth, and pretty much everyone doing some digging/learning... nothin wrong with that.
Besides it seems the current owners of the 1st Gens are getting more from them than pretty much all of the old owners did, and still making progress. You gotta like that. .
This is an honest effort to be constructive, as was a couple of posts in that thread, and respond to KTA' from the other thread ...
Here, for example is a direct quote from the "Fuel System" section for the VE pump, taken directly from the service manual... ...
"..... The mehanical lift pump delivers fuel under low pressure of 21-35 kPa (3-5 psi) to the injection pump through the fuel/water seperator filter. The injection pump supplies high pressure fuel of approximately 59,000 kPa (8,000 psi) to each injector in precise metered amount at the correct time... ... "
Now I didnt' go back into the manual at the time I mentioned 8,000 psi, because I was fairly certain that was correct at the time I posted it...
There is no doubt that under some circumstances the pump may well generate higher peak pressures or spikes in pressure... but I'm having real trouble understanding how it could spike up into 17,000 or 18,000 psi or more, under ANY circumstances.....
Now, I've made my share of mistakes, and I suspect I'll make plenty more in the future, but I don't believe that ridiculing some of our guys for an honest mistake is an option. I don't care who makes the mistake either. .
If you can't help me learn, then don't help me at all... or should I say hinder me at all...
I don't get cranky often, but condisention doesn't work for me. . on the other hand, if someone wants to join and contribute, you'll get a First Class welcome and an eager ear to your thoughts and opinions.
BTW, I've spent the last 2 hours going thru as many posts as I could and I have not found any example of the kind of sarcasm that is referenced by one or two, on the other thread in question.
Guys, don't let this grow into a scrap and blow our record for getting along. .
Just let it go, carry on with our train of thought(s) and see were it takes us...
Bob - 1st Gen Moderator
The day people on this forum start laughing at, and ridiculing one another for trying to learn, or even just throwing out some thoughts is the day I walk away from here, and don't look back.
I have NO problem ZERO, ZIP, if someone wants to jump in...
I am dissapointed that someone would want to deliberately turn a thread or discussion away from being productive for ANY reason... be it sales $$$, or whatever...
cerberusiam,
I mentioned earlier, I think to fletch(?) that many times a post will result in alot of us going back to re-think or look again at things, usually with good results.
Thank you for the last post, and I mean that with no sarcasm.
I personally have had to go back and look at, and think about the internals, their function(s), affects on other downsteam components etc. THAT is a GOOD thing...
Post on bud... .
Hey Sled',
Thanks for point out that item... . I'll leave my personal opinion of that out of here since it has no place in here. .
Whether to change out the gov spring or, just use the high idle screw was one of the thoughts being discussed. . it had nothing to do with safety, or anything other than is it necessary/advantageous or will the simple method do just as well.
That has resulted in some good back and forth, and pretty much everyone doing some digging/learning... nothin wrong with that.
Besides it seems the current owners of the 1st Gens are getting more from them than pretty much all of the old owners did, and still making progress. You gotta like that. .
This is an honest effort to be constructive, as was a couple of posts in that thread, and respond to KTA' from the other thread ...
Here, for example is a direct quote from the "Fuel System" section for the VE pump, taken directly from the service manual... ...
"..... The mehanical lift pump delivers fuel under low pressure of 21-35 kPa (3-5 psi) to the injection pump through the fuel/water seperator filter. The injection pump supplies high pressure fuel of approximately 59,000 kPa (8,000 psi) to each injector in precise metered amount at the correct time... ... "
Now I didnt' go back into the manual at the time I mentioned 8,000 psi, because I was fairly certain that was correct at the time I posted it...
There is no doubt that under some circumstances the pump may well generate higher peak pressures or spikes in pressure... but I'm having real trouble understanding how it could spike up into 17,000 or 18,000 psi or more, under ANY circumstances.....
Now, I've made my share of mistakes, and I suspect I'll make plenty more in the future, but I don't believe that ridiculing some of our guys for an honest mistake is an option. I don't care who makes the mistake either. .
If you can't help me learn, then don't help me at all... or should I say hinder me at all...
I don't get cranky often, but condisention doesn't work for me. . on the other hand, if someone wants to join and contribute, you'll get a First Class welcome and an eager ear to your thoughts and opinions.
BTW, I've spent the last 2 hours going thru as many posts as I could and I have not found any example of the kind of sarcasm that is referenced by one or two, on the other thread in question.
Guys, don't let this grow into a scrap and blow our record for getting along. .
Just let it go, carry on with our train of thought(s) and see were it takes us...
Bob - 1st Gen Moderator
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Issue 128 – Digital Version
Digital Magazines
FREE!
TDR Test Drive - Digital Edition
Renew
Subscribe
Gift Subscriptions
Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
The Perfect Collection
The Perfect Collection Vol. II
TSB Updates
Dodge/Cummins Historical Overview
Cameron Collection
What Makes Us Tick?
Product Showcase
Advertising
