Engine/Transmission (1994 - 1998) Variable timing P-pump?

[CogginsP]

Anybody ever seen or tried anything like this? variable timing gears have been around for a while. Basically as RPMs increase, then the gear advances. Has anyone ever tried using such a gear on a p-pump in our engines? I have been told that heavy machinery does it but I was thinking about how cool it would be on our trucks. Please share knowledge...

 

[Forrest Nearing]

it would take some serious hardware... at full tilt, I think a P7100 can take 50+ hp just to turn it...



variable valve timing on a honda? sure... variable injection timing on an injection pump the size of a small engine? yes, it could be done somehow, but you'd run into the point of deminishing returns pretty quickly I'd think.

 

[AFoulk]

I've seen trucks that use it. Mack's Midliners (built by Renault) had a set up like that on their pump drive gear and their pumps actually look very, very similar to a p-pump and are made by Bosch. This set up however was the most reliable thing in the world. Older Mack V-MAC engines (pre-etech) had a timing advance unit bolted between the pump and the engine that used engine oil press. and the module to control it. And again, they used a bosch pump that looked similar to a p-pump, only bigger and the fuel rack was controled by the engine module as well. I'm not saying any of these would work on a 12v, but there are examples out there.

 

[zstroken]

I have recently thought of such a system. I am thinking of one that would allow some tunability. Would probably require a modification to the front cover. Just need someone who has some time on a CNC.

 

[Vaughn MacKenzie]

Dynamic timing in a P-pump would be the ticket wouldn't it? Building a special gear with some sort of centrifugal advance might be one way, but it would have to be designed where it wouldn't be affected by drag induced by fueling demands. Hydraulic advance sounds like a complicated problematic approach. Maybe some internal pump mod controlled by the governor springs that would delay spill port filling at lower RPM, effectively retarding timing. In that case set the pump up way advanced, and not allow full timing until 3500 RPM or whatever.



The range of timing change would have to be considered, maybe 10 degrees total, something like 12 degrees at idle and 20 at 3500.



I believe the old VE pump 1st gens have some mechanical timing advance, not sure how many degrees of range it has.

 

[AMink]

I have thought that being able to easily adjust how far forward the plate is would be cool. Kind of like a box for 24 valvers. Maybe a cable or something that you could move from inside the cab. Drive around town with the plate back, forward for fun.

 

[ROADWARRIOR]

I have thought that being able to easily adjust how far forward the plate is would be cool. Kind of like a box for 24 valvers. Maybe a cable or something that you could move from inside the cab. Drive around town with the plate back, forward for fun.

Didn't ATS make a system like this back in the day? Or maybe they still do? I remember an add that showed a cable to the cab.



Dan

 

[zstroken]

Use a centrifigal setup with a helix on it. Yes you have to consider the 50HP it could take to run the pump, but the helix with enough weights on it would compensate for it.

 

[CogginsP]

Dynamic timing in a P-pump would be the ticket wouldn't it? Building a special gear with some sort of centrifugal advance might be one way, but it would have to be designed where it wouldn't be affected by drag induced by fueling demands. Hydraulic advance sounds like a complicated problematic approach. Maybe some internal pump mod controlled by the governor springs that would delay spill port filling at lower RPM, effectively retarding timing. In that case set the pump up way advanced, and not allow full timing until 3500 RPM or whatever.



The range of timing change would have to be considered, maybe 10 degrees total, something like 12 degrees at idle and 20 at 3500.



I believe the old VE pump 1st gens have some mechanical timing advance, not sure how many degrees of range it has.

Nice thoughts! If only there was a simple way to get variable timing on our injection pumps, I would like to see something like that researched! We could give all the common rail folks on the third gen forums a swift kick in the nutz

 

[zstroken]

Dynamic timing in a P-pump would be the ticket wouldn't it? Building a special gear with some sort of centrifugal advance might be one way, but it would have to be designed where it wouldn't be affected by drag induced by fueling demands. Hydraulic advance sounds like a complicated problematic approach. Maybe some internal pump mod controlled by the governor springs that would delay spill port filling at lower RPM, effectively retarding timing. In that case set the pump up way advanced, and not allow full timing until 3500 RPM or whatever.



The range of timing change would have to be considered, maybe 10 degrees total, something like 12 degrees at idle and 20 at 3500.



I believe the old VE pump 1st gens have some mechanical timing advance, not sure how many degrees of range it has.

I was thinking for competion only. Then you just assume fuel throttle and set your adjustment for that. I mean how many times do you need the huge advance for a part throttle run.

 

[bmoeller]

I have thought that being able to easily adjust how far forward the plate is would be cool.

Most of us have one. It's called a right foot. :-laf



A valet switch would somewhat have a similar effect. Albeit it really won't be adjustable. Either on or off.

 

[dpuckett]

Vaughn- you're right, the VEs have a timing advance the increases with internal vane pump pressure- all of which increase as RPMs increase. I'm not sure on the numbers, but I seem to recall a 10-12deg advance over base timing at peak RPM, bringing you up to the mid to high 20s at 2500-3500rpm. Greenleaf knows all that stuff, I just read it here.



So, the P7100s increase RPMs with fuelling only? You get 16deg at idle and 300RPM? It's a wonder they get as good of MPGs as they do. Or am I missing something?



Daniel

 

[dzlpwr]

The big Mack trucks that utilize the V-Mac system do use a P7100 pump with an advance mechanism as part of the drive gears. We have converted over a couple of them to use on the 400 series internatial engines for tractor pulling applications and they work very well. It wouldn't take a whole lot of fabricating to make one work on a 5. 9L. The type of electronic governor that both Mack and John Deere use is called an EDC governor. It is used on both the P3000 series and P7100 series pumps. I could be used on any P-pump and all it used is a tone ring in place of governor weights to monitor cam timing and pump rpm. A very large actuator or solenoid moves the rack foward as you apply voltage to it and there is a rack sensor to provide feedback as to how much rack travel you have. It wouldn't be very hard to use this pump on our trucks. If you had a V-MAC ecm, a few sensors for feedback, and used thier accelerator pedel it would work quite well. You can set up a potetiometer to vary voltage to the rack solenoid to put the rack at any amount of travel you want. Kind of like turning up a radio. Thats exactly the way that I run them on the stand. You just make sure all of your feedback is within specs, and place the rack wherever you want and calibrate to specs.

 

[zstroken]

The big Mack trucks that utilize the V-Mac system do use a P7100 pump with an advance mechanism as part of the drive gears. We have converted over a couple of them to use on the 400 series internatial engines for tractor pulling applications and they work very well. It wouldn't take a whole lot of fabricating to make one work on a 5. 9L. The type of electronic governor that both Mack and John Deere use is called an EDC governor. It is used on both the P3000 series and P7100 series pumps. I could be used on any P-pump and all it used is a tone ring in place of governor weights to monitor cam timing and pump rpm. A very large actuator or solenoid moves the rack foward as you apply voltage to it and there is a rack sensor to provide feedback as to how much rack travel you have. It wouldn't be very hard to use this pump on our trucks. If you had a V-MAC ecm, a few sensors for feedback, and used thier accelerator pedel it would work quite well. You can set up a potetiometer to vary voltage to the rack solenoid to put the rack at any amount of travel you want. Kind of like turning up a radio. Thats exactly the way that I run them on the stand. You just make sure all of your feedback is within specs, and place the rack wherever you want and calibrate to specs.

Is this actually advancing the timing or just moving the fuel rack?

 

[Vaughn MacKenzie]

Vaughn- you're right, the VEs have a timing advance the increases with internal vane pump pressure- all of which increase as RPMs increase. I'm not sure on the numbers, but I seem to recall a 10-12deg advance over base timing at peak RPM, bringing you up to the mid to high 20s at 2500-3500rpm. Greenleaf knows all that stuff, I just read it here.

Well 10-12 degrees is a wider range than what I would've guessed. I'll have to ask greenleaf, we've talked lots of trains but I didn't know he knew about VE pumps

The big Mack trucks that utilize the V-Mac system do use a P7100 pump with an advance mechanism as part of the drive gears. We have converted over a couple of them to use on the 400 series internatial engines for tractor pulling applications and they work very well. It wouldn't take a whole lot of fabricating to make one work on a 5. 9L. The type of electronic governor that both Mack and John Deere use is called an EDC governor. It is used on both the P3000 series and P7100 series pumps. I could be used on any P-pump and all it used is a tone ring in place of governor weights to monitor cam timing and pump rpm. A very large actuator or solenoid moves the rack foward as you apply voltage to it and there is a rack sensor to provide feedback as to how much rack travel you have. It wouldn't be very hard to use this pump on our trucks. If you had a V-MAC ecm, a few sensors for feedback, and used thier accelerator pedel it would work quite well. You can set up a potetiometer to vary voltage to the rack solenoid to put the rack at any amount of travel you want. Kind of like turning up a radio. Thats exactly the way that I run them on the stand. You just make sure all of your feedback is within specs, and place the rack wherever you want and calibrate to specs.

Dang, I find it surprising no one has attempted to adapt the V-Mac advance mechanism and governor control system to a 12-valve Dodge yet. The governor piece is fascinating because it's exactly what I was speculating about in a thread several months ago. . . computer-controlled mechanical IP. Rugged durability of the P-pump married to electronic control. If I had loads of cash and time I'd be all over this, especially since one of my nicknames is "V-Mac"



Vaughn

 

[JTEdieselram]

I like the idea of an actuator to advance timing as the rpms increase, I have had thoughts of that setup myself for years. I just threw together a CAD file for a school project that is a timing cover with an adjustable pump gear that protrudes through the cover with a seal so a quick painless timing adjustment can be made, this is not a variable setup, but I think it would be useful. NOTE, these parts were not drawn to scale, like I said, it was a school project, but let me know what you think!



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[dzlpwr]

The advance mechanism controls the amount of advance according to oil pressure and rpm. The actuator in the EDC governor controls the amount of rack travel. It basicly lets the computer control rack travel based on throttle inputs, sensor inputs, and its parameters. There is no governor to deal with and the fuel output can be controlled very precisely. If you guys are interested in how the EDC system works I can post some pages out of the book that better explain it when I get ahold of a good scanner.

 

[Vaughn MacKenzie]

That would be great dzlpwr, thanks.

JTE you have a good idea, only catch being seal life wouldn't be that great if you have a large-diameter protrusion through the cover due to high outer-surface speeds. But after doing at least a dozen 12-valve timing jobs I could greatly appreciate a setup like that.

 

[Vaughn MacKenzie]

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[Missouri Mule]

As I understood it the p7100 and the VE would both advance timing. Reading an article in the TDR magizine many years ago you don't increase engine speed by just putting your foot on the go peddal and adding fuel the injector pumps advance timing similar to distribitor.



An article in the TDR magizine in the last couple of years stated the the VP44 was capable of variable timing, one of the reasons the 24 valve engine made emission standards in 99 thru 2002.