Pump timing

[btoscano]

Daniel Puckett and I changed the injection pump and injectors in my truck yesterday. During the procedure we ended up removing the timing cover and moving the gears around. My old injectors were 900 off. The new injectors tested at 3800-4000. I haven't seen a big jump in fuel economy. 16. 35 MPG running 72-78 MPH on the last tank home. I am wondering if the pump timing is off. I am wondering if we have the pump one tooth retarded.



How much variation does one tooth in the pump-cam gear make?



Can anyone post information about where to get the adapter for the dial indicator?



Now that I've seen Daniel in action my engine I figure I will be about 2 weeks into the rebuild pump warranty before I start wanting more engine power and about 3 weeks before I start turing screws and changing timing, gauges, etc.



-brian

 

[bgilbert]

Why did you guys mess with the gears inside the timing housing? Couldn't get enough timing within the pumps slots? Yep sounds like you guys shoulda post poned til Sat, when I woulda got there.

 

[btoscano]

The key for the pump gear fell out.



-brian

 

[Greenleaf]

Ohhhh... . Boy.....



Youz Guys :-laf



-S

 

[btoscano]

The criticism is much better accepted if you also answer the questions. So how about it? What happens if the gear is one tooth off and where can I get one of the adapter to use my dial indicator and really know what the timing is?



Thanks,

 

[btoscano]

I'll also add that even though I was expecting a 2 hour job, I was real curious what was under the timing cover all these years and now I know.



-brian

 

[TKingsbury]

I'll also add that even though I was expecting a 2 hour job, I was real curious what was under the timing cover all these years and now I know.



-brian

Let me guess..... a bunch of gears? :-laf

Travis. .

 

[btoscano]

-brian

 

[Greenleaf]

You guys..... this poor man needs our help, so get on track.



I don't know what direction you would have rotated the pump drive gear... ... . That would either way advance or way retard the nominal timing that is acomplished via the pump slots/timing mark.



I'm not sure if it would run right if you jumped a tooth. Where is the pump located at now?... ... ... ... ... 'er I mean, where is the pump located at now in relation to the timing marks? Did you have to retard it or advance it to get her to run right???????????????????



I sure hope you guys looked at the dowel pin while you were in there..... right??!! AND, tightened ALL the case to block bolts... ... ... .





-S

 

[JLEONARD]

I'm thinking that if it starts up quickly and "sounds" right you can't be too far off.

As far as mileage and old vs new injectors, I'm not convinced via my limited experience that it makes a lot of difference. Bad injectors show up with delayed starting, rough idle, esp when cold, and more smoke when cold. All this due to poor and or uneven atomization

When the engine is hot it will burn the #2 in just about any form. To a point that is.

Jay

 

[bgilbert]

I'm still wondering why you guys messed with the pump gear??? Why move it? I've read each tooth is like 7 degrees or so??



Daniel, why didn't ya just unlock the shaft on the new reman pump, turn it to the 1 o'clock position, turn the engine over to where the old pump keyway is at the 1 o'clock position, pull the old, put on the new?????



But as Jay said, if it starts up quickly and sounds right you're ok or not far off. Where is the pump at in relation to the timing mark on the case and how much room between the cylinder head and pump top?= what GL said.



Daniel, I thought you had a dial indicator??



Yep, youz guys :laugh:.

 

[Greenleaf]

The dial adapter can be made with a hydraulic hose fitting and other commonly found items found 'round the shop.





I too don't think you will see a milage increase just cause you have new squirty things.

 

[btoscano]

I am not sure why Daniel didn't turn the pump so the key was at 1 o'clock. I wondered about that too. The gear came off only to get the keyway out which fell behind it. Smoke seems about the same before and after the work (almost none) so the timing is probably pretty close. I was hoping to fine tune it for the best fuel economy/power ratio. We inspected the KDP and I will need to get a final fix for that.



Thanks,

 

[btoscano]

So basically we are to fab a base with a hydraulic hose fitting, etc. Does Cummins or the dealer have a special tool number for it? I am curious.



Thanks,

Brian

 

[dpuckett]

Much needed clarification.....

Ok, here I am to explain stuff and clear the fog. And guys, the sarcasm is better appreciated if you actually supply an answer or suggestion afterwords.



ANyway, moving on. To answer Bill's question about the pupm key, I have never had much luck turning the pump shaft and getting it to stop where I want it to. The key fell off the old pump, and we had to get the old key out anyway. SO, after driving around 2-1/2 hours to get parts at CUmmins, and fighting with those nit-wits , we finally got back to the house at around 4pm. I got in a bit of a hurry (first mistake). WE had the pump on the housing, all the lines attached (hence, the lack of deisre to take the pump out), and were trying to fit the gear back on the pump shaft with minimal luck. Since the gears are helical cut, we knew the gear wouldnt slide STRAIGHT on (though later experience showed us it was almost srtaight on), someone got the bright idea to turn the engine and try to slide the gear on while turning the cranksshaft (mistake #2). Neither of us thought to double check to make sure the marks were still in time (hurry- it was nearing dark, and I had been at it 6 hours on a 4hr-max job; mistake #3) .



GOt it back together, and it was getting fuel to the injectors, but wouldnt start. Took the oil filler neck and elbow out, and saw the "E" on the pump gear, but no "0" lining up with it. Took front cover back off, and sure enough, they were out of time by 7 or so teeth. WIth some turning of the engine, and slipping the gear on and off several times, we got the "E" and "0" lined back up. PUt it all back, and it fired right up, and he went home.



KDP was protruding about 1/16th of an inch, maybe a thin 1/8", but I couldnt get it to move, tapping on it with a hammer and short punch, hammer & screwdriver, etc. Did tighten the 3 bolts I could get to. FIgured since I didnt have a tab handy, and it wasnt in any IMMEDIATE danger, let it be for the time being. IT WILL need attention soon, though (6mo or less).



Jay- re: injectors. His were about 900psi below stock, which will make a huge drop in MPGs. I had a set popping almost that bad, and getting them cleaned and reset added 4MPG. I was surprised he only gained 2-2. 5MPG, but with the higher popping pressure retarding the dynamic timing, it may have offset the new sticks a little.



Brian- WIth this engine being broken in already (212K), I dont think you will see any improvement as time goes on without changing a few things. But, you woule be wise to wait a tank or two before making any changes.



Daniel

 

[btoscano]

After a few tanks I'll report any fuel economy changes. So far nothing has been noticed. With the old setup I could get 15. 5-17. 2 MPG here in Tennessee. The tank before last was 14. 6 which is the lowest ever.



Brian

 

[Greenleaf]

Jeremy will have to tell you the exact details... ... ...



Use a hydraulic hose fitting w/MALE threads. This will thread into the pump's head.



Use a large (wood) nail 10 penny or so for the plunger to activate the dail.



Drill ahole into the body of the hose fitting (@ the far opposite end of the threads) and weld a nut to the fitting where the hole you just drilled is and thread a thumb screw into that. The thumb screw will tighten onto the stem of the dial holding it tight in the hydraulic fitting.



I did mention that the stem of the dial must fit snugly into the hose fitting. The thumb screw simply secures the dial inside the hose fitting.



Now somebody get out there in the shop and make a batch of these bad boys. Only problem is... they be difficult to use as you gots to remove some of the high pressure lines to install it and check timing. Just easier to listen to the tone of the engine... . IMHO

 

[btoscano]

I was afraid you'd use the word welder. I don't have one yet.



I got 16. 38 MPG on this last tank travelling from Nashville to the TN-VA state line mostly at 82 MPH (previous tank was 16. 35) so I think I will be tweaking the timing a little. What are the dangers of tweaking it too far and should I have gauges before I do this? Or should I ask a Cummins mechanic to do this on?



Brian

 

[jbolt]

Timing gauge

Brian- I have a timing gauge you can barrow if you like. PM if your interested.

 

[Greenleaf]

Listen to the sound of the engine. It will begin to produce a very distinct knocky/ping when timing is too far advanced and the top of the injection pump will be almost touching the side of the cyl. head.



Just for fun..... rotate the top of the pump down and snug it up. Operate at this setting for a few minutes to obtain an "ear" for the sound and then advance it to the desired position.



Funny thing... the factory manual clearly states that if pump to engine timing is not properly set to factory specs, it will not run... ... ... ... ... . huh??