Oil & Fuel Setting Injection Pump Timing

[paroxysm3]

At the factory they set the fuel injection pump timing by simply lining up all the timing marks on the gears. But, how do you set the timing on an injection pump if you don't have access to the timing marks? I developed the following method after I removed my injection pump but did'nt adequately mark the alignment.

The JD manual for my Yanmar motor suggests the fuel spill method. After trying it I decided it was far too crude for a setting that has to be plus or minus one degree.

The tantalizing thing was that through the gear access port I could see the corresponding mark ("B") on the idler pulley.

The manual warns however that due to an odd number of teeth, this mark does not always indicate Top Dead Center (TDC).

The way I should have marked them to be able to put the pump back in to the tooth. But the shop manual is pretty rotten on these and other points.

I tried rolling the engine around until the "Bs" "lined up" but it turns out that this is not reliable either. So here's how I did it.

Step 1. Realize that although "B" only lines up with TDC once in a blue moon, "b" wants to line up with TDC every revolution. So, rotate the crankshaft until the "b" is in sight,

Step 2. Turn the crankshaft to TDC on the flywheel (make sure it's TDC on the compression stroke.), On my motor the alignment marks are for cylinder #3 TDC not #1.

Step 3. Mark the center of where the two gears mesh exactly.

Step 4. Remove gear from pump (enough so that the pump doesn't turn with the crankshaft. Rotate the crankshaft until the marks align.

Voila. I know this works because I ended up tearing down the engine and the
timing was spot on.

Of course, this is for a Yanmar motor in a JD 855. It may not apply to your situation.

 

[mfreund]

Thanks for the tutorial! :thumbsup: My hope is I will never need it!

 

[AKfish]

Great information.. thanks for sharing.

Although, aligning the pump with TDC for cylinder #3 was kinda different. Did the manual state that you needed to work from cylinder #3? Or, was that more of your "detective work"?

Excellent pictures, too!!!!

Thanks again.

AKfish

 

[paroxysm3]

Thanks. I found the reference to the #3 cylinder as the TDC reference in another section and even there it is just mentioned in passing.

 

[oceanroaming]

Ok, paroxysm3, great tutorial and nice to have such clear pictures. I've just found myself in the same predicament. I removed my fuel injector pump for a rebuild. I didn't mark the idler gear before removal because I had to run to catch a flight and some additional support gear supplied in front of my engine fuel pump access plate prevented me from removing that plate and marking.

My thought at the time was, "I'll bring a grinder and cut enough of the gear brace upon my return and since my manual simply states "line the marks up" I "ASSumed" that I could simply line-up 'B' with 'b'.

After reassembly, the engine refused to run... I checked the timing and found the injection was all off... how could this be? Well on my Yanmar it has a 51 tooth idle gear, 24 tooth crankshaft and 48 tooth Camshaft & Fuel Injection gear, which means they only "line-up" once in every 34 revolutions of the engine and good ole yanmar didn't provide access to "view" at least one other 'A' or 'C' mark to confirm proper alignment. http://www.tractorbynet.com/forums/images/smilies/new/confused2.gif

So I understand that since the crank has 1/2 the teeth of both Camshaft and Fuel Injection, their teeth need to always be in proper alignment at TDC, thus 'A', 'B' and 'C' are engaged on the idler gear at this same moment, regardless of the idler gear position. What I'm missing from your description is a confirmation that when 'B' is moved to the position you marked for TDC, 'B' is supposed to be centrally aligned in the idler gear because it's at this point the injector pump is to squirt fuel into (in my case cylinder 1, yours cylinder 3)? I don't have anything in my service manual that confirms this but this is the only thing that makes sense... Correct?

I know its been a year but hope to hear back from you...

 

[paroxysm3]

Sorry to hear you are in the same boat.

Basically my system creates a new, temporary TDC mark on the idler gear.

On my engine fuel injection is timed at 16 deg before TDC. Whether this is the start of the injection "squirt" or the cut-off, the manual doesn't say. But you can undo your #1 injection line, and watch the outlet like a hawk as you manually turn the crank. You can at least verify that you are in the right ballpark.

But this doesn't matter for my system because the injection pump lined up at TDC includes the timing advance. All you have to make sure of is that you are on the compression stroke when your flywheel marking is at TDC for the reference cylinder. And be careful to mark the teeth at the exact tangent point. Hope this helps. Let us know how it turns out.

 

[tedroy11]

Do you have any pics of a 2.9 l 2001 JD 5210?

 

[tedroy11]

Was aalking about the gears

 

[stingray1]

Good info.and pics.Thanks

 

[JDneophyte]

Great post!!! I did exactly what you're not supposed to do when rebuilding a John Deere 3320 engine (Yanmar 3TNV-88).......I loosened the timing bolts!!!