Deere/Yanmar Injection Pump Static Timing - 5 Qs

[paroxysm3]

This is for a JD 855 w/Yanmar 3TN75. I had the injection pump rebuilt, but in the battle to remove it (I broke one gear puller) I lost the alignment mark I'd painted on the gears. The Component Technical Manual (CTM3-10AUG93) has a procedure for setting the timing, but I have a few questions to understand if I've done this correctly.


Q1. Is the timing set at the beginning of the injection cycle or the end?


First is confusion over whether the timing mark is set by start of the injection or at the end. The CTM calls for a Timing tool "No 1 fuel injection line cut off at first bend." Later the manual asks to observe when the "tip of the timing tool becomes MOIST [sic] with solid fuel."

I'm not cutting off my fuel line, so I've been doing this by observing the smallest change in the number 1 injector. However, I've also read about doing the timing using the "Spill Cut Off Point" method which waits till the pump cycle is finished. Is this the purpose of the Timing Tool? That is, is the fuel line cut off at first bend approximately one "dose" of fuel?



Q2. Are the injector lines labeled correctly?

"The number one injector is toward the flywheel." I had thought the number one injector was closest to the radiator, but the 855 flywheel is at the "back" of the motor. See photo below.



Q3. Turn flywheel counterclockwise from driver/operator seat point of view?

The manual says to "turn flywheel clockwise(as viewed from the flywheel end). I've been turning the fan clockwise. It's the only way the BTDC marks show up before TDc.

The spec for the 855/3TN75 is 16 deg. BTDC. The manual illustrates the timing marks behind a rubber plug in the flywheel housing. My 855 has no such housing. I found TDC by observing the piston rise and fall. At TDC the TDC mark on the flywheel lined up with the cutout shown in the picture below.


Q5. Should I try to get another degree closer?

The photo also shows the timing at what I make to be 17 deg. BTDC. Whithin the 1 deg spec. However, there is no fine adjustment left to advance the timing. When I look for index marks on the drive gear I find a "b" only 4 teeth away from an "a" on the drive gear. The manual doesn't mention these marks,

 

[dfkrug]

I think you are making this harder than it has to be. To get the FI pump
off, you had to remove the front cover. If you look closely, there are
letters stamped into the gears that drive the FI pump. There will be an
'a', a 'b', and a 'c'. You found a couple of them. The letters must be
aligned on each of the gears. There is only one way that all the letters
will be aligned, a-to-a, b-to-b, and c-to-c. The center gear has all
3 letters, and the FI gear has only one (a 'b' if I recall). Cam gear might
be 'c'. Crank the engine around until you get all the letters aligned.
Put the FI gear on the FI pump so that it aligns b-to-b. You will
have to rotate the pump shaft for that to happen. Put everything back
together.

Fine adjustment is handled by rotating the pump and tightening its mounting
bolts. Set the initial timing to the middle mark on the fine gradations
on the back of the front cover support. If the eng does not run well, you
can advance or ****** the timing slightly until it does.

I have the TM1360, but not the CTM3 manual. I used the I&T manual for
my 955 engine rebuilds.

 

[paroxysm3]

Thanks for the reply. I didn't remove the entire front cover, only the FI gear access plate. Thus I can't see if "c" aligns to "c". Why wouldn't they mention this in the manual?

Won't I still need to know the other answers to my Qs to fine tune it?

 

[dfkrug]

I didn't remove the entire front cover, only the FI gear access plate. Thus I can't see if "c" aligns to "c". Why wouldn't they mention this in the manual?

OK, I see what you did. When removing the FI pump access panel, you
marked the 2 gears before removing the pump. Is that correct? I would
have rotated the engine until the two b's lined up, but that does not help
you now.

The relationship between the FI pump gear and the timing of the injectors
should remain the same, even with a rebuilt pump, so using the proper
gear alignment method I described above would still work with no special
fine timing adjustment. Unfortunately, that requires removal of the front
cover if your gear tooth relationship is lost. The timing procedure in the
manual assumes that you can not get the FI gear back exactly as it was
when removed.

Removing the front cover while the engine is installed is doable, but it may
not free up from the oil pan if that is not removed first. My engines were
all out for rebuilding when I did this.

You could try this to avoid removing the front cover: Rotate the engine to
get the 'b' showing on the middle gear. Install the FI gear and pump so the
b's line up. Do a rough check (cam position and injector activation) to see if
that is the right timing. There are several crank/cam positions where the
b's will align, as I recall.

I am surprised that the JD manual does not cover this essential aspect
of engine rebuilding. I guess that the I&T manual on the engine was not
as bad as I thought. At time I bought it, I had not found a good deal on
the JD TM1360, which I now see does not even cover engine rebuilding!
(I eventually found a PDF of the TM1360 for $30 or so on eBay.)

 

[Spudland_Dave]

I am surprised that the JD manual does not cover this essential aspect
of engine rebuilding. I guess that the I&T manual on the engine was not
as bad as I thought. At time I bought it, I had not found a good deal on
the JD TM1360, which I now see does not even cover engine rebuilding!
(I eventually found a PDF of the TM1360 for $30 or so on eBay.)

Looking at my digital version of CTM03, Deere DOES go over the timing marks...and the procedure to install & time it...I guess because i've never had to do this I'm not seeing the problem with the Deere manual...

 

[dfkrug]

Looking at my digital version of CTM03, Deere DOES go over the timing marks...and the procedure to install & time it...I guess because i've never had to do this I'm not seeing the problem with the Deere manual...

Glad to hear it, Dave. The rest of TM1360 looks pretty good....I was
very disappointed to find it did not include the engine info (CTM03). That's
a shock, and this thread is the first I have heard that.

With respect to the FI gear, my 955's engine was easy to preserve the
timing relationship with disassembly/reassembly, if you lined up all the
letters on the gears. With my 4300 engine, the FI gear is mounted with
oblong slots for the bolts, so you could REALLY mess up the timing if
you did not get the bolts on just so. Fortunately, I saw that before
removal and scribed some lines on one of the slots. It makes no sense why
the designer did that....the x55 engine was much easier/safer.

 

[paroxysm3]

I stand corrected. The timing marks are alluded to in a prior section. They are not mentioned at all in the FI removal section. It's odd because they suggest one chalk mark the gears before ren=moval, when one could simply align them to an exiating mark.

I'll try this once the weather warms up above freezing.

I would still like to know if on the static test the state at 16 deg BTDC is fuel injection initiated or complete?

 

[dfkrug]

I would still like to know if on the static test the state at 16 deg BTDC is fuel injection initiated or complete?

I sure don't know. Maybe someone on TBN has actually done the FI timing
adjustment they talk about in the manual. I would like to know, too.

What happened to the pump to cause it to fail and need rebuilding? Where
did you take it for rebuilding? I have never been inside a Diesel FI pump.

 

[paroxysm3]

I'm not sure it's the root cause, but once removed it was found that all its seals had been eaten by biodiesel. I run B-100 most of the time.

I took it to Fisher Implement in Oregon, but they farm it out to another shop. $895 later it's better than new.

 

[dfkrug]

I'm not sure it's the root cause, but once removed it was found that all its seals had been eaten by biodiesel. I run B-100 most of the time.

That's good to know as one of my 955s was being run on new vegetable oil
for a while....I am not sure what mix w/ Diesel. Possible 100% at times.
I imagine B-100 is more caustic. I will tell the owner (again) not to do it.

 

[paroxysm3]

okay, I"m back. I can set the injector pump timing as described in the manual by watching for fuel at injector 1. But, I'd like to confirm this by using the timing alignment marks. The problem is I can only see one gear pair. The gear driving the pump gear is marked "A", "B" and "C". The pump gear has only a small "b" on it.

My approach was to rotate the engine until fuel started to spill out of injector #1 opening (16 deg before TDC). Then rotate a bit further until the "b" marking was at the point where the gear tooth would mesh with the other gear.

Then disconnect the pump gear and rotate the engine until both the engine flywheel markings were at piston #1 TDC AND the "B" is visible at the point where the gears would mesh. Then button it up and check the timing.

My thinking was that this is TDC for both the injector pump and the piston so it shoudl be close. But alas, no. When I do this, the pump always delivers fuel at piston #2 TDC not #1.

Do I have cylinders confused (manual says piston #1 closest to the flywheel (i.e. driver's seat))?

Am I not using the right index indicator for TDC (I don't have a portal, instead the timing marks seem to line up with a notch in the flywheel cover and since I have the injectors out, I'm able to confirm that this mark is piston #1 TDC)?

Am I looking at the right injection pump outlet (I'm looking at the one closest to the flywheel)?

Am I rotating the engine the wrong way (counter clockwise facing the flywheel. This seems consistent as the 3 timing marks appear before TDC)?

Help please.

 

[dfkrug]

Do I have cylinders confused (manual says piston #1 closest to the flywheel (i.e. driver's seat))?

#1 is at the back, closest to the FW, as stated.

When rotating the engine the degree marks on the FW will go from higher
# to lower, like 15-deg BTDC, then 10-deg BTDC. I don't recall if that is
CW or CCW at the crank pulley bolt.

Do you have the valve cover off to see which cyl has both valves closed?

 

[paroxysm3]

No. I guess that's next. I feel I'm on the slippery slope to a complete rebuild.

 

[Chilly807]

Ok, I'll try to walk you through this.

To establish the right rotation, remove the valve cover and watch the valves. As you rotate the engine, the exhaust valve should open, then as it begins to close, the intake should open on the piston down stroke. The intake should close as you reach BTDC, from that point on for the next 180 degrees you're on the compression stroke. Remember that the injection pump only fires on every second rotation of the engine. and near the end of the compression stroke.

That's the easy part... if you're going to time the engine using the spill cut off method, that measures the beginning of injection, not the end. The fuel rack has to be in a certain position, usually full fuel position. If your tractor has a pull cable for shutdown, it must be in the start position. If it has a fuel solenoid, that has to be energized, or in the "run" state.

Shut off the fuel supply before you start. There is a "delivery valve" and spring that must be removed from the pump element you're setting the engine to, normally #1. It's removed by loosening the clamping bolts across the top of the injection pump, then removing the "delivery valve nut" at the top of the pump for that cylinder. Once the nut is carefully off, you should see a small spring with upper seat and the delivery valve under it. Remove the upper spring seat, spring, and valve (leave the valve body in place), and replace the nut to the same position/torque it was before. Probably about 30 ft lbs torque.

You need to make a "spill tube" out of an old fuel injection line, it will extend vertically about 4 inches above the pump, then smoothly bend 180 degrees downward with about a 2 or 3 inch radius, the end with no nut (injector end cut off) should be cut off at 45 degrees angle to form a sharp point.

You're going to put the spill tube on the pump, and turn the fuel on. It will flow from the cut off spill tube after a few seconds, have a can handy to catch it.

Slowly turn the engine with a breaker bar in the right direction (you should have it positioned on the compression stroke about 45 degrees before TDC before you start this) The fuel flow will continue through the pump and out the spill tube until the plunger in the pump rises enough to cut off the fuel flow. This is the beginning of injection. You'll notice the flow beginning to diminish, then slow to a trickle, and finally a slow drip over the space of a few degrees of rotation. When the drip actually stops, that is the point of injection, be careful not to go too far too quickly. Turn it back and forth a couple times to get a really good feel for the exact point where it ceases to flow.

To make sure you're on the upward travel of the plunger, once the fuel flow has ceased, turn the engine in the direction of rotation a few quick degrees, there should be a few drops of fuel "injected" from the spill tube. If not, you're way off on your timing marks.

Check the flywheel pointer. If you're off, decide by how much and rotate the FI pump on it's mounting studs a little bit and try again. Trial and error as to which way to turn the pump. Once it's set correctly, shut off the fuel, remove the spill tube and delivery valve nut, and replace the delivery valve plunger, spring, and upper spring seat. Everything has to be rinsed in clean fuel first. Any dirt is a killer here. Re-torque the delivery valve nut and re-tighten the clamp bolts.

If this sounds complicated, it is... unless you do it for a living every day. I happen to do that, and we still learn from our mistakes. Every engine is different too, you need a good shop manual to get this right. I've outlined the process as best I can in print, an experienced mechanic is worth their weight in gold to help hands-on with this job.

Unless you're really good mechanically, this is a good job for a dealer or shop. Diesel fuel injection systems are something most of us aren't equipped to work on, either tool-wise or experience.

Hope it works out for you, and good luck!

Chilly

 

[paroxysm3]

Chilly, thanks for the extensive instructions. I'll give it a try if plan "G" fails (as did plans A thru F).

PLAN G:

I reread the entirety of my shop manual on this engine tonight looking for the overlooked and in the section on the idler gear (2-61) is a small note, "When all timing marks on gears align, the position closest to the water pump is TDC." That is piston #3 not #1 as I had assumed. This explains why my results were consistent but wrong. I'll try agian in the morning and report back.

 

[paroxysm3]

Problem solved. Once I understood the gear timing marks were TDC for piston #3 and not piston #1 everything just fell into place. I used the procedure I outlined earlier to line up the injection pump. Then I disconnected the FI pump gear and rotated the engine until I had both #3 TDC and "B" at the gear mesh point. With the rocker cover off it was easy to see the exhaust, intake pattern. Then I buttoned her up and took the caps off all three injection ports on the FI pump. Since 16 deg BTDC is marked for all 3 cylinders, it was easy to verify that injection was starting at just about the right moment for each cylinder. I'll fine tune it tommorrow.

Thanks for everyone's patience and help. I'll followup in a few weeks when I try to fire her up.

 

[paroxysm3]

Problem not solved. See my new post on how to set the timing here.

After I finally got it back together it still was hard starting and lot of white smoke. Compression test 200-180-225 psi respectively. Supposed to be 355. Cracked open the engine and found the cylinder bores out of round. Will be rebored this month.

The saga continues.

 

[owner]

I need to know how two time my fuel injection pump on my yanmar two cylinder tractor please

 

[veto56]

Ok, I'll try to walk you through this.

To establish the right rotation, remove the valve cover and watch the valves. As you rotate the engine, the exhaust valve should open, then as it begins to close, the intake should open on the piston down stroke. The intake should close as you reach BTDC, from that point on for the next 180 degrees you're on the compression stroke. Remember that the injection pump only fires on every second rotation of the engine. and near the end of the compression stroke.

That's the easy part... if you're going to time the engine using the spill cut off method, that measures the beginning of injection, not the end. The fuel rack has to be in a certain position, usually full fuel position. If your tractor has a pull cable for shutdown, it must be in the start position. If it has a fuel solenoid, that has to be energized, or in the "run" state.

Shut off the fuel supply before you start. There is a "delivery valve" and spring that must be removed from the pump element you're setting the engine to, normally #1. It's removed by loosening the clamping bolts across the top of the injection pump, then removing the "delivery valve nut" at the top of the pump for that cylinder. Once the nut is carefully off, you should see a small spring with upper seat and the delivery valve under it. Remove the upper spring seat, spring, and valve (leave the valve body in place), and replace the nut to the same position/torque it was before. Probably about 30 ft lbs torque.

You need to make a "spill tube" out of an old fuel injection line, it will extend vertically about 4 inches above the pump, then smoothly bend 180 degrees downward with about a 2 or 3 inch radius, the end with no nut (injector end cut off) should be cut off at 45 degrees angle to form a sharp point.

You're going to put the spill tube on the pump, and turn the fuel on. It will flow from the cut off spill tube after a few seconds, have a can handy to catch it.

Slowly turn the engine with a breaker bar in the right direction (you should have it positioned on the compression stroke about 45 degrees before TDC before you start this) The fuel flow will continue through the pump and out the spill tube until the plunger in the pump rises enough to cut off the fuel flow. This is the beginning of injection. You'll notice the flow beginning to diminish, then slow to a trickle, and finally a slow drip over the space of a few degrees of rotation. When the drip actually stops, that is the point of injection, be careful not to go too far too quickly. Turn it back and forth a couple times to get a really good feel for the exact point where it ceases to flow.

To make sure you're on the upward travel of the plunger, once the fuel flow has ceased, turn the engine in the direction of rotation a few quick degrees, there should be a few drops of fuel "injected" from the spill tube. If not, you're way off on your timing marks.

Check the flywheel pointer. If you're off, decide by how much and rotate the FI pump on it's mounting studs a little bit and try again. Trial and error as to which way to turn the pump. Once it's set correctly, shut off the fuel, remove the spill tube and delivery valve nut, and replace the delivery valve plunger, spring, and upper spring seat. Everything has to be rinsed in clean fuel first. Any dirt is a killer here. Re-torque the delivery valve nut and re-tighten the clamp bolts.

If this sounds complicated, it is... unless you do it for a living every day. I happen to do that, and we still learn from our mistakes. Every engine is different too, you need a good shop manual to get this right. I've outlined the process as best I can in print, an experienced mechanic is worth their weight in gold to help hands-on with this job.

Unless you're really good mechanically, this is a good job for a dealer or shop. Diesel fuel injection systems are something most of us aren't equipped to work on, either tool-wise or experience.

Hope it works out for you, and good luck!

Chilly

Im with you, off to the shop I would go.

 

[110797]

I am trying to find out what to do to rmove my injection pump from my eng so as not to get it out of time.