Injection pump removal with timing gear

[helidiesel]

So everything I have read here says when replacing an injection pump not to pull the filler neck gear cover and injection pump timing gear as an assy because it will be very hard to get timing of that gear and gear sets below back together. The other day in class (we have an IDI on a stand in the shop that has proved to be a great learning tool for me) we pulled the pump, lines, gear cover and gear as a whole with the motor set at #1 cylinder at top dead center. The manual said there would be two white lines on the peaks of two gear teeth and one tooth on the pump gear with a dot and that tooth must be placed between the other two marked teeth. So just to see we pulled it apart and sure enough there was the lines below on the two gear peaks and the tooth with the dot...

So what Im getting at is WHY is it so frowned apon to pull the assy out as one unit?? Just seems so much more user friendly. There is a huge possiblity I will be doing this job in my near future so im researching details now. thanks for all the help men.

 

[cpdenton]

Pulling it the way that is recommended here, taking the pump off without removing the gear cover, only takes about 20 to thirty minutes, and you KNOW the gear is in exactly the right spot. Working on the engine over the top of the radiator support laying over the truck is quite different from lining everything up on a stand. The hardest bolt to get to on this pump is on either side of the bottom of the pump. These are no problem with the correct wrench( or one bent just right). Sure those bolts would be easier with the gear cover off, but you still need to loosen and tighten them while setting the timing, so you still need a tool.

I say, it can be done, but why risk another problem.

 

[helidiesel]

Your points are valid sir.

 

[cpdenton]

And your questions are valid! Don't ever feel like you shouldn't ask a question. Some people get short with folks sometimes, and I tend to just ignore that. I have changed my pump several times now, until I finally bought my Moose pump. Had a couple of leakers belching fuel all over my intake area, so I figured out pretty quick what I thought was the best way.

Good luck with yours if and when it needs to b changed.

 

[stumpjumper3]

I've pulled the gear cover on a 7.3 because we wanted to paint the cover and reseal it. We just rolled it to TDC found the dot with an inspection mirror and then lined up the dot on the IP gear. Was it a pain, eh not the worst but i had a good mirror and penlight. I can see how if you were rushing it, you could be in a pickle.

 

[riotwarrior]

Rolling the engine to TDC does NOT guarantee your IP will be in the correct spot, as the engine could be TDC on exhaust not compression, thus this poses an inherent risk of being off.

Most don't have the luxury of doing this on the stand in a clean safe environment as already mentioned, this saves potential for error when one doesn't get it to TDC in an outside raining and dark vs a nice clean shop on a stand in a clinical situation.

This also saves work leaving it on NOT having those 4 bolts to loosen and then reseal that cover as well.

For the sake of simplicity and being almost IDIOT proof the IP gear tower/cover left on is the preferred method as already said.

 

[stumpjumper3]

Rolling the engine to TDC does NOT guarantee your IP will be in the correct spot, as the engine could be TDC on exhaust not compression, thus this poses an inherent risk of being off.

Most don't have the luxury of doing this on the stand in a clean safe environment as already mentioned, this saves potential for error when one doesn't get it to TDC in an outside raining and dark vs a nice clean shop on a stand in a clinical situation.

This also saves work leaving it on NOT having those 4 bolts to loosen and then reseal that cover as well.

For the sake of simplicity and being almost IDIOT proof the IP gear tower/cover left on is the preferred method as already said.

So i understand the TDC issue you mentioned. But if the engine isn't turned, and neither is the gear when left bolted to the injection pump. Assembly would be reverse of disassembly. Maybe i'm not seeing it though. I've only done it once and it worked.

 

[helidiesel]

No tooth markings at TDC on exhaust stroke. Nothing to line up to.

 

[NTOLERANCE]

Ive asked the same question, and I have a van.....

Leave the timing cover in place.....its not a bad job...even in a van....

 

[riotwarrior]

So i understand the TDC issue you mentioned. But if the engine isn't turned, and neither is the gear when left bolted to the injection pump. Assembly would be reverse of disassembly. Maybe i'm not seeing it though. I've only done it once and it worked.

The engine not turned isnt the issue,

The issue stems from once you remove the IP gear cover then remove the IP from the gear, the gear is free floating and falls out of the IP gear cover. Or you remove the IP, and then install a new one but have no way of knowing if you moved the gear or not as it free floats when the IP is removed...

TDC exhaust and TDC Compression are both TDC so you must KNOW you are on compression stroke and that, my friend is not as simple as it may sound, watch valves with the valve cover off to find out when...or it's determine compression via GP hole and knowing how to do that safely is the KEY to that method. I'm not going to get into that here today.

Al

 

[helidiesel]

So it's really not the end if the world. Just not a mistake one would want to make. So let's say you are off one tooth. What would be the symptoms if the pump was retarded or advanced?

 

[1995voyagerES]

When I was replacing my valley pan and wanted to paint everything I removed the pump as a whole assembly (lines, pump, pump 'tower').
Before I removed the tower I opened the little inspection plate on the front and drew a line on the IP gear and on the tower itself.

I didn't rotate the engine so I thought what could go wrong? .... nothing!

I wouldn't recommend this if you can't be 100 % sure not to rotate the engine !!!

 

[icanfixall]

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What happens when you take the housing and gear with the pump off is you risk changing the gear timing. You have no possible way of seeing the gear match up to the cam gear because its so low in the front cover. And by the way the cam gear has 2.. Not just one gear timing mark. The mark you need to see is the "Y" and not the "dot" mark. The "Y" mark matches up to the injection pump gear "Y" mark. The "dot" mark matches up to the crank mark. If your off by one or 2 teeth you can't get the engine to time properly. You run out of timing adjustment. Now these engines will run that way not not very well. In fact they can run 180 degrees out of time too. Thats when you get the dot and the Y mark mixed up because you have no idea whats happening. Here is some pictures proving what I have posted. In the end its up to you if you want to take the chance of messing up the gear timing. I have the tools to loosen the pump adjusting nuts and have made several of them. If anybody wants this tool just let me know. I will make some up and sell them cheap. In all of my timing meter rentals is this tool.

 

[typ4]

I have never seen those white marks, I bet they go away in 100k miles, What I do any time the cam gear is out or cover off is to grind a small chamfer on the 2 teeth beside the dot, then if you ever have to pull the IP housing its easy to find right spot on the cam gear

 

[helidiesel]

Gary. I would buy a special tool from you!!