Fuel injection pump MEP-803A

MEPNoob

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Just got my Mep-803a with a reman date of 10/2010 and about 9 hours on the meter. Problem is someone along the way took the injection pumps off of it with the corresponding shims, I have new injection pumps and some shims does anyone have a general idea of how many shims each pump takes?
 

Light in the Dark

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In the -24P pertaining to the engine in this set, that item is called out as quantity V. I believe either they were shimmed individually at the factory, or each location has a different amount of shims. I'd have to put a set of eyes on a few here... see if there is any consistency between machines.
 

MEPNoob

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In the -24P pertaining to the engine in this set, that item is called out as quantity V. I believe either they were shimmed individually at the factory, or each location has a different amount of shims. I'd have to put a set of eyes on a few here... see if there is any consistency between machines.
Oh I would really appreciate the help I’m trying to get my unit running before we start getting hit with some storms.
 

Light in the Dark

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The 803 I am preparing for shipment appears to have (1) plate and (1) shim per metering pump, just like it appears in the TM. I did not disassemble, but each appears to have only one of each in place. Will check other machines later.

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zarathustra

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I read somewheres that the shims affect engine timing. I just took two injector pumps of a scrap 802a engine and there were several shims on each.
I will go out and count them. They tend to stick together. It's been a while, but if I remember correctly the shims are peculiar to a pump so one pump may have one number of shims and another pump may have more or less. Any time I take a pump off I use a zip tie to keep the shims with the pump.
 

Light in the Dark

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I am not certain, but I think the shims may vary between the engines because of tolerance issues with after-cast grinding (with the block being cast iron after all). I would imagine these would have been 'paired' at the time of assembly with each lobe. Some spots may have required additional shims due to simply manufacturing variance. But like I said... its just what I think. I am sure someone knows definitively.
 

MEPNoob

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I am not certain, but I think the shims may vary between the engines because of tolerance issues with after-cast grinding (with the block being cast iron after all). I would imagine these would have been 'paired' at the time of assembly with each lobe. Some spots may have required additional shims due to simply manufacturing variance. But like I said... its just what I think. I am sure someone knows definitively.
Interesting there has to be a procedure to know how many shims they need I mean parts go bad and break lol I didn’t think it would be so complex
 

jamawieb

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Interesting there has to be a procedure to know how many shims they need I mean parts go bad and break lol I didn’t think it would be so complex
Procedure is in the TM. The shims control timing of the pump. Every engine is different. The shims stay with the pump location, if you have to change pump the shims will remain at the same location. The timing is difficult, because you have to measure the piston height at TDC. Good luck
 

MEPNoob

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Procedure is in the TM. The shims control timing of the pump. Every engine is different. The shims stay with the pump location, if you have to change pump the shims will remain at the same location. The timing is difficult, because you have to measure the piston height at TDC. Good luck
Guess I’ll be calling a tech to handles this for me I don’t have the skill nor time to do this. If I would have known this I would have tried to negotiate the gen set a bit more
 

Ray70

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I believe the shims come in different thicknesses as well. Black is in the .005" range and the green ones are only like .002" maybe less?
I've typically seen 1 to 3 shims under the dozens of pumps I've removed.
I have also put together a dozen or more motors without knowing what shims came out of it.
I typically put 2 black or 1 black and 1 green depending on what I have.... and I nave never had a problem and I have never noticed any difference in power from 1 motor to the next.
You will not damage anything by being off a couple thousands from "Perfect"
I would throw in 2 shims and set the pump rotation so the fuel hose is about touching the pushrod tube.
Once its running you can turn the pumps is you notice more than a 5* difference in EGT from 1 cyl. to the next.
Don't worry, you will not hurt anything.
 

MEPNoob

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I believe the shims come in different thicknesses as well. Black is in the .005" range and the green ones are only like .002" maybe less?
I've typically seen 1 to 3 shims under the dozens of pumps I've removed.
I have also put together a dozen or more motors without knowing what shims came out of it.
I typically put 2 black or 1 black and 1 green depending on what I have.... and I nave never had a problem and I have never noticed any difference in power from 1 motor to the next.
You will not damage anything by being off a couple thousands from "Perfect"
I would throw in 2 shims and set the pump rotation so the fuel hose is about touching the pushrod tube.
Once its running you can turn the pumps is you notice more than a 5* difference in EGT from 1 cyl. to the next.
Don't worry, you will not hurt anything.
Thank you for the info, I sent the pumps out to get cleaned I’ll try it one I get them back. I’ll keep you all posted.
 

Guyfang

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I believe the shims come in different thicknesses as well. Black is in the .005" range and the green ones are only like .002" maybe less?
I've typically seen 1 to 3 shims under the dozens of pumps I've removed.
I have also put together a dozen or more motors without knowing what shims came out of it.
I typically put 2 black or 1 black and 1 green depending on what I have.... and I nave never had a problem and I have never noticed any difference in power from 1 motor to the next.
You will not damage anything by being off a couple thousands from "Perfect"
I would throw in 2 shims and set the pump rotation so the fuel hose is about touching the pushrod tube.
Once its running you can turn the pumps is you notice more than a 5* difference in EGT from 1 cyl. to the next.
Don't worry, you will not hurt anything.
This is more or less what every CECOM guy ever told me, and we always did "something" like it. We never had problems, and if it ran a tad rough, we did just what Ray suggested. Turn the pump a tad, to iron it out.
 

MEPNoob

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Thank you all for the great info. I really appreciate it once I get the pumps back from the rebuilder I will give it a shot
 

MEPNoob

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Seems like I’m having an issue with my rack when I drop a pump in it doesn’t move side to side when I take it off it moves side to side, I’m sure I have gotten it in the slot what could be the issue?
 

Light in the Dark

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If the rack isnt moving when you are putting it back in, its not in the rack. Its really not a big deal if you take all 4 pumps out, to get them back in the rack. It just takes a little trick to know what you are feeling for on the rack (a small locator, which you can see on the TMs that would accept that pin on the metering pump.
 

MEPNoob

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If the rack isnt moving when you are putting it back in, its not in the rack. Its really not a big deal if you take all 4 pumps out, to get them back in the rack. It just takes a little trick to know what you are feeling for on the rack (a small locator, which you can see on the TMs that would accept that pin on the metering pump.
Pretty sure I got them in the rack i think my problem is that the rack is hanging up once it has to move they pumps, when I put my finger in and feel the rack and move it, it moves freely but once I put a bit of resistance with my finger it hangs up and doesn’t move once I take my fingers off it’s returns back to the shutoff position
 
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