MEP_003A Plunger guide question

[Ray70]

Hello guys, I have a question regarding an MEP-003A that I'm working on.
It is a machine with 6 original hours on it, has been sitting a very long time. I purchased 2 of them on a M1061 trailer from a nearby municipality.
I went through the machine doing all the regular pre-start stuff, flush fluids, change filters, flush the tank, check the IP etc.
I got it started but I think the injection timing is wrong. ( Not from anything I did )
It starts very difficult and slowly, takes a lot of pre-heating even with it hot outside.
Once it starts it does not come right up to speed, it slowly builds RPMs over the course of a minute or 2.
While running it is billowing white / gray smoke , mainly from cyl.4 and spitting raw fuel out of that cylinder, but also getting very hot on cyl 4. I've checked, cleaned and set the pop pressure on all 4 injectors, tested compression ( well over 300Psi on all cyl. ) and checked the valve lash.
So far I have only found that the Delivery valve seal is virtually gone... just little chunks of plastic left.
To me ( based on reading other posts here ) it sounds like the IP timing is somehow wrong, so I wanted to ask you guys: If the plunger guide has cracked, causing it to skip on the plunger, but is still intact enough to turn the plunger but its now out of time, I assume I will notice a problem if I do the static pump timing test to see if fuel flow stops at the PC mark?
Or does anyone have experience with a destroyed delivery valve seal to know what ill effects that would cause?
My plan is to do the timing test and pull off the pump if anything looks wrong, but wondering if you think it would be worth while to buy or scavenge a delivery valve seal from another machine and try it before taking the pump out, if that could be causing the problem?

 

[Ray70]

This morning I took a few minutes to check the static timing and something is definitely wrong. With the #1 cyl. valves closed and the engine set with the pointer at PC and verified a 1/8" drill fits into the notch under the small screw, I removed the spring from the delivery valve and removed the #1 injector line, turned on the pumps and fuel flowed out of the #1 line. Fuel flow stopped at approximately 70-80 degrees after the PC mark. ( when turning the engine CCW when looking at the blower wheel )
If I recall correctly, the plunger guide has sort of a square hole with 1 side slightly rounded, my theory is that the guide has split but not broken in 1/2 and the plunger slipped 90 degrees and is now at the wrong position, but is turning ( way out of time ) still allowing fuel to be pumped to the cylinders.
I think today I'll be making a call to that " Nice Lady" at Ambac to place an order.

 

[Guyfang]

Ray, that's a failure I never saw, so didn't chime in. Are you going to take the IP apart and look at it when you have replaced it? Might make for some interesting info/pictures.

 

[Ray70]

Yes, I just ordered some parts from Ambac, so I will have some stuff on hand. I'll pull the pump out and see what happened internally. Should be fairly obvious once I get it apart.
I've done a few of these pumps before, so it will be interesting to see what went wrong on this one. I'll post some pictures if I find anything interesting!

 

[jamawieb]

Ray70 you did everything perfect. Yes, I guarantee the plunger guide broke and let the plunger spin with causes the timing to be off. I've had this happen a couple of times. The Delivery Valve seal doesn't matter. I don't ever replace them because Ambac wants $20 for the stupid thing. I've seen no difference in operation if its there or not.

 

[jamawieb]

I've actually had some units with cracked (not broken all the way) guides which would flow test perfect but when the motor ran it would have the same symptoms as a plunger guide failure. They were cracked enough to let the plunger spin just a little with the thrust of the motor but would sit back down to its correct position with the engine off. Very frustrating!

 

[Ray70]

Well, last night I pulled it apart and found nothing obviously wrong yet. Plunger guide was in place and not damaged ( I think ) and plunger is in the guide oriented the way you would expect, with the round side aligned with the round side of the guide. However, do you guys know if the TM has an error in the picture of the plunger installation?
If you look at the TM it shows the alignment notch that catches the 1/8" drill bit being aligned with the notch in the plunger when you install it, but in reality it is 180 apart if you install the guide so that the shape matches the shape of the plunger. The plunger guide will also fit on the plunger 180 out but then the rounded sides are opposite each other.
The other thing I recall now is that when I tested the timing in the machine, I had fuel flowing out of #1 line from the point I started at which was PC until 80 degrees later. Shouldn't the fuel only have been flowing for much less engine rotation, not 80 degrees or more?
Sounds like I need to take a closer look at the guide under magnification before I go further.

 

[Ray70]

I just printed out the Ambac service guide and the pictures are identical to the TM, so I'm suspecting the plunger in mine is 180 out from it's correct alignment.
I'll verify it tonight and assemble according to the diagrams, although I'd still swear the writing on the plunger guide seemed contradictory to the pictures as far as how to orient the guide and align with the 3 flat sides of the plunger.

 

[Ray70]

Threw the pump back together and replaced the delivery valve spacer and pump seals, installed pump ( without moving engine ) and its running good now. The pump timing is about 2 notches advanced but its running pretty good now. I didn't find anything wrong other than little pieces of delivery valve spacer still in there and my initial pump timing was done wrong, I didn't hold the throttle open and was turning the motor the wrong way, already past PC of cyl #1.
Got a few things, including the timing button to address, but it's on the road to recovery. Hopefully it's twin that was on the same trailer goes a little smoother.
A pair of 003's with ASK's and 3-6 hours on each, should be nice when finished.

 

[Guyfang]

Looking good Ray!

 

[Ray70]

Hey Guy... as an update, I prepped the other matching 003A this weekend. flushed fuel system, filters etc. filled the IP with carb cleaner and let sit a couple days. Fuel pumps were both gummed up and check valves stuck, so got those pumping. Fuel tank was full of crud and had some holes after steam cleaning it, so for now I just put on a spare tank.
Hit the switch and it fired up almost instantly with not a puff of smoke or anything bad. This machine is an 83' ASK with 3 hours on the clock, still has the break-in oil tag on the dipstick.
Looking at the 2 matching machines that came off this radio trailer, they are both legitimate original 3 hour machines that have probably been sitting for 25+ years ( based on the dark brown fuel and date codes on what is left of the cracked open, dried out batteries ) and she still spun free and fired right off with just the normal pre-flight service! Something you may never see with an 802 / 803 sitting that long.

 

[Guyfang]

Ray,

Right you are. If I had to chose between a 803 or a 003, I would not wait a heartbeat to pick the 003. KISS. Keep it simple stupid. That statement was good 100 years ago, and still is good today. You guys sure make me want to get on a plane!

 

[Ray70]

Hello guys, This weekend I decided to go back to working on this 003AASK with 3 original hours on it. When I last left it, I had redone the IP and it would start up but still billow light colored smoke for about 30 seconds then gradually clear up completely. There is no blow-by pressure in the crankcase when running and after a minute of running it is perfectly clear and takes a load without a hitch. The smoke at start-up was annoying me because obviously something is not right.
Previously I had made a compression adapter and all cylinders would easily peg the 300 PSI gage I was using. ( previous experience with 802 and 803's I need 250 psi+ for them to run clean ) so I thought compression was good and focused on a fuel issue. Yesterday I pulled the mufflers so I could see which cylinders were causing the smoke ( coming from both mufflers ) I found cylinder 2 started up clean, 1 and 4 would smoke for 8-10 seconds and 3 would smoke for 30-40 seconds with cold exhaust, then it would begin to pop, sputter and eventually clear up and the exhaust would warm up. Compression tested again and compression seemed at least 325 psi, but gage only went to 300 on scale. So I put air pressure into the cylinder through my adapter, loosened the rocker arms and Viola!, the exhaust valve is leaking substantially.
I bet cylinders 1 and 4 are also leaking a little and #3 is leaking a lot. #2 is obviously running good.
My guess is the 002/003 takes substantially more compression to ignite the fuel because of it's single stream injectors as opposed to 802/803 style injector and swirl top pistons.
For my next trick I'm going to try removing the valve springs and spinning the valves while air pressure is applied to see if there is rust on the valve face that will rub off.
This has revitalized several "no compression" MEP-803A's for me in the past.
If that doesn't fix the valves, Then OFF with the heads!