Compression Testing on MEP 002A/003A

[RichardR]

LuckyDog,

A big THANK YOU to LuckyDog for the explanation of compression ratio and maximum measured cylinder pressure. It's been many years since I took a thermodynamics course and I never understood, until now, why the measured pressure wasn't simply atmospheric pressure * compression ratio. Makes perfect sense now!

But I have a question also. I seem to recall that some folks (and maybe you, too, LuckyDog) have had problems with MEP-002A's and -003A's that run for a couple of minutes and then die like a fuel supply problem, but accompanied by excessive exhaust smoke. Could this be caused by crankcase pressure building up due to blow by overwhelming the crankcase breather and causing it to spit oil directly into the intake manifold? Your post #16 seems to indicate that this would happen if the breather was hooked up normally. And I recall from somewhere a report that such a scenario even resulted in oil being puked out of the intake manifold into the air filter.

The reason I asked this question is that I just acquired a couple of MEP-003A's that have oil in the air filter housings -- something I have never seen before. I haven't started them up yet, but maybe I should look for excessive blow by in these machines? Or maybe some "helpful" technician just oiled the filter elements to make them work better, even though there is a label that says not to do that.

My advice on your cylinder #2 problem is the same as what derf said -- the piston and rings must be the source of the problem. You could probably fix it good as new by lightly honing the cylinder and replacing the piston. But it might be easier to replace the entire engine with one of the rebuilds frequently available on our favorite auction site. Less than $250 should get you a complete zero-time engine, and with a lot less work and uncertainty than trying to repair the one you have.

Good luck with your situation and thanks for the compression ratio lesson,
Richard

 

[LuckyDog]

...

But I have a question also. I seem to recall that some folks (and maybe you, too, LuckyDog) have had problems with MEP-002A's and -003A's that run for a couple of minutes and then die like a fuel supply problem, but accompanied by excessive exhaust smoke. Could this be caused by crankcase pressure building up due to blow by overwhelming the crankcase breather and causing it to spit oil directly into the intake manifold? Your post #16 seems to indicate that this would happen if the breather was hooked up normally. And I recall from somewhere a report that such a scenario even resulted in oil being puked out of the intake manifold into the air filter.

That might be N1OTY's reply to me in another thread. http://www.steelsoldiers.com/auxili...a-valve-adjustment-procedure.html#post1207614

It might also happen on an 003A.

The breathers (PCV valves) are VERY different between the two models. The 002A has a breather mounted on the block under the #2 glow plug. The 003A has a breather mounted in each head, under the valve covers. Since the oil drains back from the heads to the block through the push rod tubes, it would make sense that, after running awhile, all that blow-by would start pushing oil through the breather.

The reason I asked this question is that I just acquired a couple of MEP-003A's that have oil in the air filter housings -- something I have never seen before. I haven't started them up yet, but maybe I should look for excessive blow by in these machines?

I'd suggest a compression test. Either NJ_Toolnut's adapter, or see if buck's (http://www.steelsoldiers.com/auxili...-cylinder-smoking-start-up-2.html#post1211150) is working and he'll make another one.

Even doing the test cold could tell you a lot about the condition of the cylinder or head.

...might be easier to replace the entire engine with one of the rebuilds frequently available on our favorite auction site. Less than $250 should get you a complete zero-time engine, and with a lot less work and uncertainty than trying to repair the one you have.

A member has contacted me with just such an option. A bit more than the $250 you mentioned . But it is within driving distance, and ready now.

My concern is, while I know the generator puts out the correct voltage, I haven't been able to load test it.

BUT, I have a lot more experience with electricity / electronics then diesel engines. Could be worth the risk.

Decisions...
Decisions...
Decisions...

 

[storeman]

Stan,
I tried to use the adapter with my 2000 psi gauge but no-go. just ordered an 800 psi wet gauge and will let you know how it works. can't seem to find a pressure relief fitting to reset the gauge so will do it manually unless gauge is responsive enough to follow compression strokes. The unit I'm working on now is the first one needing compression testing
Jerry

 

[LuckyDog]

Stan,
--- just ordered an 800 psi wet gauge ---

can't seem to find a pressure relief fitting to reset the gauge

Jerry

Jerry,

The guage set up I bought at NAPA has two schrader ?SP? valves ... capture and release. The guage is only readable to 300, but it has a lot of white space before it hits the pin on its way around.

TM state 350 - 400 psi is normal.
Below 325 psi - Troubleshoot and repair.

So, with the NAPA guage, I can be certain cylinder pressure is greater than 325 and see if all the cylinders are close enough.

Just my cheap-bastard way of doing it. (and I have adapters for gassers too.)

Does the 800psi wet guage your ordering have 1/4NPT threads? If so, I'd like the PN so I can get one and use it with my NAPA rig.

 

[Speddmon]

Stan,
I tried to use the adapter with my 2000 psi gauge but no-go. just ordered an 800 psi wet gauge and will let you know how it works. can't seem to find a pressure relief fitting to reset the gauge so will do it manually unless gauge is responsive enough to follow compression strokes. The unit I'm working on now is the first one needing compression testing
Jerry

Unfortunately Jerry, without the relief/check valve I'm afraid your gauge will just jump around with the cylinder strokes. It will build pressure and relieve pressure each stroke. Even wet gauges are responsive enough to catch that kind of difference as slow as the engine rotates while cranking. Remember you only have one stroke out of 4 to build pressure, but 3 to releive it.

 

[storeman]

LuckyDog,
I'll know when I receive it, but am sure it is 1/4 npt, as my other one is. I need to find a schrader fitting to work.

Tom, I'll let you know how it goes. Might a check valve from the fuel line work? ( I know it offers no relief, but it should offer highest compression registered and is the right thread.)
Jerry

 

[Speddmon]

yeah, the fuel line check should be good enough for what you want to do. Just make sure you get it in the correct way.

 

[NJ_Toolnut]

LuckyDog,

I still have that 003A short block from my original GL purchase that "ate" the nut in the gearbox. It was a recent Tier 2 reset with only about 2 hours on the Hobbs, and the cylinder bores are perfect. It even appeared to have new pistons. I was considering keeping it for spare parts, but since the end of the crankshaft where the timing gear is located was scored and the Woodruff keyway distorted during the crash, the crankshaft would have required reconditioning by spray-weld buildup and re-machining, not financially viable compared to the typical cost of a used short block. The bottom line is that I have at least two known good pistons (#s 3 and 4, the ones that did not get hit by valves when the cam lost sync with the crank). It means that if you are willing and able to do the wrenching and have the necessary tools (i.e., ring compressor and maybe an arbor press for the piston pin) you could just hone your #2 cylinder if necessary and replace your broken piston/rings with an essentially new piston/rings from me, for a lot less than $250. I would only charge a nominal fee for the disassembly wrenching on my end, and for shipping.

Best regards,

Stan

 

[Speddmon]

I've never had one torn down that far...are the jugs removable on these engines? If so, a new/used piston and jug should get you running in pretty short order.

 

[NJ_Toolnut]

No jugs. Both 003a and 002a have a monoblock design, with crankcase and cylinders all incorporated into an integrated casting. However, from the photos and from the observation LuckyDog made that he could not catch a fingernail in the vertical marks on the cylinder walls, it does not appear they are badly damaged. Based on the excessive blow-by observed, I suspect cracked compression rings. Those cylinder walls should clean up with light honing, or even with very fine wet or dry sandpaper.

Stan

 

[storeman]

FYI:
Today I tried adjusting both sets of valves from the "A". Got black smoke instead of blue/white.) Removed the 002A's head, tore it down, cleaned the valves (one had a slight stickiness to it), checked out the cylinders (clean and smooth) and put 1/8" marvel mystery oil in each. Had to use a towel to get the oil out 3 hours later.

Reassembled with new head gasket, adjusted valves per TM, got lots of white smoke again. Am waiting on gauge, etc to be able to use Stan's fantastic adapter. Meanwhile, since I made my own injector tester, sometime in the next couple of days, I'll adjust the injectors. I'm running out of ideas and tools at this point. It will run indefinitely smoking away with about 30% power.
Jerry

 

[LuckyDog]

... It means that if you are willing and able to do the wrenching and have the necessary tools (i.e., ring compressor and maybe an arbor press for the piston pin) you could just hone your #2 cylinder if necessary and replace your broken piston/rings with an essentially new piston/rings from me, for a lot less than $250. I would only charge a nominal fee for the disassembly wrenching on my end, and for shipping. ...

No jugs.
... However, from the photos and from the observation LuckyDog made that he could not catch a fingernail in the vertical marks on the cylinder walls, it does not appear they are badly damaged. Based on the excessive blow-by observed, I suspect cracked compression rings. Those cylinder walls should clean up with light honing, or even with very fine wet or dry sandpaper.

Stan

Man, I am liking this option.

The trailer has a flat at the moment. Hope to get it repaired soon. (M101A1 ) Had to find a truck place. Now I need to haul the tire over there. MAN, them tires are heavy.

Soon as I get the tire patched, I'll run over to "Diesel Dave's" shop (local diesel mechanic) and get his opinion.

I did the IP work at his shop. When I fired it up he said the motor was toasted. Didn't want to believe him. Was hoping a little run time would clear things up since it sat for so long. Oh Well...

My next question is:
how hard / easy is it to get gaskets? Will I be making most of them? I tried looking for a DJE head gasket without luck. Onanparts.com is out-of-stock.

Let's see, I'll need:
Head gasket - Where??
Oil Pan Gasket (Onanparts.com has it)
O-rings (packing preformed) for the push-rod tubes
Valve cover gasket? No tears
Intake manifold gasket? It isn't torn (yet)

Just because I can (fix it) - Does that mean I should????


If I knew how to set up a poll, I would set one up with three options...
Go with:
1. Buy Stan's Piston, Pin and Rings.
2. Buy the rebuilt motor and swap. (Then part out the old one)
3. Go back to bidding on GL for another unit (Get at least one running out of the two)

4. Ditch it all and run away?

Did I ever mention that I think too much

 

[storeman]

Lucky,
I have two 002a complete generators I've been stripping for parts and the engines will go to scrap yard, though I have no reason to think them bad. Could not get the units functional for other stuff that was missing or bad. (Can only have so much metal under the deck.) I'm about 8 hours from you. If interested, e-mail me "Jerry@queenscreek.com"

Take both for scrap value if it will help you.

Jerry

 

[NJ_Toolnut]

Hi LuckyDog,

Thinking too much is impossible, unless it leads to paralysis. First, consider the pros and cons of repairing vs. parting out/junking. If you decide to repair, consider each repair option in terms of cost, effort, risks and required vs. available resources and then decide which plan makes the best sense. THEN MOVE FORWARD!

Only YOU can make these decisions, since only you know whether you have the tools, skills, confidence and patience needed to pursue the two wrenching options. In my opinion, the option of going back to GL for another one carries the biggest risk unless you inspect in person, and even with inspection there is a lot of uncertainty regarding what you are bidding on.

The option I suggested is the most extreme in terms of wrenching, but it is likely the lowest in cost and the least risky, since you already know what you have and what is wrong with it, and you have the ability to pay enough attention to what you are doing (this is not rocket science, but mainly just common sense) to ensure a high quality repair. I've never been into one of these units beyond cylinder head replacement and rebuilding from a short block out, but I feel confident I could repair yours if I was challenged to do it. I've probably had more experience than you since I once rebuilt a chevy small block V-8 from the crankshaft out, but the TMs are a huge help compared to the much more limited documentation available for most commercial machinery. For piston replacement, I would need to buy a piston ring compressor to insert the new piston/rings in the bore, but that's it. When I did the wrenching on mine, I was able to easily and fairly cheaply obtain all of the gaskets you mentioned, except I did not have to deal with the oil pan. I may have noted how I sourced gaskets in my thread. If not, and if you decide to pursue this repair option, I will be happy to look up the invoices. I seem to recall obtaining intake and head gaskets from Delks. I reused the old push rod tube o-rings with good results (no oil leaks). They should be fine for re-use as long as they are still pliable.

There is a lot of wisdom in first looking at the rod and crank bearings before deciding, but if this was a fresh Tier 2 reset as you seem to believe, all may be well in the lower end of this engine.

I hope this helps,

Stan

Whatever you decide, I hope you take the #2 piston out to see whether there are cracked rings and let us know.

Best regards,

Stan

 

[n1oty]

A couple of great options on the table here.

John

 

[derby]

LuckyDog, If You decide to rebuild the unit, I have new pistons in the box that i would be willing to donate to your cause. Send me a pm if interested.

 

[storeman]

Well said, Stan! Lucky....you are becoming a "project".

Jerry

 

[Speddmon]

Now, this is why I love this site so much. Lucky has been having this problem for quite some time now. Now that he is getting into the meat of the issue. The AWESOME members of this forum are coming up with great ideas for a solution and availability of parts to make the necessary repairs. This site is truly one of the best and has the best people as members.

 

[RichardR]

A very interesting thread...

NJ_Toolnut pretty well sums it up in post #34 and IMHO he has the most relevant experience, having successfully rebuilt his MEP-003A starting with a short block. But he has not only very considerable wrenching skill but also more motivation than I would be able to summon if I were to find myself in LuckyDog's situation.

That is why I would go with the new/rebuilt engine option, mostly because I am lazy and that option requires the least amount of shopping and wrenching. Fresh rebuilds are currently available from GL (or from the folks who have recently bought them from GL), which was not the situation when NJ_Toolnut had his rebuild experience.

Nevertheless, it is LuckyDog's choice to make and I am sure he will make the one that is right for him. I know this will have a happy ending.

Regards,
Richard

 

[LuckyDog]

How to ensure power doesn't go out....

So, big thanks to everyone here at SteelSoldiers, especially everyone who posted on this thread for the encouragement and advice.

Thanks to Stan for the piston assembly from his trashed motor. That was all it took for the repair.

So, Saturday I was able to go to my friends garage and unload the generator from the trailer and put it inside to work on. Sunday I was priming the fuel lines and she tried to start.

Man, is thing easy to work on (with the correct tools). I was able to borrow all the specialty tools from AutoZone. That is an awesome service they provide.

So, now that the generator is up and running strong, with no smoke, I feel confident that Hurrican Sandy won't visit RI.

So, here are the pictures:
The first three are of the M101A1 she sits in. No cargo cover or bows, so I made my own out of 1/2" pvc conduit and a 2" conduit back bone. I did make sure to use a GREEN tarp.
Guess we can see the reason for the low compression and where all the blow-by was coming from.