Oil pressure drop on my MEP 005a

[jlxb]

Hello all, I have two MEP 005a's in my shop. Having trouble with both! Perhaps the same issue with both - though their histories are a little different.

Generator 1 was in great shape when I got it 2 years ago. Changed fluids, filters and flushed the fuel system. with 1200 hours on it already, it took off and has run perfectly until recently. I have put on about 400 hours this winter. 3 weeks ago suddenly it stopped. I checked it over thoroughly. Could not find anything wrong. So I hit the start switch. It cranked fine but after a very few seconds, the dip stick flew out and hit the wall. With it came at least 2 quarts of oil on the floor. Pressurized oil pan......Crap!

Fearing the worst and hoping for the best I dumped a can of Seafoam into the oil pan and started it up. At first, I was detecting some pressure at the dipstick but the breather on top of the engine seamed fine with a very small amount of oil mist coming out. After one hour there was zero pressurization at the oil pan and zero oil mist at the breather so I changed the oil and filter. The oil that came out was BLACK and loaded with ash. At this point everything was fine.

Late last week, I noticed that the oil pressure would fall very very slowly as it ran. At start up it would go directly to 45-50 psi. after 2 hours or so it had fallen to barely 20. On a few rare occasions, it will shut off from low oil pressure. Now the trouble begins! It will not restart when it is hot. Zero oil pressure after several seconds of cranking. Not even if I pop it with ether. After many hours of cooling (50 degrees F) it will only start if I give a shot of ether. But then it starts right up and goes to 45psi OP. If it is up and running for a few minutes with good oil pressure (long enough to come up to operating temp) I shut it down - It will not re start until I let it cool down. In fact, it acts like it has no compression even though it ran beautifully just seconds earlier. On one occasion, I flushed all the hot oil out and replaced with cold (new) oil. It started right up but only with a hit of ether.

1) have gone through the fuel system beginning to end - everything OK
2) Never ever needed ether before
3) If the oil pump was clogged or broken, why would I get great oil pressure at start up with cold oil?
4) If the oil pump is not clogged or broken why am loosing oil pressure with hot oil?
5) This engine does not smoke, or burn oil. The level on the dipstick is checked every day.
6) When it is running it runs great. It does not over heat. No power loss or missing. It runs level and steady.
7) Other than the ash in the oil and a brief experience with pressurized oil pan, I have not seen any of the classic signs of blow by.
The starting issue (even cold) mystifies me. I have religion against the use of ether. My generators are indoors and never get wet or cold. The room is climate controlled - it never gets above 80 F.

What do you think? Rings?

Generator 2 has been a problem child. When you buy these things you hope for the best and usually get it. Not this one. The fuel injection pump was seized and was rebuilt for the modest sum of $850.00. Geeez those guys think highly of them selves.

Getting the pump reinstalled properly was quite a trick. Having never done it before, I made every mistake. The first three attempts resulted in massive amounts of red dyed fuel in the oil sump. I think I could probably do it now and not screw up but I don't want to seem over confident in front of you all.

This generator will start up perfectly (no ether) every time. But like generator 1 above it has an oil pressure problem. This gen runs for exactly one hour. At start it has 40-45 psi oil pressure. At 60 minutes it will have fallen very slowly to below 20psi and shut itself off. You can set your watch to it. When hot, it will not restart. When cold it is perfect.

1) This generator smokes and shows all indications of wet stacking - 260 hours on the meter. - I have not run it heavily loaded yet.
2) I have flushed all the fuel out of the oil pan and filter.

Same issue? Does anybody know if the oil pan and pump can be pulled from these generators with out removing the engine from the machine? Has anybody tried using an external oil cooler on these units? I see that there are ports that can be used for this - or just put it in line with the external oil filter.

Sorry for using so many words. I thought it better to cover the bases rather than minimize. Any help is greatly appreciated.

 

[dangier]

Sounds like you have a couple of different things going on (in my un-expert opinion). Reduction of oil pressure from reduction of viscosity and/or excessive bearing clearance. The hot not starting might be a symptom of low compression-you mention wet stacking (rings?).

Just trying to get the conversation going....
David

 

[dangier]

Brain storming here...
Oil pressure regulator/bypass issues? Same thing with both units-not having TM in front of me-easily accessible?
David

 

[dangier]

...Could the excessive bypass be overheating the oil?
Do you have the ability to fully load the units? Be interesting to see how they react.
David

 

[jlxb]

Hi guys, thanks for your replies.

I do have the ability to fully load generator 1. It operates under pretty heavy load normally. It does not seem to make any difference. Though, it does warm up faster.

William at delk,s just suggested that I pop off the oil pan to see if anything is clogging the oil pick up screen or causing the bypass to open. He also indicated that the bypass spring may require a shim to increase tension. This makes some sense to me. Might explain why cold dence oil has pressure and warm thin oil has none. The transition being very slow. I don't think it explains why after 15 minutes of warm up time still showing excellent oil pressure, if I shut it down and then try to re crank, I get no oil pressure at all.

The TM does not address this issue directly. It does however, give pretty good instructions on what to look for in a warn out or broken bypass spring. I am going to get dirty today.

 

[PeterD]

What oil are you running in it right now?

 

[jlxb]

Peter, good question! I have tried several varieties and weights. It was suggested to me sometime ago to use a 15w-40. I have been using 15w-40 for most of the last year.

 

[PeterD]

Well, 15W-40 is what I use, and it works for me... Maybe oil filter issues?

 

[jlxb]

You maybe right but not likely the filter itself. I have changed it out a couple of times.

 

[jlxb]

Here is an update. It was suggested to me that there was apparently something wrong with the oil pump and/or bypass valve. So I spent the weekend taking out the oil pan to get access. Guess what I found!!!!!



Wow it took me an hour to figure out how to add these pictures.

I found nearly a coffee can full of this stuff in the oil pan. but that is not all. This junk is some kind of polimer base. It is rubbery with some elasticity. Beyond the small particulates, it also coated most of the inside of the oil pan as well as the underside of the engine - glued on! The underside of the engine looked like melted plastic had been sprayed on and then spun off with centrifugal force, leaving thin strands of plastic like hairs. Has anyone ever heard of this before?

Break kleaner would not even touch it.

I pulled the oil pump and found it completely clogged solid with this black plastic material. I tried everything to get it out and off with very little progress. After I soaked it for an hour in a water based degreaser with no effect I put my propane torch to it. That is how I found out how flammable it was. Holy crap! Even though it was still wet, it took off like gasoline. Oil will light up with some persuasion. This stuff only needed a match and continued to burn until all fuel was gone. I was able to disassemble the pump and get it completely free and to my surprise completely functional including the by pass.

After 10-12 hours of scrapping pealing and swearing, I put it all back together. I was very thorough about making sure all the oil passages were clear and functional.

When I started it, It wasn't long to find out that all that work had absolutely no effect on the function of the generator. It still has exactly the same symptoms.

1) Starts and runs fine when the engine is cold.
2) looses oil pressure very slowly over time. (but does not over heat)
3) Engine will not restart if the engine is warm. Oil pressure will not come up and acts like it has no compression. Once it cools down, will start right up.

Thanks for your help. I am lost.

 

[1800 Diesel]

A couple things come to mind & a few more questions too.

I hate to say it but you may need to completely disassemble the engine & have the block & head hot-tanked to remove all traces of that crud from the oil system. I'm thinking that stuff has been forced through the oil passages in the crankshaft and all other passages in the engine. Possibly what's happening is the oil is not draining back to sump fast enough to keep the pump fully primed & it's sucking in some air which will cause a lowering oil pressure. If the drain passages are also clogged this would restrict the flow of oil back to the sump. Immediately when the engine shuts down have you checked the dipstick reading?

Have you pulled the valve cover to see if there's any of that crud in and around the rocker arms? It's a crazy long shot but if there was a bunch of that material floating around under the valve cover, maybe it's getting between some of the rocker arms & pushrods & holding valves open during the compression stroke...

Also, while you had the oil pump disassembled did you happen to check gear-to-cover plate clearances, backlash & body clearance? If end clearance is too great, oil pressure will decrease when the oil gets to operating temp.

Last question--did you check you oil pressure switch to see if some of that crud made it inside? If in doubt, swap out the switch with another one.

This is a very unusual situation so hopefully you can work through it. That's all I can come up with for now. Hoping you get it sorted out.

Kevin

 

[dangier]

Wow! Someone's attempt at sabotage? Concur with 1800 Diesel's comment with needing to tear down and boil out the block. If not, you will be chasing this problem forever. Any signs of the same material in the other unit? Is this material under the rocker cover also?
Will be watching your progress.
David

 

[jlxb]

1800 Diesel - No, I have not taken the valve cover off but it is easy enough to do. I fear you are correct on all counts.

quote - "I'm thinking that stuff has been forced through the oil passages in the crankshaft"

I would have no doubt about it.

quote - "Possibly what's happening is the oil is not draining back to sump fast enough to keep the pump fully primed & it's sucking in some air"

Yesterday after reassembly, my first start up found that I did not have a tight seal on the oil filter housing. OIl came shooting out -just another quart on the floor. However, this oil was different. Instead of being jet black, it was super charged with air. I had never seen this before.

I have checked the oil on shut down and every time it looks ok. I did notice several weeks ago that if I over filled the oil ( a few quarts over full) the oil pressure would stay higher for a longer period of time. I have run for up to 18 hours like that. How ever, that is also what lead me to my first catastrophic symptom. The gen would just stop and apparently for no reason. On restart, I would pressurization of the oil pan. My guess is the breather passage was clogged. That is when I added the Seafoam and cleared that symptom - and thus revealing the junk in the oil pan. Now knowing how nasty this junk is, the likelyhood that I removed all that junk from that passage is zero. just enough to stop the pressure build up in the oil pan.

quote - "Also, while you had the oil pump disassembled did you happen to check gear-to-cover plate clearances, backlash & body clearance? If end clearance is too great, oil pressure will decrease when the oil gets to operating temp."

Way over my head! I hate being ignorant and/or inexperienced. But what you say sounds good. I cleaned and reassembled the pump very carefully. It pumped furiously just turning it by hand. That is unfortunately the limit of my ability. I did not see anything that looked adjustable. The spring in the bypass was clogged with junk. I was able to clean and clear it and it looked functioning to me.

quote - "did you check you oil pressure switch to see if some of that crud made it inside? If in doubt, swap out the switch with another one."

No, but I think the switch is performing properly. (correct me if I am wrong) When I attempt to restart, I am getting zero oil pressure. With zero oil pressure the pressure switch should not allow the gen to start (it will not turn on the fuel). The pressure sensor is working properly. My guess is that because the sensor is up stream from the filter that the cause of the drop is up stream of the sensors - meaning pump. Like you said, Either not enough oil to pump or the pump becomes less powerful as the oil becomes thinner from heat. All that leaves me to believe that the pump can not achieve any pressure when the oil is hot. A new oil pump might solve the problem or disprove the theory. Though I would hate to install one with the probability that I did not already get all the crap out of the engine.

All that said, If I warm up the engine say just 10 minutes, this engine is running strong with full oil pressure. If I shut it off, it will not start and will show zero oil pressure until it cools down.

 

[jlxb]

Thanks David,

Sabotage or stupidity! While I am not above a stray thought of some trying to #### me, It is more likely some grunt in this generators lifetime just did something stupid. The material looks and behaves like the spray on bed liner in my truck. It could also be a radiator stop leak. With 1000 hours what are the chances some one pored the wrong stop leak into the oil to stop the smoke caused by running it unloaded?

Even the thought of a complete tear down exceeds the value of the generator. I have my eye on a pair locally that I can get for less then the cost of a boil out and probable machine work. And, once it is disassembled it should also get new pistons, rings, seals and bearings. Anybody know what a complete rebuild kit costs? Is one available?

No! Not yet anyway. I have changed the oil three times. Twice soaked in diesel fuel. I have seen no sign of the black stuff. The symptoms are impressively similar though. Not enough time to work on that one now.

 

[dangier]

Keep your chin up-you will get ahead of the problems eventually. I had to replace the pistons in one of my 002's due to the excess use of starting fluid. I won't say who. I may have just finished it off.

I have found that "Purple Power" (Lowes/Home Depot), is good for taking the diesel smell off your skin. Hard on your skin though. I don't know what is worse-going in the house stinking like fuel oil or rough skin.

David

 

[Ray70]

I agree with pulling the valve cover. With all that garbage in the pan I wouldn't be surprized if you found the the passages up in the head blocked off preventing the oil from draining back to the pan fast enough, like 1 800 Diesel suggests. I've seen this happen in a gunked up car engine before, probably due to not changing the oil regularly. That would also explain why it runs longer when you have the oil over filled. Cleaning it out thouroughly could be a whole other story...

 

[jlxb]

If I open the valve cover and find a lot of junk up there I can clean it out . If the passages are clogged will I be able to do anything about it?

 

[dangier]

There should be a diagram of the oil flow in the TM. You won't be able to reach much of it from the head. There is a oil passage feeding every rod and main bearing that you can't get to without pulling the engine down. Most cranks that I have seen have passages drilled in them. I am sure there are many more I can't think of right now. The only sure way to clean the passages and feel confident that you have proper flow is taking the engine apart and boiling them out. Wouldn't take much of that #### to break free and block a passage to a bearing and then you will have more damage to contend with.
David

 

[1800 Diesel]

jlxb,

The overfilled sump scenario (allowing unit to run longer with good oil pressure) points further to drain-back issues. I wouldn't go over 2 quarts though or you'll be having more engine problems.

If you do get back into the sump, the oil pump gear check can be done with feeler gauges--IIRC, the allowable clearance range for cover plate-to-end of gear is 0.002"-0.004". I haven't come across backlash problems except on an engine run near empty of oil.

I think you would do well to get another engine if you don't want to tear that one down. The more I think about the small diameter passages (such as crank journals, pushrods, connecting rods, etc--any of these could still be partially clogged while still seeing "good" oil pressure.

While you had the oil pump disassembled did the screen get covered with the crud too?

Back to the oil pressure switch--I would still swap that out with a known good one. The reason I suggest that is because of the symptom of the engine not starting after a shutdown & oil is hot. There could be a large chunk of that stuff right at the inlet that could be closing the passage from the pressure side. This would have the effect of the switch seeing no oil pressure and the fault system doing its job, though I am confused about it not starting at all. It would seem like the engine would start & then immediately be shut down by the safety. You could also leave the switch out & connect some tubing to the block side threads & run the tubing into a clean bucket. Then spin the engine over (with IP fuel lever in stop position). Then you can see if any crud is cleared out into the bucket.

Kevin

 

[jlxb]

Kevin

I wouldn't go over 2 quarts though or you'll be having more engine problems.

I have overfilled other engines and proceed with great care.

While you had the oil pump disassembled did the screen get covered with the crud too?

Oh yes, the screen was completely covered by the junk. The pump was totally clogged and the bypass was stuck. I am surprised it could pump at all. When I was done it was squeaky clean and like new "looking".

I spoke to william this morning. He indicated that even if the oil pressure switch was shot, the engine should still start. When the start switch is engaged all safety sensors and switches are disabled. So it should start with no oil pressure. I am pretty certain that it will not start with no compression. I barely get a flutter with a pop of ether. Clearly, the diesel fuel is not igniting if there is any being injected. Even with a cold start it now requires a pop of either. That is not right!

Tomorrow morning, I am going to:
1) replace the pressure switch - I have one
2) Check to see if the fuel solenoid is engaged during a warm restart - why would it be on during a cold start and not on a hot start?
3) I am pulling the valve cover off just to see - If it is full of junk, I know what needs to be done.
4) Call my local engine shop to find out how much to boil it out and hone the cylinders if I deliver it.
5) Get a price on a new oil pump.

I am not intimidated by a tear down. I am sensitive to cost. I am not likely to find anything in there that is cheap. I can get a rebuilt engine for 2500.00. I can get another used 005a for $1500.00. I can not beat either of those prices if I tear down this engine and have to rebuild it. There is a considerable risk and money I don't have in all three options.