002a excessive blow-by

[dangier]

You guys have been great for help in the past. I have a new one for you. My 002a (3rd one), has been giving me fits and then some. Fixed a4 and vr boards and tested-work great in working unit. Still have no power when running on this one, but that is for later. IP was bad and have a working one thanks to Gimpy. Now that I have the unit started, I get all of the engine oil puking out the fill cap vent. I had done a compression test a while ago and got a reading of 380 and 385 IIRC. This was with my shop made injector adapter and a harbor freight gauge set. Pulled breather assembly and it was not blocked. There is just too much pressure for the breather to handle. I had left the bottom baffle plate in the block and started unit. Oil and the plate went 10 feet in the air..... Pulled head and everything looks ok to me. Pictures below.

View attachment 442561

There is no scuffing or groves in the cylinder wall, so I would not suspect broken rings. Could the rings just be stuck?
Anyone have any other ideas?
Thanks,
David

 

[Jimc]

You dont have excess blowby. Its normal. Read this thread. Its all explained there.

http://www.steelsoldiers.com/showthread.php?109791-002-breather

 

[dangier]

Read your link and I don't believe what I have is normal. With the oil fill/dipstick cap on and tight, the oil squirts out the vent and soaks the ip pump. I went through 2 quarts of oil in about 4 minutes of running. Found it all on the floor under the unit. I also can not get the rpm up to 1800. Throttle handle is pulled all the way out. My hand held meter is showing around 40-45 hz.
David

 

[Jimc]

Yeah that obviously isnt right.

 

[storeman]

Have you pulled the fan shroud to check condition of oil cooler? If cooler is damaged, flow of oil is restricted. Also, I seem to recall a thermostat that I removed from a unit I scrapped. Could have nothing to do with anything but oil flow.
Jerry

 

[Jimc]

Yes there is an oil pressure regulator behind the flywheel i believe. Just a spring and ball. If ball is stuck then there could be over psi on the oil system. With excessive oil flow and the natural crankcase psi if the 002 it could maybe make things look really bad and more like a bliwby problem when in fact its not. Just a thought

 

[johnray13]

I think I would pull the pan and take a look at the bottom end of the motor. I suppose you could have a busted connecting rod that is really splashing up the oil. That could also limit your RPM's if you were limping thru a cylinder cycle. Is it smoking?

John

 

[Jimc]

i think if that were true the pistons would not stay even as the crankshaft is rotated around. atleast it looks that way in the pics.

dangier, when the engine is running did you notice if the oil psi gauge was pegged?

 

[storeman]

"dangier, when the engine is running did you notice if the oil psi gauge was pegged?"

Good point Jim, I should have asked same thing.
Jerry

 

[dangier]

Did not notice oil gauge pegged. As I recall, it was in the 45 psi range as all of my units are when cold. Both pistons move in tandem. This unit is the one I wrote about having the ip block shims glued with some red stuff (like leak-lock). O-ring was also missing on ip. I was looking at the pictures and noticed something yellow on the top of block around the head gasket. Went and looked at the unit and there is something sticky around the head gasket area. If some kind of adhesive was used on the head gasket and got onto the rings, would that stick them?
I might be looking for a tear-down just to see if the rings are indeed stuck. I might try laquer thinner or acetone on the exposed stuff to see if it dissolves it. Maybe could seep some around the piston rings and let drain out the oil drain. That stuff evaporates so it shouldn't cause harm if I get oil around before unit was started. If I could clean them up without dropping the oil pan it would be much less work. I would have to guess as to when they would be freed up.
Still thinking......
David

 

[Jimc]

i am just guessing here but i really dont think there could be enough blowby to make 2qts of oil come out the breather in a few min, especially if you have good compression. why would there be that much oil up there right next to the breather to even be pushed out by the pressure. i could see it if the crankcase was waaaay overfilled with oil but i know your much smarter than that. i have been wrong many times before but i have a gut feeling there is something else going on here.

 

[Isaac-1]

Jimc, that last comment made me think of something, I think the MEP-002a and MEP-003a have similar looking, but differently marked dip sticks, if this unit has a MEP-003a dip stick installed it may be off on oil level. Just a thought, I am not sure how much different they are or which reads higher or lower.

 

[Munchies]

I had a saab engine with bad rings on one cylinder that caused excessive blowby. Very frustrating....

 

[dangier]

Isaac-1 the dip stick is marked 002a.
When I lost the oil, being that low, it was still blowing out the breather. I am still thinking the rings are stuck. I don't know why, but something tells me that much blow-by has to come from the combustion pressure. I did a compression test before I had tried to actually start it. The head gasket has a lot of sticky stuff on it. When I get to it, I think I will go ahead and drop the oil pan and pull the pistons. Its the only way to know for sure....

We are going to Corolla, NC for a week and I am not going to worry about this.
Really appreciate the feedback.
David

 

[Munchies]

Might be worth pulling the piston and re-ringing with a light hone

 

[johnray13]

If the rings were stuck, would you see compression at 380 and 385? Spec is between 350-450, so you're right where you should be.

Have you completely drained the oil and then refilled to spec to see if that makes any difference? Of course I like your idea of pouring some lacquer thinner into the cylinders before changing the oil.

Oh yea, and what about the smoke when you had it running (black, grey, white, blue, none?).

John

 

[Munchies]

Good point, I missed that. On my Saab, it was about 40% low on the offending cylinder and oil brought it up quite a bit...... It still makes the most sense and the symptom is correct....

If there is a restriction in the oil circuit it should flow from the bypass back into the pan. I dont know how it could come shooting out.... Crankcase air pressure seems the culprit.

 

[Jimc]

with both pistons moving up and down together the crankcase is going to build pressure like a compressor. basically the volume of both cylinders and its being forced with all the energy of the engine running. you pull that dipstick out on an 002 its no joke. oil and pressure is blowing out like crazy. it makes it look like you have a severe blowby problem when in fact there isnt. with the compression correct i just dont think the rings are the issue. question is why is there so much oil blowing out the breather which is at the top of the crankcase. that part seems odd to me. if there is a restriction in the oil then like munchies said it should go back into the pan unless of course the bypass/psi regulator is stuck. whole issue is bizarre really. i am really curious to see what it is.

 

[Munchies]

Ima go stick a rubber glove over a 002a dipstick and see if i cant make it blow up a bit...Curious about this as well now.

 

[Munchies]

Thinking aloud. What if the PCV /breather is clogged? That would do it.. Compression and excessive blowby...