EJ 25 Subaru question

[j4flyer]

A friend of mine recently converted an EJ 25 from fuel injection to a regular carb set up. He did this to overcome a consistent problem with the computer that could not be traced and fixed. He is using a trigger fired ignition system and the gyro seems to run excellent. Except--at 3000 RPM the engine pumps oil out of the valve covers via the breathers. This isn't a little oil but a lot of oil. The crank case breather was checked and was not plugged. The PVC valve appers fine and had no oil residue on it which would indicate the oil is reaching the PVC valve. Any suggestions on things to look for/try would be welcomed. Thanks all

[GyroRon]

You need to get a special type of compression tester and do a leakdown test on the cylinders. I would think you will find at least one cylinder with bad rings and the compression is goiong pas them and into the crankcase and picking up oil on it's way out the breathers.

I had the same problem with my old EJ-22 till one day something on it got worse and it pumped out 3.5 quarts of oil within 5 minutes of flight. All out the breathers!

[Vance]

Ron, I would think that would shorten the service life of the engine and create a time consuming clean up job, although an autogiro with smoke is an interesting concept. That is good advice.

Bob, a leak down tester injects air into the cylinder through the spark plug hole. It reads in percentage of leak down. You need a good source of air. You can identify the problem cylinder from the leak down readings, lower is the bad one. If you listen carefully, usually you can hear where it is leaking. Pull the cap on the oil filler and you will probably hear the air going past the rings on the bad cylinder. I don't know enough about that paticular engine to give you good or bad numbers. You are more concerned with finding the weak cylinder. Thank you, Vance

[Jerseywing]

I believe it's called blow-by. I have a '53 Chevy pickup that has a "road tube" (the crankcase is vented directly to the atmosphere) When I got the truck there was so much smoke comming from this thing that people would pull over to let the guy behind them get behind me to avoid the smoke. The good side was that there was very little rust on that side of the truck because it was so well coated with oil !!!. I now have a remanufactured engine and it is back to "acceptable" levels. Back then PCV valves weren't made yet and hydrocarbon emissions weren't that important. The wife wanted to call the truck Ol' Smokey as she had to follow me for several hundred miles like that when I brought it home. (the things I put that poor woman through )

[automan1223]

most likely a cracked ring or scored cylinder.

computer was what year ?

2.5's are cost prohibitive to rebuild.

[j4flyer]

Thanks guys, I don't know why I didn't think of blow by as a possible problem. I guess I was looking at the forrest and didn't see the trees-Bob

[j4flyer]

Just an update: A compression test was done and confirmed there were problems with all the cylinders. The engine hadn't been run for a few months and apparently the inside of the cylinders picked up some corrosion. Do any readers know of any tricks to try to regain the compression prior to a total rebuild? Thanks

[Friendly]

What was the compression numbers? Bob, the blow by may have alerted you in tiime to prevent serious damage to cylinder walls. Its approaching winter and this is a good time to do the rebuild if it is necessary. I don't have a 2.5 , I have a 2.2 so, I don't know why rebuild would be that much difference. If its got to be rebuilt, it's better to do so before the walls are scored or you have to trash the engine.

[j4flyer]

The compressions using an aircraft type guage was 30/80, 50/80 and that was a constant. Using an automotive guage it was 110/ 150/160/160 and last year they were recorded as all 190lbs. Not looking good-Bob

[Jerseywing]

Looks like one of them may have a real problem. The rest are within 10% of each other. You could try some marvel mystery oil and run it for a while then re-test it. I had an old timer tell me that it's good for loosening up stuck rings. (they'd get that way after he was at sea for a while so he'd do it as a matter of practice when he got home to get his engine back into shape). Sometimes a couple of hours of running will free them up too. Do it on the ground I'd be a little leary of running it up there yet.