Topic: Dry and wet compression test results, need some insight from the experienced

[bambbrose]

I've got an old worn down 22RE that is sitting in my pickup currently. I'm working on an engine swap that will be going in next winter but for now I need to get this motor into good enough shape for this season. I needs to last another 10k RELIABLE miles.

I haven't owned the pickup very long and have put less than 500 miles on the current motor. The previous owner said that the motor was rebuilt at 150k and the truck currently has 187k. It is a 91 4x4 even though that likely doesn't matter.

On to the symptoms.

-Timing chain is going bad, lots of clanking and sounds like a diesel. Needs replacement asap.

-very minor milk forms on the underside of the oil cap (takes about 150 miles to collect). No noticeable milk in coolant. Small enough that it's probably a very small head gasket problem OR perhaps coolant is making it's way into the oil somewhere around the timing chain problem.

-Excessive blowby. There is absolutely no smoke in the exhaust at any time during running or warmup, but if you remove the oil cap or breather while it is running lots of crankcase pressure is trying to escape and smoke is coming out.

-Various oil leaks on the engine, I haven't been able to pinpoint them all just yet but it seems like it all eventually makes it's way back to the bellhousing and drips off. There are usually oil puddles on the top of the valve cover after a long trip, probably leaking out of the breathers from the blowby. Lots of random oil all over the front timing cover as well.

-Low power, rough idle, smells like smoke when beating on it or revving high (probably the blowby pushing out somewhere).


So basically I'm guessing it was rebuilt by an amateur and needs a lot of work, but I don't want to put any money into it because I want to just get by for another year until I can put a better motor in.

On to the compression results:

DRY
146, 104, 96, 145

WET
152, 132, 110, 159

TOTAL INCREASE DRY TO WET
6, 26, 14, 14

PERCENT INCREASE DRY TO WET
3.9%, 21.2%, 12.7%, 8.8%

So....

obviously I have a problem. Normally the large difference between 2 & 3 and 1 & 4 would be an obvious head gasket issue, but that wouldn't explain the blowby. I'd love to get a leakdown tester in on it but that's more money that I don't want to waste on the 22re. Also it is strange that the increase from the wet test wasn't nearly as strong on cylinder 3 as on 2, and even though the wet tests are showing a decent increase, 2 & 3 are still much lower than 1 & 4 even when wet.

I'm almost thinking that when it was rebuilt that cyl#2 had the rings clocked wrong or maybe the piston to bore clearance was a bit off, and now that is showing up as blowby. Then on top of that maybe the head gasket is failing as well?

My current plans are to just order a timing chain and gasket kit from engnbldr.com and doing the chain and head gasket. When I have the head off I'll have it checked and decked.

but that said I really don't want to put all the work into it and have the problems of low power and and excessive blowby to be strong as ever.

Questions for the experienced 22RE people

Can blowby be caused by something head gasket related such as some sort of port such as the oil drain that runs between the head and block (keep in mind it doesn't smoke out the tailpipe)?

Is there anything that has to do with the timing chain issue that could cause excessive crankcase pressure?

Any other insight?


Thanks in advance. Sorry for the long read.

[Plekto]

Usually the symptoms you're describing with that kind of variation are either bad valves or bad rings.

[93tonkatoy]

I would drop the oil pan, and with each piston at TDC, do a good visual inspection of the cylinder walls (I did this when replacing rod bearings). Check for gouges, galling, and piston slap. All of these can cause excessive blow-by, and the pan gasket is pretty cheap for what you'll find out. If your hands are flexible enough, you could probably use a feeler gauge to get a pretty good idea of the piston to cyl clearance, also, but it would be from the bottom side. I am having a similar concern with mine. The engine does not smoke, but when running at 3000 rpm's or higher (highway speeds), the engine will lose a quart of oil in a half-tank of gas. Running lower rpm's uses less, but it still uses. No drips, or other signs that the oil is leaking out. I do know that with the oil cap off, and the engine running, I get quite a bit of air being expelled from the oil fill hole (why I suspect blow-by). I am just trying to nurse this one as long as I can, and am planning to rebuild another engine.