Can/Should one Replace Rings with Engine In?

[fmarkus]

So, my trusty 67,000-mile 2.2L Turbo Town & Country has been collecting oil in the airbox. Runs fine (not super powerful), doesn't smoke visibly (from the rear-view mirror) most of the time. I performed an ancient TSB to seal the oil-separator under the valve cover, and have re-engineered the PCV plumbing, and the problem remains.

I Just did a compression check and found 0, 60,60,60 psi. No compression even with oil in the #1 cylinder. Oil in the sump is clean, no sludge under the valve-cover. Really not thinking there's a head-gasket explaining those readings. Excessive blow-by seems to explain the airbox oil pretty well too. So. Ring job.

Any chance I can do a ring-job without pulling the engine? Would it be ten-times more work to do it that way?

Thanks

[Kwagon2]

Hi
Doing a ring job with the engine in the car is fine if the block is not worn to a point where you need to do a re-bore. Once the Turbo plumbing , the Turbo and head etc. are removed the 2.2 block is wide open ,(the Turbo stuff makes it a bit more work as its a snap to do the job on a Naturally Aspirated 2.2) ....after that It would just be a matter of removing the oil pan and then protecting the con rod journals while you hone the cylinders & clean and check out the pistons & rods. LIke I said the big one is the cylinder condition, also if you have a cracked ring(s) (A distinct possibility if the engine has had a history of detonation) the cylinder wall could be scored also requiring a re-bore. The "0" compression would worry me a bit but you don't know what the deal is unless you actually have a look , usually with no improvement in compression with the addition of oil would generally indicate a valve leakage problem. Bottom line is if the cylinder taper and out of round are within spec for a re-ring you've saved yourself some work.
Generally I've found the 2.2 to be a well wearing engine (as tough as the Slant six!) I've found ultra High Milers with no cylinder ridge to remove and very nice cylinder walls if that helps any.......

[fmarkus]

Thanks!

My kingdom for a borescope. I may see if I can find someone that has one. Having a peek around in there through the spark plug hole sure would add confidence that deconstructing the top of the engine was worth the trouble in advance.

I certainly saw no evidence of a collapsed lifter or anything with the valve cover off. I've also never noticed any detonation. That's the weird thing. I drove the car 4 or 5 miles to warm it up for the compression check. It starts easily, idles smoothly, and it doesn't feel like a 3-cylinder engine or a worn out engine (it also doesn't exactly feel like a 145-hp engine). I don't typically see blue smoke in my wake. My main symptom is a completely oily air cleaner after 1000 miles.

[Kwagon2]

Hi Again!
No doubt the Turbo is sustaining the engine and making it driveable, with 67,000 miles it's kind of a youngster to be blowing oil. I'm used to seeing the 2.2's start that kind of stuff by the time they clear the 90 to 100 thousand mile mark or better. Like I mentioned they're like Slant sixes .....delivering major miles of service even with oil changes being done "whenever".
If you don't mind would you/could you post your findings .....much appreciate it!

[fmarkus]

Borrowed a Borescope tonight. Piston crown looks undamaged, and I can see the cylinder honing cross-hatches on the entire bore. Why in the heck is there no compression?

Various other experts I've consulted suspect head gasket, but where could it be compromised such that the oil remains looking like honey and there's no coolant loss or white smoke?

This wasn't the $20,000 borescope that can see above itself and check the valves, so I'm not sure what's going on up there. I suppose a valve seat could be totally ruined in 1. An exhaust valve with very poor sealing might explain the zero compression, but not the blow-by that's creating the oil in the airbox. I suppose a burned exhaust valve in 1 and just generally poor ring sealing in all of the cylinders (60 psi is really low for the others) might explain everything. I think at this point that's my best guess. But it doesn't square with the car's 67,000 mile gentle life. Old lady owner for the first 6-8 years, then 3 fellow car-club owners who've trundled around to shows in it for the rest of its life.

I worked as an engineer at Chrysler from '85-'91 and always had the impression that, as you say, these things were bulletproof for at least 100,000 miles.

This is a real head-scratcher.

Thanks for your input!

Frank

[Kwagon2]

Hi !
Just thinking ....one thing left to try is a leakdown test just to see where the air is going ....it appears as though a tear down is unavoidable but it could provide a greater idea of what to look for.....
Just a comment on the head gasket....failures at the fire ring between cylinders did occur but that affected two cylinders not just the one. That particular failure is what the cylinder "cross drilling" cured.
Once again if you wouldn't mind posting your findings as you move through your repair ..... again its appreciated!

[fmarkus]

Leak-down test results:

We pulled the valve cover (again) to ensure complete valve closure. Then when pressuring the number 1 cylinder air shot up through the oil-return passages. So it’s gotta be rings or a piston crack that we can’t see with a low-res borescope. Now to muster the time, tools, and courage for a dismantle. And with the increased risk that major machining May be required, rethink the wisdom of an engine-in job...

[89ARIES]

Thanks you guys for keeping this board going. What could have caused his loss of compression? My 1989 Dodge Aries with 289,000, last I checked, still has over 100 psi each cylinder.