New engine trouble

[Walker]

I hope someone can help me with this problem. I just finished rebuilding a 2.25 petrol engine out of an S3. I've put about 400 miles on it driving on flat land, not over 50 mph. Lots of power (realatively speaking) but it smokes like a Pensylvania steel mill! It burns about a quart of oil in a hundred miles (10w40). The mechanic keep telling me 'the rings have to set'. This sounds like so much BS. Head was done, new rings, anything I could think of was replaced. What can be causing this? Will it burn this much oil until 'the rings are set'? In Calif. I'm liable to be shot driving an oil burner. Thanks for any input.

[jp-]

Replacing parts alone will not cure oil burning. Did you hone out the cylinder walls, and check the ring clearance?

Rings do have to seat, but I have become a believer in the technique of flogging the engine out during the break-in to seat the rings rather than running it easy. Also, no syntheic oil for the first 5000 miles.

Someone on here originally posted this link:

http://www.mototuneusa.com/break_in_secrets.htm

[jp-]

Note: Some oil burning, especially during the first 1000 miles is normal. My 88 smoked a little until about 200 miles. However, excessive smoke could be another problem besides the rings alone. Your mechanic could have installed the valve stem seals incorrectly, or have damaged one or more of them. You need to isolate the oil buring to a single cylinder if you can. Pull out each spark plug and see if there is a black oily buildup on the tip. If it exists on only one or two plugs, then those are your problem cylinders.

How much smoke are we talking about? James Bond smokescreen? or what?

Is there less smoke or more smoke if you rev the engine?

[daveb]

I thought the Pennsylvania steel mills were all closed. So you should be running pretty clean.

Sorry couldn't resist.

Agree with the others, you don't want to rev the piss out of it 100% of the time but you need to run it at a variety of rpm's. Short bursts of WOT force the rings to expand tight against the cylinder walls and help them bed in.



I hope someone can help me with this problem. I just finished rebuilding a 2.25 petrol engine out of an S3. I've put about 400 miles on it driving on flat land, not over 50 mph. Lots of power (realatively speaking) but it smokes like a Pensylvania steel mill! It burns about a quart of oil in a hundred miles (10w40). The mechanic keep telling me 'the rings have to set'. This sounds like so much BS. Head was done, new rings, anything I could think of was replaced. What can be causing this? Will it burn this much oil until 'the rings are set'? In Calif. I'm liable to be shot driving an oil burner. Thanks for any input.

[sven]

How is the PCV system? Is it still there? Check the PCV and hoses, etc.

[Walker]

Thanks for the info.Yeah, I know the steel mills are shut down. Anyway, cylinders were bored to 20 over with approriate pistons and rings (mechanic says they were "file to fit" whatever that means), new seals, valve guides, valves and seats reground, etc. I'll start looking at the plugs for oil buildup. PCV system is in place and appears to be in good order. Any possibility of pressure buildup in the crankcase causing the engine to suck oil thru the PCV system? Suggested by a 'jeep' friend.

[daveb]

file to fit? gapping the rings? does anybody do that on 2.25's??

if you haven't done a compression test, do one now. engine warm, throttle blocked open. take down the numbers.


Thanks for the info.Yeah, I know the steel mills are shut down. Anyway, cylinders were bored to 20 over with approriate pistons and rings (mechanic says they were "file to fit" whatever that means), new seals, valve guides, valves and seats reground, etc. I'll start looking at the plugs for oil buildup. PCV system is in place and appears to be in good order. Any possibility of pressure buildup in the crankcase causing the engine to suck oil thru the PCV system? Suggested by a 'jeep' friend.

[singingcamel]

What about your valve seals . where they replaced?

[s3landy]

I'll second the compression test but also make sure all plugs are out. Also check the diaphram in the pcv valve and make sure it is not ripped. otherwise you will be sucking oil into the intake.

Mike

[Daurie]

I'll second checking the PCV system. I've seen first hand the smoky, oily mess an
incorrectly plumbed or inoperative PCV system will make.

[Walker]

The PCV system seems to be plumber correctly - per green bible. The only issue may be that the valve is tilted a bit, not straight and level. Would this make that much difference?

[s3landy]

Open the valve up and check the rubber diaphram inside for tears.

Mike

[Walker]

Thanks for the suggestions. So far this is what I've found: Compression leak-down test is 6-7% in each cylinder. Pulled the PCV vale and replaced it with an in-line Japanese model and oil consumption has dropped to almost nil. Still get a white cloud on occassion but nothing like before. Thanks for all the suggestions, folks.

[Daurie]

Try disconnecting all the PCV system and sealing up all holes except the valve cover. If smoke dissapears completely then there you go. Wether or no to run a PCV system has been hotly debated in a past thread and it's mostly an environmental thing.