Engine Rebuild Guide / Difficulty?

[RobertK]

After removing the air box and intake boot to clean the throttle body I found a nice chunck of blow-by which would explain why engine burns a chunk of oil when first starting it.

A friend of mine mentioned that this is most likely caused by bad rings and that the only way to fix it is to go ahead and rebuilt the engine.

Does this sound right? Do I have any other options and if not is there a good eninge rebuild guidefor the 2.5? Look to be a long summer.

-RK

[nando]

what do you mean you found a "chunk" of blowby? if you mean you found oily residue in the intake, that is normal. also, if your breether tube (it's under the intake manifold) isn't on all the way or the seals are bad it will suck oil into your intake.

[RobertK]

There was oily residue all in the boot and throttle body. I hope you're right. How hard is it to check to see if that seal is bad?

Is there a noticable difference between having the problem you described and having bad rings?

[nando]

yeah, that's completely normal.

trust me, you'd know if your breather tube was leaking.. when I put my head back on I didn't have it quite in all the way and it sucked a whole quart of oil into my intake and filled my airbox with oil.

[RobertK]

I didn't have any oil in my air box and further more if it were my rings wouldn't my engine put out alot of bluish smoke?

[kansas-ix]

yes it would and you would see it in your review when driving if they were really bad, like old crhylser minivan bad, or civic ricer bad.

[RobertK]

Mine only puts out a cloud of bluish smokes when I first start her up otherwise she runs a little rich so after that she will put out some black smoke here and there. Nothing excessive like what you described.

[Old'n'Slow]

Sloppy valve guides will allow a little oil to dribble into the combustion chamber overnight. A little puff of bluish smoke at startup is the result. Bad rings burn oil all the time, so if you get smoke while at idle, then you have a more serious problem. I'd say a compression check is in order. Good compression+smoke at startup=worn valve guides. Not an emergency, but head work is on the horizon.

[kansas-ix]

then keep on truckin'

The 528e we have, has 330k on it and if you gun in 4th getting on the highway it puts out heavy buy and goes through a quart every 2k, as the rings are starting to go.

Rings on BMW's as with there honings are solid. won't need to be done on a m20 until at least 200k.

My IX has 250k and the honing and rings are fine.

[nando]

Mine only puts out a cloud of bluish smokes when I first start her up otherwise she runs a little rich so after that she will put out some black smoke here and there. Nothing excessive like what you described.

that is usually a sign of bad valve stem seals. no biggie. valve guides don't seal the combustion chamber either so those have little to do with compression. not a bad idea to have it tested though, you can buy a testor for $50 and DIY.