burning oil - getting worse.

[SnakeyesTx]

Valve seals? Consider a head rebuild?

[infurno]

Some of you probably remember my spark plug & oil burning problem... Taking the advice I was given from original thread given I decided to bite the bullet and ordered:

• fuel injectors
• gasket kit
• valve seals
• head bolt let

A friend is coming by in a few weeks and were going to get it all installed.



Meanwhile, the problem is getting worse... I used to only burn oil when the car first started... Now i'm burning oil while driving. Clouds of smoke pour out the exhaust as I rev the engine. I'm having to add half a quart of oil every 3 days on my ~50 mile trip to work and back. Something is very wrong.

Trouble is... I'm not so sure the replacements are going to fix my problem. It sounds more like bad piston rings right?

I did compression tests a little while back and got results of ~190 on about all cylinders except for one at 178 or something.

Quick reference to what my spark plugs look like after a while... Spark plugs 1-4 foul up very bad. The rest do too eventually, but manage to stay a bit cleaner.

http://www.buysmartpc.com/temp2/plugs/4.JPG
http://www.buysmartpc.com/temp2/plugs/3.JPG

What do I do?

Continue with the replacements? Or is it time to start to look for a new m20? Possibly a new E34...

[AngryPopTart]

This happened to me, but it only had the problem on #6.

When I originally bought the car it needed an intake hose and that helped it run better, but it still had a problem. We ended up finding that it had a burned valve. Sent the head out and had the valve replaced and the head surfaced. Thing was fine, aside from the cruddy idle it's always had. Then in #6, one of the Bosch* plugs came apart at the porcelain and dinged up the cylinder wall/combustion chamber really bad (Or so we found when we one day took the head off, again!) and then it started fouling out #6 just like the plugs in your pictures, and I would have to clean it every few days... actually, I cleaned it and swapped it with one of the others, in a sequence, every few days. Finally, I found that the car was getting oil in the water, and one day I noticed it got a little hotter than normal and I could smell something funky. I got to the shop, popped the hood and one of the heater hoses had popped and had oatmeal coming out of it. I popped off the radiator cap and oatmeal started belching out all over the place. Then replaced with an M20 out of a parts car which ran more beautifully than this clickety-clackety mess ever did.

We never figured out what exactly was wrong, but assume that the head or block must actually be cracked somewhere. The new-used motor is much quieter and runs strong, but it still has a cruddy idle so there is either still a vacuum leak in my system that I don't know about or more likely some of my sensors are bad.

*The typical Bosch plug for these motors is notorious for coming apart and causing these problems. If only I had known before it happened.

[whiskychaser]

Your plugs look dreadful but the compressions dont seem too bad. Its possible the compression rings are ok but the oil rings are shot. If you are taking the head off anyway, they normally say use a new ring near the top of the bore (where all the wear is) and check the gap is within tolerance. That way you know if the bores have had it. Imagine you can rebore and fit oversize rings. New valve guides and seals would be a must but read up on how to remove the cams or you may snap them. I'd also want to make sure the oil pump is ok while its down. All depends on how much time - and money - you want to spend

[infurno]

Your plugs look dreadful but the compressions dont seem too bad. Its possible the compression rings are ok but the oil rings are shot. If you are taking the head off anyway, they normally say use a new ring near the top of the bore (where all the wear is) and check the gap is within tolerance. That way you know if the bores have had it. Imagine you can rebore and fit oversize rings. New valve guides and seals would be a must but read up on how to remove the cams or you may snap them. I'd also want to make sure the oil pump is ok while its down. All depends on how much time - and money - you want to spend

Could you elaborate on the "oil rings"? I'm having trouble finding this part, is there a more technical name?

If i'm going to do anything with cylinder rings, or a rebore, I may as well as just pick up a new m20. I have seen them for sale for about $1,000.

[whiskychaser]

Could you elaborate on the "oil rings"? I'm having trouble finding this part, is there a more technical name?

If i'm going to do anything with cylinder rings, or a rebore, I may as well as just pick up a new m20. I have seen them for sale for about $1,000.

Sorry, I mean piston rings. The top one or two are for compression but the ones underneath are oil rings. If the engine has not been used for a very long period of time, these can stick in the grooves. You never get them to come out again though I've got away with honing the bores and new rings on engines before but must admit they were not BMW. But as I said it all comes down to time and money - how much another engine costs compared to fixing this one