diagnosis ideas?

[geof33]

3.0 CIS went "poof" from a 5000rpm to 3000rpm drop, smoke, oil in exhuast, oil in the air intake. Dropped one cylinder. Not sure which, PO told me this.

Removed sump, plugs. No obvious signs od fouling, and no metal at all in the motor.

Any ideas? Not a great shot, but here are the plugs:

[Tim Walsh]

that's not a very good pic but are any of the oily, or have any mechanical damage?

[geof33]

There isn't any oil... that's the weird thing. They are fairly carboned up... but no oil. I'll take some better shots. And no, there really isn't any outward sign of failure or anything. they looked pretty darn good overall.

I'll shoot a better pic tonight.

[Wayne 962]

This is a good read for your problems:

http://www.pelicanparts.com/techarticles/mult_Engine_Rebuild/mult_engine_rebuild-1.htm

-Wayne

[geof33]

Wayne,

I've already ordered the book. The motor was coming out for a total rebuild anyway, bumped to a 3.2 or 3.3 "S" cams and Carbs... I'm just trying to figure it out before hand!!

Thanks.

[Wayne 962]

Check out the tech article - it will show you how to diagnose the problem...

-Wayne

[geof33]

Wayne,

Great article BTW... Lot's of good info. The biggest problem is the engine is not currently "hooked up" so I can't crank it with the starter. After reading the article it sounds like it is valve related, maybe a piece of carbon stuck... I'll be finding out for sure in the next couple of weeks as the teardown begins!

Thanks again...

[350HP930]

The plugs could have just fouled up from oil consumption, whether it be from bad valve guides, rings or a little of both.

[Wayne 962]

Originally posted by geof33
After reading the article it sounds like it is valve related, maybe a piece of carbon stuck... I'll be finding out for sure in the next couple of weeks as the teardown begins!

Thanks again...

Right - very important. As much as I like to sell engine rebuild parts, there's no need to rebuild an engine that doesn't need it (the Ferrari disease!). Make sure that you have determined that you really need to rebuild prior to tearing it down.

I didn't think so at the time, but this article has become the number one useful article on this (and the BMW) site. I'm actually including it as a project in the new BMW book.

Everyone who thinks their engine is dead should read it first...

-Wayne

[afterburn 549]

Start with a leak dwn teast.......then you will know if its just ez or mech.

[Wayne 962]

How were you planning on getting to a 3.3? Carrera crank + Turbo cylinders + JE pistons?

-Wayne