Valve Seal question

[rkramer]

Greetings;

Has anyone replaced valve oil seals? I've heard some techniques to do this without removing the head but don't know if they apply to a 1986 e30 engine. The kit is inexpensive and I'm comfortable with the wrench-work part of it, just don't know if it can be done easily on this engine. Any feedback would be most appreciated!

Thanks

rkramer
86 325e sedan
87 325 coupe

[Yurick]

Realistically, you are looking at removing the cylinder head to do this. That makes this project significantly more expensive, because once you have the cylinder head off, you might as well have a machine shop rebuild it for you.

[Jeron]

Agreed.

The expense isn't too much, $500-1000 but the personal labor required is ~40 hrs.

[alpine325]

Your better off pulling the head.

[Manolito]

I'm gonna play the Devil's advocate here and argue the "if it ain't broke" point of view.

I have never done this particular engine, but I have put valve seals on several other engines, and I tend to favor the head-in-place procedure.

If the car is low-miles, and the only problem is the age of the seal, then there is no reason to spend the money to pull the head, as there is nothing else in there that needs to be done.

If the car is high miles, and the valves are loose in their guides, then just doing the seals will help, but is only a temporary fix, so you have to as yourself if you intend to drive this car another 10k miles or another 100k miles. Once you pull off the head, the tough questions start. Where to stop? Valve guides and seats? How do those cylinder bores look? Hone and new rings? Perhaps bore and new pistons? What about the bearings? Re-machine the crank?

I tend to fix what is wrong, save my money, and put off the tough decisions until I have to make them.

[rkramer]

High miles but had a rebuild (not sure how long ago) in order to run as well as it does. However, just can't tell what was done when. This is mostly an attempt to A) save money and B) possibly eliminate a problem, or at least define it: where is the oil coming from? I know if I pull the head I'm going to want to do the entire thing. If I can replace the seals and stop an oil burning problem, then I can keep driving and rebuild the head later on my terms!

Thanks for the advice,

Originally Posted by Manolito

I'm gonna play the Devil's advocate here and argue the "if it ain't broke" point of view.

I have never done this particular engine, but I have put valve seals on several other engines, and I tend to favor the head-in-place procedure.

If the car is low-miles, and the only problem is the age of the seal, then there is no reason to spend the money to pull the head, as there is nothing else in there that needs to be done.

If the car is high miles, and the valves are loose in their guides, then just doing the seals will help, but is only a temporary fix, so you have to as yourself if you intend to drive this car another 10k miles or another 100k miles. Once you pull off the head, the tough questions start. Where to stop? Valve guides and seats? How do those cylinder bores look? Hone and new rings? Perhaps bore and new pistons? What about the bearings? Re-machine the crank?

I tend to fix what is wrong, save my money, and put off the tough decisions until I have to make them.