How to remove and replace a BMW M42 head.

[Phreon]

Okay, so bumping a way old thread for the sake of a previous comment I made.

I couldn't find the write up I mentioned. But I just did this last night.

I pulled the belts, and pulleys. I then pulled the harmonic balancer and associated parts. I was then able to pull the covers and reseal without removing the head.

But I had more fun then you taking the whole thing apart.

[MrAlan]

Great description mate, ive had a few problems and will def be using this for guidance thanks!

[kslb1]

First of all I'd like to thank the OP for posting this write-up.  It's among the most helpful I've seen regarding head removal on the M42.

I recently undertook the task myself, and now that I'm reassembling the engine I've run into an issue of concern.

I'm to the point where the engine spins fine without the chain tensioner installed, but one I install it I can only turn the motor over a couple of times before the engine binds up.  I'm not sure why.  Is this normal as oil flows into the tension unit?

If I loosen the 19mm hex cover that holds the tension device in place even a few threads the engine spins freely as it should, four whistles and back to TDC.

It seems like the chain is binding up under the modest oil flow from hand cranking the engine, and what's weird is that I can turn the motor over again after it sits for a few minutes.  I guess this might be normal, but I don't want to fire the engine until I know it will spin free with all of the timing gear installed.

Any advice from others who might have had the mixed fortune of completing this task before?

Cheers,

--Ben

[Geoff]

interesting write up,  thanks for taking the time.   One thing I found out that makes the job easier,  you had mentioned getting the headers off was a pain.
   You can also just remove the 4 bolts at the flange and leave the headers in place and just lift the head out with them on.  They can be removed easier afterwards,  or just left in place.
                                                Geoff

[kslb1]

For what little it's worth to future readers, I installed the tensioner without compressing it and it wouldn't allow the timing chain to move once it filled with oil. After it sat for a while and compressed, it turns out it was fine.