Using 731 head compared to standard 200 head

[Atle_323i]

After having 200 heads fail on two occasions due to cracks under the cams I gave up and fitted a 731 head. There were no problems at all with this install other than the inlet ports being larger, so I used the e30 gaskets.

I had 3x 200 heads in my stock, two had visible cracks under the camshaft, the third looked good, I even had it crack tested but it also failed, I believe the action of just torquing down the head can cause it to crack from my experience.

Incidentally when building a 2.7 its the 855 head which is preferred.

Is the 731 head more durable than the 200 head, when it comes to crack, or is it just the same head quality?

[hans25]

The 731 and 200 cylinder heads, found on BMW M20 engines, are generally considered to have the same level of durability when it comes to cracking.

[e21Keith]

Maybe, but that's not my experience. I've seen three cracked 200 heads, zero cracked 731 heads and zero 885 heads. I've owned over 30 BMWs with the M20 engine.

[uwbuurman]

Well, that 885 head will crack. Mine did. A little bit of over heating and it was gone.

I bought an AMC head. Those are thicker and more solid. There are a few forums on the internet that discuss the differences between them

[Atle_323i]

Thanks alot for all the feed back guys. I learned alot about different heads etc for M20 engines.