bmwe21.net forums

can anybody shed some light on this... are the e28 m30 3.5 heads interchangeable with the e12 3.5 block and vise versa ,and does this give a lower compresion ratio, and if any gain in performance.. or will the the cam from an e28 3.5 head (shrick 272) fit the e12 head??
Daniel.

?

you might have better luck with this on a old school 5 series forum / 6 series tbh dude - i for one dont have a clue -

what you could do i suppose is check part numbers on RealOEM perhaps?

e12 used a biggerbore for the pistons, but the head will bolt up, no idea on compression and the cams will not swap unless you upgrade the e12 to motronic.

The big differince in thease heads are the coolant ports and ignition(dizzy).
The older ignition system has/uses a gear on the front of the camshaft to drive the ignition dizzy while the e28 has the dizzy on the camshaft end.
The older M30/M90 engine has a double timing chain while the later has single.
So in short even tough the head bolts on you will have problems with the ignition system and the camshafts are not interchangeable between old/later style heads. There are three types of heads, all with a small change in the combustion chamber and design. L-jet & carb heads(e3,9,12,23,24) Motronic 1.0(E23,24,28) Motronic 1.3(e32,34). The early carb&L-jet M30 heads are weaker than the motronic ones, but the early blocks are stronger due to better casting and metal used, they are allso a bit heavyer.

cheers chaps... plan was to swap the bottom ends... ie e12 block with the e28 head... and continue using the exsisting mangement..
Have noticed a very slight knock on tick over from the current lump!