M88/s38 rebuild e28 m5 ,head gasget gone?what about stroking

[Brent in NZ Hartge 535i]

hi guys has anyone done a rebuild on a euro spec e28 m5 ,e24 m635csi or e23 M745i s38 engine .

i have a 86 e28 M535i with a s38/m8 engine fitted in it from a SA 85 e23 M745i .
i use the car on the track quite a lot .
and yesterday it looks like its done its headgasget after 24years and about 250,000km


so looking at maybe doing a bit of a rebuild on it .

maybe fitting the later e34 e32 e28 e24 crank from a 535i 735i engine .
to stroke it out like the later e34 m5 3.6l engine.

has anyone done this . doesn't look like there is to much difference between the M5 86mm stroke crank and the m30 86mm crank .
weight is close .
e28 m5 crank 28.2kg
e34 535i crank 29.5kg
e34 m5 3.6l 27.3kg

and what rods should i use the M5 rods seam be stronger lighter ones , maybe go after market or get the std m5 pistons machined down so they dont hit the head??
or go custom oversized ones made and bore the block out a bit .

i have not pulled the head off yet , but maybe also while we are in there fitting some over bore pistons??

i have acces to lots of old m30 engine parts from early 535i 635i etc also later blocks etc .



any thought woulb be appreciated ..

[mooseheadm5]

Using the longer stroke M30 crank will work, as this is what Metric Mechanic does to build a 3.6L S38 engine from a 3.5L here in the US, though I suspect that they lighten the crank. You will want to use the correct rods and pistons, and can contact paul burke here on the forum since he can get you whatever custom pistons you will want. I am planning to do this as well but I already have an S38B36 crank and rods. I would definitely not machine the piston tops.

[CSBM5]

hi guys has anyone done a rebuild on a euro spec e28 m5 ,e24 m635csi or e23 M745i s38 engine .

Interesting thread on topic: http://www.m5board.com/vbulletin/e28-m5 ... 231-a.html

...and follow-on thread on install: http://www.m5board.com/vbulletin/e28-m5 ... 1-a-2.html

[japandrew73]

hi guys has anyone done a rebuild on a euro spec e28 m5 ,e24 m635csi or e23 M745i s38 engine .

Interesting thread on topic: http://www.m5board.com/vbulletin/e28-m5 ... 231-a.html

...and follow-on thread on install: http://www.m5board.com/vbulletin/e28-m5 ... 1-a-2.html

I just read that whole thing while I'm at work. It's absolutely stunning the amount of work that went into that engine. It's very fun to watch!