316i, 318i m40 heads

[charlie316]

Is the only difference in the 318i and the 316i m40 engines the stroke length? Is there any difference in the cylinder heads. eg size of the valves.

cheers.

[smithy318i]

I removed a cylinder head from a 318i and sold it to a guy who wanted to put it on his E36 316i.
He didnt complain so it must have fit.

[gcorky]

think heads are same from what i remember

[gcorky]

just checked head,camshaft same for both m40 engines...hth

[charlie316]

Thats great, cheers for the help.

[Brian28]

Slight topic drift. I'm reading this as to change a 316i M40 to 318i M40 spec, I'd need to use the 318 crank, otherwise they are the same? So 316i block, con rods, pistons, heads, valve size etc are all the same, just the 318 crank has a longer throw?

Thanks
Brian

[Brianmoooore]

There must be a difference in con rod length or pin height in the pistons, otherwise they would come out of the top of the block!

[charlie316]

As i understand the only difference is the stroke length in the bottom end, so there would be no gains made from fitting a 1.8 head onto a 1.6. So porting the head would be the way forward.

[mummy-boo]

i chainged my 316 head for a 318 head and felt a little differance (a few more power/revs at the top end was 4750 top now hit the rev liiter before i run out of power ) then fitted a high lift cam and felt a hell of a differance just put a 318 (bored out) throttle body and i'm hoping to feel a slight improvment.

[Brian28]

There must be a difference in con rod length or pin height in the pistons, otherwise they would come out of the top of the block!

Doh, was writing the question too early this morning! It's sounding like a bit too much aggro, plus if anybody ever appeals my car I'd like to be sure that the engine is all standard 318i just in case. Sounds like there could be quite a few bits to change, and I'm not sure if the pistons etc of the lump I have are any good to swap them over.

Cheers all
Brian