nebie m42 vs m44 tech question

[Froos]

Hi guys,
New member here from Belgium. Can anybody confirm to me that the m42 has a 84mm stroke and an m44 a 83.5mm stroke? Is it possible to fit m44 cranck+pistons into a bored out m42 block and get a little extra displacement?
TIA
Friso

[Dan318-is]

you dont need any boring out etc.

the m44 crank will go straight on to give a 1.9 displacement, but in terms of build quality is inferior to the m42 crank (m4 is forged crank)

Cant remeber if you use m42 or m44 pistons though

[tim_s]

this thread's confusing! and tut tut dan you're wrong!
m42 stroke = 81mm, m44 stroke 83.5mm
to get an m42 to m44 displacement you need m44 crank and pistons, plus it will need a rebore!

[tim_s]

and the m44 crank is alright. the m42 is nicer, but the m44 one is fine. ok so not fully counterbalanced, but its proven to be v strong and reliable etc, and is lighter by virtue of the less counterbalances! unless you're going to be running stupid rpms (which you won't cos of hyd lifters, vib damper etc) the m44 crank is just the job!

[Dan318-is]

So what pistons go straight in?

[will325is]

http://dave.maisenhelder.com/bmw/Files/engines.htm

here you will find dimensions of all BMW engines

[tim_s]

a few bmw pistons physically fit, depends what you're trying to achieve with them though obviously mate. not sure what you're driving at lol!

[Froos]

Aight thx for that info, the reason im askin is because my "new" is engine has 179K km on it and was thinking about "servicing" it some new parts(pistons/cranck/rings and rods) which are offered for not that much $$. Ill sleep over it thou.
Good to see that you guys reply fast!!!

[will325is]

the M44 crank has a 83.5 throw which is the biggest of M4 engines and a 85mm piston which is also biggest in M4 engines nothing for you to stroke or bore with, well e46 stuff is bigger but thats not an option you would just swap whole lump

[Froos]

Eh I dont get you on that last bit?