hello I want to build a 3l m20 for my 323i

what do I need ?



thanks

maarten

Take your stock e21 323i engine and fuel system and throw it in the trash.
Take an 1989 e30 325i engine, as a 2.5 liter as a starting point.
By an S50 e36 m3 crank that is 86mm. Buy S50 rods,
bore your block 85mm or 86 mm. You need custom pistons.

If you bore your block 85 mm, with the s50 crank than you have a 2.9 liter M20.
If you bore your block 86 mm you have a 3.0 m20 stroker.

You need bigger 19lb mustang injectors and the 325i Motronic fuel system to fuel the new stroker.

im still debating whether to do that or the 2.8! im slapping a turbo as well! so...ya!

hello I want to build a 3l m20 for my 323i

what do I need ?



thanks

maarten

Money!

I have seen on this forum that somebody used m42 pistons dus that fit ?

thanks maarten

Metric mechanic makes custom pistons that fit.

Forget M40, M42 pistons.

You need specific forged pistons based up the stroke and bore.
So If you have bored it 85 mm, and your crank is the s50 86mm,
than you give that to you machine shop and he will order them for you.
CP, JE and WEISCO offer these pistons.

Most people do not got more than 85 mm, although I have heard of 86mm.

Money!

Yes thats true brother

Metric Mechanic offers stroker M20s, so does Korman, and Pete Mchenry.
Why pay them when you can do your own? MM wants about 10k for an M20 3.0liter
and its not worth it IMO.

and pistons of the s50 will that fit to?

and pistons of the s50 will that fit to?

S50 Rods, and S50 crank.
I do not know if S50 pistons will work, but since they are going into an
m20 i do not think so. :nono
I can get the correct pistons - they are custom forged Weisco ones,
from my machine shop R&L engines for aprox $950 USA.
Metric Mechanic also sells the correct pistons.
Any good engine building shop should be able to supply you with them.