M50 Limits

[dicko]

I have just got a non vanos m50 engine to work on for my super charger project ,
I hear the non vanos valve train is stronger than it vanos version,
What is the safe rev limit for one of these engines ,
I am also thinking of fitting a m51 tds crank and using m20 b20 rods ,this will lower c/r a little and stroke it out to 2.75 liter .

Is it true that m20 b20 rods are 5mm shorter than b25 rods ?
I will be fitting a MLS headgasket and ARP bolts , Should I invest in forged rod aswell ?

I am also thinking of reboring the block to take S50 86mm pistons as I presume the bores aret great , any one know where to get these or better ?

Now there is a few questions for all you master engine builders .

My goal is to get about 300/330 bhp and loads or torque with a eaton m90 and home made intake manifold with built in charge cooler ,
I will also be fitting a s50 exhaust manifold

[DanThe]

You dont really want to be going over 7k too much, the E36 1.9 engines use 85 or 86mm pistons, overboring is a good idea if you are changing stroke

[Jhonno]

I am breaking an S50 lump.. So have 6 good pistons

[Ant]

or leave the CR as is, use factory O/S Headgasket and enjoy..

M50 non TU is a strong engine, I have one on the stand with 301K on it, bores are perfect to factory dims, shells were dirty but unscored too.


cant see the logic in a capacity increase TBH, the M90 will give 100% VE 100% of the time so negates the effect of the stroker/overbore really, so unless your bores/pistons are V badly worn I'd offer an alternative...

Rebuild with new shells, oil pump, rings and enjoy ! ARP the rods for a screamer if you want belt and braces.

S50B30 manifold modded to suit would be all thats required on the hotside.

[dicko]

Thanks lads , Jhonno am intersted in them pistons , I will have a look at bores first ,to see how they are .What sort of money are you looking for .

Ant what sort of Boost do you reckon standard c/r is safe for , I was going to change shells and ARP the rods and head ,

Dan you reckon 7 k is a safe limit once you are sensible ,

Would i need to Arp main Bearing as well or is that over kill.

[Jhonno]

£20 a piston +P&P