M30 stroker?

[Money$hit]

Has anyone concocted up a recipe for a stroked M30 yet? Ive searched but cant find anything. Ive heard M30s are beefy, torque laden and cheap, so why not stroke one?

[ZiMMie]

why stroke when u can boost?

[RickSloan]

why just stroke or boost when you can stroke AND boost???

but seriously i believe euroshark has spelled out several recipes as of late and before for a solid stroked M30

[der affe]

IIRC you can use an M-5 (S-38) crank in an M30B3.5 as a stroker.
i think it was MM that offers it, with whatever it takes to make the timing chain work.

[E30SPDFRK]

Start with an m90 (euro m30 from e28? I think) and put in a b35 crank. Comes out to around 3.7 iirc. Not exactly a stroker, though.

Euroshark would know best.

[BDK]

or you can do what I am doing...
M90 Block (you can use s38 too) to go out to 94-95mm bore,
a 90mm crank from the s38b38,
S38 rods,
Custom LTW Piston to go 10-1 CR
B35 head with 290 cam...
will put out around 300 hp and 300 ft/lbs tq with custom chip...
I have had the 90mm crank and rods for awhile, was waiting for a harmonic balancer to come along at a good price and finally found it...
No, it is not =to turbo numbers but it is a reliable, very solid, bullet proof, non boosted M30 motor...
I can't wait to feel this cranking my cabriolet

FWIW, both the B34/b35 use the same 86mm crank...M90 has 84mm stock

[moatilliatta]

where did you come across the b38 crank?

[Lurker27]

Any man will tell you being blown is better than being stroked.

[RickSloan]

but being stroked while blown is always the best ;)

[Good & Tight]

Any man will tell you being blown is better than being stroked.

But both at the same time is the best.

[BDK]

where did you come across the b38 crank?

I have connections in Germany and The Nederlands....

if you are wanting to do this,
I have an extra B38 harmonic balancer I will sell you for $250... they list over $600...

[moatilliatta]

You using the s38 rods to? ive herd about using some sbc rods to ;)

[euroshark]

Using an 86mm crank in an M90 block will get you 3535cc, the same measurement as the S38B36 since the two engines share the same 93.355mm bore. Honestly, you might see a slight difference in power and torque but it probably will not be very dramatic. I bet the most valuable gains will be seen in mid-range torque.

You can't bore the M30 blocks out too big because they don't have a huge amount of material between cylinders. BMW bored the S38B38 to 94.6mm and this is actually beyond the 94.0mm maximum that BMW engineers determined during the good old days of racing the M88 powered cars. The B38 has a 90mm stroke, so I'd think for maximum gains this is the recipe I'd use.

The problem that you run into using the long stroke cranks is that the rods and/or pistons are too tall and end up protruding from the block. M90 strokers typically pop out about 2-3mm, so most of those guys just have the piston tops shaved. With a 90mm crank I would think that you will need to use B38 rods and possibly even custom pistons. These measurements will get you in the high 3700 range and probably be a serious beast with all of that low and mid range torque.

[moatilliatta]

ive came across a set of 94mm pistons, i have to match it up and see if it will work. If i cant find the 90mm crank ill go lookin for a 88mm e9 crank. lol, both rare to come across here in the us.

[BDK]

Using an 86mm crank in an M90 block will get you 3535cc, the same measurement as the S38B36 since the two engines share the same 93.355mm bore. Honestly, you might see a slight difference in power and torque but it probably will not be very dramatic. I bet the most valuable gains will be seen in mid-range torque.

You can't bore the M30 blocks out too big because they don't have a huge amount of material between cylinders. BMW bored the S38B38 to 94.6mm and this is actually beyond the 94.0mm maximum that BMW engineers determined during the good old days of racing the M88 powered cars. The B38 has a 90mm stroke, so I'd think for maximum gains this is the recipe I'd use.

The problem that you run into using the long stroke cranks is that the rods and/or pistons are too tall and end up protruding from the block. M90 strokers typically pop out about 2-3mm, so most of those guys just have the piston tops shaved. With a 90mm crank I would think that you will need to use B38 rods and possibly even custom pistons. These measurements will get you in the high 3700 range and probably be a serious beast with all of that low and mid range torque.

all true ...

but by using the longer S38B36 rods instead of the b38 rods, it helps to reduces side load on the crank bearings,
I have parted prolly 5- partial S38B38 motors over the last 7yrs and they all have spun crank bearings. The B38 is known to do so after 65K and I have even seen complete motors with excessive bearing wear at 65K.
By using the longer rods, it should help with this plus I really don't want to be changing crank bearings every 65k, that's too much like a timing belt type thing.
You can use custom pistons to move the pin higher into the piston to allow for this clearance. Using a B35 head also helps due to the larger combustion chamber.
I want to use custom pistons for the weight savings too, the factory pistons are abut heavy compared to what is out there in custom LTW pistons.
Running a 290 cam with this set up should definately yield somewhere in the 300 squared range which is pretty damn good without all the turbo fuss and tinkering..

we'll know by spring what is what with this setup...