Stroker M50: 3.1lt Can it be done?

[Stevin]

So i've been pondering this for a bit now.

I was thinking of using a 89.6mm throw crank from a M54 and 86mm pistons from a S50b30. That should give me 3.1lt.

I figure it should be possible but is it possible using all BMW parts? I'm not sure on the gudgeon pin heights, I know the M50 has a flat top piston while the S50 has a dished one. I also know these pistons can be machined down to a flat top (I did this in my m20 2.9lt stroker).

So this leaves me with the rods. I think that if I use the M52b28 or M20b25/ or S50b30 rods. The pistons will come out the bore by 1.5mm give or take.

Does any of this sound feasible?

[DanThe]

You wont be able to use S50 pistons on M52/M50/M20 rods as the gudgeon pins are different diameters.
Ive been considering a similar build myself, if I did I would be using custom rods to give maximum height

[Stevin]

You can just by machining a new small end bush. If I remember correctly from my M20 build the S50 piston has a smaller diameter gudgeon pin than the regular BMW's.

[bss325i]

A 3.2, 3.3 and 3.4 M50/M52 is possible.

[MarkT]

What combination of pistons, rods and crank for 3.4?

[Gunni]

custom, custom, custom as done by Hartge, AC Schnitzer or Racing Dynamcis,
I can´t remember who went the farthest.

[MarkT]

Ah so no OE route then!

[bss325i]

custom, custom, custom as done by Hartge, AC Schnitzer or Racing Dynamcis,
I can´t remember who went the farthest.

Alpina is the only one i know of to take an M52 to 3.4 with the engine used in the E46 B3S and Z4 roadster.

I have rebuilt one of these engines and yes custom crank, rods and pistons.

Even the head gasket is unique and that cost over £300!

[DanThe]

The rods in my B3 3.2 are custom, they have some German markings scratched into them

[jaistanley]

You could go to 3.2 easy enough if you bought an S52B32us set of crank, rods and pistons from the US couldn't you? Shipping on the crank would probably hurt a bit so you'd want to trust the yank selling it!

Jai

[StuMc316is]

So i've been pondering this for a bit now.

I was thinking of using a 89.6mm throw crank from a M54 and 86mm pistons from a S50b30. That should give me 3.1lt.

I figure it should be possible but is it possible using all BMW parts? I'm not sure on the gudgeon pin heights, I know the M50 has a flat top piston while the S50 has a dished one. I also know these pistons can be machined down to a flat top (I did this in my m20 2.9lt stroker).

So this leaves me with the rods. I think that if I use the M52b28 or M20b25/ or S50b30 rods. The pistons will come out the bore by 1.5mm give or take.

Does any of this sound feasible?

An 89.66 crank will work well with U.S. S50 pistons and 135 rods. The pistons will need machining, which gives you the ability to go ahead and set the c/r somewhere around 11:1 (maybe more, you might have better gas on your side of the pond.)

[alexbaby88]

You could go to 3.2 easy enough if you bought an S52B32us set of crank, rods and pistons from the US couldn't you? Shipping on the crank would probably hurt a bit so you'd want to trust the yank selling it!

Jai

Given that the M54 crank and S52US crank are identical, you might be able to save on shipping just the S52US pistons over from the US.

[jaistanley]

Given that the M54 crank and S52US crank are identical, you might be able to save on shipping just the S52US pistons over from the US.

That's a useful piece of info!

[booomer]

so if i wanted to make my e34 525i (m50) a 3 litre i'd definately need a crank from an m54/s52 but what other parts would i NEED for an OE conversion.

[alexbaby88]

so if i wanted to make my e34 525i (m50) a 3 litre i'd definately need a crank from an m54/s52 but what other parts would i NEED for an OE conversion.

You would also need the pistons and 135mm conrods from the M54 to convert your b x s to 84 x 89.6 and 3.0L displacement. Basically an iron blocked M50B30. If you could get your hands on an M52 (say from an E36 328i) alloy block you would shave off some weight from the front improving f/r weight distribution.

BTDT Cheers

[N00b]

Would the gains be worth the extra cost though, given that you can screw around 250bhp from an M52 2.8 fairly easily?

[booomer]

So all the parts i need are obtainable from the M54B30 engine and its the crank, con rods and piston heads?

[alexbaby88]

Would the gains be worth the extra cost though, given that you can screw around 250bhp from an M52 2.8 fairly easily?

If you think you can get 250 from a B28, what could you achieve with a B30?

For me the added torque was a significant improvement in daily driving environment.

[alexbaby88]

So all the parts i need are obtainable from the M54B30 engine and its the crank, con rods and piston heads?

Yes, plug and play. How much you decide to refresh your engine given you have it open is up to you (and your wallet).

For software you could use the USm3 chip (assuming you have the S50us cams)

[N00b]

Would the gains be worth the extra cost though, given that you can screw around 250bhp from an M52 2.8 fairly easily?

If you think you can get 250 from a B28, what could you achieve with a B30?

For me the added torque was a significant improvement in daily driving environment.

That's not my point though.
Ok Stroking it would make more than 250, but at what cost? You only really need a few hundred quids worth of parts to get the M52 into the 240-250bhp ball park, possible even 260bhp with the right cams, but crank/piston/rods etc take the costs up quite a lot. It's a bang for your buck argument, really.

[DanThe]

A pair of reasonable cams cost more than a few hundred quid

[Kos]

you need more than a few hundered quids worth of parts to get 250bhp on an m52 2.8, and you almost certainly need cams to get 250bhp.

235bhp is about the ball park for a 2.8 m52 with every bolt on mod and a decent map, maybe on good day you may nudge 240bhp.

[N00b]

A pair of reasonable cams cost more than a few hundred quid

Ok, but how much compared to the cost of a crank/rods/pistons.....plus if you've decided to stroke the motor you'd probably opt for changing the cams as well.

[DanThe]

A pair of schrick cams is approx £800, second hand stuff is cheaper but very hard to find, S52 cams approx £400

M54B30 stuff rarely comes up for sale as it is more likely to be repaired, ive dropped on a few lucky buys but generally its going to be expensive as its not that common

[N00b]

A pair of schrick cams is approx £800

Can you tell me why pretty much all of Schricks cams are so expensive?

[E30BeemerLad]

I think they are cut from blanks rather than just being reprofiled, but that could be t'intenet guff

[N00b]

I think they are cut from blanks rather than just being reprofiled, but that could be t'intenet guff

I suppose it the material they use is particularly exotic it could explain the price, but the profiles themselves could surely be copied as near as dammit by another company?

[DanThe]

They use BMW blanks, BMW US S52 cams are over £500 per cam, so in comparison they are not expensive

I believe Catcams are around £100 cheaper per cam than Schrick

[alexbaby88]

US S50/S52 cams come up for sale all the time on Bimmerforums at about USD300 +/- per pair. For a M50/52 stroker, you need not go with $hricks.

Using OE parts I reckon holding out for M54 rotating parts, US S50/52 cams is the most straightforward route to get 3.0L (+).

[ryan_gwa]

Sorry to dig up a relic thread, but I've had a M54B30 bottom end laying about for ages and want to do something with it.

Installing these into a M50 - is the only head option the M50?

Also want to clarify cams, Ive read rumours of being able to use the M54 inlet cam instead of forking out for Schrick?

[DanThe]

The M54 cam is nothing like a Schrick, I will post some pics later but here are a pair of Schricks with an M52 2.8 cam in the centre
These are going into a 3.0 M52 I am building for somebody at the moment

[ryan_gwa]

Some difference there!

Everything just pops into a m50/m52 without modification or spacers?

[Automaton]

I think they are cut from blanks rather than just being reprofiled, but that could be t'intenet guff

I suppose it the material they use is particularly exotic it could explain the price, but the profiles themselves could surely be copied as near as dammit by another company?

From www.bimmers.com:

"...The most well known aftermarket BMW cam manufacturer is Schrick. These are German cams made from new chill cast billets."