'92 M50 - 2.9L Stroker Project

[uber e36]

Anyone have experience with this? I'm looking into doing this in the next year or so...

-Geoff

[Furious]

talk to thinair, he gave me my info on it. i did a bit of research on it 2 years ago, its a good project to look into.

[SpeedInfusion]

Originally Posted by geoff@bmw

Anyone have experience with this? I'm looking into doing this in the next year or so...

-Geoff

i was thinking about doing it....jason (triggerhappi) knows a good deal about it...

[triggrhaapi]

Here's what you need:

S50 crankshaft
shorter pistons (preferably from the M54, but the M52b28 will work if you machine the valve pits in them)
new bearings
S50 ECU/Software modified to remove VANOS control/tuned to run 244/242 camshafts.

[uber e36]

Have you done this, or you've just researched it?

I thought all you needed was:
- S50 Crankshaft
- S50 Connecting Rods

I thought that additional modifications for more power (but not necessary) included:
- Pistons
- Cams

[triggrhaapi]

Originally Posted by geoff@bmw

Have you done this, or you've just researched it?

I thought all you needed was:
- S50 Crankshaft
- S50 Connecting Rods

I thought that additional modifications for more power (but not necessary) included:
- Pistons
- Cams

I'm doing a 3.0L M52 stroker which is the same exact thing but the OBD II bottom end. I'm using an S50 head, the block from a M52B25, an S52 crank, M50NV rods, machined pistons (11.5:1), new bearings, seals and head gasket, OBD I harness/ sensors, S50 ECU, S50 TMS software with S50 injectors.

I know quite a bit about this stuff.

[uber e36]

I was told that the M50NV will not accept S50/2 Camshafts. Do you know if this is true?

I wanted to go with the M50NV engine with the addition of S50 Cranks. But if this is true, then I'm probably best to go with M50 (with vanos) with S50 Crank, M50NV Rods and S50/2 Cams.

[uber e36]

More research has confirmed what I said above.

So looks like this is my gameplan:
- M50B25TU engine
- M50B25 rods
- M50B30 crank
- M50B30 cams

[uber e36]

Well cams are ordered and will go in this fall/winter.

I've started sourcing the parts for the stroker (just bought M50NV rods) and that will happen in the spring (if I have a daily driver) or next winter.

triggrhappi....

Regarding the pistons, you suggest S54 or M52b28. I planned to use my M50b25TU pistons and shave them 0.4mm. Is there a reason you would suggest the others over my plan?

[uber e36]

You can follow up on 2.9L Stroker info here: Rob's Not-so-FI Build (2.9L Stroker) - Bimmerforums - The Ultimate BMW Forum

[triggrhaapi]

Originally Posted by geoff@bmw

Well cams are ordered and will go in this fall/winter.

I've started sourcing the parts for the stroker (just bought M50NV rods) and that will happen in the spring (if I have a daily driver) or next winter.

triggrhappi....

Regarding the pistons, you suggest S54 or M52b28. I planned to use my M50b25TU pistons and shave them 0.4mm. Is there a reason you would suggest the others over my plan?

Don't use S54 pistons, they're too big. You need 330ci pistons (M54)

[theruss1an1]

Originally Posted by triggrhaapi

Don't use S54 pistons, they're too big. You need 330ci pistons (M54)

Wait those are e46 pistons... Im confused... Those work?

-Serge

[uber e36]

M54 Pistons eh... So the M54 pistons are 84mm?

I would be interested to see what the difference in distance between the top of the piston and the top of the wristpin is.

Do you suggest these pistons because they are shorter than the M50TU pistons, and therefore no shaving is necessary?

-Geoff

[triggrhaapi]

Originally Posted by geoff@bmw

M54 Pistons eh... So the M54 pistons are 84mm?

I would be interested to see what the difference in distance between the top of the piston and the top of the wristpin is.

Do you suggest these pistons because they are shorter than the M50TU pistons, and therefore no shaving is necessary?

-Geoff

Yes, and yes.

[robstah]

Jason, maybe you can help me out in my current pickle of a situation. Right now I was trying to build a 2.9L non-vanos stroker. Here's the cut down parts list:

- Non-vanos head, stock cams
- Non-vanos block
- Vanos pistons
- Non-vanos rods (135mm)
- S50 Crank

Now, with this setup, we are looking at a 12.45:1CR if I leave everything else stock. Now, to get 11.4:1CR, I can shave .7mm off of each piston top, or go with a .098" MLS headgasket. So I have that planned out. Now, the thing that has been stopping me is the stupid block. The first non-vanos block had a big nick in one of the cylinder walls (new coffee table), The next vanos block in which I got the pistons from had ridges, so a bore is required and I can not use the stock pistons (new coffee table), and the non-vanos one I just recieved via Fedex has a broken water pump ledge (happened in shipping, looks like another coffee table).

Now, my situation is either I get the vanos block with ridges bored to 86mm and go 3.0L instead (I do have S50 pistons), find someway to repair the non-vanos block, or find another block. The boring is an issue because it's hard to find someone willing to overbore +2mm, and I can only find a set of piston rings for 100 a set, meaning 600 just for piston rings. I can see if I can get the water pump area welded back together, but I worry about later on issues with that, and so on. I am just stuck and I am in dire need of some direction and help.

Here is the picture of the broken block (thank you Fedex!):



Help...