Greetings, working on my 2.9 stroker M50 swap.

[PiercedE30]

Is the 2.9L stroker option (using S50 crank) that much better than a 2.8L stroker (using M52 crank)? After all its only 0.1L. Plus you dont run into problems requiring mods to the pistons and M52 cranks are way cheaper and more easily available.

Even discounting the 2.8, why bother with the 2.9L when you can do a 3.0L stroker using S52 crank?

I'm coming from M50 vanos perspective of course.

Actually, if you run the math on everything, using a S50 crank only gains you 10 cc's per cylinder as opposed to using the M52 crank. If you go that route, which I am leaning towards, then it helps to bump down the compression enough to be able to use a stock thickness head gasket (hopefully, I still need to go out to my motor and check the deck clearance).

[adrock1]

I put one of these engines together at my shop for a customer in NJ. we used s50 crank and rods with .120mls headgasket from vac. also used s50 cams. this was a single vanos engine. the head was shaved that was the reason for the bigger headgasket. it's a pretty cool combo.

[alexbaby88]

M50 stroker

Is the 2.9L stroker option (using S50 crank) that much better than a 2.8L stroker (using M52 crank)? After all its only 0.1L. Plus you dont run into problems requiring mods to the pistons and M52 cranks are way cheaper and more easily available.

Even discounting the 2.8, why bother with the 2.9L when you can do a 3.0L stroker using S52 crank?

I'm coming from M50 vanos perspective of course.

[FredK]

He decided to go with a full S50 build after he discovered his M50 block had a taper to the cylinder bore. He got it bored to 86mm.

[PiercedE30]

Which is exactly why I decided to bump it.
Also, I have access to a 2.8L crank (84mm stroke). I threw it in my block with a NV rod/piston and the top of the piston actually sits 5mm (+/- .5mm) above the top of the block. Now, the top piston ring is only 9mm below the top of the piston leaving you with only 4mm of clearance from the piston ring to the block deck. If you use a 3.0L S50 crank (85.8mm stroke - correct me if I am wrong here) then you would have your piston sitting 5.9mm above the block deck and have only 3.1mm of clearance from the top piston ring to the block. That is cutting it REAL close.

[e30 gangsta]

this is a crapload of info...

[PiercedE30]

triggerhaapi: any update on your build? I am in the middle of mine and am looking to see what people are doing with theirs....

[SchnellerVert]

http://www.vacmotorsports.com/cgi-bin/view_cat.pl?cat=Engine+Components#Cylinder%20Head%20Gaskets

[tjhartge]

no no no....don't shave the head, just go ahead and get a 0.098" thick MLS head gasket to lower th compression to 11.45:1.

Pierce,

could you point me to the direction of a MLS thick head gasket?

[e30polak]

looks like everyone got off their intelligent pms and r back to normal...that was the longest, drawn out argument i've ever seen, i can't wait to see ur results on the car triggrhaapi, wish u all the best

[PiercedE30]

no no no....don't shave the head, just go ahead and get a 0.098" thick MLS head gasket to lower th compression to 11.45:1.

[tjhartge]

No grinding is needed, you only need to machine out the valve pockets by .45mm each.

so if i dont shave the cylinder head, i will get a very high compression then?

how about if a 11.3:1 is required, how much should shave the cylinder head off, and if i do shave it off, must the i machine the valve pockets further too?

[triggrhaapi]

I'm looking at doing the same 2.9 stroker, reason being the US version of the s50 is relatively easy to do the upgrade
Over on this side of the pond its practically non-existant, but thanks to DHL i can realise the 2.9l stroker

Would really appreciate the info ,especially the grinding down of the pistons and measurements.I'm looking to get 11.5:1 compression

No grinding is needed, you only need to machine out the valve pockets by .45mm each.

[tjhartge]

:rofl: Nice.

I really didn't want to be a dick about it at first but I have to admit I gave in to temptation in the end.

Yes, I do admit that this project has spun out of the cost stratosphere in terms of what I intended to pay, but I get a fresh motor out of it with brand new bores and everything. Plus I have to admit that I really enjoy tearing a motor apart and rebuilding it. I feel more like it's mine that way.

I'm done arguing, I've said my piece and I don't want to come off as an asshole at all. I'm here if you guys want to know absolutely anything about what I've done. This will be my second S50 rebuild, so I know the motor pretty well.

I'm looking at doing the same 2.9 stroker, reason being the US version of the s50 is relatively easy to do the upgrade
Over on this side of the pond its practically non-existant, but thanks to DHL i can realise the 2.9l stroker

Would really appreciate the info ,especially the grinding down of the pistons and measurements.I'm looking to get 11.5:1 compression

[triggrhaapi]

Mike and I aren't fighting...

:rofl: Nice.

I really didn't want to be a dick about it at first but I have to admit I gave in to temptation in the end.

Yes, I do admit that this project has spun out of the cost stratosphere in terms of what I intended to pay, but I get a fresh motor out of it with brand new bores and everything. Plus I have to admit that I really enjoy tearing a motor apart and rebuilding it. I feel more like it's mine that way.

I'm done arguing, I've said my piece and I don't want to come off as an asshole at all. I'm here if you guys want to know absolutely anything about what I've done. This will be my second S50 rebuild, so I know the motor pretty well.