my stroker recipe: good/bad?

[guibo09]

well you're talking about the S50B32.. which is an entirely different engine from the S52. the bearing journals are a different diameter as is basically everything about that motor. You can't use an S50B32 crank in an M20 block anyway, but the S52B32 crank does fit.

ah yes that makes alot of sense. so to summarise, S50B30 (85.8 ) and S52B32 (89.1) both work in an m20. the S50B32 (91) is no good for the m20.

[nando]

well you're talking about the S50B32.. which is an entirely different engine from the S52. the bearing journals are a different diameter as is basically everything about that motor. You can't use an S50B32 crank in an M20 block anyway, but the S52B32 crank does fit.

[guibo09]

I think it's closer to 89.6mm. but why are you so set on the S50 crank? the S52 crank will work too.

here are some unverified specs i picked up

engine / (bore x stroke) / displacement / displacement with 86mm bore
s50b30 86x85.8 2990cc (2990)
s50b32 86.4x91 3201cc (3171)
s52b32 86.4x89.6 3152cc (3122)

ive never seen anyone use a 91mm, i think there is not enough height on an m20 engine for it to work. i would prefer the s50 crank because it will produce a fairly square engine vs the 89.6 crank. it is also lighter and wont require clearancing cuts on the m20 block. but i guess if a s52 crank falls in my hands i wont say no.

[nando]

I think it's closer to 89.6mm. but why are you so set on the S50 crank? the S52 crank will work too.

[guibo09]

I know a guy with a s50 crank, Im not sure on shipping to canada though.
I will talk with him.

its gotta be from the 3.0L though, the s50b32 crank is 91mm i believe.

[e30this]

I know a guy with a s50 crank, Im not sure on shipping to canada though.
I will talk with him.

[guibo09]

thanks e30this for the killer photo!! :-D

yeah looking at the photo i can see why the 135mm are more popular, the 140mm look pretty much like the stock m20 rods, thick and heavy. i wouldnt be suprised if they are even heavier than the m20 rods.

so i guess i will go with 135 rods, hopefully i can pick up a crank and rod set from a s50b30.

[e30this]

140mm M50B25 vanos rods on the left and 135mm M54B30 rods on the right.

[asubimmer]

No vanos M50s have 140mm rods.


rod lengths:
M50B20: 135mm (non VANOS engine)
M50B20: 145mm
M50B25TU: 140 mm
M50B25: 135 mm (non VANOS engine)
M52B25: 135 mm
M52B28: 135 mm
M54B30: 135 mm
M20B20: 130 mm
M20B23: 130 mm
M20B25: 135 mm
M20B27: 130 mm

[Jesse30]

135mm rods will work fine just have your pistons made to work with them. 140mm wouldnt be worth much more effort.


i hate plugging their parts all the time but i've had a lot of time looking at the rods that ireland sells. get their 135mm forged rods. affordable and they get shit done. :D

they may even sell a 140mm if your really really keen on that idea.

[SpecM]

ok, I've been wrong before

[guibo09]

ah, it's the choked out M50B25 "puke update" motor that has 140mm rods.

I think it would be easier to use 135mm rods and just have the pistons made to match them.. the both the S50 and S52 use that same length anyway.

i think if i source the s50 crank and it comes with rods ill probably just stop my search there and use 135mm.

but if i do fall onto 140mm, i think i would be tempted to use them. a longer rod is always better unless they are much heavier than the 135mm. anyone have weight specs for the 140mm? i know the 135mm weigh 565g.

[nando]

ah, it's the choked out M50B25 "puke update" motor that has 140mm rods.

I think it would be easier to use 135mm rods and just have the pistons made to match them.. the both the S50 and S52 use that same length anyway.

[e30this]

No vanos M50s have 140mm rods.


rod lengths:
M50B25TU: 140 mm
M50B25: 135 mm (non VANOS engine)
M52B25: 135 mm
M52B28: 135 mm
M54B30: 135 mm
M20B20: 130 mm
M20B23: 130 mm
M20B25: 135 mm
M20B27: 130 mm

[nando]

AFAIK all M50s have 135mm rods. Maybe the M42 has 140mm? in any case MM specs a specific rod for their pistons and I think it's even longer than 140mm.

sounds like a decent build though!