M50B20TU 2.8 stroker (M54B30 crank) help please?

[szacsi72]

Okie guys, first of all sorry for posting this here but I didnt get any answer in the Engine Tuning section...

So I have an M50B20TU and i would like to make a stroker. Online I've read that you can just add in m52b28 rods and crankshaft. But I'd like a bit more. I want an M54B30 crank. What rods do i need to use to make it fit?
As far as I know the current rods are 145mm, and M54B30 has 135mm rods. Now, that means that the piston will go 1.8mm higher. That's already a problem, but an even bigger problem is the compression ratio.
By my calculation, it would be 19.66 and well thats no good.
With 130mm rods, the CR would be 10.14. That sounds pretty good to me. Maybe grind off 1mm off the block and its 11.18. Almost the same as the stock one.

So, in what engine can I find 130mm rods, to make this build complete? Has anyone ever done this, or is everybody using m52b28 cranks "only"?

Thanks in advance.
Dave

[szacsi72]

Edit: What if I would use a thicker head gasket (0.12" maybe?) and mill down 1mm from the top of the cylinders. Then I could use the 135mm rods of the M52B28 or the M54B30, which would make the build much easier.

[4dri4n]

You cant do that because you would rotate the cam sprockets as the chain remains the same length it had before removing 1 mm from the block.
Get your m50 block bored to 84; get a used head from an m50b25tu or m52b25 or b28 and then swap your m54 crank, rods and piston. Get a 413 red label and wiring for obd1 bosch and then you have a proper stroker.

[XCRN]

I don't know too much on the B20 but I am doing this on a B25. The compression height on the M54 pistons is lower and comes out to be about 1.5mm below the deck I believe, not above it. Again this is on a 2.5 block not a 2.0.

[szacsi72]

4dri4n: why would I mill down from the block? I said remove 1mm from the cylinder's top, to get less compression.