Author Topic: S50 Piston Specs (Read 4423 times)

flyingbrickperformance · « **on:** November 05, 2007, 03:30:45 PM »

I'm building up a slightly stroked engine based on the M42 block, M44 crank, S50 pistons, and custom rods. For designing the rod specs, I'm trying to determine the compression height of the S50 pistons so that I can make the rods the correct length to avoid any piston machining, since this simplifies the build. Does anyone happen to have these? I have a set around they could measure, or have the specs on them? I don't have a caliper to measure mine, but they appear to be just about 1mm less than a M20 piston, just don't want to guess.

flyingbrickperformance · « **Reply #1 on:** November 05, 2007, 04:40:10 PM »

Nevermind - I found them on Mahle's site - they're 31mm exact. That's actually almost 3mm different than the m20's I have so something seems odd but I'll trust Mahle's site on this one.

[Edit] that doesn't appear to match after looking further. They're a bit different depending on a variation of factors. Mine appear to be 32.8mm after further research which seems closer to what I had thought based on a comparison to the M20 pistons.

Crille74 · « **Reply #2 on:** November 30, 2007, 05:15:20 AM »

M3 E36 euro 3,0 31,6mm its the same as stock m42b18
M3 E36 euro 3,2 32,8mm

koyota · « **Reply #3 on:** January 24, 2008, 03:35:38 AM »

Any idea, are there any BMW rods which will work with M42 pistons and M47 crank lenghtwise?