M42club.com - Home of the BMW E30/E36 318i/iS

DISCUSSION => Engine + Driveline => Topic started by: peytonnoel on December 07, 2017, 01:33:52 PM

Title: M42 Upgrade Ideas
Post by: peytonnoel on December 07, 2017, 01:33:52 PM
So I've heard conflicting sides on whether the M42 has forged pistons and rods, do they or should I replace them with such? I plan to turbocharge the engine, head gasket is getting replaced now, new head studs, machining, hot tank. What else should I look into doing while I have the engine disassembled?
Title: Re: M42 Upgrade Ideas
Post by: DesktopDave on December 08, 2017, 08:04:06 PM
I've always understood that the M42 had a forged crank and rods, but cast pistons. The M44 is all cast. If you're lowering the compression ratio, definitely go forged. If you're keeping it stock CR, I've heard that a max of 6psi is advisable. I'm also told that Honda pistons are a good fit for turbocharged motors. Check out some of Warsteiner's posts for details.

I'd definitely replace the half thrust bearing with a full shell from an M50. I'd also be tempted to get a crank scraper. I think Ishihara has one.