M42 build

[m42'd]

Hello, I have a 91 325i that has a 318i drivetrain. Weird but I actually like it. I have owned "fast" cars but with this I'd like to build a really well balanced light car instead of the normal route of m5x or s5x swap and make the nose 200lbs heavier. the car already has the suspension sorted, where do I start with a build? Should I source a spare m42 long block to start with? Does it matter if is the obdii e36 version? Anyone have a shopping list other than drop $9k on a metric mechanic motor? I would honestly consider that route if they weren't so damn far away. Pleas drop the m42 knowledge on me lol. I know it's not ideal my end goal is 180-200hp and light as possible.

Thanks

[word is bond]

Head over to m42club.com
There are a bunch of builds over there that fit your description and plenty of advice. Hope you start a thread here or there once you get going!

[roguetoaster]

The first step in considering an M42 engine build should really be the crankshaft. If you can go M47/do the work/expense required there, great, if not consider a build based around a stock crank.

If you don't want to build an engine, but would rather have more power without a big weight penalty consider a mild turbo kit, a jakeb for example.

[m42'd]

I do have an m42club forum account but they seem pretty dead over there. I don't really want to deal with turbo issues, I have had many Fi cars currently daily a 400whp 335i. So far I have done an intake , conforti chip, and long tubes. The rest is all suspension mods. Really I'd like to be able to keep up with the brz frs in autox without Fi or a heavy 24v swap. We also have a e36 m3 but before I start toying with that I want to start a light weight build path. Not sure where to pick up a m47 crank. Wasn't that a diesel we never got in the USA?

[m42'd]

Cars..

[benz-tech]

If I had mine to do over again, I'd do it all exactly how I did it, minus a bit lower compression. I should have listened to MM and milled the S50 pistons flat to the dish to end up around 10.7:1. Realistically its in the strong 160-170 hp range with a broad usable torque curve. Real cams would help. Anyway, its great for a daily commuter, not-so-much for winning races. There's a build thread here and on m42.com. HTH

[varg]

A small turbo would be a lot lighter (for your wallet) than trying to get 180whp out of an NA M42. A turbo setup adds 30lbs+ though, even though you could do that with a 60 trim T3 and a small intercooler. From what I've seen you have to do pretty much everything it's possible to do to an NA engine to get 100hp/l out of the M42.