M20 swap help

[tjclemens2]

Hello,
I’m looking to buy a used m20b25 for a swap and I have a few questions. First off, is there a big difference in performance between the 12v and 24v. I was told 24v came in the 325i and z1 and the 12v came of the 5 series 525i. Also if I buy a used m20, what should I go through and check? Should I tear the whole engine down and do a complete check? I want this thing to look nice and to be reliable but I don’t want to drop thousands to rebuild it if it’s not necessary. Finally what are the major fail points of the M20 just so that when I have it out on the engine stand I can do all of the work that needs to be done to make it super reliable!

Thanks!!

[jbontke]

I think you should start reading up on BMW engines. Start with Wikipedia, its simple and will list the engines and cars the engine came in: https://en.wikipedia.org/wiki/List_of_BMW_engines

Power is subjective to the car. 180hp in an e30 will be much different than 180hp in a 1998 740i. The e30 doesn't need much power to be a handful.

You bought a BMW, spending thousands is what we do for reliability. The cheaper the parts, the less reliability you purchase.

The M20 timing belt will should be replaced as the the valves and pistons will make contact causing more expensive repairs. I have ran my e30 with lots of oil leaks and basic maintenance, without a rebuild. It runs great. You may not need a rebuild.