M20 Forever

The e30’s clutch is starting to slip so it’s only a matter of time and miles before it falls out on the road and leaves me stranded. This would be the time to do a s52 engine swap but I’ve decided to buy a low-mileage donor m20 and have a clutch kit installed.

I have no logical explanation for reversing my decision: there was absolutely none, zero doubt in my mind that a s52 engine swap was the right thing to do up until three weeks ago. Something happened: I got sentimental. The pros and cons that I fabricated to pacify the logical side of my brain follow but ultimately this is an emotional decision. I like the m20. It seems like the right motor for me and the car: it’s modest, dignified and adequate.

I expect to pick up the new motor this weekend.

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Above: A clean example of the BMW M20 engine.

Pros of Staying M20


  • I’ll save about $6000 on parts and labor by sticking with the M20 motor. This is not my primary motivation but cash is always a consideration. The car needs so much more work: racing seats, dents pulled, paint, steering rack. There’s no shortage of other places to spend money besides the engine.
  • The m20 will not win any drag races but it has plenty of power especially in gears 2 and 3. To be completely honest it’s already more car than I can handle (as I learned at the last Car Control Clinic) and once my abilities match those of the car I can reconsider the swap.
  • The m20 is a great learner motor and I have everything yet to learn. It has fuel injection, modern fuel management, a computer and is easy to repair with minimal equipment. Anything newer will just be more complicated and harder to maintain for a novice like myself.
  • I could learn a lot doing an engine rebuild myself (someday). Once I’ve mastered that, learned all I can about m20s and enjoyed the results I could do the s52 swap and become an expert in that too. This appeals to me more than just paying someone else to do it now and learning little from it – one of my primary motivations in buying this car to begin with was to learn about cars.
  • The m20 looks like a motor. Perhaps this is the worst reason to choose an engine but I’m a visual person and I like the way the m20 looks. There’s wires, hoses and lots of moving parts. On the s52 everything is covered up.

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Above: s52 motor in an e30.

Pros of Going S52


  • Win drag races.
  • Ungodly amounts of power and acceleration.
  • Sounds like a wild animal!

The Possibilities…


  • There are other engines I like better than the s52. Like the s54 which I find to be an attractive looking motor that’s relatively servicable. If I wait then I may be able to afford that motor some day.
  • Waiting gives me a chance to get a place with my own garage and not only learn about the m20 but take on a new project car – perhaps even a dedicated track car.

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Above: s54 motor in an e30.

To be continued…

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April 5, 2013 status