- 02/02/2017
- 2 Min Read
- By: Michael Hurczyn
Picking a Donor Engine for the FCP Euro BMW E30 Endurance Race Car
In case you haven't read the article yet, we broke a connecting rod in our relatively stock BMW M20B25 during our last race at Watkins Glen. The engine may still be salvageable, but with only about a month before our next race at Palmer Motorsports Park, I thought it may be best to find a good donor engine versus machining the existing hardware.
There are so many variations of BMW 325i e30 engine swaps out there. Obviously the easiest thing to do would be to stick in another M20B25. The car is, after all, built to Spec E30 rules, however, since I don't think the car will be raced in Spec E30 anytime soon, so why not go for a little more power?
So, the search for power begins, but that is not the only factor. The criteria for me is simple- It needs to be cheap, it needs to be able to be installed quickly, and I want to be able to reuse as many existing parts as possible.
I've always wanted to do a M60 V8 swap, but I don't think it meets any of my criteria at the moment, but that sound...
A very common E30 swap is to use an M50/52 or S50/52. The S52 route is very tempting, but it has more power than the rest of the car's suspension and braking capabilities at the moment. Being able to adequetly handle the available power is more important than the power itself.
The M50 conversion, especially one from an early OBD1 car, was a very viable option. Only minor modifications needed to be made to the car such as the brake booster delete or relocation, but I didn't want to deal with sourcing a transmission and drive shaft, and plus I have so many spare parts for M20's.
So I decided to stick to the M20 route. I looked at a few cheap cars on Craigslist, but they all seems like to much of a headache or with unknown history.
My friend referred me to his friend that had a 1986 325e with a M20B25 swap. The engine has a built head (cam, springs, port, etc...). The car runs and drives but the body is rusting away. I didn't need all of the parts on the car, so for $1500 I could have gotten most of what I need, However, after seeing it in person and driving it, and doing a compression test, it was not what I was looking for.
Ben McGilliard, who helped crew at the first race, is an E30 guru. Actually, I'd say he's an 80's and 90's BMW guru. He suggested we look for an 1988 Super ETA motor out of an E28 528e. Well, actually, he just went an bought a $400 1988 BMW 528e with good compression numbers knowing it's not going to get much better than this:
Looks rough, I know, but if the car was maintained well, the engines are pretty much babied since they don't rev past 4800 RPM. As long as it never ran out of oil, the bottom end should be in fine shape. The Super ETA came with an 885 head which is the same as a "i" motor, but used different valve springs, a different cam, and different intake manifold. If you'd like more details, this page is a pretty comprehensive resource.
Last night we had a dismantling party. We got the motor out in about 2 hours. Having a lift and a forklift made things go faster too.
Yes, that's FCP Euro's own Gareth Foley, BMW Catalog Manager, lending a helping hand!
And there is the crime scene- Engine out and ready for disassembly! Shortly, I'll have it on an engine stand and start taking off the accesories, and remove the head. It will need to be cleaned and I will check the head for cracks, but I should be reaching out to Gareth before the end of the week and ordering all new seals, gaskets and valvetrain components. FCP Euro already has seal kits put together and available on their website, but it's reassuring to know that they have knowledgable people available to answer questions.
