Re: Rebuild> To Stroke or not (archive)

That all seems pretty interesting, but what about keeping the 3453cc of the engine and mod it a bit so it would match the 34*bhp of the later M5s (I don't mean the contemporary V8s of course)? It's basically the same engine, so there shouldn't be much to change (maybe in the injection system, plugs, etc...). Does anyone know how to do this?

The E35 M5 engine has a LONGER STROKE than the E28 M5 engine. You can easily drop the later S38B36 (3.6L) crankshaft into the S38B35. You should also use the E34 harmonic balancer.

The 1993+ Euro M5 had an even longer stroke to bring it to 3.8L. Dinan stroked the E28 M5 engine up to 3.88L and then even slapped a turbo on it to get 575HP. They deemed it couldn't handle the power, so it was tuned to put out 475HP at the crank. There is one for sale on eBay right now, too.

Of course, stroking or even *rebuilding* the S38 is REALLY EXPENSIVE. Cams are a PITA on the US head, as the Schrick cams have too much lift and require machining the cam-box to clear the lobes. Custom forged pistons with higher compression ratio are cheaper than factory pistons. Rings, bearings, and seals can all be sourced from resellers. The problem is tuning it all. If you want serious power, you should either consider the Split Second MAF kit or a complete E34 M5 engine swap. The only complications I know of are the passenger side engine mount and the air-inlet to the intake plenum. You will have to move the PS reservoir, but that's easy. You will get 315HP from the factory, bigger throttles, bigger headers, bigger cams, better torque, and it can be chipped to 330HP easily. You'll need the engine wiring, brain, and complete engine. Then you can SELL your good, running E28 M5 engine, brain and wiring for a small fortune to any E24/E28 guy.

JamesM
JamesM

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