I'm sure this has been discussed but my search skills obviously aren't up to par. I've got an opportunity to pick up a spare engine for my '04 R53 for $150 but it's out of a 2002 R50. Is the only difference between the R50 and R53 the supercharger and intake or is there something more that prevent this engine from being useful to me down the road?

 

 

I think he means as far as mounting it up, are the engine mounts the same, ecu, harnesses,etc.

 

Thanks Dave! I suppose if the block and heads were the same I could buy a forged rotating assembly but that wouldn't make sense financially. I'll just keep my eyes peeled for a proper S motor. Mine is running fine but getting up there in miles and I have an LSD trans waiting to swap in so I thought I might build a higher HP engine on the bench at the same time and just swap it all together.

 

the exhaust valves are different, the R53 has piston oilers, and I believe the crank at the rear may be different, where the pilot bearing would go, the R53 rods and pistons are forged, I'm unsure about the block casing, there may be no facility to attach the oilers, the head castings are the same though, and the camshaft, and rockers and shafts.

 

An R50 complete motor for 150$ is not a bad deal. If you are going to build out a race motor or really strong street motor, it is a great cheap start.
The Bock and the Head are the same. As Dave mentioned all the internals are way too weak to use. You would need a Crank from a R53 or a billet unit, Forged Rods and Forged Pistons. If you are sending the head out for a big valve and porting they are going to throw the valves out anyway.

I have done this a couple of times so if you have questions feel free to post them here.