So I have an r50(2003) with 250,000miles on the motor.
The midlands just blew up yesterday and a 6 speed swap was just about to be started. I am going to have a spare r53 engine and know the internals are different and are not a completely straight swap. My questions are two fold….

1. Can they head from the r53 be bolted onto the r50 without issue? I am aware the valves are different but through research have found the cam and head itself is the same.

2. can the block be stripped and rebuild using an r50 crank, rods, pistons, etc?


the purpose of this is to have a motor on the bench being built while I continue to drive the original motor in the car. The purpose of the vehicle itself is mostly commuting and autocross, so I would like to make it as reliable as I can.

Any advice is appreciated.

P.S. the guy that owns the donor R53(2003) put a Honda engine and AWD drivetrain in the r53, though it is not complete yet.

He stated the r53 engine was bad, though no specific information in regards to how it’s bad

 

If my memory serves me from a phone call with Jan from RMW the blocks are identical with the only difference being that the R53 block has oil squirters already installed and the R50 has the blocked tapped to accept them, they just aren't there.

Perhaps WMW can chime in and correct me if I am wrong.... I have been known to mix things up from time to time.

 

Yes you can put the R53 head on the R50 with no issue. The difference is the S exh valves are sodium filled as the non S ones aren't. So you can't put the R50 valves in the S, but the S to R50 is fine.

The blocks are the same just have to do some swapping around with the water pump flanges and pistons, oil jets and so on. But those are minor things.