Hey guys I'm new to the whole Mini thing. I just bought an 06 mini R50 with a bad motor and I was wondering if the 03 R50 motor would swap in without changing any of the wiring harness. I know its an older motor but I found one for a great deal with 95k on it. Both the R50's are Manual. Is there anything I'd have to change on the 03 R50 for this to work? Thanks in advance!!!!

 

Yes it will be a direct swap since they are both an R50.
I would use the wiring harness from the 06 and it's accessories if they are lower mileage.

 

If the car is a manual make sure to stick with the flywheel off of your car, there are two different flywheels for the R50s between the Midland and Getrag trans, if you have the wrong flywheel in the car the clutch doesn't engage/disengage properly.

I'd recommend resurfacing the flywheel and possibly replacing the clutch while you're in there at that magnitude of a job.

 

thanks guys! i went to pick up the 06 yesterday turns out it was an S. I brought it home away. For such a low price i had to! I tired cranking it over but theres no compression. Pulled the spark plugs and the combustion cambers were full of anti freeze. I woke up this morning and pulled the head off. Everything looks good beside the gasket i can see where it blew between the cylinders so i dropped of the head to get resurfaced and pressure tested + new valve seals. the one thing i noticed was there was oil in the charged air plenum. I'm not very similar with S.C.s so I'm gonna do some digging around the forum. Any suggestions ?

 

A small amount of oil in the intake tract isn't uncommon.

What are your plans with the S engine? You'll not easily be able to run it in your car.

 

Having oil in the intake isn't uncommon? I'm looking into maybe rebuilding the S.C. or at least taking it apart this week and cleaning it up. I don't like the idea of oil making it into my intake manifold wouldn't that cause it to smoke ? But as far as it not being able to run in the car easily I think you misunderstood. The 06 I picked up ended up being a mini S R53. The photos I received before buying it weren't the best but after making the trip to the car I noticed it was the S. I purchased it from a family friend who couldn't tell me much about the car and assumed it was an R50 and because my lack of knowledge in Minis I couldn't tell the difference. The S badge on the hatch was removed the one photo of the driver side I received the fender side marker was missing as well. That's where my assumption of it being an R50 came from and she was sure if it was supercharged when asked.

 

Having a small amount of oil in the system isn't a big problem, it's a trait of the PCV system in these cars, but a significant amount is a problem.

Gotcha, from your original wording it came across as it being an R50 not a 53.

 

So both the car and the "new" motor are R53's? If so great! If the new motor is from an R50 that engine will not last long. Internals and exhaust valves are all different. Internals in the R53 are stronger in the R53 and the exhaust valves are different in the R50.

 

the car i picked up to fixed is a 06 MCS R53 and i purchased an 03 Mini non Supercharged R50 swap ( hope i got those numbers correct R50/R53 lol ) I have a friend who works at a well know auto salvage yard where I'm from and his system at work says these cylinder heads are identical. I'm going to do some research on the part numbers for the S and non S and see if in fact these internals are actually the same.

 

if not ill have a ton of parts for sale! lol

 

My understanding is the heads are the same, the exhaust valves are different on the R50 non-supercharged engine. The crank and the connecting rods are cast in the non-supercharged engine. The supercharged engine has forged crank and connecting rods. The piston heads in the supercharged engine are also different. I have no idea what will happen if you strap the supercharger on to the non-supercharged engine.

Compression for the non-supercharged is 10.something:1 and the supercharged is 8.somthing:1.

Again, my understanding is that the block, head, intake valves and cam are the same and will transfer over. The exhaust valves and the engine internals (crank, con-rods and piston heads) are different and will not transfer over. You could go R53 to R50 but not R50 to R53.

 

The way I see it is for those like the atmospheric engine it sux that no one make a good set of forged piston with 10.5:1 compression that you can drop into the R53 short block. This will allow you to use everything in the R53 engine and keep the compression ratio.

I suspect that even if you are willing to use the non-forged R50 piston, the wrist pin dimensions and height are likely not compatible with the R53 forged con-rod.

 

so if i did a valve job on the R50 cylinder head with R53 valves i should be able to run the R50 Head(with R53 valves) on the R53 block. I'd be basically creating a R53 head

 

I would advise be very careful with everything you read on the web. While many have pointed out the published differences of the R50 vs R52/R53 head there may be more than what meet the eyes. Just because Bentley said one is forged and the other is casted but with same valve sizes, there may be other surprises. The valve seats may be different, despite the same head casting. The valve stem guide may be different but should be a easy check. The valve seat grind angles (more than one) may be different, and a good auto machine shop should be able to tell you. The R53 OEM valves aren't cheap. Not being an insider it is hard to tell if the much cheaper "non-OEM" valves are inferior or just as good.

 

The exhaust valves in the R53 engine are probably made from a much more heat resistant material than on the R50 engine (stainless steel, Inconel, Titanium, etc.) They could also be sodium filled for cooling. Plus, the cam will be way different as well as the valve springs.

 

My head hurts from trying to understand all of this......so do we have two "S" engines?? One "S" and one "non-S" engine??.......are you swapping a "S" engine into a "non-S" car??

Inquiring minds, like mine would like to know exactly what's taking place here

Bryan

 

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