Just a little FYI for those with the R53 S model. 130K always well maintained and running like a champ lost compression in cylinder 3. cyl 1. = 150 cyl 2. = 150 cyl 3. = 70 cyl 4. = 150
Thought it was bad wires or plugs until a compression test showed otherwise, pulled the head and cyl 3 intake valve was not sealing correctly. I tested this by turning the head upside down and filling the all the compression chambers with kerosene. Only cyl 3 chamber drained after a few minutes. Local machine shop did a clean up and valve job and seals for under 250.00, will be assembling shortly with new gaskets, bolts and injectors. keep you all posted.

 

Thanks for the info. Same happened to my 2003 R50 with about 110K miles. The "Service Engine Soon" light came on with the code for Misfire in cylinder #3. Replaced the plugs, wires, and coil. The connector on the old coil for #3 was indeed corroded so that looked like the problem. Cleared the code, but the light came back on again. Did the compression test and saw the same thing as you, where #3 was under 100.

Took the car to my local mechanic, they removed the head, saw the burnt valve, and sent the head to a machine shop. A day or two later I got the news from the machine shop that they could not obtain the valve seals - supposedly could not be ordered anywhere. This was about a year and a half ago. Googled for re-manufactured R50 cylinder heads and found a place in Florida named Clearwater Cylinder Heads selling them for $695. RockAuto had them for $900. Bought one from Clearwater and had it shipped to the local shop. Total bill was about $2500, which included the head, local shop labor, and couple other things they found, including a broken motor mount.

After the fix, I drove the car more than another year with no issues. Recently sold it on Craigslist for $2500 because I just didn't trust it as a daily driver any more, and replaced it with a 2015 F56.

 

[QUOTE=wjones14;4513304]Thanks for the info. Same happened to my 2003 R50 with about 110K miles. The "Service Engine Soon" light came on with the code for Misfire in cylinder #3. Replaced the plugs, wires, and coil. The connector on the old coil for #3 was indeed corroded so that looked like the problem. Cleared the code, but the light came back on again. Did the compression test and saw the same thing as you, where #3 was under 100.

Took the car to my local mechanic, they removed the head, saw the burnt valve, and sent the head to a machine shop. A day or two later I got the news from the machine shop that they could not obtain the valve seals - supposedly could not be ordered anywhere. This was about a year and a half ago. Googled for re-manufactured R50 cylinder heads and found a place in Florida named Clearwater Cylinder Heads selling them for $695. RockAuto had them for $900. Bought one from Clearwater and had it shipped to the local shop. Total bill was about $2500, which included the head, local shop labor, and couple other things they found, including a broken motor mount.

LOL, mirror image of my issue and failed repair. I shopped on ebay for heads and yes Clear water cyl was one of several for $599 exchange. Since I am doing the repair myself ( bought the timing tool ) should cost under 600.00

 

After several days of waiting for all the parts to arrive I started the reassembly process. Taking my time and dbl checking every step I am very close to being done. All in all not a difficult job, I need to button up the electrical and air box, mount the front wheel and add fluids. I'm stuck working a dbl shift today or I would have had it done tonight. keep you all posted.

 

The Mini is back and running great. My cost was under $600.00 and that's including the cam sprocket holding tool and rebuilt upgraded injectors. I have not checked compression but will at a later time. Happy its all done.