2008 R56 Mini Cooper S JCW. Mileage: 150,799 Despite mileage this is a meticulously maintained car with a full and comprehensive service history. It is a Mini Cooper S with dealer fit JCW extras (including certificate). During my ownership all maintenance/servicing has been completed by my local BMW Mini specialist (Burch Motor Works, Christchurch and the gearbox rebuilt by Gearlink (Salisbury). Any work that has been advised and needed to be completed has been done e.g timing chain, walnut blast of inlet valves, stem seals, clutch, turbo have all been replaced (see photos for more info). Unfortunately this week Burch Motor Works, have identified that cylinder 4 has low compression, 50 psi (all other cylinders are between 135-150 psi). The engine is running lumpy at idle and in first gear pulling away, and MPG is down and smoking a bit from the exhaust on acceleration, generally when driving. The engine when started and is running poorly/misfiring at idle. When driving and the engine RPM is raised, the misfire disappears and it drives smoothly. Slight blue smoke is intermittently present. Under load at low RPM was applied to attempt to misfire enough for the engine light to come on, but it did not. When the vehicle was in the workshop a diagnostic test was carried out, but no engine faults were stored; all was okay. Each ignition coil was disconnected to check which is causing the misfire, as it is suspected that cylinder 4 is causing the misfire/rough running. As suspected, the engine note did not change when unplugging cylinder 4's ignition coil, proving the fault is on this cylinder. A compression test was carried out on all cylinders and found compression down at 3.45 bar on cylinder 4, but the waveform is correct (have print out), proving the cylinder head valves are not leaking. A cylinder leakage test was carried out on cylinder 4 and found a leak is present into the crankcase; air is present when the oil filler cap or dipstick is removed. A borescope was applied into cylinder 4 to check piston and cylinder, no visual damage seen. A suspected chipped piston. This would make an excellent project for someone as so much work has already been completed. I am disappointed to be selling but time to get a bigger car. The car can be driven. MOT valid until April 2025. Two keys. See photos for information about modifications and maintenance. Private plate not for sale, original plate is BL08HPO . Please contact me for any further details.