On re-assembly of the cylinder head it became apparant that i had an issue with the standard camshafts not allowing the inlet valve to fully close. After some head scratching i realised this was due to the seats having to be dropped in the head when skimming the head face to get the combustion chamber volumes as per the engines desired compression ratio. The seat being dropped allowed the valve, bucket and shim to move up closer to the base circle of the cam lobe thus when the cam was rotated and i should of been measuring a valve gap i still had a valve that was open and the shim was still in contact with the base circle of the cam lobe.
After many option and idea discussed with Chris at Toovey race engines we decided to send the inlet cam to Piper Cams to have the base circles re-profiled and give me my valve clearances as per BMW’s specs.
TWINCAMMINI.COM 