Gunsons Compression Tester

Checked the compression in the cylinders. Took plugs out and checked each cylinder in line and wrote down the readings (i mistakenly noted bar rather than the psi reading) – when converted the readings are about 180psi which represents 10:1 compression ratio which is good and quite high. A previous owner had the engine bored out to +40thou and had the head skimmed 55thou – these would certainly continue to the high compression ratio.

If one of the readings (or all) are low then by adding a small amount of oil into each cylinder and if the reading increases significantly then rings are suspect – if no difference then valves could not be seating properly.