SteveHall64Healey
Jedi Trainee
Offline
I've just finished re-installing the cylinder head on my BJ8, following a head rebuild by a reputable local shop. I've set the cold clearance to 12 thou and have gone through them twice. The carbs are off the engine, so nothing is restricting intake. Before re-installing the head, I measured the stroke and all 6 were highly consistent at 3.5" +/- .007". Head bolts were installed at 75 ft-lbs with the correct sequencing observed. The head was minimally decked by the machine shop. I measured compression (twice):
1- 115, 115 psi.
2- 100, 100 psi.
3- 130, 130 psi.
4- 122, 125 psi.
5- 122, 126 psi.
6 - 100,100 psi.
Much lower and with more variance than I would have expected. Each cylinder is holding pressure for at least 15 seconds. Has anyone encountered this before?
Prior to rebuild, the combustion chamber and piston tops were significantly caked in carbon. Compression readings were:
1 - 155 psi
2 - 140 psi.
3 - 155 psi.
4 - 158 psi.
5 - 155 psi.
6 - 150 psi.
Strange .... any ideas?
Steve
1- 115, 115 psi.
2- 100, 100 psi.
3- 130, 130 psi.
4- 122, 125 psi.
5- 122, 126 psi.
6 - 100,100 psi.
Much lower and with more variance than I would have expected. Each cylinder is holding pressure for at least 15 seconds. Has anyone encountered this before?
Prior to rebuild, the combustion chamber and piston tops were significantly caked in carbon. Compression readings were:
1 - 155 psi
2 - 140 psi.
3 - 155 psi.
4 - 158 psi.
5 - 155 psi.
6 - 150 psi.
Strange .... any ideas?
Steve