My poor old slant has quite a miss: random misfires at all RPMs that are occurring more and more as the years go on.

All the usual suspects have been eliminated (ignition system changed, no vacuum leaks (inc manifold gasket), valves redone (and lash carefully set), etc.

Compression is 105 across the board, which is about right for this tired engine.

Today I tried the timing chain test. Seems I can rotate the dampener over 1/2 the width of the timing tab before the distributor rotor responds.

Will a slack timing chain randomize the spark timing enough to cause significant misfires?

- Mac

It can indeed. That's pretty loose. At 105# cylinder pressure, my inclination would be to pull it, and rebuild.

2¢

CJ

_________________
Part of Tyrde-Browne Racing