what causes wandering timing

[DarkoStoj]

i went to check the total timing and i got a weird problem on this new car I bought. Its a 65 fastback with a 87 302HO roller motor. it has a msd distributor with mech advance, msd 6a, and a msd coil with taylor plug wires. When I start to rev the motor the timing will start to bounce around between 30 and 40 like crazy making it impossible to actually set the timing with the #1 plug wire. What would cause something like this? Everything on the motor seems new with very little use.

 

[dennis112]

i went to check the total timing and i got a weird problem on this new car I bought. Its a 65 fastback with a 87 302HO roller motor. it has a msd distributor with mech advance, msd 6a, and a msd coil with taylor plug wires. When I start to rev the motor the timing will start to bounce around between 30 and 40 like crazy making it impossible to actually set the timing with the #1 plug wire. What would cause something like this? Everything on the motor seems new with very little use.

The MSD is not friendly with your brand of timing light once the motor is reved. That is a common problem, and one that I have too.

Supposedly some of the timing light models available from Sears work OK.

 

[DarkoStoj]

The MSD is not friendly with your brand of timing light once the motor is reved. That is a common problem, and one that I have too.

Supposedly some of the timing light models available from Sears work OK.

well I have a older bare bones timing light. 2 clips to the battery for power then a clip around the #1 plug wire and a trigger on the light. I also only get the problem at over 2500 rpm. the timing is very stable at idle. I just dont want something to be wrong with the timing chain/ cam gear/ dist gear.

 

[DarkoStoj]

i just went out and pulled the rotor off the dist. I have a decent amount of movement back and forth on the main shaft in the dist