Timing bounce

[Cazbah362]

OK- 440 with MP orange box, new distributor and cam is set to the 3 degree retard key. So, trying to time this and I set the overall at 34 and the initial stays at 34, set the initial at 16 and the overall stays at 22? then the marks start to bounce on the idle? cam is a MP 464 and a new chain, are my mechanicals freaking out, distributor is a NAPA rebuilt? or is the orange box the issue? I hate to just buy stuff - any insight would be great.

 

[67 B-body]

3 Deg retard seems unusual for a camshaft install.....

 

[Moparsmitty]

Check if your mechanical advance in the distributor is working properly. Spring pop off, or weight came loose maybe? Easy to check for starters.

 

[67 B-body]

Is that (bouncing) reading with vac advance hooked up?

 

[440roadrunner]

I didn't think this was possible, but a member over at FABO actually had an orange box that was "false triggering"

 

[Cazbah362]

The vac - advance was installed when I did the OVERALL timing but disconnected for the idle.

I will check the weights in the mechanical, was my first thought, but also was wondering on the Orange box, I have read in a lot of places where they are having issues with them.

I have the original voltage regulator on right now, I am going to convert to a digital before I start chaing the gremlins. Half wondering if there is a a surge or possible current pulse issue?

and 67 - 3 degrees on the crank side

 

[67 coronet]

a mechanical volt reg can surge alot at idle,so it could be your problem.have you double checked mechnical link of the motor.i know you said all new parts,but cant hurt to be sure.just roll the motor back by hand at the crank while watching the distrib rotor to check for any play.make sure there isnt a worn oil pump drive gear as well.

 

[Cazbah362]

OK - Think I got it. Changed to a Electronic volatge regulator and square back alt - NO TIMING BOUNCE and seems to run a LOT better. Does not pulse doing down the highway, no flicker on the dome light at low idle.

Wow - who would have thought that?