timing jumping

[mopar_madman]

When trying to set my timing on my 340 it will set at one spot then jump back, its not moving back and forth constantly it moves randomly. My mechanic thinks somthing is worn in the distributer. Was wondering if you guys had any thoughts. Car has accel dual point distrib. (older one) orange box and mopar blaster coil.

[myk]

Yeah, sounds like serious wear in the distributor, but instead of repairing it why not go elecectronic?

[Plumcrazy]

There are several possibilities.  Worn timing chain or distributor are the most likely.
Also a worn oil pump drive shaft or bushing is possible

[deputycrawford]

I would definately go with the new distributor first. Go with anything in the electronic area and try the timing again. Work from simplest to have no desire to change.

[mopar_madman]

Thanks guys, the consensus here is distributer also, so looks like I'll just get a new one.

[Nacho-RT74]

I'm on same deal. My time is jumping around +/- 2 degrees when I'm lamping. That was after I replaced the dist bushing that I didn't find the right one: I had to use the Chevy starter bushing what is same outer diameter, but smaller inner diameter. I had to enlarge the hole untill dist shaft fit.

The original bushing even worn ( elongated hole ) never got me jumping timming.

[deathcharger71]

could having a bad idle where the rpm was jumping around also cause this? mine seemed to jump around a little until i removed my vacuum advance and now its fine. removing vacuum advance also helped my idle, so i assumed that wasnt coincidence.

[resq302]

I was always taught that when you checked your timing, the vacuum advance should be disconnected and plugged so you could get an accurate reading.

[Ghoste]

Yes.

[TylerCharger69]

I had that problem once  and  the bushing that houses the shaft was worn out....it even caused my oil pump shaft to snap in half.  Year One helped me out there

[T16]

This bushing.. could it be replaced easily..? Planning on chaningin my oil pump drive.. and maybe the bushing to