[Formulajones]

Originally Posted by scott70

So is the problem inaccurate timing ,timing mark bounce,or something else? My old chrome sunpro with mechanical dial seems very steady. Should the RTR be ok? I dont use a box.

If you've ever experienced it, it's the timing mark bouncing around. It's actually caused by the MSD CDC boxes. It's not the MSD ready to run distributors or any of that stuff. It's the multispark boxes.

I get the issue with any car here that I run the box on. Even when I add the box to a points ignition system it goes from being perfectly fine as a standard points setup but as soon as I switch the coil wires around and fire up the box it goes to a very bouncy timing mark that is difficult to time.

Some lights work with it and some don't. It's hit and miss. I've heard of people having good luck with the Innova timing light that you're looking at. Just have to try and see. If you're not running a box, you'll be fine.

I have an old Craftsman chrome mechanical dial back timing light, (father has one too) identical to your Sunpro dial back, and neither one of ours likes the MSD boxes at all. What I do is run the engine above 3000 where the multispark is inop and set my total. Below that usually the timing flutter isn't too horrible, you can still hone in on the timing once you learn to read between the flutter, you'll get to know what's accurate and what isn't as far as base and curve. I know our engines are solid as far as internal cam timing, the chain and distributor gear, and I know what the distributor is going to do based on the setup I build it with, so I pretty much know what to expect anyway.