Holley Sniper with Duraspark and timing control

[Broncobowsher]

So a few years ago I did a Holley Sniper. One of the reasons I picked it was the timing control it offered. Of course Holley wants to sell you a brand new distributor to take advantage of that feature. Look inside, looks just like a Duraspark pickup coil. Why spend the extra money?

So I took the Duraspark apart, closed up the centrifical advance, locked it out. Vacuum advance was next. Can't just take it off, it controls the plate the pickup coil is on. So I put a piece a piece of safety wire in there. Put a little S-bend in it for a reason I will get to in a moment. Now I could pull the vacuum advance off. The cap indexes of the vacuum advance so I cut the vacuum advance apart and put the screws and a little bit of the vacuum advance back in place. A little Ultra Gray RTV filled the void and you don't even see it.

The Duraspark pickup wires in just like the instructions for using MSD. I did have to buy a sacrifical distributor cap. I just got the absolute cheapest one I could find. Then use a hole saw and put the biggest hole(s) you can in the top. You want to see the rotor and a plug wire it is pointing at.

To avoid a rare and expensive adjustable rotor, which is used to align the rotor with the ignition trigger. You adjust the trigger instead. Hence the S-bend in the locating wire I mentioned earlier. Timing light (set to 0 if adjustable) and get the engine started. Once running you go in and use the manual timing setting tool in the controller. You want to swing through the range of timing that the engine will see. From very low at idle to pretty high at part throttle cruise (mechanical and vacuum together the old school way). There is no way the pointer can stay pointing at the post for the whole sweep. But you can keep it fairly close on either side of it. You just dial in the S-bend in the wire until you get the sweep you can live with. Each adjustment of the wire will change the base timing as well. So one the sweep is correct, follow the Holley instructions on setting the timing. Basically use the same timing adjustment setup and set the timing to match. Put your good cap on and go tune the timing to what works. Too bad there isn't a self learn for the timing curve.

Here is a picture of the magic safety wire lockout adjustment. Pre-vacuum advance hole plugging.

If you are planning on running a Sniper and don't want to buy a new distributor, try this.

 

[DirtDonk]

Good write up. Thanks.
Why did you, or did you, remove the internal ground?

 

[Broncobowsher]

Did not remove the ground. As far as I can tell that is stock 1977 Duraspark.

 

[DirtDonk]

Interesting. Thanks.

 

[turbotim2]

Are you still running the DSII ignition?

 

[Broncobowsher]

Are you still running the DSII ignition?

No.
The sniper kit comes with a little coil driver if you want to keep it basic. When I got the truck it had a new mystery brand ignition module in it. I took that out and replaced it with one from Intellatronics (actually it was the Summit racing house brand made by them). Was working perfect when I sold the truck. That ignition box took the Sniper ignition trigger perfect. I think I used the simulated points trigger style of ignition.

I don't think there is a way to keep the factory Duraspark module. You can probably put the coil driver module inside the Duraspark shell to look original. You might be able to run a TFI module heat sinked inside the duraspark shell as well? Really not sure what all the options are. I did the one that worked for me and didn't play around with what all my options are.