Pertronix and Timing

[albersj51]

So, a couple of weeks ago I put a Pertronix Ignitor into my 25D and also installed an epoxy filled FlameThrower coil. Using a timing light we got her timed dead on for 3 degrees BTDC, as recommended in the green bible. She was running like a raped ape and started on the first push (new E fuel pump helps). Go to drive her later and she is running like crap; bogging down, backfiring, etc. Replaced the crappy wires, no change (already a new cap and rotor). Buddy comes by with his timing light and its too advanced (rich). So we set it again, so we'll see if it holds.

Question: Why would the timing change like that? Pinch bolt was tight so I doubt the dizzy moved.

[Tim Smith]

Could the pickup have moved inside the dizzy?

[vkjar]

I just did the same swap to pertronix the whole 9 yards wires, coil, cap dist. I had the same issue. rumming fine then got worse.

make sure your distributor clamp is secured and tight, mine slipped and with the rotation of the shaft advanced it way too much.

[albersj51]

The Dizzy was tight with no movement, so I am pretty sure thats not it (I've been known to be wrong though!). Last night while searching I found a post talking about removing the Vacuum Advance when timing, I did not do this either time so that could be the issue. Is my logic sound? Also, why disconnect the VA to time it? Thanks!

J

[jac04]

The factory timing spec is for static timing - meaning no vacuum advance hooked up.

[albersj51]

Thanks, Jac!

So if I leave the VA attached I should time by ear. Otherwise, warm up the engine, disconnect VA and time to spec? The Green Bible doesn't mention the VA, which threw me off.

[albersj51]

Can one of you fine gentlemen assist me in timing my Rover appropriately? Timing is off again, so I am 75% certain my issue is I didn't disconnect the vacuum advance.

How do I disconnect it for timing purposes? Do I pull the cable from the carb?
Does the truck need to be at normal operating temp or cold?
Do I get the truck up to temp and, while it's running, disconnect the VA, connect timing light and then set?

J

[jac04]

Engine should be at operating temperature. Pull the vacuum advance hose off the carb or the VA unit. If you pull it off the carb, then cap off the port on the carb. If you pull the hose off the VA unit, then plug the end of the hose. You can then set timing.
I would just time it by ear.

[albersj51]

Jac,

you are a scholar and a gentleman. I'll give it a shot tomorrow. Thanks!