manolis1969

Hi guys..i made a vid on how to check rotor phasing on distributors..hope some of you benefit by this..also check for my other vids of my 1991 camaro rs..thanks!

Damon

OK, not bad. Showing the spark phasing through the hole in the cap like you descibed would really help illustrate the point in sparking detail. I know that would be difficult to video (nearly impossible?) but once you've see it in-person most people do the old V-8 "smack to the forehead". "Oh, I get it now!"

Important to point out that there are only TWO things that can affect distributor phasing:

1. Cap position relative to distributor body. When you spoke about having a cap that can be moved until you get best distributor phasing you hit the nail on the head. Us "old guys" used to do that, especially before the modern era of magnetic pickups. A huge PITA back then to do it, just as it is a huge PITA to do it that way today. Best to leave the cap alone and do it an easier way......

2. Vacuum advance. This is the real key to rotor phasing. Vacuum advance, by it's nature (moving only the mag pickup) alters rotor phasing between it's fully-advanced position and fully-retarded position. It's unavoidable. AND DISTRIBUTOR MAUFACTURERS KNOW THIS. So they "split the difference" in the factory phasing half way between the full-advanced position of the canister and the fully-retarded position of the canister.

That's why if you run a vacuum advance distributor, while leaving the vacuum advance disconnected, you often find that the spark is happening "too late". Spark happens when the rotor tip is already passing the plug terminal. But if you hook up vacuum advance and move it to the full-advance position (vacuum advance canister arm fully retracted by vacuum) you will find the opposite- it's happening TOO EARLY!!!

So..... if you are looking at getting perfect phasing for strip-only (no vacuum advance) you get a vacuum advance lockout kit and start tweaking it. MSD sells one for the ProBillet distributor that you used in your video and my experience is that it gets the phasing pretty close, but not perfect. You can tweak and tune with slight modifications from there. Stock distributors you're into "DIY" solutions in this area.

Initial timing setting and centrifugal advance have NO effect on rotor phasing. They move the necessary components in unison to maintain constant phasing position.

AlkyIROC

I use a crank trigger so my distributor needs to be phased. The magnetic pickup inside the distributor does nothing. All my distributor does is directs the voltage to each plug so I want the cap phased when the crank trigger collapses the coil field to fire a plug. I use a hole in a cap and aim a timing light at it while the engine is running. I can see where the rotor is and move the distributor until it's on a leading edge of the contact in the cap. Moving my distributor CW or ACW does not change the timing, only the phasing.

I jumped through that video to get past the boring commentary and never saw anything useful to anyone but I also made big jumps. The theory of phasing is explained however you're not going to easily phase an OEM distributor and even an MSD distributor can't be easily modified to change the rotor position in relation to the magnetic pickups.

Moving the distributor to change the timing does not change the rotor phasing. If your distributor is so far out that it needs to be phased, you probably need a new distributor.

manolis1969

Thanks for your input guys..check out my other vids..and yes you are correct, crank triggers do work differently..i mentioned that all setups a different..this was a general rotor phasing vid and to make people aware of this concept..

Also i do know regular timing changes do not affect rotor phasing...

Also subscribe to my channel to get updates on future thirdgen projects i will be working on..thanks