MSD Rotor phasing

Tom Kirkham · #1 (**permalink**) 09-28-2009, 04:50 PM

Well with all the problems with phasing distributors, I thought I would take some pictures on how to make a tool and phase your rotor in your distributor. You will need an old distributor cap and a timing light.

The first step is to modify the distributor cap. The V shaped notch on the top is to check and make sure that the top of the rotor is contacting the terminal inside the cap.

I cut two large windows so I could better see what is going on.

Next I marked the rotor with a Sharpie.

Putting everything back together

In this picture I hooked up the timing light to the post I wanted to illuminate. This picture was taken with the engine running and with the timing light hooked up. Note that the mark is lined up with the post. This is what you want.

Hope this helps.

sllib · #2 (**permalink**) 09-29-2009, 07:42 AM

Thanks, Tom. This is something I've been meaning to do. For those of us who DON'T have a box of old MSD caps laying around, will the cheap parts store caps do as well for chopping up?
Bill Stradtner

Jerry Clayton · #3 (**permalink**) 09-29-2009, 08:05 AM

there used to be a clear cap available---I used one on my pro stocker--don't remember who made it

vector1 · #4 (**permalink**) 09-29-2009, 08:42 AM

drill a hole next to #1 terminal on top between button and terminal, white nail polish on top of bug pointer and use a timing light as described above works well. then you can plug the hole when done or leave open and use as vent system.

Rick Parker · #5 (**permalink**) 09-29-2009, 09:30 AM

MSD has also suggested doing as Vector 1 suggested. View from above. Use a sacraficial cap or one that s being replaced. MSD markets a Rotor with an adjustable tip that fits several applications including the small diameter billet distributors that are popular with several of our engines. #84211. Originally designed to remidy issues associated with EFI, it can be used with carbureter application if needed.

http://www.msdignition.com/product.a...69&terms=84211

cobred · #6 (**permalink**) 09-29-2009, 10:32 AM

What is the reason for doing this, Im not sure I understand.

Argess · #7 (**permalink**) 09-29-2009, 10:46 AM

The closer the rotor points to the correct dist cap terminal, the less chance of going to the wrong terminal (crossfire) and the shorter spark means potentially more energy to the plugs.

He is getting it bang on because he can. No mech advance inside the dist. With an advance mechanism, the rotor has a range of movement around the respective terminal.

Large rotor caps have reduced the need for this to some extent (for the crossfire problem), but it's still a good idea.

Did I get that right?

Rick Parker · #8 (**permalink**) 09-29-2009, 10:51 AM

It is a means on verifying and correcting as necessary the rotor position so it is lined up with the conductor post in the distributor cap when the coil discharges.

Tom: Don't send it back to MSD for a warranty claim.............

scottj · #9 (**permalink**) 09-29-2009, 11:23 AM

Quote:

Originally Posted by cobred

What is the reason for doing this, Im not sure I understand.

For a carburated application, using a crank trigger, rotor phasing is adjusted by rotating the distributor and this would be the method to verify that adjustment. If you are using the magnetic pickup in the distributor then this method verifys that MSD built the distributor correctly.

Got the Bug · #10 (**permalink**) 09-29-2009, 12:18 PM

If the phasing is off, what action do you take?

Argess · #11 (**permalink**) 09-29-2009, 12:44 PM

you can buy adjustable rotor buttons

patrickt · #12 (**permalink**) 09-29-2009, 12:56 PM

Quote:

Originally Posted by Got the Bug

If the phasing is off, what action do you take?

This is the little flier that comes with the MSD distributor.

Eljaro · #13 (**permalink**) 10-04-2009, 04:20 PM

The phasing on my distributor was off, not by much but enough to give me hesitation on full advance. I did loosen up the magnetic pickup and moved it as much as the holes allowed in the most advanced position ( it was firing well past the terminal) and it was enough. Now the rotor lines up perfectly and the hesitation and misfiring is gone.
My MSD distributor out of the box was NOT phased correctly. I never checked the phasing because MSD claims that it is factory set correctly and I believed such an apparently serious company.
I wasted a lot of time and bought a new 6AL box, a new mag pickup, a new cap, new springs, new weights and made myself several cables connecting the 6Al to the distributor, shielded and twisted and you name it.
In the end upon seeing this thread I modified a distributor cap and saw that the phasing was off. My problem is solved, but some money and time was wasted

:mad :

RodKnock · #14 (**permalink**) 10-08-2009, 05:11 PM

Here's a dumb question. How does one know if he or she has a "crank trigger" system? I'm running a 8594 MSD Billet distributor and a MSD Digital 6 ignition, but now I'm curious, and would like to check my rotor phasing and I know that "crank trigger" systems are treated differently according to the MSD instructions.

patrickt · #15 (**permalink**) 10-08-2009, 05:18 PM

Quote:

Originally Posted by RodKnock

Here's a dumb question. How does one know if he or she has a "crank trigger" system? I'm running a 8594 MSD Billet distributor and a MSD Digital 6 ignition, but now I'm curious, and would like to check my rotor phasing and I know that "crank trigger" systems are treated differently according to the MSD instructions.

That's not a dumb question at all. The violet/green wires from your MSD box will run to either your distributor or a crank trigger. If the little wires that come out of your distributor run to nothing (the plug is not hooked up to anything) then you have a crank trigger. If they run to your MSD box then you have regular magnetic pickup. The overwhelming odds are that you do not have a crank trigger.

Got the Bug · #16 (**permalink**) 10-08-2009, 05:20 PM

Quote:

Originally Posted by RodKnock

Here's a dumb question. How does one know if he or she has a "crank trigger" system? I'm running a 8594 MSD Billet distributor and a MSD Digital 6 ignition, but now I'm curious, and would like to check my rotor phasing and I know that "crank trigger" systems are treated differently according to the MSD instructions.

The other question is, if you're not experiencing any symptoms whatsoever, how much are you really going to gain by checking the phasing. Seems like a lot of tweaking for a small or no payoff.

patrickt · #17 (**permalink**) 10-08-2009, 05:21 PM

RodKnock, if your engine is revving nicely, then don't even touch the distributor cap.

RodKnock · #18 (**permalink**) 10-08-2009, 05:33 PM

Quote:

Originally Posted by patrickt

RodKnock, if your engine is revving nicely, then don't even touch the distributor cap.

To be honest, I don't have a ton of seat time, so I don't know if it's an acute or chronic issue, but yes, there's was some disturbance in the higher rpm on my last run that I took last weekend. Now, I also need to check the rev limiter to see what's the RPM limit too. I may have been bumping against the rev limiter.

patrickt · #19 (**permalink**) 10-08-2009, 05:33 PM

See the two wires coming down out of that black spirally looking thing on the base of the distributor? That's your magnetic pickup. That will lead to the violet/green wires in your MSD box. If those wires are not hooked up to anything, then you have a crank trigger. I'm almost positive though that you don't.

patrickt · #20 (**permalink**) 10-08-2009, 05:38 PM

Quote:

Originally Posted by RodKnock

To be honest, I don't have a ton of seat time, so I don't know if it's an acute or chronic issue, but yes, there's was some disturbance in the higher rpm on my last run that I took last weekend. Now, I also need to check the rev limiter to see what's the RPM limit too. I may have been bumping against the rev limiter.

Less than 5% of Cobra patients respond to a rotor-phasing. I would treat empirically with a basic tune up, after confirming of course that you don't have a simple rev limiter issue.