To be honest, I just noticed this yesterday when I was changing my plugs. I ordered a new cap and rotor today. I will also add an extra ground cable to see what happens

This post reminded me to check my rotor and cap - just ordered a new cap and rotor from Summit. Actually, from the looks of the cap I'm surprised it ran at all.

You need to check the rotor phasing. MSD had some of their spark boxes wired backwards. Also note that the phasing of a MSD 6-AL and a Digital six are opposites.

Tom,
I'm not sure I know what you mean. I have the MSD Pro-Billet dist and 6AL box. What am I looking for?

Thanks.

What coil are you running?
 

Bunkie314 Is it possible that the center contact is burnt off and not worn off? I just replaced my cap and rotor after 5 years. I use all MSD, The HVC coil does do a number on the cap and it has burnt marks into the rotor. Some times you have to run a ballast resistor in some of the ignition systems. This cuts down on the voltage to the coil. MSD tech Should have an answer for you. Grounds are important also for being clean and tight. Rick

The MSD caps are crap. The POS graphite balls crumble at times, fall out other times and wear out quickly most of the time. I've done all the "fixes" (the grounding, the contact, the grease, double checking the box, the coil, etc.)...they are still crap. Making sure of the contact seemed to provide the best fix.

That being said...they are still crap. There's really no reason why they couldn't be made out of just metal. As Pat says, the Chevy caps (BB I'm pretty sure) work the best, but require changing over the wire connectors. I still use the POS MSD crap caps, but I change it out every 1,000 miles and always carry an extra one. Many folks have had the problem...seem to be different runs. You'll get a good one, and then the next one crumbles apart.

Not one of MSD's better ideas...and it makes it worse when they suggest all kinds of fixes under the hood.

Again, to summarize...they are crap.

Proper distributer phasing is when the coil is firing when the rotor is lined up with the terminal on the cap. If the box is out of phase the coil will fire between the terminals. This will play havoc with the cap and rotor... On cars that have been phased properly I have not seen a problem. On cars that are phased backwards less than 1,000 miles for a new cap and rotor is not uncommon.

Tom,

I am still confused about the phasing of the dist. cap. If you move the cap to try to align the rotor to the cap wouldn't that change the timing?

Could someone please explain what is needed to align this.

I guess to check this you need a clear distributor cap and a timing light?


With the MSD distrib, it has a magnet, a ? rotor vane ( 8 vanes), and an induction coil. As the rotor vane moves past the induction coil it induces a current that the spark control box senses, and subsequently charges the coil for the spark release. To adjust the phasing, I'd guess you'd have to change the orientation of the rotor vanes with respect to the rotor.

Speaking of Rotor Phasing..
 

MSD has a new adjustable race rotor out for 2008 that gives you +-20 degrees. Here's a link: http://www.msd6al.com/new_products/8421.html

When, on advice from MSD, I switched to the MSD Blaster 3 ("George Jetson") coil, my caps never had a problem.

The two wires coming out of the distributer can be switched. This will change the polarity of the signal and screw up your distributors phasing.

In simple terms,(like the old days) the points need to close at the same time that the rotor lines with the cap.The newer systems don't have points but a rotor like Anthony said above.Shoot me down if you like but today you can buy a FORD HEI distributor and never have any more problems.

The MSD dist. instructions come with a paper telling how to check the phasing Tom is talking about. All you need is a timing light.
I had the same problem with the cap and rotor wear. I bought an a.c. delco brand cap and rotor for a small or big block chevy with points ign. (70 chevelle) So far so good.

Drilll a hole or grind out a slot in the cap
 

Bunkie I have an FI system and use the distributor as a cam sign for sequiential fuel injection. I used an old cap and grind a slot around the #1 terminal for the plug wire. The slot is about 1" long. This way you can align everything up with TDC, as long as your balancer is also setup for TDC on the groove to the timing mark. This will get the car running and makes it easy to set the timing and look inside and see everything is ok in the housing. Then swap caps and you are good to go. Rick L. You are not going to get zapped as long as you don't put and metal tools inside or around the cap slot.

If you go to the MSD (Many Suspicious Devices) web site you will find numerous threads about this problem. The MSD techs offer several suggestions for the problem. The most common are bad ground, incorrect rotor phasing and center terminal of the rotor is not in contact with the center terminal of the cap.

The bad ground theroy is easy to eliminate by simply adding another ground directly from the battery to the engine block. Chances are this is not the problem but it is easy to do. Usually if you have a bad ground on the engine you have other associated problems.

Here is their page to check rotor pahsing: http://www.msdignition.com/pdf/tech%...or_phasing.pdf.
On this page they state that every one of their Pro-Billet Distributors are checked for correct phasing during the assembly process at the factory. Again like the ground it is not hard to check but requires destroying a cap and if they do as they say during the manufacturing process this should not be the problem.

So that leaves the last option. The rotor is not manufactured properly and there is a gap between the rotor and center terminal of the cap. This is easy to check by doing some carefull measuring or placing a thin coating of dielectric grease on the tip of the rotor and seeing if it is transfered to the center terminal of the cap.

It just seems to me they should just make the rotor correctly. For the money they demand for their caps and rotors I don't think this would be asking too much. I also wonder why they don't offer a replacable center terminal for the cap. I'm just kidding, if they make this stuff properly or sell replacement parts for the cap they would not be able to rip you off for new caps and rotors every 500 miles.
MSD=Many Suspicious Devices.

Absolutely.

You'd think that they would design and manufacture the rotor with the carbon button so it would be cheater to replace