I have MSD Digital 6 boxes with MSD billet distributors and recently tried to switch over to a crank trigger. Installed a GM pickup .050" off a MSD trigger wheel. Everything was in phase and looks good, except the engine breaks up over 5500 and it is caused by the pickup it looks like. When I switch back to the distributor trigger all is fine. Could it be the pickup is not compatible with the MSD? Any ideas greatly appreciated!

Is your distributor advance locked out ? you may be jumping the timing around in the distributor.. or the magnets on the trigger may be picking up on the lower pulley if its steel not aluminum. what type do you have ? are the magnets on the wheel or on the pick up side?

I think your distributor timing is not centered with the crank pickup. The timing on a crank trigger never varies. The MSD distributor has a centrifugal advance mechanism in it that must be locked out and then the distributor needs centered to the crank trigger.

If these steps have already been performed, then maybe you DO have a mismatch with the pickup, but I doubt it. I think it is the rotor being out of time with the ignition pulse.

You could very well have a problem with compatibility with the GM trigger and MSD wheel. The Magnets are in the MSD wheel Hotrod. When I had a crank trigger I ran an entirely different MSD distributor....it could not be used when I converted back to a "normal" set-up.

I know where the magnets are on tyhe MSD wheel jdnca1, GM however did offer crank trigger wheels in the reverse order and the above post says a GM pick up !(units were prduced by Moroso for GM because of metal sending false signals at some tracks) I haven't seen any of these in about 12 yrs but they could still be around.(e-bay the dumping grounds) The problem is more than likely that the distributer is not in Phase with the wheel....Check MSD's web site for instructions on how drill a distributer cap to check this and I'm sure you will find the problem.

The magnets are in the MSD (aluminum) wheel I believe. We did drill the hole in the cap (big ford type) and the rotor appears to be on phase. The motor would begint to break up around 5500 and act like it was on the rev limiter once it got to 5900 or 6000. We then simply unhooked the sensor and wired into the distributor and all worked well. The distributor is locked in at 30 degree. I have determined, so I am told that the GM sensor is a "halofax" or something close to that, in signal. Supposedly the MSD requires a different signal??? Thanks for the thoughts so far!

Bob

That's "Hall Effect Sensor".
Maybe that IS the problem. A Hall-Effect trigger uses electromagnetic flux feedback off of a nonmagnetized piece of iron passing across it. This is different from a magnetic trigger which fires when a magnet passes across its face.

If the MSD trigger wheel has MAGNETS in it, then it may help to drill them out and replace them with steel slugs. Since magnets can be ceramic or nonferrous, compatibility may indeed be the issus. I'm thinking that factory GM crank triggers do NOT use magnets in either the trigger wheel OR the pickup cause steel shavings and stuff could get stuck to them and cause warranty issues...


G'Luck. I'll be interested to hear the outcome.

I don't think this will help your problem, but for any others who are reading I have an MSD crank trigger system with an MSD distributor using a Crane Hi-6M ignition box/system----they work fine together.