MSD ignition delivers it's voltage over a 20 degree duration using multiple sparks. This is most prevalent at rpms under 1000. At 1500 I believe its 2 to 1 and at 3000+ its 1 to 1.

I too have the Craftsman 2134 timing light with a plastic carrying case that I purchased many years ago. Having used a newer MSD timing light, I’d purchase that one now if needed as it was very good in the daylight.

quote:

Originally posted by markemark:
MSD ignition delivers it's voltage over a 20 degree duration using multiple sparks. This is most prevalent at rpms under 1000. At 1500 I believe its 2 to 1 and at 3000+ its 1 to 1.

I too have the Craftsman 2134 timing light with a plastic carrying case that I purchased many years ago. Having used a newer MSD timing light, I’d purchase that one now if needed as it was very good in the daylight.

It only delivers sparks until the plug fires, at 3000-ish RPM the multi-spark ceases.

I had a Craftsman since probably 1976 and it finally gave up, it got to where it was so dim it was useless. Then I got an MSD which was very bright. Had it less than a year before it started working intermittently and I did not trust it any more. I was stuck and needed a timing light right then so only thing available was a Harbor Freight one and it is actually very good.

As for 7AL-2 ignition boxes I have had about 4 go bad. One would run 5.09 one pass the very next pass 5.49 banging, popping and missing. MSD kept saying my box is good as I had one of the MSD ignition testers and it tested good with it. They led me on multiple wild goose chases before I got another box and it went 5.04, 5.04, 5.04 with no more problems.

Another box that I had go bad the motor never missed or banged, popped or anything it just acted like it did not want to turn over 6,000 RPM. Changed the box out and ran great all way up to 7600 RPM shift point.

Timing jumping around a lot could be something mechanical like timing chain slop. You may need to shim distributor to reduce the slop in the cam gear drive.

Electronic specialties model 130 Amazon. Three years now very happy battery operated.
Five years sorry..

Happy Monday. Thanks again for the input on this. Going to invest in a new light. Not happy/confident in the ones I have. Out of my 3 old Craftsman units, one doesn't light up at all, one has a weak flash and is all over the place, the best of them has the adjustable advance dial. It stabilizes in the 3000 rpm range that's been suggested. Not 100%, but far better than the other. I'm pretty confident in where I think the timing is set now. Having been told the advance option isn't a good solid unit, I'll feel better having a new unit. Since this is the MSD ignition, may go with one of theirs. Figure they should know how to put one together that works on their stuff, right? LOL. Still planning to try a couple different things to see if they make the light any more stable.

Have a great evening.