[i82much]

happy with my MSD ready to run. I have one in my GTO and one in a big block chevy. Both were built after the corrosion issues were evidently resolved. Both have digital 6 AL2 boxes and have been flawless. Easy to tune, too, with the bushings and weights.

The only thing I’d like to see them add is a nice adjustable vacuum advance with both the internal hex-adjustable rate mechanism and a total vacuum advance limiter. I think Crane used to make such a part but I haven’t messed with tuning lately so I am not sure.

[Formulajones]

Originally Posted by i82much

happy with my MSD ready to run. I have one in my GTO and one in a big block chevy. Both were built after the corrosion issues were evidently resolved. Both have digital 6 AL2 boxes and have been flawless. Easy to tune, too, with the bushings and weights.

The only thing I’d like to see them add is a nice adjustable vacuum advance with both the internal hex-adjustable rate mechanism and a total vacuum advance limiter. I think Crane used to make such a part but I haven’t messed with tuning lately so I am not sure.

Crane does still make adjustable cans, and a few others on the market now. Pretty easy to add one on the MSD, they use the standard points style vacuum advance unit.

In fact the original vacuum can that came in the MSD in my chevelle gave up just this year after 25 years of use. I pulled it out to find that MSD had used the popular B28 can in it.
I simply swapped in an adjustable unit from Crane, modified it the way I've mentioned on the forum here in the past.

[i82much]

Originally Posted by Formulajones

Crane does still make adjustable cans, and a few others on the market now. Pretty easy to add one on the MSD, they use the standard points style vacuum advance unit.

In fact the original vacuum can that came in the MSD in my chevelle gave up just this year after 25 years of use. I pulled it out to find that MSD had used the popular B28 can in it.
I simply swapped in an adjustable unit from Crane, modified it the way I've mentioned on the forum here in the past.

i probably got the info on the crane from one of your old posts. been meaning to upgrade the vac advance on both of mine for years. somehow i never managed to prioritize that with two kids, a busy job, cutting the field, plowing the driveway, going back into the military as a reservist ... i have no idea how people put as much time into this hobby as they do!

[Formulajones]

Originally Posted by i82much

i probably got the info on the crane from one of your old posts. been meaning to upgrade the vac advance on both of mine for years. somehow i never managed to prioritize that with two kids, a busy job, cutting the field, plowing the driveway, going back into the military as a reservist ... i have no idea how people put as much time into this hobby as they do!

LOL Completely understand

[scott70]

I maybe getting a msd ready to run small body. At the track now,,,only made 2 runs and traction is a problem with the street tires. Anyway I left the house and was right on 32 total. Drove little over an hour to the track and made 1 run. Checked total after and it went to 29. Adjusted it to 33 and tightened as much as I could. Made another run and now is 34 total. This is what's been going on with it sinceI bought it...I've had other makes of dist and never had this problem before.

[Formulajones]

Originally Posted by scott70

I maybe getting a msd ready to run small body. At the track now,,,only made 2 runs and traction is a problem with the street tires. Anyway I left the house and was right on 32 total. Drove little over an hour to the track and made 1 run. Checked total after and it went to 29. Adjusted it to 33 and tightened as much as I could. Made another run and now is 34 total. This is what's been going on with it sinceI bought it...I've had other makes of dist and never had this problem before.

Sounds like something funky going on with the dwell time in the module.

[Schurkey]

Originally Posted by scott70

You can tighten the clamp all you want but for some reason it can creep advance or retard after you run it hard a few times. Just did it again,,,they set total at 32 on the dyno...once in the car I confirmed 32 total with my gun. Git a few miles on it now and it crept back to 30. I let it cool off over night and checked it again this morning...30 total.

Originally Posted by Formulajones

Sounds like something funky going on with the dwell time in the module.

Anything is possible, but unlike a "points" ignition, the electronic dwell in the HEI module isn't known for changing the timing.

Originally Posted by scott70

Now I noticed one of the wires that goes from the external module into the bottom of the dist has some burn spots on the insulation. The only way I can see that happening is if the wire leaned on the module which might of been hot. Or it got hot from the inside. Look at the yellow wire,,there's like 3 burn spots.I'm just kinda tired of it.

The yellow and black wires connect to the W and G terminals of your module. That means they're the pickup coil wires. They don't conduct enough current or voltage to burn the insulation. Something really weird is going on, or there's something else overheating the wires. I don't suspect the heat sink for the module as being hot enough to cook insulation under normal conditions.

If my distributor wouldn't stay put, I'd be looking at the hold-down bolt for being too long--jamming against the bottom of the bolt hole instead of clamping the hold-down, and I'd make sure there was a fresh distributor gasket between Mister Distributor and the block. Less likely--are the bushing in the distributor housing overly-tight? Have you actually checked to see if you can move the distributor when the hold-down bolt is tightened? That might determine whether the timing shift is mechanical or electronic.

There's the wild, outside chance that the damper outer ring is moving around, or the vacuum advance doesn't move smoothly, so it jams in semi-random places/patterns..