Can't seem to get more than 6-8 months out of these recently? Ate a few of these on different cars of ours recently...anyone else having these issues?

almost eat a cap a year here...

meanwhile the locked out stock distributor with cheapo cap and rotor have been on another engine for 3 years.

Went through 2 SBC last spring. The the last one I got is still working good.

What specifically has happened to your cap and rotor ? I just cleaned mine yesterday, some carbon deposits, but looks ok. Any tips on what to look for ? Thanks

We have 1 car that eats them up pretty regularly also. It has a 12 gauge wire that grounds the intake to the battery. I thought about grounding the heads to the battery with a heavier gauge wire to see if that helps. No issue with the other cars however.

They start mis firing and burn the button off cap on inside. Change them and seem to be too frequent when we have had them last much longer in yrs past.

I run the MSD 8 plus ignition, HVC 2 coil with the little crap cap and haven't had any problems

I added a ground to each head directly connected to the battery addressing a grid issue.

Never have a miss, just have a nightmare starting the car when the cap and rotor start to go south.

Possibly they have cheapened the alloy and it degrades faster than previous versions. Just a guess. I only have 50 passes on this one but you got me curious enough to pull it off and take a look.

This can be caused by high resistance in the secondary ignition. Try the ground strap between the head and the block. My main battery ground goes to the block, then from the block to the frame.With an aluminum head especially.

I remember some time ago that the little spring steel piece that contacts the button was not getting bent correctly. Now I always pull them up some so they put more pressure on the button. I can't say it will fix your problem but it was a known issue I read about.

Torque converter is to looooose! Call me

You need to bend the tab up significantly so when you just SIT the cap on without clips the tab is actually holding the cap up off from the base....

This^^^ it’s no longer just take the rotor out of the package and screw it down. It’s been about 10 years since MSD started to include a rotor tab height gauge in the package.

What others said about rotor tang is a must. It needs to engage the top button on the cap the last 1/8” – 1/4" prior to cap seating to the distributor housing.

Drilling two 1/4” holes on opposite sides, in the side of the cap between the plug towers even with the side of the rotor center can help also. Here’s my cap interior with over 500 runs and I’m using a Grid 7720 amplifier. The spark plugs were run that long also and the 030 gap going in was at 042 when they came out.

Make sure your rotor is phased properly also. This is easy to set and check using the hole I put in the cap side and placing a mark on the side of the rotor to indicate phase. Aim your timing light at the 1/4” hole and line up the mark on the rotor.

MSD makes a Black Heavy Duty dist cap to correct this issue that uses a special rotor ball material. My car used to eat caps until I put this cap on, problem solved.

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quote:

Originally posted by WHOMPWHOMP:
You need to bend the tab up significantly so when you just SIT the cap on without clips the tab is actually holding the cap up off from the base....

This! Bend the tab up before installing or replace after a few months or even less.

This thread just made my day. Old guy here and ever since I started messing with cars (1969 then they had pionts) and latter HEI I would always lift that rotor up and set the cap on so there was just a little contact between the two. Still do it to this day on the race cars and never knew if it was right or wrong just my old habit from when I was a kid and never did it any other way. I also drill the holes in an MSD cap but that did not start untill the 90's.