MSD HEI Problems with notes

gr8vet

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I'd rather be in Bonaire
Hey guys, thought I would share my findings on the MSD 85 series in the rebuilt 1982.

Started having issues after rebuilt engine goes in.

1. Erratic idle, over heating, low performance on top end, found vacuum leak going to headlights, and a bad fuel pressure gauge was causing suspicion to fuel pump.
2. Idle got better but still had a stumble. Engine no longer getting super hot, now I was able to obtain correct timing. Top end performance still bad, much stumble at WOT. Swapped out a borrowed carb, things got worse. Now engine will shut down after running at operating temps after maybe 15 minute drive. Had to keep foot into pedal to keep it going.
3. Did alot of reading and had an idea now it may be the MSD dist. Replaced the dist., went back to old carb, went back to old plug wires, it appears so far everything is good, even after hard running and getting very hot.

I did find that the #1 and #3 plugs had alot of carbon on them. The other plugs had a nice brown color. I checked all the plug wires and they showed good.
Question: Is it possible for the MSD to have spark issues on the #1 and #3 plugs only? Stumble as previously stated.

Obviously the MSD module after getting hot was going goofy. I think.

No stumble now, running great. Just wanted to share not to overlook the obvious. Vacuum, wires, HEI setup.

tt
 
About 4 years ago I was having a COW with intermittent crappy idle and it got so bad it God AWFUL on running also....I simply could not figger out WTF was going rong, tried about all I knew, then one bright sunny day, I was leaning over the driver's fender and that damn #5 sparked to the header right under my nose.....8 ceramic Jacobs plug boots later THAT issue has never returned....

:smash::thumbs: I was fighting a combo of circumstances, but that was the worst of it.....the rest turned out to be something about the injectors, then the injector hose type in the plumbing....and of course, WATER in the gasoline, just for shits and giggles...

:surrender:
 
Thanks for sharing, good to know I am not the only one struggling with this crap, can turn alot of car fun into a nightmare when so many problems hit at once and I HATE trouble shooting! I am going to add some boots too. tt
 
Thanks for sharing, good to know I am not the only one struggling with this crap, can turn alot of car fun into a nightmare when so many problems hit at once and I HATE trouble shooting! I am going to add some boots too. tt

They didn't hit all at ONCE, but it seemed to get slowly worse over time, and here in Florida, the groundwater will pop a inground concrete steel bar reinforced swimming pool outta the ground like a cup on water...if the pool is pumped dry...go figger, and so I have serious doubts about any gas stations as their inground storage tanks are subject to the same ground water pressures, I dunno how in hell they keep water outta them tanks....and from the 3 known sure fire instances here, the first two killed the vette instantly...

the last one was about a gallon or two in the bottom of the tank....that one took some time, found by total accident...long story, don't matter...

having FI, with return line to tank under constant high flow, I have a large demand rate on the suck side....I suspect higher than most carb cars would...

:hissyfit::crylol:
 
MSD= not on my car.
I have seen to many problems over the last 25 years with MSD products.

Whether it is at the local roundyrounder or drag track, or on national tv such as Nascar or Pinks, MSD boxes fail all to often for how little actual run time they're subjected to.
 
MSD= not on my car.
I have seen to many problems over the last 25 years with MSD products.

Whether it is at the local roundyrounder or drag track, or on national tv such as Nascar or Pinks, MSD boxes fail all to often for how little actual run time they're subjected to.

I tend to agree, but with a personal observation record of 3 failures, I was hesitant to say much....

:surrender:
 
MSD= not on my car.
I have seen to many problems over the last 25 years with MSD products.

Whether it is at the local roundyrounder or drag track, or on national tv such as Nascar or Pinks, MSD boxes fail all to often for how little actual run time they're subjected to.

Yeah, I'm always a bit hesitant to badmouth a product, but in all honesty, I can't disagree with what you said.
 
MSD= not on my car.
I have seen to many problems over the last 25 years with MSD products.

Whether it is at the local roundyrounder or drag track, or on national tv such as Nascar or Pinks, MSD boxes fail all to often for how little actual run time they're subjected to.

Yeah, I'm always a bit hesitant to badmouth a product, but in all honesty, I can't disagree with what you said.

Can you imagine the fall out if year after year, decade after decade GM built an ignition system that was only good for a few hours of use and then failed.
The sad thing is there is not much competition in the market plac to force MSD to build amore reliable product.
 
I went with the MSD HEI on the suggestion from Summit 3 years ago. The built motor came with another MSD HEI. Bummer eh? What would you guys suggest when this one fails? When I began to read I found all kinds of complaints about MSD. thanks in advance. tt
 
When I converted from points, I went with DUI after some research and suggestions by others.

I got the tach drive unit from them. The tach cross gear broke within a month. They took it back and sent a new dizzy very quickly. About 3k miles later, running great.

It woke up my BB beyond my expectations.....but then again, my points unit was old and tired..not getting the job done.

http://www.performancedistributors.com/
 
I went with the MSD HEI on the suggestion from Summit 3 years ago. The built motor came with another MSD HEI. Bummer eh? What would you guys suggest when this one fails? When I began to read I found all kinds of complaints about MSD. thanks in advance. tt

DUI with tach drive is hard to beat. If no tach drive, a stock GM recurved, or an MSD 'Fireball" or whatever it's called is fine.
 
I'm running an MSD 8571 dizzy with a Summit branded Mallory box. So far, no issues. That's the billet, ball bearing, tach drive, no vacuum advnace model with a pickup coil instead of points.
 
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