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Expert
Posts: 1348
Location: Valley Forge, Pa. | I was cruisen along at 60 MPH when my Suburban shut off. The gases built up in my exhaust and split both my new mufflers down the sides. That was loud!
I have a GM style HEI dist. and this is what was inside it when I pulled the cap. Everything was totally melted. Is this rare? I've never seen anything like it.
It was running great with no issues over the past 5 years that I've had that dist. I'm guessing it had to happen in seconds?
If it was over time, how did it keep running? The cap and rotor were red. The coil melted way up inside of it.
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Attachments ---------------- DSCN9722.JPG (243KB - 167 downloads) DSCN9723.JPG (243KB - 172 downloads)
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Expert
Posts: 1348
Location: Valley Forge, Pa. | Sorry, under wrong subjest. |
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Expert
Posts: 4054
Location: Connecticut | You should be using the stock distributor that is designed for your car. This is what happens when you jury-rig things. Ron |
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Expert
Posts: 3577
Location: Blythewood, SC | Looks to me like your coil was too high of a voltage for the stock cap and rotor. Maybe try a better made MSD cap and rotor and a stock HEI coil. |
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Expert
Posts: 1348
Location: Valley Forge, Pa. | It's not a "jury-rig". No, I didn't duct tape an HEI cap to an original distributor but I WOULD if it could get me home and that would be a "jury-rig".
I'm just glad that I have the knowledge and common sense to be able to do that. In my opinion, if you want to enjoy an regularly drive a 70 year old vehicle, you better know how to "jury-rig".
I had constant issues with original dist.. I've had one professionally rebuilt, 2 NOS ones, ect.
I ran 6 different distributors over the 1st 10 years I owned it and finally, this inexpensive HEI set up has been running for the last 8 years with no issues.
This could have happened to a 60 year old distributor too. It's just a cap, rotor, and coil. Surely you must have replace your cap, rotor, and coil before?
I'm not unhappy with what happened, I was just wondering if this has happened to anyone else and what caused it? Rather than mess with a new HEI coil, cap, ect.
I can just buy a complete new HEI dist., drop it in literally a couple minutes and be happy again for less that $60. What do you do if your rotor shatters?
MAYBE you can find one at a parts store or they'll have one there in a few days.
I'm not modifying the car. It can be put back to original with no issues. I have all the original parts.
If i can find a good reliable inexpensive [fuel injection?] sub. for the 2 bbl carb, I do it as fast as I can afford.
I drive my car 7000-10,000 miles a year. Tow my boat 7 hrs up to Canada. It is not a trailer queen or show car. I want it to be dependable, easy to fix with readily available parts,
keep it as original as possible but also be reliable and safe. I'd rather enjoy it than worry about it. To each their own as long as it makes you happy, that's it.
I could care less if what I do bothers others, it's not their car.
I did find a similar example destroyed cap/rotor issue. It was thought that a bolt or something came loose in the inside.
Something can happen to ANY distributor to shut a car down it's just that this was visually very dramatic but not the death of my car.
Oh well, just wanted to show what happened to others and ask.
It was also suggested the the coil button wore down and broke inside the cap so IF you use the HEI dist. it might be worth it to check the button at least?
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Expert 5K+
Posts: 9706
Location: So. Cal | I suspect that the resistances built up inside the cap due to wear & use, and caused it to heat up. The heat caused the resistance to go up, and that caused more heat etc. until you get melt-down. This is somewhat common with the coil-in-cap design and is why many GM guys prefer to use the one year only '75 HEI version that has the coil outside the cap. The only way to prevent it is to replace the cap & rotor on regular intervals. |
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Expert
Posts: 1740
Location: Alaska | The center contact in the cap is supposed to be in constant contact with the rotor to prevent arcing. GM HEI develops around 40,000 volts so that contact which is usually made of carbon gets worn so that it is no longer touching you get the arcing which causes a lot of heat, enough to melt everything. If you continue to run this type dizzy maybe you should check the cap and rotor occasionally. These carbon contacts in the cap usually have a spring under them to compensate for wear, I have seen these fall out before. |
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Board Moderator & Exner Expert 10K+
Posts: 13055
Location: Southern Sweden - Sturkö island | I second that, the hei is normally very reliable, so they tend to be forgotten. A check-up every now and then will prevent disasters |
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Expert
Posts: 3780
Location: NorCal |
https://www.onallcylinders.com/2017/01/20/ask-away-jeff-smith-rotor-... |
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Expert
Posts: 1348
Location: Valley Forge, Pa. | Thanks all. I'll start checking it regularly. Now I know.
I have another complete new HEI dist., just didn't have it with me.
When I take long trips or long day trips, I carry spare parts that I know i can't get at Pep Boys.
I carry a dist., fuel pump, carb., belts, hoses. IF you were to carry spare parts, what would you also have?
Are water pumps readily available? With no rear facing seat, I have a fair amount of unseen storage. |
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Extreme Veteran
Posts: 406
Location: Hilltown, PA | Back when HEIs were commonplace I would see this every now and then. As stated, the HEI is a reliable, and powerful, ignition system. Output voltages can be as high as 80Kv, and near the end of their production life they were regularly used to fire spark plus with gaps of .080.
A drawback to this dependability and power is they tend to get ignored. An ignition that can reliably fire an .080 gap plug will function perfectly fine with the ground and center electrodes worn to nothing, I've seen the center electrodes worn pretty far down inside the porcelain insulator. Ditto for the cap and rotor components. O.E.M. and standard replacement cap and rotors had issues with the rotors pin-holing near the contact spring, leading to a no-start condition. Your aftermarket parts are much more robust to prevent that. Unfortunately that center carbon button does wear, and sometimes they fracture, leaving an air gap between the bottom of the coil and the rotor contact. What happens then? Not much - the coil can easily overcome that large gap, and will happily do so, ramping the output voltages to extremely high levels. Of course this makes heat, and the results you see here.
The HEI has become a go-to aftermarket ignition for almost every engine out there. The combination of easy installation (only 1 wire - 12v from your ignition switch), low maintenance, reliability, almost supermarket level parts availability, and high output capability combined with very accurate timing events to well past 8000 rpm make it hard to pass by.
There is a member here who sells an adapter to mount the GM HEI ignition module on the base of a Chrysler electronic ignition distributor. This uses the remote mount coil and the Chrysler cap and rotor. This is a great set-up as you get the advantages of the HEI with very stock appearance. Of course you'll want to use top quality caps and rotors - economy parts won't last.
Gregg
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Extreme Veteran
Posts: 371
| Wow the last time I saw that was when my brother put a blaster coil on with a single point distributor and didn't put the famous chrysler resistor back on. Too much zap a pow and boom. |
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