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GMC V6 and V12 Engines Engine repair and rebuilding

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  #11  
Old May 21st, 2017, 11:01 AM
George Bongert George Bongert is offline
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Default Re: HEI vs Pertronic pointless ignition systems

Quote:
Originally Posted by bigblockv6 View Post
I'll be the first to tell you about the HEI conversion, I built it back in 1991 and was immediately happy with the results. The HEI is a much hotter ignition than the Pertronix, after the 478M conversion I built it up with the MSD coil and digital module with a built in rev limiter that includes a second Tach lead which will come in real handy when I decide to go with Howell Fuel Injection. As far as reliability I just keep a spare module in the glovebox that's easier to change than a set of points.

Greetings BigBlock!

While the GM HEI does produce a hotter spark and all of that, it is not without its drawbacks. I owned two Buicks, both equipped with the HEI, and never had the ignition module itself go bad. The part that went bad on both of my HEI's was the pick-up coil that was mounted on the "breaker plate" and had two little wires that were notorious for having one of those wires breaking, and there was no simple "roadside fix" since the entire distributor had to be removed and disassembled to replace the pick-up coil. Personally, I'd go with the "small" distributor (if you can find one) used on later Big Block V-6's and the Pertronix conversion. The Pertronix unit is much simpler and much easier to change than any of the parts in the GM HEI. I've used the Pertronix in agricultural applications, and I am very pleased with them and their simplicity of design.

But then, that's just my two cents worth here. Both the GM HEI and Pertronix have their advantages and disadvantages. It all boils down to a matter of personal choice.
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  #12  
Old May 21st, 2017, 03:22 PM
bigblockv6 bigblockv6 is online now
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Default Re: HEI vs Pertronic pointless ignition systems

Yes I know about those two wires on the pickup coil, though I've never had them break under normal conditions. The only time I had the wires break on me is when I was gutting out a Pontiac HEI for parts.
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  #13  
Old May 22nd, 2017, 05:43 AM
BobBray BobBray is online now
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Default Re: HEI vs Pertronic pointless ignition systems

I used to work on a lot of late 70's- up GMC 6500's with 366's and 427's in them, all HEI. Very little ignition problems, but when they did happen it was most often carbon tracking on the cap and rotor. Wouldn't leave you stranded but would miss and backfire a lot.

No question HEI delivers a hotter spark than Pertronix, even if you use their 'Flamethrower' coil. I went with Pertronix for the stock appearance and I was concerned of clearance issues with the stock air cleaner. Never measured, will HEI work with the stock air cleaner?
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  #14  
Old May 22nd, 2017, 02:14 PM
George Bongert George Bongert is offline
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Default Re: HEI vs Pertronic pointless ignition systems

Quote:
Originally Posted by bigblockv6 View Post
Yes I know about those two wires on the pickup coil, though I've never had them break under normal conditions. The only time I had the wires break on me is when I was gutting out a Pontiac HEI for parts.

Greetings again!

Long story short, both of my Buicks were 1978 Electra Limited cars, and from what I was told at my local parts store was that the wires on the OEM pick-up coils were not heavy enough to stand up to the flexing they received whenever the vacuum advance moved the "breaker plate" that the pick-up coil was mounted to. The replacement pick-up coils had visibly heavier wires than the OEM coils. After replacing the coils with after market parts, I had no more problems involving the pick-up coils. The only other problem that I had with the GM HEI was that I had one ignition coil go bad. Other than that, the GM HEI was a fairly reliable ignition system.
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  #15  
Old May 22nd, 2017, 03:57 PM
WE7X WE7X is online now
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Default Re: HEI vs Pertronic pointless ignition systems

To anyone is interested in the HEI conversion;
** I still supply the Custom Spacer/Sleeve for the even fire Buick V6 distributor HEI conversion, a shown in the Ed Erlbacher drawings on the 6066 GMC web site.* Over 100 of these Spacer/Sleeves have been machined, and most have been sold to members of this 6066 GMC fraternity over the last 20 years or so.
** The Custom Spacer/Sleeve comes as a kit; which includes the Spacer/Sleeve and some small parts which are sometimes difficult to source in small quantities.
The small parts are: new O-ring for the distributor body, new roll pin for the drive gear after it is drilled, and a couple of thin shims for the distributor shaft to take out any excess end play, if needed, after the drive gear is installed.

* The Custom Spacer/Sleeve kit is $55 including shipping via USPS.

Rod Johnson
Issaquah, WA.
WE7X@aol.com
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  #16  
Old May 23rd, 2017, 03:18 AM
bigblockv6 bigblockv6 is online now
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Default Re: HEI vs Pertronic pointless ignition systems

No question HEI delivers a hotter spark than Pertronix, even if you use their 'Flamethrower' coil. I went with Pertronix for the stock appearance and I was concerned of clearance issues with the stock air cleaner. Never measured, will HEI work with the stock air cleaner?[/QUOTE]

Bob, When I get home this weekend I'll take some measurements on my 68 with HEI. I also have a 67 351E air cleaner to make the comparison. You are running the Holley 500 carb, right?
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  #17  
Old May 23rd, 2017, 03:21 AM
bigblockv6 bigblockv6 is online now
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Default Re: HEI vs Pertronic pointless ignition systems

Quote:
Originally Posted by George Bongert View Post
Greetings again!

Long story short, both of my Buicks were 1978 Electra Limited cars, and from what I was told at my local parts store was that the wires on the OEM pick-up coils were not heavy enough to stand up to the flexing they received whenever the vacuum advance moved the "breaker plate" that the pick-up coil was mounted to. The replacement pick-up coils had visibly heavier wires than the OEM coils. After replacing the coils with after market parts, I had no more problems involving the pick-up coils. The only other problem that I had with the GM HEI was that I had one ignition coil go bad. Other than that, the GM HEI was a fairly reliable ignition system.
Sounds like the replacement pick-up coil will make a good upgrade for my HEI
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  #18  
Old May 23rd, 2017, 07:35 AM
BobBray BobBray is online now
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Default Re: HEI vs Pertronic pointless ignition systems

Quote:
Originally Posted by bigblockv6 View Post
No question HEI delivers a hotter spark than Pertronix, even if you use their 'Flamethrower' coil. I went with Pertronix for the stock appearance and I was concerned of clearance issues with the stock air cleaner. Never measured, will HEI work with the stock air cleaner?
Bob, When I get home this weekend I'll take some measurements on my 68 with HEI. I also have a 67 351E air cleaner to make the comparison. You are running the Holley 500 carb, right?[/QUOTE]

Yes, Holley 500. Found an aftermarket air cleaner base that fits with the stock 351/WWC air cleaner lid, so I run that for a stock appearance. Thanks, I might go with an HEI one of these days.
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