HEI Plug Wires Coming OFF
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Joined: Jan 2016
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From: Allen TEXAS
HEI Plug Wires Coming OFF
Hello to all. I have been suffering from HEI spark plug wires coming off!! Have never had this before.
I just finished a Holley Sniper EFI and Hyperspark HEI distributer, coil and ignition box on my 1970 350/383. I started by going with Accel 4041 wires, and thought they would do the trick. BUT, during every of my seven drives to check out and calibrate the upgrades one, or up to three, wires would come off plugs. EVERYtime!
I then looked for AC Delco, since using from the '70s with no issues, but no one could confidently identify which set would work for me. Auto parts stores are just over the counter sales, and no one knows what they are selling or why.. O'Reilly's found MSD wires for a '75-'82 Vette. They carry AC Delco, but he could not locate that model. On first drive with these, after a cruising four blocks in my neighborhood, the #6 wire came off.
Have you ever heard of such a thing?? I have changed wires since the '70s, and my dad was a Chevy mechanic. We have never heard of wires coming off on every drive. I have new R43 plugs.
Thank you in advance,
Bill
I just finished a Holley Sniper EFI and Hyperspark HEI distributer, coil and ignition box on my 1970 350/383. I started by going with Accel 4041 wires, and thought they would do the trick. BUT, during every of my seven drives to check out and calibrate the upgrades one, or up to three, wires would come off plugs. EVERYtime!
I then looked for AC Delco, since using from the '70s with no issues, but no one could confidently identify which set would work for me. Auto parts stores are just over the counter sales, and no one knows what they are selling or why.. O'Reilly's found MSD wires for a '75-'82 Vette. They carry AC Delco, but he could not locate that model. On first drive with these, after a cruising four blocks in my neighborhood, the #6 wire came off.
Have you ever heard of such a thing?? I have changed wires since the '70s, and my dad was a Chevy mechanic. We have never heard of wires coming off on every drive. I have new R43 plugs.
Thank you in advance,
Bill
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Joined: Nov 1999
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From: Front Range
Are the boots binding on the plug shafts? You might have connected the terminals, but the boots are pushing back a bit. Could use dielectric grease to let them slide on more easily if so. Just throwing out ideas. Cheers.
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Joined: Jan 2016
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From: Allen TEXAS
the boots do not seem to be binding. I twist them each a bit as I push them onto the plug. I was not sure if any lubricant might help them come off.. They all had the usual resistance when I removed the previous set, including the ones that were prone to coming off.
Safety Car
Joined: Nov 2008
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From: Seattle Washington
Do the Spark Plugs have the little Bushings screwed on the Tips where the Plug Caps go on ? Some engines back in the 60's and 70's had them removed. If there gone the Plugs would have a threaded stud coming out the end. When You push a Spark Plug Cap on does it feel like it is locking on ?
Drifting
Joined: Oct 2020
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From: Wisconsin
Wow, never heard of that much trouble with wires popping off. I’ve got probably the cheapest set of HEI wires you can imagine, and they’ve stayed put for 3,000 miles.
It sounds silly, but I wonder if the boots have such a tight seal that the heat buildup (either from engine heat or an arcing contact) causes the trapped air to expand and push the boot off. I’d pick one that likes to pop off and try slipping a toothpick or something non-conductive in alongside the plug to just break the boot seal and see if that helps.
Oh and don’t take this the wrong way, but you are putting the spark plug boot on the plug and not the dizzy cap end, right? Just want to make sure we have that simple mistake out of the way…
It sounds silly, but I wonder if the boots have such a tight seal that the heat buildup (either from engine heat or an arcing contact) causes the trapped air to expand and push the boot off. I’d pick one that likes to pop off and try slipping a toothpick or something non-conductive in alongside the plug to just break the boot seal and see if that helps.
Oh and don’t take this the wrong way, but you are putting the spark plug boot on the plug and not the dizzy cap end, right? Just want to make sure we have that simple mistake out of the way…
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From: New Or-leens Loo-z-anna
I actually had one Delco spark plug that blew off the boot after a couple hours of driving.
No matter which cylinder I moved the new plug to, it would blow off the boot.
I finally realized the new spark plug leaked compression gases after a couple hours of driving.
But 3 diiferent boots in your case...I doubt you have my problem.
No matter which cylinder I moved the new plug to, it would blow off the boot.
I finally realized the new spark plug leaked compression gases after a couple hours of driving.
But 3 diiferent boots in your case...I doubt you have my problem.
Burning Brakes
Joined: Dec 2005
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Buy a tube of SilGlide @ NAPA. Put a squirt in each boot. Makes it easier to put on AND take off without tearing the boot
5 years from now.
Push it on until the plug wire SNAPS onto the plug.
I suspect you're just not pushing hard enough. You'll hear / feel it snap. Do you?
You putting the correct end on the plug, and on the HEI post?
The only other choices are exceedingly poor tolerances on the HEI posts or defective wires.
5 years from now.
Push it on until the plug wire SNAPS onto the plug.
I suspect you're just not pushing hard enough. You'll hear / feel it snap. Do you?
You putting the correct end on the plug, and on the HEI post?
The only other choices are exceedingly poor tolerances on the HEI posts or defective wires.
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From: Allen TEXAS
Wade, thanks for the input. I questioned myself on this, but surely I am now stronger and smarter than when in high school (I hope). I can feel the tip going in place, but lacks a distinct snap, like they did on the distributor.
I have not yet applied silicone in the boot. I think that will be my next try, along with a little tightening of the clip in the boot.
Thank you!
Bill
I have not yet applied silicone in the boot. I think that will be my next try, along with a little tightening of the clip in the boot.
Thank you!
Bill
Le Mans Master
Joined: Jun 2019
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From: Indiana
no clue what size fits HEI non GM.. but i got AC DELCO OEM wires from rock auto for a 79 HEI and the yare very high quality.. maybe try those.. and cheap enough.. any parts that say OEM (not professional, gold etc..) are great still!
Safety Car
Joined: Nov 2008
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From: Seattle Washington
In the above post there was mention of a bad spark plug leaking combustion gas into the boot. I have never herd of such a thing but anything is possible. Maybe try a different set of plugs or at least the clyinders that you know have popped of in the past.
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Joined: Jan 2016
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From: Allen TEXAS
All, THANK YOU for all of your inputs. I have been working with plugs and wires and all things cars since the '70s, and have never had these types of issues... The missing link is apparently some dielectric grease.
I have concluded (for now) that the boots must be of a different material, and not slipping over the plug completely, and the compressed boot then pushes itself off the plug. My technique of installing by twisting and securing the connector of the plug is the same, but unsuccessful.
My current solution is to use small amount of dielectric grease on a swab to use inside the boot. This seems to have helped slide the boot completely onto the plug, and not becoming compressed. I finally had a successful calibration drive, without a boot coming off. I hope that continues, or I will be back with an update. When I get some spare time, I may grease the set of Accel 4041 wires and reinstall them to confirm this technique.
Thank you again!!
Bill
I have concluded (for now) that the boots must be of a different material, and not slipping over the plug completely, and the compressed boot then pushes itself off the plug. My technique of installing by twisting and securing the connector of the plug is the same, but unsuccessful.
My current solution is to use small amount of dielectric grease on a swab to use inside the boot. This seems to have helped slide the boot completely onto the plug, and not becoming compressed. I finally had a successful calibration drive, without a boot coming off. I hope that continues, or I will be back with an update. When I get some spare time, I may grease the set of Accel 4041 wires and reinstall them to confirm this technique.
Thank you again!!
Bill
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Joined: Sep 2016
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From: Michigan
I've experienced this recently also. Moroso wires on A/C plugs.
I ca trace my issue to just 2 particular boots, and they're the ones that are closest to their respective header pipes.
So, I think the heat contributes to their susceptibility to pop-off, especially during a long, hot drive.
When I start to hear some back-firing on decel (I also have a Holley EFI), I know I've got to pop the hood and check plugs #3 and #4.
I've got the finger burns to remember this by!
I ca trace my issue to just 2 particular boots, and they're the ones that are closest to their respective header pipes.
So, I think the heat contributes to their susceptibility to pop-off, especially during a long, hot drive.
When I start to hear some back-firing on decel (I also have a Holley EFI), I know I've got to pop the hood and check plugs #3 and #4.
I've got the finger burns to remember this by!
Le Mans Master
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
I don't know how you guys route your wires but. I run 10 mm Taylor wires that have been on 10 years with no issues. Perhaps it's your sniper system. I don't know.