Quality Ignition Parts
Thread Starter
Instructor
Joined: Aug 2015
Posts: 154
Likes: 17
From: LA
Quality Ignition Parts
This craps getting old. This cap has less than 1000 miles on it. I was out test driving a new carb, when it started missing terribly. Thank goodness I was only 10 miles from home. Either my car has some sort of electrical gremlins, or these parts are just junk right out of the box. I’m now on my third cap and rotor in less than 2 years. 🤨
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
If all three units came from the same supplier, then yes they are suspected quality. If all three are different brands / suppliers, YOUR system is suspect. I wonder if your coil under the cap is running unusually hot for some reason? Not grounded properly? Faulty spring button? Rubber washer in place under the coil? IDK
Thread Starter
Instructor
Joined: Aug 2015
Posts: 154
Likes: 17
From: LA
The first cap and rotor appeared to be generic that came with the HEI unit. Used unit off of eBay. Next was an Echlin from Napa, this one was from Oreillys......don’t remember the brand. Improper grounding is something I hadn’t thought about. The previous owner hacked up a lot of the wiring at the firewall in an attempt to splice in an after market MSD unit. It ran poorly, so I replaced with standard HEI unit. Did my best to straighten out the wiring to get the right connectors to connect to the cap. Thought I had it because the car runs good and the tach functions as it should. The tang on the rotor looks burned as well, and I know there’s a recommended clearance, but I’ve never attempted to check it. Not sure how you would. And I’ve never bent the tang, just installed as is out of the box. I put another cap and rotor on yesterday evening......back to running good again.��
Last edited by 73BBVette; Jun 28, 2018 at 09:31 AM.
Race Director
Joined: May 2006
Posts: 18,709
Likes: 2,574
That cap doesnt appear to be using brass for the contacts, How about an Accel cap and rotor?
https://www.holley.com/products/igni...ors/parts/8122
https://www.holley.com/products/igni...ors/parts/8122
Pro
Joined: Jan 2016
Posts: 502
Likes: 103
From: Reno Nevada
You didn't mention the brand at Oreily's. I have stuck with purely AC Delco or Holley for years due to this very issue. There may be a few other brands that are good too. Unfortunately while Accel used to be a great brand, I hear their quality has gone down in recent years and is basically the foreign brand for Holley these days. Not sure if that is true or not.
I have replaced too many brakes, alternators, starters, etc with parts from NAPA, Autozone, OReillys, etc. Their "guarantee" is not worth much if you have to replace the part 5 times.
Stick with the best quality, genuine AC Delco cap from wherever you wish to buy it from. Yes, you will likely pay more, but you hopefully wont have to replace it again anytime soon.
For the HEI cap:
https://www.rockauto.com/en/moreinfo...sn=940&jsn=940
I have replaced too many brakes, alternators, starters, etc with parts from NAPA, Autozone, OReillys, etc. Their "guarantee" is not worth much if you have to replace the part 5 times.
Stick with the best quality, genuine AC Delco cap from wherever you wish to buy it from. Yes, you will likely pay more, but you hopefully wont have to replace it again anytime soon.
For the HEI cap:
https://www.rockauto.com/en/moreinfo...sn=940&jsn=940
Last edited by 73racevette; Jun 28, 2018 at 04:27 PM.
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Thread Starter
Instructor
Joined: Aug 2015
Posts: 154
Likes: 17
From: LA
Thanks for the suggestions. Most of these caps look like molded plastic and are thin. I believe the originals were Bakelite and much heavier. I’m going to try and find one of those, and If I still have issues, then it’s an electrical issue.
Burning Brakes
Joined: May 2018
Posts: 797
Likes: 156
From: England AR
DuPont™ Rynite® modified polyethylene terephthalate (PET) resin is well-matched to applications requiring durable electrical and electronic performance such as coil forms and electrical encapsulation, and offers a high-gloss finish. Its lightweight, glass-reinforced composition provides dimensional stability, making it a prime candidate for the replacement of die-cast metals and thermosets. This stiff, UV-resistant polymer offers a balance of thermal, mechanical and chemical properties.
Le Mans Master
Joined: Nov 2003
Posts: 5,772
Likes: 694
From: Maryland
St. Jude Donor '05, '09, '15
The first cap and rotor appeared to be generic that came with the HEI unit. Used unit off of eBay. Next was an Echlin from Napa, this one was from Oreillys......don’t remember the brand. Improper grounding is something I hadn’t thought about. The previous owner hacked up a lot of the wiring at the firewall in an attempt to splice in an after market MSD unit. It ran poorly, so I replaced with standard HEI unit. Did my best to straighten out the wiring to get the right connectors to connect to the cap. Thought I had it because the car runs good and the tach functions as it should. The tang on the rotor looks burned as well, and I know there’s a recommended clearance, but I’ve never attempted to check it. Not sure how you would. And I’ve never bent the tang, just installed as is out of the box. I put another cap and rotor on yesterday evening......back to running good again.��
Tom
Team Owner
Joined: May 2001
Posts: 87,334
Likes: 1,590
From: Western NY
If the "tang" you are talking about is the center contact on the rotor there should not be clearance between it and the center contact in the cap. There should be contact. If there is clearance you will see just what you have. A melted cap from the spark jumping across the gap which creates heat.
Tom
Tom
To the OP, is the rubber "gasket" in place, between the base of the distributor cap and the bottom side of the coil? Does it have a good coating of dielectric grease on both sides?
Thread Starter
Instructor
Joined: Aug 2015
Posts: 154
Likes: 17
From: LA
Originally Posted by Sky65 [img]images/buttons/viewpost.gif[/img]
If the "tang" you are talking about is the center contact on the rotor there should not be clearance between it and the center contact in the cap. There should be contact. If there is clearance you will see just what you have. A melted cap from the spark jumping across the gap which creates heat.
[img]images/smilies/cheers2.gif[/img]
Tom
[img]images/smilies/iagree.gif[/img]
To the OP, is the rubber "gasket" in place, between the base of the distributor cap and the bottom side of the coil? Does it have a good coating of dielectric grease on both sides?
If the "tang" you are talking about is the center contact on the rotor there should not be clearance between it and the center contact in the cap. There should be contact. If there is clearance you will see just what you have. A melted cap from the spark jumping across the gap which creates heat.
[img]images/smilies/cheers2.gif[/img]
Tom
[img]images/smilies/iagree.gif[/img]
To the OP, is the rubber "gasket" in place, between the base of the distributor cap and the bottom side of the coil? Does it have a good coating of dielectric grease on both sides?