Cap and Rotor life?
Thread Starter
Melting Slicks
Joined: Jul 2010
Posts: 2,759
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Cap and Rotor life?
How often do the cap & rotor need to be changed on a '77 with HEI, all is stock?
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,330
From: At my Bar drinking and wrenching in Lafayette Colorado
The HEI system was designed to reduce maintenance and increase service intervals. The HEI components will easily run 50,000 between cap/rotor replacements, and I've run them as much as 100,000 before getting misfire and issues (I put 500,000 miles on an HEI-system Vette that I used as a daily driver with no engine or trans rebuild or any other maintenance issues, replacing cap and rotor only when it started misfiring around 100K). 
Lars
Lars
Last edited by lars; Jan 14, 2018 at 11:18 PM.
Le Mans Master
Joined: Dec 2006
Posts: 8,837
Likes: 1,027
The HEI system was designed to reduce maintenance and increase service intervals. The HEI components will easily run 50,000 between cap/rotor replacements, and I've run them as much as 100,000 before getting misfire and issues (I put 500,000 miles on an HEI-system Vette that I used as a daily driver with no engine or trans rebuild or any other maintenance issues, replacing cap and rotor only when it started misfiring around 100K).
Lars
Lars
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
I have changed them more frequent than
50k.
I might be on my 4th in 85k.
I finally went to a brass electrode cap.
thing doesn't show the arc wear the alum one do.
cheap part anywho.
50k.
I might be on my 4th in 85k.
I finally went to a brass electrode cap.
thing doesn't show the arc wear the alum one do.
cheap part anywho.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,330
From: At my Bar drinking and wrenching in Lafayette Colorado
You were replacing HEI system components every 21,000 miles..?? That's crazy: That's the tune-up and service interval of the standard points-type systems. The whole design purpose of the HEI was that it would easily outlast points service interval by 100%. You must have been getting some exceptionally poor quality components - I've never seen HEI components fail after 21K, and I worked at the GM Training Center as an HEI Systems Instructor in the mid-70's - I had access to the failure and service records. There were occasional module failures, but never a cap or rotor failure in 21K. Never.
Lars
Lars
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