Spark plug gap for 68 350 w/ Pertronix?
#1
Spark plug gap for 68 350 w/ Pertronix?
Upgraded to a Pertronix electronic ignition a couple months ago and put in some AC Delco R46S that I bought from ebay but lately I've been experiencing some misfire and rough idle/engine shake at idle. I came to the conclusion I just dont trust the old plugs. Going to be replacing them with either Autolite 86 or NGK but need to know the proper gap. I fished through threads and some recommended keeping it at stock .35 and some say take it up to .45. It has a Mallory high output ignition coil. I will most likely be going with the Autolite 86 plugs for cost efficiency. Suggestions? Thanks
#2
Just an Olds Guy
Join Date: Jul 2008
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
I'd start the new plugs at .040 and see how that works. A gap of .35 or .45??? I don't think so. Just messing with you. I know you meant .035 , .045
The 80's and 90's HEI's would run gaps of .050 - .080 depending on year. I don't think you want to go that high.
The rough idle and shake doesn't sound spark related, suggest you check your timing and fuel mixture settings
The 80's and 90's HEI's would run gaps of .050 - .080 depending on year. I don't think you want to go that high.
The rough idle and shake doesn't sound spark related, suggest you check your timing and fuel mixture settings
#3
I agree with Allan. Pertronix suggested with my unit to go up to .035 from .030 gap for my application. Thats where I am at now and it seems good. I run Autolight 85's. They seem to hold up pretty well.
I haven't had the best of luck with ebay/internet buys related to my car. When I can, I like to have the part in my hand to do the old chinese diagram to see if the peice/part fits my application.
Your problem may be timing related.
I haven't had the best of luck with ebay/internet buys related to my car. When I can, I like to have the part in my hand to do the old chinese diagram to see if the peice/part fits my application.
Your problem may be timing related.
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