Lead Substitute with 68 heads?
March 9th, 2018, 06:26 PM
#1
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Join Date: Jan 2016
Posts: 99
Lead Substitute with 68 heads?
I have a 71 olds 455 that I have 68 C heads installed on, the heads are stock as far as I know.
I always assumed from the start that the lead substitute was necessary, but I thought I'd ask.
Do 68 C heads require lead substitute?
What happens if I stopped using it?
I always assumed from the start that the lead substitute was necessary, but I thought I'd ask.
Do 68 C heads require lead substitute?
What happens if I stopped using it?
March 9th, 2018, 06:43 PM
#2
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Location: Poteau, Ok
Posts: 40,525
Its up to you if you want to use a lead substitute or additive. I've never used any and have seen no ill effects on any of my nor any others here in Texas. People have said that you get valve seat recession but as of yet I have never seen nor heard of any.
March 12th, 2018, 05:49 PM
#5
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Location: central Indiana
Posts: 5,233
If the engine is run hard, at high rpm consistently, you will eventually have valve seat issues. If the heads are on the car, and you don’t have any problems I’d wait until you do need to pull the heads for other reasons. If it ain’t broke don’t fix it.
Last edited by matt69olds; March 14th, 2018 at 08:27 AM.
March 12th, 2018, 10:04 PM
#6
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Join Date: Mar 2011
Posts: 558
The way it was explained to me, exhaust valves get red hot. The hot valves microscopically weld themselves to the seat and very gradually and pull away seat material if the seats are not hardened.
Thats why if the car is ran hard there’s a greater chance of running into issues. Hotter conditions + more rpm results in a more likely event of seeing recession.
The next logical step I can think of instead of replacing seats is using softer valves so the seat wins the boxing match. But I don’t know if that’s a thing. Never heard of it talked about.
Thats why if the car is ran hard there’s a greater chance of running into issues. Hotter conditions + more rpm results in a more likely event of seeing recession.
The next logical step I can think of instead of replacing seats is using softer valves so the seat wins the boxing match. But I don’t know if that’s a thing. Never heard of it talked about.
Last edited by VinMichael; March 12th, 2018 at 10:07 PM.
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