Additives to fuel?
Thread Starter
Racer
Joined: May 2003
Posts: 432
Likes: 0
From: Manchvegas NH
Additives to fuel?
The Marvel Mystery Oil thread has lead me to this question:
When I bought my car, the owner told me that he had the engine rebuilt once, and he used the original type valves and lifters that require leaded gas as a lubricant. For years, I have been adding the Lead Substitute to my fuel, with the hopes that this is the best thing to do to protect these parts.
Is this true - is this the best thing I can do? What do you other owners of the older C3's do? I tried the MMO in the fuel for a season, but didn't feel satisfied that it was protecting the engine, so switched back to the additive. Or is the additive just bunk and really doesn't so anything?
When I bought my car, the owner told me that he had the engine rebuilt once, and he used the original type valves and lifters that require leaded gas as a lubricant. For years, I have been adding the Lead Substitute to my fuel, with the hopes that this is the best thing to do to protect these parts.
Is this true - is this the best thing I can do? What do you other owners of the older C3's do? I tried the MMO in the fuel for a season, but didn't feel satisfied that it was protecting the engine, so switched back to the additive. Or is the additive just bunk and really doesn't so anything?
Race Director
Joined: Jun 2001
Posts: 16,483
Likes: 1
From: The Only Corvette in Gila Bend, Az.
St. Jude Donor '09
Re: Additives to fuel? (pra4sun)
The only thing the lead did was to lubricate the top end & valves, I might be wrong by saying this, but I think you could run without the additive, and not worry about harming anything for many miles....
Burning Brakes
Joined: Jul 2001
Posts: 1,160
Likes: 0
From: Ajax Ontario
Re: Additives to fuel? (pra4sun)
I was told by my engine builder that for vehicles that see limited use (mine sees about 4,000 miles per year) that it isn't worth the risk of putting the hardened seats in it. The risk is that you can damage the heads during installation or have a seat "let go" when running which could be fatal to your engine. It's not as simple a procedure as it sounds. His advice was put lead additive in if it makes you sleep better, but otherwise just drive it and don't worry about it. I have the "double hump" heads with 2.02/1.60 valves.
Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Additives to fuel? (pra4sun)
Thanks 68shark!
It's good to know that not using the additive won't cause any huge damage.
I'll probably keep using it - force of habit! :D
It's good to know that not using the additive won't cause any huge damage.
I'll probably keep using it - force of habit! :D
Burning Brakes
Joined: Jul 2001
Posts: 1,160
Likes: 0
From: Ajax Ontario
Re: Additives to fuel? (BeaterShark)
I don't agree that it won't cause any damage. When I bought my car, it had 3 burnt exhaust valves due to the unleaded gas and no additive.
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Drifting
Joined: Sep 1999
Posts: 1,411
Likes: 1
From: Wylie TX
Re: Additives to fuel? (68shark)
I can't be 100% sure, but I had 3 dead cylinders (ran the same with plug wires disconnected) and when I pulled the heads, it had a bad case of valve recession. The heads were rebuilt with hardened seats and it ran *much* better.
I don't know what else causes valve recession, but I do know that running unleaded gas w/o hardened seats will. Also, the machine shop thought is was due to unleaded gas.
I don't know what else causes valve recession, but I do know that running unleaded gas w/o hardened seats will. Also, the machine shop thought is was due to unleaded gas.
Burning Brakes
Joined: Jul 2001
Posts: 1,160
Likes: 0
From: Ajax Ontario
Re: Additives to fuel? (BeaterShark)
Something I forgot, seeing it's been three summers since I had my engine done was that the headwork included a "three angle valve job". I'm not the best guy to explain it, but as I understand it, the angles effectively broadens the area of the seat that could otherwise be prone to failure. I was told I would probably have to rebuild/re do other items in the engine, long before I had seat recession problems.
This is an interesting topic with many differing opinions. Friend of mine has owned a '64 coupe (300hp 327) since 1981. Drives it a fair bit, has been "spotty" with using the lead additive and in twenty years of driving, car still runs fine on prem. unleaded. He doesn't know the mileage because the odometer has never worked during the time he's owned it.
This is an interesting topic with many differing opinions. Friend of mine has owned a '64 coupe (300hp 327) since 1981. Drives it a fair bit, has been "spotty" with using the lead additive and in twenty years of driving, car still runs fine on prem. unleaded. He doesn't know the mileage because the odometer has never worked during the time he's owned it.
