Oil Change
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
If your engine is stock (L-48 or L-82), just purchase a good quality oil with a viscosity rating suitable for your local climate. Your engine does not require any zinc additive other than what the oil already contains.
BTW, you will get lots of folks on either side of this issue, but the increased levels of zinc are usually recommended for engine valve trains that use highly loaded springs which generate lots of loading on the flat-tappet lifters. Your lifters are hydraulic type...not solid lifters; and the valve spring rates nominal.
BTW, you will get lots of folks on either side of this issue, but the increased levels of zinc are usually recommended for engine valve trains that use highly loaded springs which generate lots of loading on the flat-tappet lifters. Your lifters are hydraulic type...not solid lifters; and the valve spring rates nominal.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
http://forums.corvetteforum.com/c3-t...ppet-oils.html
Stock flat tappet should have 1000 PPM ZDDP. Modern SM-SN rated oils are 600-800 PPM thanks to the EPA.
Higher lift, spring pressure and solid need more depending on how extreme the build.
There are quite a few locally available oils reasonably priced.
Stock flat tappet should have 1000 PPM ZDDP. Modern SM-SN rated oils are 600-800 PPM thanks to the EPA.
Higher lift, spring pressure and solid need more depending on how extreme the build.
There are quite a few locally available oils reasonably priced.
Last edited by 63mako; Jul 17, 2012 at 12:47 AM.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
There are a million opinions as to the correct engine oil. There are outfits that sell the ZDDP additive, if you want to try that.
You also might like to install an oversize truck type oil filter when you do change your oil. The bigger filters have more surface area inside, so the pressure drop across the filter is less. I suspect a small (AC 25) car type filter is in bypass mode a lot of the time. You can swap in a pickup truck type filter (AC 35) or even a medium truck sized filter (AC 932), if you don't have headers. (Those are the old numbers from out of my head- I'm know a good counterman could give you the current replacements.)
PS- When I had my engine rebuilt, the builder put on an El Cheapo Fram filter when he delivered the new engine. I ran it for an hour on initial startup and then changed the oil and filter. When I cut the filter open, I was puzzled to discover there was nothing on the filter media. I replaced it with a AC Delco pickup truck sized filter. After 1000 miles, I removed that filter and cut it open. It was absolutely filled with lint from shoprags. The Fram filter had stopped nothing. It was likely so restrictive that no oil actually got pumped through the filter- it was in bypass mode the whole time.
You also might like to install an oversize truck type oil filter when you do change your oil. The bigger filters have more surface area inside, so the pressure drop across the filter is less. I suspect a small (AC 25) car type filter is in bypass mode a lot of the time. You can swap in a pickup truck type filter (AC 35) or even a medium truck sized filter (AC 932), if you don't have headers. (Those are the old numbers from out of my head- I'm know a good counterman could give you the current replacements.)
PS- When I had my engine rebuilt, the builder put on an El Cheapo Fram filter when he delivered the new engine. I ran it for an hour on initial startup and then changed the oil and filter. When I cut the filter open, I was puzzled to discover there was nothing on the filter media. I replaced it with a AC Delco pickup truck sized filter. After 1000 miles, I removed that filter and cut it open. It was absolutely filled with lint from shoprags. The Fram filter had stopped nothing. It was likely so restrictive that no oil actually got pumped through the filter- it was in bypass mode the whole time.
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Team Owner
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From: Southbound
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From: Seattle WA
St. Jude Donor '14
A 1978 engine was designed for API SF oil with 1,500 ppm ZDDP. A modern API SM/SN oil will have at most 600 ppm ZDDP and approximately 1/2 that amount of ZDDP at 3,000 miles.
With the light spring pressures and comparatively mild cams of some C3 engines you *may* get away with an oil with less than 1/2 (or 1/5th) the amount of ZDDP originally expected by the engineers. And then again, you may not.
Why bet your engine on around $25 per oil change - less if you run synthetic?
http://forums.corvetteforum.com/c3-t...ppet-oils.html
With the light spring pressures and comparatively mild cams of some C3 engines you *may* get away with an oil with less than 1/2 (or 1/5th) the amount of ZDDP originally expected by the engineers. And then again, you may not.
Why bet your engine on around $25 per oil change - less if you run synthetic?
http://forums.corvetteforum.com/c3-t...ppet-oils.html
If you use a flat-tappet cam run an oil from this list or another oil you're sure has at least 1000 ppm ZDDP. No additives (other than for break-in), no diesel oils, no racing oils and no miracle cures - just the right oil.
Last edited by billla; Jul 21, 2012 at 03:35 PM.
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Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
And then you have this:http://www.nonlintec.com/sprite/oil_myths.pdf
With Billa. That link is 
. See my post on your thread on it.
Le Mans Master
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That link is from Bob's the oil guy. That guy you like to qoute all the time.
You know the guy. The same GM engineer that explained the factory phosphorous coating.
You know the guy. The same GM engineer that explained the factory phosphorous coating.
Last edited by Big2Bird; Jul 21, 2012 at 08:37 PM.
Le Mans Master
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Race Director
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From: Millington Illinois
St. Jude Donor '08-'09
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
http://www.bobistheoilguy.com/forums...Number=1049812
Best solution!
Advanced
Joined: Jun 2012
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From: Suffolk,VA
1969 427 390hp
I am a newer member to the forum, i have been reading through the posts and my question is: Is my 69 427 L36?? a flat-tappet engine. Do I need to be concerned with zinc levels inthe oil? The vavoline VR1 10w30 looks to be a good choice for added zinc. Bob
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Never going to happen- not in our lifetime anyway. Unleaded gas has been been around for 40 years and there's still people that think it's the worst thing ever...........
Last edited by Mike Ward; Jul 22, 2012 at 10:52 AM.
Race Director
Joined: May 2005
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From: Millington Illinois
St. Jude Donor '08-'09
i am a newer member to the forum, i have been reading through the posts and my question is: Is my 69 427 l36?? A flat-tappet engine. yes do i need to be concerned with zinc levels inthe oil? yes the vavoline vr1 10w30 looks to be a good choice for added zinc. Boba
there are 3 different vr1 10w-30.
1. Vr1 10w-30 racing oil,
2. Vr1 10w-30 racing oil "not street legal"
3. Vr1 10w-30 synthetic racing oil.
Any racing oil will need changed more often than every 3000 miles as the additive package is designed for racing use. Race engines get very frequent oil changes..
there are 3 different vr1 10w-30.
1. Vr1 10w-30 racing oil,
2. Vr1 10w-30 racing oil "not street legal"
3. Vr1 10w-30 synthetic racing oil.
Any racing oil will need changed more often than every 3000 miles as the additive package is designed for racing use. Race engines get very frequent oil changes..