Engine oil
Thread Starter
Heel & Toe
Joined: Feb 2024
Posts: 23
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Engine oil
I bought a 78 C3 last winter. The previous owner was using full synthetic 10/30 . The motor was rebuilt years ago with cylinders bored out and bigger cam put in. I was talking to a few people who have older cars and they both run Valvoline VR1 20/50 .They say with the zinc and heavier weight its better on the engine. Can I go back to conventional oil after running synthetic? I read where people say you can and some say you can't ?. I figured I would ask Corvette owners to make my decision. Thanks
Race Director
Joined: May 2006
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I bought a 78 C3 last winter. The previous owner was using full synthetic 10/30 . The motor was rebuilt years ago with cylinders bored out and bigger cam put in. I was talking to a few people who have older cars and they both run Valvoline VR1 20/50 .They say with the zinc and heavier weight its better on the engine. Can I go back to conventional oil after running synthetic? I read where people say you can and some say you can't ?. I figured I would ask Corvette owners to make my decision. Thanks
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I personally run 20W-50 mineral base oil formulated for older cars with a high zinc content.
Yes I live in a very warm climate. But years ago I lived in Northern Wisconsin. I ran 20W-50 back then as well. But never drove the car in the winter months.
Yes I live in a very warm climate. But years ago I lived in Northern Wisconsin. I ran 20W-50 back then as well. But never drove the car in the winter months.
Is my vette stock?? HAHA
Joined: Oct 2015
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From: Im not allowed to tell you
2020 C3 of the Year Finalist - Modified
2020 Corvette of the Year Finalist (performance mods)
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just run oil with high Zinc and Phosphorous so you dont flatten the cam...also referred to as ZDDP. I run Mobil one 15w 50 with zero issues...oil stays where its needed. Never heard of high oil pressure being a bad thing but there ya go
oil pressure is a by product of oil in the bearing creating a restriction that is felt at the pump and seen as a reading on a gauge...less restriction means more space at the bearing and no oil in there so low oil pressure reading....higher oil pressure means the oil is being held in the bearings....
oil pressure is a by product of oil in the bearing creating a restriction that is felt at the pump and seen as a reading on a gauge...less restriction means more space at the bearing and no oil in there so low oil pressure reading....higher oil pressure means the oil is being held in the bearings....
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Your feet are several decades old, but you don't wear Keds 'high top' gym shoes anymore. Put synthetic oil in the engine and allow it to live a much longer life. If you feel you need to add zinc, have at it.
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