I’m in California and changing my transmission fluid. I figured I could change the oil while I’m at it. Thoughts on oil for a 302? After doing some searching it seems like people have varied opinions on synthetic vs. conventional.
It’s not going to make any noticeable difference except at the cash register when you buy it.
Any suggestions on oil? 10W-30? Would the synthetic last longer?
The owner’s manual will tell you what oil grade to use for any given temperature. The only way a synthetic oil makes sense is if you put lots of mileage on a vehicle in a short calendar period. Otherwise you get no benefit, because you should change oil at least annually to get rid of accumulated moisture from humidity in the air and condensation inside the engine.
The advantage of a synthetic oil is almost nothing in an old technology engine like yours. It is recommended and even mandatory in some newer high tech cars or trucks, especially in turbocharged or supercharged applications where oil really takes a beating and high oil temperatures are present.
flat tappet or roller camshaft? with flat tappet cam and lifter you’ll need more zink additive. Synthetic oil is not necessarily better for old engine.
My recommendation, for a flat-tappet motor, is an engine oil with a API classification of SF, SG or older. This ensures a satisfactory and high level of ZDDP. 15W40 or 20W50 conventional oil is good chance in warm CA, 10W in colder areas.
My car is 1970 / 351W with flat-tappet camshaft.
I use Z-Rod from Amsoil, actually a 50/50 blend of 10W-30 & 20W-50. They both contain the right quantity of ZDDP (Zinc additive needed to protect flat tappet) along with other additives to protect engine against humidity and rust during long storage. I blend them to approximate the 10W-40 viscosity that I would like to have. They are synthetic, some say that synthetic oils leak more than mineral oils, especially if you already have leaks - but this has not happened in my car with these ones. They are not cheap, but you do not need to add Zinc seperately.
Links:
https://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-10w-30-synthetic-motor-oil/?code=ZRTQT-EA
https://www.amsoil.com/shop/by-product/motor-oil/gasoline/z-rod-20w-50-synthetic-motor-oil/?code=ZRFQT-EA
While not really a factor for the classic cars, just adding that I find synthetic oil helpful in our daily drivers during winters in the frozen Northeast. It flows better in extreme cold, so when you’re in ski country & its 5 below & your car’s been sitting for a few days, it can still crank over. Conventional oil tends to resemble molasses at those temps.
What part of Cali?
My engine builder recommended that I use Joe Gibbs (now known as Driven) racing oil, even though my car is just a 289-2V driver. It has higher levels of Zinc than regular oils, and other helpful additives supposedly. I still have the break-in version of their oil in my Cougar currently, since I’ve put less than a mile on it since the rebuild.
Personally I use Valvoline VR-1. It has the same ZDDP that it has always had, which is to say a lot. It is sold at every Wal Mart in the country for $24 / 5 quart jug. You can’t buy any better oil for your Cougar. It comes in a variety of grades so you can use it in summer or winter.
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Royce, I hear you and agree about synthetic oil losing it’s benefits where most of us change based on time rather than miles. But my local Walmart has VR1 synthetic for about the same price as petroleum based. I’m tempted to go synthetic, thinking I can then go from 1 to 2 years between changes.
But I also know synthetic can find its way past seals and leak easier. I don’t currently have any oil leaks, and my engine has all new seals, valve guides, and gaskets. But would I be pushing my luck going to synthetic?
I run 10W-30 in my 351C as recommended by the owners manual, and don’t change oil based on seasons. I’m in KC, so a little cooler than where you are. What viscosity do you run?
I run what my (now deceased) engine builder recommended - Valvoline VR-1 20W-50.
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20W-50 makes sense for high temp summer driving. We probably aren’t driving our cars when it’s below 0. Anyone have opinions on synthetic vs. regular oil if both are same price?
One of the wonderful things about synthetic oil is if you have an oil leak….it will find it. If you have an oil leak… it will make it worse.
OK. If your engine is smoking, synthetic will not blow smoke as noticeable. So, there is that.
I’m sticking with a good dino oil with a zinc additive. The advantage of synthetic just not worth it to me.
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Ok, thanks for confirming! I agree and am heading to Walmart now for some Valvoline VR1 dino oil.