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I want to get people’s opinion of full synthetic oil for a low mileage L68. Synthetic has come a long way and has been proven to enhance all motors. Having said that, I still have no problem with high grade non synthetic. I always ran synthetic in my Harleys, but that’s a little different. I’ve always been a fan of Castrol and Mobile One. Usually 10/40. Your opinion would be greatly appreciated, thx
Dave
I have used Dino oils since '73 w/61K and the same after the rebuild at 112K, now at 242K. Used Castrol 10W40 up to 230K, then switched to Shell Rotella 15/40. Dennis
My view is I use synthetic in cars I put a lot of miles on and tend to rack up a lot miles between changes. That doesn’t fit the use pattern of my old cars. Nothing wrong with running synthetic (of proper API) in an old car with limited use and changing it out every 500 to 1000 miles and 10 to 15% of its useful life.. It’s only money.
I want to get people’s opinion of full synthetic oil for a low mileage L68. Synthetic has come a long way and has been proven to enhance all motors. Having said that, I still have no problem with high grade non synthetic. I always ran synthetic in my Harleys, but that’s a little different. I’ve always been a fan of Castrol and Mobile One. Usually 10/40. Your opinion would be greatly appreciated, thx
Dave
Your oil needs zinc in it. You may have to add it to synth oil.
Oil technology has come a long way and also engine technology in the last 50 years. Sealing of the combustion chambers, better ring and valve sealing, along with more efficient fuel burn has nearly eliminated the contamination of the oil. Thus 5,000 or 7,000 or even 10,000 miles between changes is not unheard of.
In these old relics, the oil is going to get dirty in 1,000 to 2,000 miles and the dirt that is not filtered out will eat at the bearings in the engine. Thus the life expectancy of the old relics is much less.
If you want to use synthetic oil with zinc for flat tappet cams and change it at the same interval as conventional oil, I can't think of any reason not to use it other than $$$$$$.
Just $.02, take it for what it is worth.
My take is that synthetics are especially useful for long drain intervals and for high-heat environments, like turbo bearings. The latter is why I use full synthetic in my modern cars.
In the old cars, though, I just run Rotella and change it every two years (typically around 1000 miles).
I have used Dino oils since '73 w/61K and the same after the rebuild at 112K, now at 242K. Used Castrol 10W40 up to 230K, then switched to Shell Rotella 15/40. Dennis
Rotella carries "C" API ratings. The C represents Commercial (primarily diesel) formulation. API ratings starting with S (Service) are mostly for gasoline/ignition engines. Older engines with flat-bottom lifters also require zinc in the oil formulation, which was removed when cars started using catalytic converters. In days past, we thought of the C for Combustion (diesel) engines and the S for Spark (gasoline) engines.
Use whatever you want, these are just some basic observations. As others have said, the API designation is the most important part of choosing engine oil. An API rating brochure is attached.
Last edited by carterchris; Jul 17, 2023 at 07:33 AM.
It's fully synthetic.
It's phosphor/zinc content is 1200/1300 ppm
It's certified API SP, SN, and SN+
It's available at Walmart for $25 for a 5 quart jug.
I think that's a great choice for the engine you mentioned. I also mess with old British cars and engines - Triumph & Jaguar mostly. Triumphs are OHV with flat bottom lifters, and Jaguars are DOHC with flat cam followers. After much research, I use Castrol GTX 20w50 High Mileage with a Rislone ZDDP additive. The synthetic blend makes it nice and slippery, 20w50 was originally specified, High Mileage gives the oil seals some juice, and the ZDDP addresses the flat lifters/followers.
Not that anyone asked, just contributing. BTW - I use full synthetic Mobil 1 in modern, non-vintage engines.
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Originally Posted by SDVette
I run Mobil1 15W50 in my LT-1.
It's fully synthetic.
It's phosphor/zinc content is 1200/1300 ppm
It's certified API SP, SN, and SN+
It's available at Walmart for $25 for a 5 quart jug.
Oil question
Dennis
