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I will be changing the oil in a 1973 350 L48. I was wondering if anyone had any specific motor oil recommendations for durability and reduction of wear etc. Thanks.
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Re: Speaking of Oil
!5W-40 HD diesel engine oil. API service category CI-4, any brand.
Duke -
Re: Are you seriousl
Why diesel oil...Comment
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Re: Are you seriousl
Do some research in the archives. This has been hashed over a number of times.
DukeComment
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Re: Are you seriousl
Curtis,
Search the archives for "Duke" and "diesel" as your key words and you will find much good info on the subject.Comment
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Re: Are you seriousl
HASHED, BASHED, SLICED AND DICED. I still use 10-30 QS.Comment
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Re: Speaking of Oil
If I were to use API service category CI-4 Diesel oil could I still use the pf-25 oil filter which I picked up from Paragon at Carlisle?Comment
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Re: Speaking of Oil
Sure, use any quality replacement oil filter. CI-4 oils have similar base as spark ignition motor oils, either mineral oil or synthetic.
The difference is the additive package - DI-4s have more detergent, dispersant, anti-wear and anti-corrosion additives than modern spark ignition oils. Modern SI engines don't need as much because precise fuel control means less crankcase dilution, and modern engines have less sliding surfaces like valve lifters and pushrods.
The major nation brand mineral oil-based CI-4s are Chevron Delo, Mobil Delvac, and Shell Rotella. They also offer synthetic based CI-4s, but they are unecessary on vintage engines that see low mileage accululation between their annual oil changes.
DukeComment
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Re: Speaking of Oil
Charles-----
Also, most, if not all, of the diesel oils are also rated for gasoline engine service. The PRIMARY rating is the "C"-prefix diesel rating. However, the secondary rating is The "S"-prefix gasoline engine oil rating (currently "SL", I think). So, they are fully approved for use in gasoline engines. So, they could even be used in new car gasoline engines under warranty requirements if it weren't for 2 things:
1) most new cars require engine oil viscosity of 5W-30 or 10W-30. The diesel engine oils are not available in these viscosities;
2) most new car warranty requirements specify that the oil has to have the "energy conserving" label on it. I don't think that the diesel oils have this.
However, for older cars there is no warranty to be concerned about (unless one installs GM crate engine). 15W-40 oil (which is a common viscosity of these oils) will work just fine in older engines.In Appreciation of John HinckleyComment
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Re: Speaking of Oil
i think the additive package in diesel motor oils will screw up the cat convertor on newer cars and that is why modern car engine oils do not contain these desired additives needed for older engines.Comment
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Re: Are you seriousl
I've been using Exxon/Esso XD-3 Diesel oil since 1967 in all of my vehicles.
I won't go into all the great reasons to use Diesel oil, however I
would say, "Why Not" use Diesel oil. The benefits have been proven my many for years.
Note: I started using a Diesel oil because GM recommended it for all HP engines.
This may never have been documented, however was recommended by a GM rep after a warranty repair on a failed 396 engine. The rep said use a diesel oil and you won't have this problem again.
Also.... Exxon/Esso XD-3 is available in 10W-30
BarryComment
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Re: Speaking of Oil
There is belief that some additives like the ZPPD anti-wear additive combustion byproducts degrade catalysts, and modern SI engines don't need as much ZDDP because many sliding surfaces like lifters and rockers are now rollers instead of sliders.
However, I know of some gasoline engine Mercedes owners who have been using HD diesel engine oils in their cars for all or most of their cars lives with up to 300K miles and are still on the OE catalyst - and the original engine with maybe just a head refresh.
The bottom line is that the richer additive package in HD diesel engine oils is more appropriate for vintage engines, and if they don't have catalysts it's a no brainer! The wider viscosity range and lower oxidation rates for synthetic based oils are of little value on vintage cars that are usually not driven in extremely cold weather and don't see high mileage accumulation between changes, and the additive package in spark ignition synthetic-based motor oils is no better than mineral oil base types. Nevertheless, if you think a synthetic base stock is worth it (I don't) you can buy CI-4 synthetic base stock oils.
I was recently reading oil labels at an auto parts store and noticed that the higher weight spark ignition engine oils like 30 and 20W-50 are still SL rather than the new SM. I looks like the SM spec may have some "energy conserving" attributes that may preclude the higher SAE weights, and it's also my understanding that some SM oils may have completely eliminated the ZDDP anti-wear addtive, and you DEFINITELY want the CI-4 ZDDP concentration in the oil you run in your vintage car engines.
DukeComment
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Re: Speaking of Oil
Duke,
You've sold me on the advantages of the HD diesel oil for my own old cars. I hadn't heard about that before, and I appreciate the education. One more question: Would you also recommend this oil for a fresh rebuild on break-in?
VerneComment
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Re: Speaking of Oil
For a freshly rebuilt vintage engine: Absolutely, yes!
DukeComment
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Re: Speaking of Oil
I've been able to get Shell Rotella-T in 10W30, although it has to be purchased by the case & from an oil distributor. Only the 15W40 is found in 'normal' retail stores like Farm & Fleet or others in this area (WI). I get an oil analysis done once/year with the used oil from each change (Blackstone Labs; about $20). You can really see the difference in the high Mg, Ca & B (corrosion inhibitors) as well as the high Zn & P (wear inhibitors) in the diesel grade. Analysis is a good way to detect minute antifreeze leakage (high sodium), lead & iron content (wear particles).Comment
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