Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

[Terry D.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Out of the top of the coil

[Patrick B.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Out of the top of the coil

The coil output is what needs a a path to ground to protect the TI box. Removing the coil wire at the distributor cap end gives a terminal that is easy to clip the clip lead on to attach the coil output to ground.

[Rick A.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

agree with Mister Ward - why change?

[Duke W.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

A couple of questions that have not been asked or answered is how many miles were are the oil and does it look clean or dirty.? Chances are the first cannot be answered, but if it's clean, add gasoline through the carb bowl vents until it just dribbles out the venturi nozzles, then do a normal cold start. As far as what oil to use you need to read the attached pdf. You may find the new CK-4 spec oil. Read the API donut and make sure the first service category is either CK-4 or CJ-4. Unless the oil looks like coal tar, get the oil temperature up to at least 180 by driving the car for at least 20 minute and change the oil HOT!

[Mark E.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Duke,

You recommend CJ-4 because "... you are essentially guaranteed a near ideal amount of ZDDP for maximum protection of vintage engine sliding surface components", which you say is 1200ppm (for P).

Would you recommend an oil which has this level of P, but does not have a CK/CJ spec?

Asked another way, are you recommending CK/CJ oil because it's likely to have the proper level of ZDDP, or for other reasons as well?

I'm asking because Mobil 1 15w-50 claims to have 1200 ppm P and 1300 ppm Zn, but does not carry a spec for compression engines. See https://mobiloil.com/~/media/amer/us...pecs-guide.pdf

[Duke W.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Mobil 1 15W-50 has about the same P concentration as CK/CJ-4, so it's fine to use in a vintage engine with sliding surface valve train components. The other issue is economic. Mobil 1 15W-50 costs two to three times the cost of C-category oils. For that you get a wider viscosity range and longer service life due to the synthetic base stocks' higher oxidation resistance. On a modern Corvette this is usually 10-15K miles before the oil monitor recommends changing, but to maintain warranty coverage it must be changed at least every year regardless of mileage. In normal road use a summer viscosity of only 30 is fine because the oil will never get hot enough to thin out to the point where film strength is an issue. Since vintage cars usually see low annual mileage accumulation, oil changes should usually be done on a time basis, say every one to two years if mileage accumulation is only a few hundred to, say, 1000-2000 miles. So the bottom line is that for the significantly higher cost of Mobil 1 15W-50 you are not gaining any benefit relative to C-category 15W-40.

[Larry E.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Mobil 1 15W-50 has about the same P concentration as CK/CJ-4, so it's fine to use in a vintage engine with sliding surface valve train components. The other issue is economic. Mobil 1 15W-50 costs two to three times the cost of C-category oils. For that you get a wider viscosity range and longer service life due to the synthetic base stocks' higher oxidation resistance. On a modern Corvette this is usually 10-15K miles before the oil monitor recommends changing, but to maintain warranty coverage it must be changed at least every year regardless of mileage. In normal road use a summer viscosity of only 30 is fine because the oil will never get hot enough to thin out to the point where film strength is an issue. Since vintage cars usually see low annual mileage accumulation, oil changes should usually be done on a time basis, say every one to two years if mileage accumulation is only a few hundred to, say, 1000-2000 miles. So the bottom line is that for the significantly higher cost of Mobil 1 15W-50 you are not gaining any benefit relative to C-category 15W-40.

Thanks Duke; always enjoy when you chime in when it comes to oil. BTW; Walmart is selling
Mobil 1 15W-50 Full Synthetic Motor Oil 5 qt.

For 25.47 per 5 quarts. Larry

[Mark E.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Mobil 1 15W-50 has about the same P concentration as CK/CJ-4, so it's fine to use in a vintage engine with sliding surface valve train components. The other issue is economic. Mobil 1 15W-50 costs two to three times the cost of C-category oils. For that you get a wider viscosity range and longer service life due to the synthetic base stocks' higher oxidation resistance. On a modern Corvette this is usually 10-15K miles before the oil monitor recommends changing, but to maintain warranty coverage it must be changed at least every year regardless of mileage. In normal road use a summer viscosity of only 30 is fine because the oil will never get hot enough to thin out to the point where film strength is an issue. Since vintage cars usually see low annual mileage accumulation, oil changes should usually be done on a time basis, say every one to two years if mileage accumulation is only a few hundred to, say, 1000-2000 miles. So the bottom line is that for the significantly higher cost of Mobil 1 15W-50 you are not gaining any benefit relative to C-category 15W-40.

Thanks Duke.

I understand the issue of greater cost vs. real benefit of synthetic. Are the only benefits of synthetic "wider viscosity range and longer service life"? What about other claims by makers of synthetic, like better viscosity control, quicker protection during cold starts, less friction, less wear, less sludge?

Hype?

If synthetic does have some of these advantages, to me they're worth the extra $12-18 per oil change.

[Mark E.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Duke,

Are oils which meet CJ-4 and SN better for a spark engine than an oil which only meets CJ-4? Is it possible the non-SN oil does not meet some specs important to a spark engine?

Which oil? Below there's Mobil 1 15w-50 with 1200 ppm P meeting SN only, and Mobil 1 Turbo Diesel Truck with 1120 ppm P meeting SN and CJ-4. Since both have acceptable levels of P (and presumably ZDDP) and both meet the SN spec, is either fine for a vintage spark engine?

[Edward B.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

When you change to synthetic oil, don't forget to put nitrogen in your tires as well.

[Duke W.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Thanks Duke. What about other claims by makers of synthetic, like better viscosity control, quicker protection during cold starts, less friction, less wear, less sludge? Hype? If synthetic does have some of these advantages, to me they're worth the extra $12-18 per oil change.

I think that's all marketing hype. For example a 15W is okay for consistent cold starts down to 15-20 deg. F, and it doesn't matter if it's a conventional oil or synthetic, and I'm not aware that synthetics have more detergents/dispersants than conventional, which are important for sludge control... same with friction, which is basically a function of viscosity regardless of the base stock blend.

[Duke W.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Duke, Are oils which meet CJ-4 and SN better for a spark engine than an oil which only meets CJ-4? Is it possible the non-SN oil does not meet some specs important to a spark engine? Which oil? Below there's Mobil 1 15w-50 with 1200 ppm P meeting SN only, and Mobil 1 Turbo Diesel Truck with 1120 ppm P meeting SN and CJ-4. Since both have acceptable levels of P (and presumably ZDDP) and both meet the SN spec, is either fine for a vintage spark engine?

As I discussed in the oil article, optional secondary categories can be confusing, and you have to take a deep dive into the API 1509 document and appendices I referenced that are available on the Web. For example if the winter rating is greater than 10W the S-category 800 ppm P limitation does not apply. That's why the 15W-50 can have a SN primary service category, but that doesn't mean common 20W-50 SN oils have more than 800. You have to check the manufacturers' spec sheets to be sure. Both the Mobil 1 5W-40 CJ-4 and 15W-50 SN have sufficient P concentration for use in vintage engines with sliding surface valve trains. Most primary category CJ-4s list SN as a secondary category. In fact among the brands I've used, Delo, Delvac, Rotella, and Walmart's house brand I don't recall ever seeing one without SM or SN as a secondary category, but even if SN is not listed as a secondary category I would not hesitate to use it in a vintage spark ignition engine with sliding surface valve train components.

[Duke W.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

I just noticed that the 5W-50 for Porsche is primary service category SN, and has over 800 ppm P. This obviously doesn't conform with the 800 ppm P waiver, but I have no explanation.

[Mark E.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

I think that's all marketing hype. For example a 15W is okay for consistent cold starts down to 15-20 deg. F, and it doesn't matter if it's a conventional oil or synthetic, and I'm not aware that synthetics have more detergents/dispersants than conventional, which are important for sludge control... same with friction, which is basically a function of viscosity regardless of the base stock blend.

Thanks Duke. I hope you understand the hesitation about accepting synthetic oil formulated for spark engines is no better, maybe worse, than conventional oil formulated for diesels. It's hard to imagine pouring farm tractor oil into a Corvette, but I do feel better about using dual spec SN/CJ oil.

I'm glad to learn Mobil 1 15w-50 SN oil with 1200 ppm P looks good for vintage spark engines even though it does not carry the CJ spec.

[Terry M.]

Re: Quick question on Oil Changes for "Sleeping Cars"(Corvettes/Camaro's)

Thanks Duke. I hope you understand the hesitation about accepting synthetic oil formulated for spark engines is no better, maybe worse, than conventional oil formulated for diesels. It's hard to imagine pouring farm tractor oil into a Corvette, but I do feel better about using dual spec SN/CJ oil.

I'm glad to learn Mobil 1 15w-50 SN oil with 1200 ppm P looks good for vintage spark engines even though it does not carry the CJ spec.

Mark
That "tractor oil" also goes into engines in Freightliners, Macks and Internationals (to name only a few) that have engines that exceed the value of many Corvettes.