Motor oil

[Guenter J.]

The archives have a lot on CJ-4 motor oil. Has anyone bought the Collector's choice motor oil from Paragon? Any difference between 15W 30? My car is a 74 L -48 , 62,000 miles Thankyou

[Lynn H.]

Re: Motor oil

My understanding is that the best thing to use is the same oil I use for my diesel truck motor, that is what I have been using in my Corvettes for the last few years.
Lynn

[Boyan B.]

Re: Motor oil

All the "designer" motor oils are exactly the same thing you can buy for diesel trucks, just with a different label and maybe some other additives you dont need, including the added price tag. Duke Williams said it best, oil is a generic product, meeting a certain minimum standard. All else is fluff. The Diesel oils with a rating of CJ-4, have enough ZDDP that it will work perfectly in our engines. Any more is money thrown down the drain.

Go to Wall Mart, buy the gallon of whatever company diesel oil you want, its around $10 a gallon, and have fun with your car.

Duke can give you a 2 hour dissertation on it, but the bottom line is, the diesel oil is fine.

Boyan

[Guenter J.]

Re: Motor oil

Dear Lynn and Boyan,
Thanks for your input. Guenter

[Michael W.]

Re: Motor oil

Go to Wall Mart, buy the gallon of whatever company diesel oil you want, its around $10 a gallon, and have fun with your car.

Making sure it has the CJ-4 designation of course.

[Duke W.]

Re: Motor oil

I might add that the Walmart SuperTech house brand is rated CI-4 and costs about 9 bucks a gallon - a little less than the national brand CJ-4s. CI-4 is not subject to the 1200 ppm P limitation of CJ-4, so it might have a bit more ZDDP, but the amount of ZDDP in CJ-4 is more than adequate for our vintage engines with OE valvetrain components.

A couple of days ago one of my Corvette buddies called and asked about a "sticky" on the Corvette Forum that states you need more than 1200 ppm for vintage engines. This is absolutely false; 1200 is about the P concentration of older dual rated oils prior to 2004, and the typical P analysis of CJ-4 is 1100-1200 ppm.

I read that sticky on the CF and it's the blind leading the infirmed! All of their "research" is based on advertising and marketing hype and other Internet sites that contain mostly myths, misinformation, and anecdotal evidence. For one thing they don't even understand how the concentration of ZDDP is measured. It is not measured directly as they state, but is proportional to the P concentration.

If you didn't read the engine oil article in the summer 2008 Corvette Restorer or if you need a refresher on the basics of engine oil, dig it out and reread it, or you can read it online in the following pdf starting on page 3. If you don't believe the summary information in the article you can download and read the API 1509 document and other references that I used to prepare the article and the entire auto and petroleum industry use to formulate, test, and certify engine oils.

http://www.westcoastwillys.com/WCW_Sept08_small.pdf

Duke