jwhite75B:My mechanic reccommends the Shell Rotella oil for my rebuild as it has higher levels of zinc. What oils are beings used other than Castrol 20/50?
Zinc additives are intended for extreme pressure conditions much like what you would see with flat tappets. Typically engine oils intended for such an environment are called HDEO (Heavy Duty Engine Oil) and are usually recommended for diesel engines due to their excellent shear stability. Standard motor oils for gasoline engines are referred to as PCMO (Passenger Car Motor Oil). The downside to high Zinc content oils is that the Zinc can have adverse affects on catalytic converters. I believe Shell Rotella T is of this type as is Chevron Delo 400 (which can be purchased at Costco for a
very good price.) and Mobil Delvac.
Also, keep in mind Shell Rotella T for 2007 will have less zinc than previously:
Is Shell Rotella® T motor oil going to have less zinc in 2007?
Yes. The API CJ-4 (next generation) Shell ROTELLA® T multigrade motor oil will have a slightly lower level of zinc than the current API API CI-4 PLUS Shell ROTELLA® T. Zinc is typically used as part of the anti-wear system within the oil. However, less zinc in API CJ-4 oils compared with API CI-4 PLUS oils does not mean increased wear. In fact, wear protection is one of the key areas where the API CJ-4 category provides improvements over API CI-4 PLUS. (Other areas include; oxidation stability and soot control). The new API CJ-4 Shell ROTELLA® T multigrade motor oil also meets the requirements of earlier API performance categories such as API CI-4 PLUS, CI-4, CH-4, CG-4, as well as others, and can be used in engines specifying any of these performance categories.
From:
http://www.shell-lubricants.com/CJ4/cj4_faq.htmlThat’s not to say it won’t work better than a typical motor oil (in your engine) as it’s still classified as an HDEO. Just something to think about.
Choosing a motor oil will also be based on your weather, how you drive the car, how often you drive, and whether you want to consider extended oil change intervals. If you plan to change the oil every 3000 miles no-matter-what, don’t waste your money on synthetic motor oil. In my opinion, unless you live in a hot environment, or you have a very tired engine, a 20w50 dino-juice (organic oil) is a bit thick at the cold end. I’d probably opt for an organic HDEO in either a 15w40 or 15w50 flavor unless you plan to race it.
Ultimately, if really want to know how your oil is doing in your engine, I recommend paying for an oil analysis every once a while to check out the condition of your oil and your engine. I use Blackstone Laboratories (
www.blackstone-labs.com) and have been very happy with the information they provide and quick turnaround.
Hope this helps.
Regards,
Adrian
Adrian Avgerinos | Mechanical Engineer
Global Sourcing Department | Moss Motors, LTD