I'm using Shell Rotella-T 15W-40 Diesel oil. I've seen a lot of discussion in several forums about the merits of using diesel oil in our older engines, especially when it comes to camshaft wear etc. Most diesel oils have zinc compounds that are no longer included in modern automotive oils. I've read that Schneider cams and Comp Cams also recommend Diesel oils too.

Diesel oils have more antiwear compounds and are designed to work well at higher pressures, so I've elected to go with it for my Z.

Fred

Tampa, FL

'74 260Z 2+2

15/40 diesel here also. Did this upon recommendation of an old friend who has run an independent oil change center for 35 years. I took my Z in for 10/40 Castrol and after discussion with him gave his favorite (Wolf brand, IIRC) a try. I've been very pleased with the results.

I'm using Shell Rotella-T 15W-40 Diesel oil.

Hi Fred,

I hate to be the bearer of possible bad news, but diesel oil in a gas engine could, again I say could, lead to a loss of compression and power in your Z engine due to the extremely high level of detergent in Rotella. Diesel truck oils are formulated to combat the high levels of dirt, soot, and ash created in a 8 to 15 liter diesel truck engine. The levels of combustion by-products in a diesel demands manufacturers to add so many additives to diesel oil.

Additives to combat heat, anti-foaming (14 gallons of oil sloshing around in an unbaffled oil pan) and prolong oil for 150,000 mile oil change intervals are also added.

No, I don't work for an oil company. I work for a Mack Truck dealership, and I would not put diesel oil in any of my gasoline engines.

I can't refute your statements about Schneider or Comp cams but I have personal knowledge of severe valve train damage done to a Honda CRV running Mobil Delvac 15W-40.

FWIW,

Chris

Chris-

Interesting. How did you manage to trace the valvetrain damage to the oil, Chris? Anyway, here's a relevant article all might find interesting:

http://www.dctra.org/?p=79

Fred

Tampa, FL

'74 260Z 2+2

As long as you're using a premium brand oil, I'd focus more on the filter. Here's a website that did some interesting experimenting with various filters.

http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html#fram-tg8a

240Zman Thank you for the information page. I had this info saved a few years ago and because of a hard drive failure lost it . Good stuff . I have been using Purolator Pure One filters for a long time. I was surprised with some of the information in the testing. I hope others will view this information and use it. Gary:rambo:

Chris-

Anyway, here's a relevant article all might find interesting:

http://www.dctra.org/?p=79

Fred

Tampa, FL

'74 260Z 2+2

Again some interesting information . I have been using Quaker for YEARS . Looks like I may need to change . Some thing I will research further. Thanks for a vary interesting page . Gary

Well, this is disturbing, to say the least. I now have two cars with flat tappet cams and certainly don't want to swap out cams that often. So GTX, which has always been a wonderfully clean oil, is now going to destroy my cam shafts?