Which oil do you use

[XfireZ51]

Originally Posted by Blue Flame Restorations

Dom, have you compared the ZDDP data from a few yrs ago vs today's levels in the Castrol you're buying? I'm told that the levels were dropped when catalytic converters were required on the big rigs.

Castrol PDS

1300 ppm zinc

http://www.castrol.com/liveassets/bp...GTX_Diesel.pdf

[XfireZ51]

Also

"BTW - The Castrol Rep also told me that the Castrol Diesel 15W-40 oil has a higher flash and shear point than the Castrol 10W-40 and 20W-50 oil I have been using in the Old Broad since she was new. Great!!! That way I don't have to worry about coking of the oil in the turbo oil cavity in the summer or winter especially after running her hard on the freeways or the streets in the summer."

....Comment on Feb 2012

[Blue Flame Restorations]

Good to hear, Dom. I was just wondering about that after a discussion with my engine guy today. Do you have cats?

[cvette98pacecar]

I generally like a heavy body Olive with a little oregano and plenty of garlic.

[A1990]

I have been using this in the Atomic Z per recommendation from Flyin Ryan

http://joegibbsdriven.com/trainingce...hotrodoil.html

[tomtom72]

With respect to this ZDDP issue and cam lobe failure, I'll pass this nugget along that showed up in a newsletter I get called LSxTV....or something like that. I get like three of them every week.

Anyway, fwiw, they had an article last month discussing oil & ZDDP & cam/lifter failures. I can't remember specifically which boutique oil company participated, but they had an oil company engineer in the discussion along with an engineer from CompCams. Anyway, the main point was that all the agony over the cam wear was due to the blank supplier to CompCams using some bad metal, and not the reduction of the levels of ZDDP to the present levels. This was CompCams' research findings.

I'll go thru their archives and if I find it I'll post a link, okay? In a somewhat related situation. I have a Q about this ZDDP thing in my own mind that I don't have enough knowledge to noodle thru to an answer: What about all the DOHC motors that are in all these economy cars like my Cobalt? Don't they need this ZDDP at the correct levels? I mean even a lot of the V6's are DOHC motors, like the base motor in the stangs & camaros, no? I guess what I don't get is would OEM's be offering these warranties knowing that new oil will cause cam failure? Sorry for my sticking my two cents in here, but something just doesn't add up to me in this whole picture.


Tom

[SteelBlueZR1]

The definitive Marc Haibeck's article on this subject says correct ZDDP is in Mobil 1 High Mileage or Amsoil - http://www.zr1specialist.com/HAT%20W...5%20Engine.pdf -
"Most modern GM engines use roller valve lifters. They have short timing chains to drive a single camshaft or dry belts to drive multiple camshafts. The need for EP protection for these engines is decreasing. Japanese carmakers that like to use long metal timing chains are evaluating the effects of the future oil standard on their designs.
My concern is for the flat valve lifters, the camshafts, the timing chains and the sprockets in the LT5. I believe that the SM oil for new cars is not appropriate for the LT5. The Mobil 1 Oil Company has also recognized the needs of flat lifter engines with respect to their products. They recommend their reformulated 15W-50 productvi for engines with high-tension valve springs. I think that 15W-50 oil is too high in viscosity for the LT5. The Mobil 1 High mileage products are also acceptable for the LT5 engine.

The Amsoil Company has addressed this issue with a product that is specifically designed for engines with flat valve lifters and high tension valve springs. It is formulated with high phosphorus and zinc protection. It meets the API SG specification that was used when the LT5 was designed. The product is named AMO 10W-40 Synthetic Premium Protection. It takes a two-pronged approach, higher EP additives and superior film strength due to the higher viscosity.
AmsoilAMOZDDPspecifications: Phosphorus 1265 ppm
Zinc 1378 ppm
Comment: Recommended for the LT5 engine. Also for other engines with high tension valve springs.

[BigJohn]

I have used Mobil 1 15W-50 for 18 years.

[Vetman]

I use "Mobil I high mileage" per forum recommendations.

[taximan]

Originally Posted by 32valvZ

Amsoil 10w40here too, for the same reason Nick says...

Amsoil also,

for the same reason Nick and 32valvZ stated