My first post and it may stir things up a bit.
Do not, under any circumstances, use GTX2 or any other modern API approved oil.
Oils aint just oils as the ubiquitous Sol used to say.
I work for an oil company up here in Qld (industrial oils in the main).
Recently a customer who drags a V8 lamented the passing of Kendall (Conoco) Pennsylvania Green.
He had not been able to find a good substitute.
Being a diligent rep with a few connections I started doing some research and what I found was disturbing:
The main antiwear component in oil is ZDDP or Zinc DialkylDithioPhosphate.
http://en.wikipedia.org/wiki/Zinc_dithiophosphate
It chemically bonds to lubricated surfaces and prevents metal to metal contact at extreme pressures.
In the latest API (American Petroleum Institute) oil formulation approvals (3 and 4) this has been all but removed.
Apparently, when an engine gets a bit worn and starts to burn oil, the zinc and phosphorous poisons the catalytic converter thus leading to a rise in tailpipe pollutants.
So unfortunately, nearly all the expensive mineral and synthetic oils you pay top dollar for, will destroy your engine over a much shorter period of time.
Here is a link to a Noria forum that discusses the matter in depth:
http://forums.noria.com/eve/forums/a/tpc/f/616604995/m/3011052071
There are still some oils that contain satisfactory ZDDP quantities - usually specially designed for racing applications or Diesel engine oils.
What you ALL need to do is search for the tds or pds (technical or product data sheets) for the product you are using and check:
1. The API classification (if given) and/or preferably
2. The Mass by volume of Zinc and Phosphorous which should be 0.15% or above - preferably well above (Calcium is not always present in all formulations and is an anti=chatter additive and desirable).
0.15% would translate as 150ppm.
I have attached three files to give you an idea of what to look for.
SHP Racing is a Hi-Tec oil (Sydney company) that is reasonable - you will see the quantities given in the table of properties on the last page - you will also notice that the SAE50 is the pick of them.
Ken GT-1 is a pds from Conoco for an SAE70 oil used for nitro-methane drag cars - 257ppm Zn and 233ppm P.
I am not recommending these particular oils - just giving you 2 examples of what to look for in a tds or pds.
By contrast, the GTX2 pds makes specific reference to low impact on catalytic converters.
It also fails to give a table of properties which, in any pds, is a glaring ommision and you have to read between the lines here.
I'll leave off now but do hope you will do some relevant research of your own.
You owe it to your engines.
If anyone has any questions just contact me.
Cheers All
Col
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