I have been using it 4 yrs now and love it, bit expensive but I get distributor pricing, I use it in Datsun and BMW engines and down in LA you would have no problem with the viscosity, it's also available in 10w40.
 

Granny, as a distributor, do you have any info from Amsoil regarding the zinc affecting the cat converter?


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I know how difficult it is to pass smog (Ventura County) so I don't chance it. Your emissions testing is the same as mine, PITA.

Edited January 5, 20206 yr by rcb280z

I know how difficult it is to pass smog (Ventura County) so I don't chance it. Your emissions testing is the same as mine, PITA.

Yeah, I’m about 30 mins south of you, so we have the same draconian California overlords telling us how to live our lives. [emoji23]



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So after a little more reading about ZDDP and zinc additive and Royal Purple HPS 20/50 (which has been used in the engine for ???? years), it turns out that stuff has the ZDDP zinc additive as well.

Point being, if my cat converter is going to be affected by the phosphors and zinc, it probably has already happened.

That said, it also appears that oil manufacturers are well aware of excessive phosphors due to evaporation affecting cat converters, and have adjusted ZDDP additive levels accordingly so as not to affect the cat....... so they say.

At this point I think it's safe to assume that if there were any damage to the cat form the Royal Purple it's already been done, so switching to Amsoil won't make a difference in regards to potential Cat damage.

Further, it looks like the 20/50 Amsoil standard and the Amsoil Z-Rod BOTH have ZDDP so..... you're getting it whether you like it or not.

I think the real question now is this;

Does the benefit of protecting the engine with the ZDDP exceed the downside of possibly affecting the Cat performance?

Oddly, it appears that if you add a third party ZDDP additive product to a motor oil that already has a ZDDP formula, it increases the amount of zinc and phosphors, but reduces the efficacy of the product. This may be where people are causing damage to their Cats, by adding more ZDDP to a balanced formula, it results in excess phosphors that damage the cat.

Anyone have some insights/experience with this?

Edited January 5, 20206 yr by mbz

BTW.... had a really nice drive in the Z through Decker Canyon this morning.

Decker Canyon Road

Anyone familiar with the area knows that drive, and if you haven't driven it, you can take the 23 South from the 101 all the way to PCH.... LOTS OF TIGHT WINDING ROADS AND HAIRPIN SWITCHBACKS.?

Edited January 5, 20206 yr by mbz

you west coast guys have the nicest places to drive. One of the reasons I want to leave florida is the exceptionally BORING drives. Still hoping for at least some action up in NW Ga as soon as it stops raining every other day.

Unless your car can run clean enough without a functioning cat, for emissions testing, then you'll need a new one to pass emissions. That is if it was damaged by using ZDDP additives. I needed to replace mine and it was just under $300 IIRC.

My Z needs it to pass.

0.5 percent CO is hard to get out of these cars without a fully functioning cat.

31 minutes ago, mbz said:

BTW.... had a really nice drive in the Z through Decker Canyon this morning.

I know it all too well. Except I don't drive it anymore.

Yeah, I kind of figure that since the Royal Purple that the PO has been using for years probably has already affected the Cat.
That said, it costs less to replace the Cat than the engine, so I’m going to protect the engine.


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you west coast guys have the nicest places to drive. One of the reasons I want to leave florida is the exceptionally BORING drives. Still hoping for at least some action up in NW Ga as soon as it stops raining every other day.

We have to have some fun to offset the high cost of living, excessive taxes, oppressive smog laws, etc. etc. [emoji23]


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5 minutes ago, mbz said:

it costs less to replace the Cat than the engine, so I’m going to protect the engine

I was waiting for that ^^

I had to wait over 3 weeks just for the cat to arrive. Make sure when you order one it's carb approved. If you do it yourself.

I'll have to read up on the ZDDP additives again. Don't recall what the hoopla is about. Memory isn't what it used to be I guess. My 77 has nearly 300k miles and I have owned it since 50k miles and have always used Castrol 10-40. The head looks really good, no abnormal wear of any type anyways.

No one feels the pain we feel mbz

"almost"

Edited January 5, 20206 yr by rcb280z