zinc zzdp additive and catalytic converters

A

alfaman

Daily Driver
i have been using this additive in my 1969 alfa romeo spider....

https://www.amazon.com/ZDDPPlus-Eng...coding=UTF8&psc=1&refRID=2Q4PK6XJKYEKZ7WDRV38

i just passed a smog test (in california) for my bertone 1986 x1/9...i know zinc can hurt the converter, and it goes without saying that i'm worried about putting zinc in the bertone....sooo difficult to pass smog at times in this state (although the bertone passed first time no problem)

guess i'm looking for opinions on this...usually use castrol gtx 20/50 with the additive in my alfa..
 
Well, ZDDP was present more or less in all oils up until recently - so your catalytic is still doing well if it still passes smog tests! I'd rather change the cat than have to worry about cam wear.

Perhaps look for an oil that has ZDDP already in it - Millers Oils sells a 20W50 like this, and I believe Valvoline VR1 20W50 (available at Walmart) also has high ZDDP. There are several others both synthetic and non-synthetic. :)
 
I have no idea really, but I've read something about the additives in modern oils precludes the need for it. Even for old engines that would otherwise be prone to premature wear. Also something similar for the better synthetic oils. But this could easily be one of those "what's the best oil" things. Which is why I said I have no idea.
 
thanks for the responses...yes...was trying not to make it a "what is the best oil discussion"...guess i am a bit paranoid living in california....my car passed smog so easily..(86 with about 35,000 original miles.)..i have had so much problems smogging my other cars, so just didn't want to mess with anything that would hurt the converter...soooo difficult to pass smog in california for a classic car, but not will have to worry for another couple of years....
I drove the car this wkend down pacific coast highway....got a few thumbs up and a guy pulled up next to me saying that the car gave him good memories of a 74 he used to own
 
I thought of another thing I've heard about using the ZDDP additive. The recommendation was it might be a good idea for a newly rebuilt engine or when brand new components (like the cam) are installed - during the break in period. But after that it isn't necessary. Once again, I am just spewing things I've heard. I do not know.
 
ZDDP is highly recommended for older engines with flat valve tappets. The machine shop that used to do engine stuff for me highly recommended it (in fact, they required it for certain warranties) for older engines. Motor oils used to contain zinc but it was dropped in most modern oils except for those designed specifically for diesel engines.

I seriously doubt it will damage catalytic converters because ZDDP was an additive in motor oils until recently, which means cars engines used to run it all the time. ZDDP will help prolong the life of engine components where two flat surfaces rub against each other -- such as camshafts, oil pumps, etc. I for one will be using ZDDP additive in my '87.
 
I switched to Valvoline VR1 20W50 a couple years ago, after the previous cam exhibited heavy wear on 3 lobes & corresponding shims, NO wear to cam journals or cam box. About 4K miles on it since then. I figured I'll look at the valve clearances & cam condition around 5K mark.
 
lookforjoe said:
I switched to Valvoline VR1 20W50 a couple years ago... NO wear to cam journals or cam box.
Click to expand...
That is good feedback, thanks.

I recall some time back a discussion (not sure if it was on Xweb or elsewhere) about VR1 and its additives.
In the past Shell's Rotella for diesel engines was a favorite for many, because it had additives like ZDDP. Easy to find, and not overly expensive like the 'specialist' oils. But Shell finally changed the formula (emissions regulations bite again) so it no longer contains the same additives. I imagine it likely has something as a substitute. But the requirements, design, and fuel for diesel engines in general have dramatically changed. So not sure how oils for them compare to those from days of past. What is unfortunate is Shell never announced the changes and for a long time lots of users do not know it isn't the same protection for older gasoline engines that it once was.

I think VR1 is one of the few "regular" oils widely available with this kind of protection; meaning other than 'specialist' products that are harder to get and WAY more expensive. It is a full synthetic, so I do not mean "regular" in the sense of type, but in terms of marketing.

Don't they offer two versions of VR1, one for 'racing' and one for production engines? Or has it been reduced to just a "off road use only" racing oil for emissions purposes?
 
I put 10W30 plus ZDDP additive in mine. 20W50 seems too thick to me, but if it works then great.
 
VR1 is what I also changed to as well. I had used Castrol for most of my life and as the recipe changed over time I moved over to the Valvoline product.

I also used Valvoline Synthetic Brake Fluid after having some trouble with Castrol LM. I am much happier with it.
 
thanks all...may i ask what problems you had with castrol LM. brake fluid..that's all i use in my cars....after i use up my zzdp additive, will switch to valvolne product for the oil
 
I found LM was changing color much faster than another car I had been forced to use the Valvoline Synthetic in due to unavailability.

I found this was the case throughout the system, it didn’t fail per se. However in my mind since the color change relates to its hydroscopic activity and most importantly heat cycling. The Valvoline product in similar use didn’t age in such an apparent way. I change fluid as close to every two years as I reasonably can.

I had been using LM since the 1970s.
 
Regarding Valvoline VR1.

Today at the SEMA Show I ran into one of the Valvoline engineers. So I asked about their oils with zinc additives. They actually have two, VR1 and another new one (sorry, forgot it's name). That second one is a "racing only" product and isn't legal for regular road use due to the lack of detergents and other EPA required additives. So I asked if VR1 is legal and fully compatible for everyday street car use, considering it is called a "racing oil" as well. He said it has detergents and the other required additives so it is good to use.
 
Last edited:
It is my understanding that Mobil-1 synthetic, in the 20W-50 and maybe also 15W-50 formulations has a high zinc content, comparable to that in the Valvoline VR-1 (which I have been using in a couple of my older cars).
 
DSpieg said:
It is my understanding that Mobil-1 synthetic, in the 20W-50 and maybe also 15W-50 formulations has a high zinc content, comparable to that in the Valvoline VR-1 (which I have been using in a couple of my older cars).
Click to expand...

Mobil 1™ FS 0W-40 already contains a higher level of ZDDP (1,000 ppm) that could benefit your flat tappet engine. We also have a Mobil 1™ High Mileage 10W-40 (1,000 ppm); see our table listing the phosphorous levels for all Mobil 1™ synthetic motor oils.

here's the table from mobil:

https://mobiloil.com/~/media/amer/us/pvl/files/pdfs/mobil-1-oil-product-specs-guide.pdf

take a look at the 15/50....for flat tappet engines

according to the corvette site:

According to the mobil technical dept the only 2 oils that have a good zinc package are the 0-40 euro syn and the 15/50 mobil 1 syn. The other mobil 1 syn oils have been neutered by the epa.
 
Last edited:
You must log in or register to reply here.
Back
Top