Zinc Dialkyl Dithio Phosphate

Bob Chaput · January 29th, 2009

I've read that the recent removal of ZDDP from motor oil is harmful to older engines. Lacking the zinc coating, the cam lobes wear out very fast. Of course, there's a product, or products, to supplement the motor oil.

Is this a "snake oil" product? If the statement is true, a lot of us need to pay attention.

I'd like to hear from some of you.

Bluesky636 · January 29th, 2009

Originally Posted By: Bob Chaput

I've read that the recent removal of ZDDP from motor oil is harmful to older engines. Lacking the zinc coating, the cam lobes wear out very fast. Of course, there's a product, or products, to supplement the motor oil.

Is this a "snake oil" product? If the statement is true, a lot of us need to pay attention.

I'd like to hear from some of you.

Read this: http://forums.aaca.org/ubbthreads.ph...ive#Post567852

imported_JohnD1956 · January 29th, 2009

I don't know what that thread Bill posted says BUT a recent talk by a local machine shop owner ( with a stellar reputation) included this. It is generally accepted that this problem manifests itself on high compression engines with flat lifters. The fix is either a additive that replaces the ZDDP or switching to synthetic motor oil.

Bluesky636 · January 30th, 2009

Originally Posted By: JohnD1956

I don't know what that thread Bill posted says BUT a recent talk by a local machine shop owner ( with a stellar reputation) included this. It is generally accepted that this problem manifests itself on high compression engines with flat lifters. The fix is either a additive that replaces the ZDDP or switching to synthetic motor oil.

Well, you might try reading the thread since it was a discussion on this very same topic a few weeks ago on this board. [img]<>/grin.gif[/img]

Synthetic motor oil is not necessarily any better than conventional oil when it comes to ZDDP levels. ZDDP has been reduced across the board in all oils. However, there are some oils, such as Valvoline VR1 (which I am switching to) that claim to have additives that keep what ZDDP there is, in the oil much longer. The thread I posted also contains a recommendation for an oil to be used in older cars that is endorsed by the CCCA.

MCHinson · January 30th, 2009

Bob Chaput,

Welcome to the AACA Discussion Forums! What type of car do you have? There have been a couple of discussions of this subject. As has been posted, it is a problem for some old cars, but for others it is not a problem. For example, it is not a problem for my Model A Ford, but others, like the owner's of Muscle Cars, better be paying attention to the subject. Again, welcome to the Discussion Forum.

Bob Chaput · January 30th, 2009

Thanks for the welcome and for the information. I have two pickup trucks, a '51 Chevy and a '47 Ford (under restoration). From what I've seen, I doubt I have a problem, as both are a far cry from "muscle" vehicles (though the Ford is a V8)

pfloro · January 30th, 2009

Hello Bob:

Again..., welcome to the forum.

I've read that ZDDP is an 'anti-wear' additive. Engines with 'aggressive' flat tappet cams are more likely to suffer from the reduced level. 'Aggressive' implies a lobe shape which allows the valves to open more quickly (and/or with greater lift) helping the engine breath better (ie: more power). Muscle car factory engines with stock cams or more aggressive aftermarket cams might have a problem with today's API 'SM' oils. Stiffer valve springs which are found in high performance engines add to the load on the cam.

IMHO, stock or mild flat tappet cams in 'standard performance' engines should be fine.

For added protection, I only use the engine's reserve power when I really need it...

OK..., I don't drive, I motor...! (What's wrong with that?)

Paul

70 Electra · November 17th, 2009

Quote:

Originally Posted by Bob Chaput

I've read that the recent removal of ZDDP from motor oil is harmful to older engines. Lacking the zinc coating, the cam lobes wear out very fast. Of course, there's a product, or products, to supplement the motor oil.

Is this a "snake oil" product? If the statement is true, a lot of us need to pay attention.

I'd like to hear from some of you.

Hi Bob,
I'd like to offer a correction as well as an answer to your question:

First, ZDDP was NOT "removed" from oils--the amount of it was reduced slightly.

Second, "Yes" these products are snake oils. They are unnecessary and can possibly cause harm.

For more on this topic, please read my new thread in BCA General forum, dated 11-17-2009.

ted sweet · November 17th, 2009

apparently cam makers and engine builders dont agree.

Twunk Rack · November 17th, 2009

bear in mind many high-dollar cars and trucks have roller tappets / - cam followers, and thus don't need this stuff.

Packard, just for one example, had them at least since prior to World War ONE, clear up until they closed down their "big car" plant in 1939.