ZDDPlus

I'm reading more and more about the concerns surrounding the absence of Zinc in our hobby (and other pre-electronic/computer driven automobile transport)!

Some very interesting articles in Model A Times about adding Zinc, or a Motor Oil with Zinc.

The Mustang guys are onto this. The diesel guys are onto this.

I bought some ZDDP for the oil, but then had to drop the pan for a loose big end. Haven't put anymore in since. Have to think about this some more.

How are things in "Small but Special"? I haven't been to Hard Labor Creek Park in 30 years. Beautiful country!
 
i use valvoline VR-1 20/50 racing oil . has zzdp . i run 55# seat pressure & 100# open . .............. steve
 
Thanks for all the comments.

As a result, I don't think this as anything to worry about. I might try some diesel engine oil, however.
 
It not only prevents cam scuffing, it reduces ring wear.
Reduced ring wear equates to longer engine life.
Now I suppose you guys with your "low spring pressure" model A's
are going to tell me you have low pressure rings also.
 
Zincdialkyldithiophosphate! Only a chemist can come up with that kind of a word. Zinc, Phosphorous, and Sulphur have been high pressure additives for many moons. The EPA has decided that they are damaging to the Ozone or cataclysmic perverters or some other such BS. They won't be happy until we are back to using castor oil in our infernal combustion engines or better yet they will ban any motor that is not electric. Just wait & see.

Kerby
 
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Pete said:
It not only prevents cam scuffing, it reduces ring wear.
Reduced ring wear equates to longer engine life.
Now I suppose you guys with your "low spring pressure" model A's
are going to tell me you have low pressure rings also.
Click to expand...

So how is ring wear and scuffing prevented in modern engines with the new low zinc oil?
 
Mike V. Florida said:
So how is ring wear and scuffing prevented in modern engines with the new low zinc oil?
Click to expand...

I don't know about ring wear (probably some fancy metallurgy in the modern rings) but cam wear is being reduced in modern engines with "roller tappets". They have a small wheel on the end of the tappet that follows the cam face. You now have rolling friction on the cam, not sliding friction.

I also believe that the oil guys in the engine lab have concluded that lower zinc levels are still effective for flat tappet engines, so they can lower the zinc level without a noticeable increase in wear. I think you will find current zinc concentrations (if the company actually tells you what it is) is about 800 ppm, where it used to be 1200 or up to 1600. Finding data on the concentration in older oil formulations is harder.

Jim
 
Pete said:
It not only prevents cam scuffing, it reduces ring wear.
Reduced ring wear equates to longer engine life.
Now I suppose you guys with your "low spring pressure" model A's
are going to tell me you have low pressure rings also.
Click to expand...

Actually, yes. Standard A rings are much thicker than modern narrow rings. The pressure is spread over a greater area. As a result, they seat slowly and pass too much oil. Because of this they also survive short periods of abuse.

Personally I use modern narrow ring pistons because they seat fast and seal better. Before the flat tappet muscle cars with high spring loads that predicated ZDDP, there were no problems with rings. Perhaps in racing with extremely high combustion pressures that tightly lock the top ring to it's land, ZDDP may be beneficial, but I can't see it helping the average "A" even if it has modern narrow ring pistons.
 
"anti-wear oil additive" I always believed that oil in it's self was an anti-wear additive. At least the packaging says it is.

skip.
 
"Actually, yes. Standard A rings are much thicker than modern narrow rings. The pressure is spread over a greater area. As a result, they seat slowly and pass too much oil. "

Actually, NO.
Aside from that, if your rings seat slowly and pass oil, you are not doing something right. Rings will seat completely in 1/2 mile of driving if done right.
As far as ring scuffing, if you will think about it, it is hard metal against hard metal, the same as a flat lifter cam. Guides and valves, same deal.
If you would Google ZDDP, engine oil, zinc/phosphorus in oil, synthetic oil or any combination of these words, you will get more reading than you can do in one day and it isn't some "hearsay", "I beleive" or "in my opinion".
 
Not needed in the Model A engine. As Mike says, the valve spring pressure is very low compared to a later, OHV, engine, plus the OHV engines have a rocker arm ratio that increases the load on the cam. A cams are also steel, late engines have cast iron cams, a big difference!
 
Pete said:
[
Actually, NO. . . .

By "NO" do you mean Model A rings are not low tension? That is what my "yes" referred to in your original question. Good luck getting those fat, 1/8 wide low tension stock A puppies to seat in 1/2 mile. They float on the oil like water skis. I don't care if you bore with a torque plate and do the latest fancy double plateau hone. After 1/2 mile you will not have the compression you will at 1000 miles. That's why I like modern rings, especially sets with a moly top ring. Those seat in a few miles. Stock A rings will never muster enough pressure to break down the film strength of oil. They will only scuff if oil starved, overheated, or run much faster than a stock A will run. I'm not against ZDDP, but it is not like the A was designed in a way that needed it and we have now been denied.
Click to expand...
 
Notice in my original post, I did not say a model A NEEDED ZDDP...I said it would prolong the life of the engine...You can run it on liquid margarine for all I care.
And Mike, you are full of it if you think one of my engines won't make more hp on the dyno after 1/2 mile break-in than it will at 1000 miles..Any engine built right will never run as good as when brand new.
One more thing, apparently you do not understand what seats rings...It is not the tension built into the ring itself.
 
Pete said:
Notice in my original post, I did not say a model A NEEDED ZDDP...I said it would prolong the life of the engine...You can run it on liquid margarine for all I care.
And Mike, you are full of it if you think one of my engines won't make more hp on the dyno after 1/2 mile break-in than it will at 1000 miles..Any engine built right will never run as good as when brand new.
One more thing, apparently you do not understand what seats rings...It is not the tension built into the ring itself.
Click to expand...

Pete, My apologies! I didn't know the discussion changed to race engines. I'm sure one of your builds will make more HP after 1/2 mile than at 1000 miles. Most race engines are ready for fresh rings at that point. I built my share of SBC's for dirt circles in the '70's. The focus here is pretty much stock A's. Most stock engines are just about broken in at 1K miles. Yes, you did not say a model A needed ZDDP, you did say it would prolong the life of the engine. I'm not contesting that. In fact, I agree. Overall wear may be less. What it won't do is ward off some early specific part failure because the "A" build design has no components with a critical need for extreme lube film strength.
 
MikeK said:
Pete, My apologies! I didn't know the discussion changed to race engines. I'm sure one of your builds will make more HP after 1/2 mile than at 1000 miles. Most race engines are ready for fresh rings at that point. I built my share of SBC's for dirt circles in the '70's. The focus here is pretty much stock A's. Most stock engines are just about broken in at 1K miles. Yes, you did not say a model A needed ZDDP, you did say it would prolong the life of the engine. I'm not contesting that. In fact, I agree. Overall wear may be less. What it won't do is ward off some early specific part failure because the "A" build design has no components with a critical need for extreme lube film strength.
Click to expand...

AGAIN....You keep reading things that are not there.....This discussion is about STOCK model A engines with babbit bearings and plain cast iron rings.
About your last statement, zinc/phosphorus will definetly "ward off" any part failure that requires oil whether it is a critical need or not.
 
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