Jump to content

Recommended Posts

I'm of the opinion that the zinc issue has been blown way out of proportion, much like removing lead from the fuel. Does anyone actually know anyone with a wiped cam lobe that can be directly traced to lack of zinc in the oil? Maybe on a few performance cars with high-lift cams and heavy spring pressures, but it isn't the widespread disaster that it seems from all the talk. I think on anything earlier than the 1950s, zinc is a non-issue since the engines spin so slowly, the spring pressures are so low, and the demands are so modest that any high-quality oil, zinc or no zinc, will adequately protect their engine parts.


However, if the zinc additive makes you feel better, there's probably no harm in it. Peace of mind is worth something in old cars so if it helps, go ahead and use it. Just remember that too much is too much.

  • Like 2
  • Haha 2
Link to post
Share on other sites

Zinc was first added to motor oil around 1951 to combat a rash of valve lifter and cam wear problems on the first OHV V8 engines, especially Studebaker and Chrysler. The heavy valve mechanism high RPM and stiff valve springs put more load on the cam/lifter area causing the oil film to break down under certain conditions.

 

It was not used in the 30s because the motors were not stressed. Not used today because overhead cam motors do not stress the valve area as much as pushrod motors. It could also be that today's oils are better, and protect the engine without zinc.

 

I wouldn't worry about any flathead or pre 1950s design engine running on today's oil. It is much better than anything made when your car was new.

  • Like 3
Link to post
Share on other sites

Matt, back 15 years ago, many 1938-1948 Cadillacs were suffering cam failure from a low/no Zinc. I saw half a dozen of them. Usually in Caravan cars driven to and from tours at highway speed for many miles. There were also some lifter galling on some others Marques. Today’s oil is ten times better than what was available pre war. There are not too many high pressure surface interactions on the pre war engines. I use Castrol Racing “R” oil in all our cars except the Duesenbergs. It’s high zinc, but it will coat a catalytic converters causing feedback loop problems on OBD 1 and OBD 2 cars. Oil is cheap, and extra zinc won’t hurt our early cars, so even if it’s not needed it won’t hurt anything. I change my oil more often than most..........to protect the car from acid and also keep an eye out for coolant and metallic particles. I run magnets in all my oil pans, and on the drain plug......a great early indication of upcoming issues. 

Edited by edinmass (see edit history)
  • Like 2
Link to post
Share on other sites

You will see with the elimination Zink and Phosphates by oil companies at the request of the government because these chemicals going past the rings into the combustion chamber was contaminating catalytic converters. At the time that Zink and phosphates was eliminated manufacturers that still used flat tappet cams and almost right after the ruling the engines were converted over to ROLLER CAMS.  Flat tappet cams is the key word because they are the cams and lifters  are susceptible to wear because they lost these high pressure lubricants.

 So you can do several things. One, If you like or use one brand of oil that does not have ZZDP you can buy the additive and add every oil change.

 Two, you can buy oil that has the pressure lubricants already in it like Valvoline VR1 racing oil, Shell Rotella,  Chevron Delo 400 and yes Delo 400 is diesel engine and gasoline compatible.

 I am just finishing up a engine for a friend who bought a fresh BBC in a Corvette recently whose cam and lifters went away and spread debris throughout the engine-what a mess! In the galleries, pump, sump and imbedded in the mains and rod bearings. Pressure lubricants are there for a reason in the use of flat tappet cams and lifters. 

 

 

Link to post
Share on other sites
1 hour ago, edinmass said:

Matt, back 15 years ago, many 1938-1948 Cadillacs were suffering cam failure from a low/no Zinc. I saw half a dozen of them. Usually in Caravan cars driven to and from tours at highway speed for many miles. There were also some lifter galling on some others Marques. Today’s oil is ten times better than what was available pre war. There are not too many high pressure surface interactions on the pre war engines. I use Castrol Racing “R” oil in all our cars except the Duesenbergs. It’s high zinc, but it will coat a catalytic converters causing feedback loop problems on OBD 1 and OBD 2 cars. Oil is cheap, and extra zinc won’t hurt our early cars, so even if it’s not needed it won’t hurt anything. I change my oil more often than most..........to protect the car from acid and also keep an eye out for coolant and metallic particles. I run magnets in all my oil pans, and on the drain plug......a great early indication of upcoming issues. 

Ed, what was wiping out the bronze dist/oil pump idler gears on the 1937-48 Cadillac V8s about 20 years ago?  I've seen some of them with razor-thin and razor-sharp teeth.  Some change in oil formulation?  When I sold my 1939 Cad 75 10 years ago, it went with a brand-new-in-Cad-box bronze gear, which is in the car now.

Edited by Grimy (see edit history)
Link to post
Share on other sites

I made a point for quite a while to add zinc each year at my annual oil change on my 52 Plymouth.  One year I did not have any and never remembered to put some in. As I have read information about I believe that because I drive very gently and relatively slow it is not necessary. The car engine will most likely outlast me at my current level of mileage accumulation.

  • Like 1
Link to post
Share on other sites
3 hours ago, edinmass said:

so even if it’s not needed it won’t hurt anything.

 

Too much zinc is too much. Playing oil chemist can have bad consequences if you do a "a little is good, lots more will be lots better"😯

 

So, what was the reason for the cam/lifter failures you witnessed, since you say today's oil is better than 30s oil (which of course it is really better, no question about that).

  • Like 1
Link to post
Share on other sites
8 hours ago, Grimy said:

Ed, what was wiping out the bronze dist/oil pump idler gears on the 1937-48 Cadillac V8s about 20 years ago?  I've seen some of them with razor-thin and razor-sharp teeth.  Some change in oil formulation?  When I sold my 1939 Cad 75 10 years ago, it went with a brand-new-in-Cad-box bronze gear, which is in the car now.


 

Yes George, the gears were cut in a way that put more load on them, and since the gear was “splash” and “mist” lubricated without the zinc the gears started to fail......mostly on cars driven very hard. Light and moderate normal use didn’t cause issues........unless it occurred slowly over time.........the hard core guys paid the price for the occasional users, and quickly the clubs got the information out. 
 

Frank, I think the failures were an accumulation of problems. Semi blocked oil passage, maybe low engine oil, overly worn engine parts, ect. The issue was flat tappet surfaces were galling. I also think many engines were just starting on E-10 and running lean.......so I think it was another factor. Overall within a year, people changed oils and the issue went away. I was told several oil companies paid for newly rebuilt engines when they didn’t disclose the zinc removal and the new motors wiped out cams in very short amount of time. 

Link to post
Share on other sites

Several years ago we did quite a few programs about this on my radio show. We had a lot of experts like the an engineer from pennzoil, the cam guy from Crane cams etc. The takeaway from these guys is the following as I remember:

1.  Zinc was added in the 50's when the manufacturers  started offering high performance flat tappet engines also had high pressure valve springs. The oil of the time was unable to handle the high pressure.

2. As the performance wars increased spring pressure increased making the use of zinc more essential.

3. With the advent of emission laws  spring tension dropped.

4. As stated earlier the zinc would effect the catalytic converter because in would plug the cells.

5. Somewhere in the 90's The converter cell count went from 200 to 400 cells per inch making them more prone to plug with zinc.

6 the increased use of hydraulic  valve lifters and overhead cam engines made zinc non essential.

so bottom line is if you have a car that is earlier than the mid 50's you probably don't need any additives, they didn't know about zinc anyway.  If you have a high performance  non CAT car it can't hurt. According to Crane they have changed the metallurgy of the cams they sell. I'm not a big fan of additives so it's your choice.

  • Like 1
Link to post
Share on other sites

I should probably add that most of the Cadillac gear and lifter failure issues were with modern parts.........maybe the modern process of manufacture or metallurgy added to the issue.

Link to post
Share on other sites

I have a 1976 Olds I special ordered, The car has 115,000 miles on it now and has it's "complete factory exhaust" including catalytic converter. In the early 90's I heard that the zinc and phosphates were be phased out and began using ZZDP which I still use to this day. From day 1 to this day the idle and cruise CO and HC never vary from .01 of one percent CO and 10 PPM HC which tells me that the catalyst is doing just fine with ZZDP being added to the oil just like the oil that was factory used and subsequent oil changes to the 1990's like when the car was new. Maybe Zink and phosphates bothers three way Cats of newer cars, but it apparently hasn't bothered my car with a two way Cat.

Link to post
Share on other sites

Anybody that wants the straight dope should buy the SAE paper on the subject.  That's what I did years ago and after that saved hours of my life never again feeling the temptation to read all the hearsay and conjecture prevalent everywhere:

 

https://www.sae.org/publications/technical-papers/content/2004-01-2986/

 

ZDDP has become the Bogey Man for everybody to excuse away their problems.  Zinc is not an "if a little is good more must be better" thing.  You can also have too much.  Most of the things on the web out there are just things regurgitated from people that do not know or if you dig deep you find they were authored by people and places selling ZDDP products.

 

Bad aftermarket lifters and cams -- poor metallurgy, poor heat treat, outsourcing to China -- all weigh heavily  in the failures we see today.  This is true of factory parts too.  In the 80's GM had issues with randomly wiping a lobe off the cam which I think was attributed to inconsistent heat treat.  The causes for problems such as these can be many.   

  • Like 3
Link to post
Share on other sites
42 minutes ago, W_Higgins said:

In the 80's GM had issues with randomly wiping a lobe off the cam which I think was attributed to inconsistent heat treat.  The causes for problems such as these can be many.   

 

The fix for that was to put a slight flat on one side of the lifter to be able add more lube to the cam/lifter area.

Link to post
Share on other sites

I like the thread it's replete with creditable information from knowledgeable people. Many of the threads, on other sites, heaven knows there have been hundreds, go off in the direction of a non-substantive  tantrums regarding why PZ should or shouldn't be used. Personally I use it in anything pre-1989. 

 

As for the GM cam lobe wiping. It always has bothered me that a manufacturer would allow their quality control to become so lax that the problem would become endemic. The problem of cam wiping didn't all go away with the use of hydraulic lifters, it was rather a combination of metallurgy, design and oil quality made it work. 

 

I have a 1976 Jaguar XJ12C with SBC (I bought the car that way) with a bad cam bad valve guide clearances. I love the car but I find it ironic that the previous owner made the swap to make the car more serviceable, but only created a series of different problems. 

Link to post
Share on other sites
6 hours ago, Buffalowed Bill said:

problem of cam wiping didn't all go away with the use of hydraulic lifters

 

Since most every GM V-8 made since 1950 used hydraulic lifters, did you mean roller lifters?

 

I have never worked on a GM product with solid lifters. Well, I mean with solid lifters from the factory. I have had STUCK lifters that acted as solids! Adjust them as solids and motor on, back in the cheap car days.😄

Link to post
Share on other sites

My comment was a response to Steve Rinaldo's comments.

"6 the increased use of hydraulic  valve lifters and overhead cam engines made zinc non essential.

so bottom line is if you have a car that is earlier than the mid 50's you probably don't need any additives, they didn't know about zinc anyway.  If you have a high performance  non CAT car it can't hurt. According to Crane they have changed the metallurgy of the cams they sell. I'm not a big fan of additives so it's your choice."

  •  
Link to post
Share on other sites
On 4/22/2020 at 5:16 PM, Matt Harwood said:

I'm of the opinion that the zinc issue has been blown way out of proportion, much like removing lead from the fuel. Does anyone actually know anyone with a wiped cam lobe that can be directly traced to lack of zinc in the oil? Maybe on a few performance cars with high-lift cams and heavy spring pressures, but it isn't the widespread disaster that it seems from all the talk. I think on anything earlier than the 1950s, zinc is a non-issue since the engines spin so slowly, the spring pressures are so low, and the demands are so modest that any high-quality oil, zinc or no zinc, will adequately protect their engine parts.


However, if the zinc additive makes you feel better, there's probably no harm in it. Peace of mind is worth something in old cars so if it helps, go ahead and use it. Just remember that too much is too much.

Actually, the difference is that most people are not driving their Pre-WWII cars much - put 10,000 miles on a rebuilt flat tappet car with a reground crank and you are going to be horrified by the damage.  And, yes we had science/engineering/lab work/ and .... involved in the CCCA oil project. 

 

https://inrccca.org/product/classic-car-motor-oil/

Edited by John_Mereness (see edit history)
Link to post
Share on other sites
On 4/22/2020 at 10:23 PM, Grimy said:

Ed, what was wiping out the bronze dist/oil pump idler gears on the 1937-48 Cadillac V8s about 20 years ago?  I've seen some of them with razor-thin and razor-sharp teeth.  Some change in oil formulation?  When I sold my 1939 Cad 75 10 years ago, it went with a brand-new-in-Cad-box bronze gear, which is in the car now.

Not sure anymore what the 1936-1948 Cadillac Distributor gear issue was ultimately found to be, but it was wiping out car after car via CCCA tour usage matched to the cam issues too.  

 

Eventually, someone designed a distributor gear to prevent problem and 10 years later I am no longer hearing about the issue.  

 

Of course a large group of our CCCA membership is using our CCCA branded oil.  The oil is made by DA-Lubricants which is heavily involved with Indy Car Racing - very good engineers there.

 

Perhaps the big difference is CCCA oil has extensive engineering regarding "suspension"/mixing technology verses some of the zinc additives may or may not suspend in the oil. 

Edited by John_Mereness (see edit history)
Link to post
Share on other sites
On 4/22/2020 at 4:53 PM, broker-len said:

CARS FROM THE 30S     I use 10/30 Penzoil--do not drive my cars hard 4 and 6 cylinder --have been adding zinc----is it of any benefit ?????

Keep doing what you are doing - just fine.

Link to post
Share on other sites
20 minutes ago, John_Mereness said:

Actually, the difference is that most people are not driving their Pre-WWII cars much - put 10,000 miles on a rebuilt flat tappet car with a reground crank and you are going to be horrified by the damage.  And, yes we had science/engineering/lab work/ and .... involved in the CCCA oil project. 

 

https://inrccca.org/product/classic-car-motor-oil/

 

So I've put about 8000 miles on my Buick with a flat tappet cam. Should I expect another engine rebuild in 2000 miles because I haven't been using zinc?

Link to post
Share on other sites
20 minutes ago, Matt Harwood said:

 

So I've put about 8000 miles on my Buick with a flat tappet cam. Should I expect another engine rebuild in 2000 miles because I haven't been using zinc?

Matt the answer is perhaps.   I will tell you DA-Lubricants had a several years of research on the issue of failure in flat tapped passenger cars matched to years and years of research on zinc  as a whole  before we got there in like 2007-ish. And DA-Lubricants showed me/us a lot of gnareled up cams that ranged from 1000 miles to 100,000 miles on them.  What I took away was that the worst scenerio seemed to be a reground cam as "the kiss of death" when matched to flat tappets. So, I put an extra $15.00 to $20.00 in my oil changes and hopefully I never have the issue. 

Edited by John_Mereness (see edit history)
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...