oil question in older cars - conventional or synthetic?

[larryabbott]

I have a '54 Special and a '62 Invicta.  I'm pretty sure the previous owners used dino or synthetic oil.  Should I switch to Valvoline VR-1 oil for both?  Or . . . ?  Thanks, Larry

[EmTee]

To me, VR-1 seems like overkill.  I'd use a good quality 10W-30 conventional oil.  You'll likely have to change it based on time way before mileage.  Valve spring pressures on both of those engines shouldn't demand racing oil.  That said, if you don't mind the price, then feel free to go with the VR1... 

[Fordy]

I have been told to be wary of synthetic oils in older engines- I think it had something to do with the clearances being greater allowing oil to seep out of critical areas when sat and resultant knocks until it builds pressure again. I had this with my 2007 car and problem went away going back to mineral oil.

[Pfeil]

1 hour ago, EmTee said:

To me, VR-1 seems like overkill.  I'd use a good quality 10W-30 conventional oil.  You'll likely have to change it based on time way before mileage.  Valve spring pressures on both of those engines shouldn't demand racing oil.  That said, if you don't mind the price, then feel free to go with the VR1... 

Did you know Castrol is making something call Castrol Classic 20-50 and has all the zink and phosphates. 

[larryabbott]

Thanks for advice.  I will look for the Castrol .  Larry

[Pfeil]

1 hour ago, larryabbott said:

Thanks for advice.  I will look for the Castrol .  Larry

         

A couple of months ago I bought it at Walmart. This time around it wasn't there so I tried all the usual auto parts stores, also not there. I ended up buying it on Amazon.

Edited July 24, 2023 by Pfeil (see edit history)

[West Peterson]

Most of our collector cars do not need zinc.

[Pfeil]

Why Put Zinc in Oil for Old Engines?

Zinc or zinc dialkyl dithiophosphate (ZDDP) in motor oil creates a protective coating on metal surfaces in the engine so it can stand up to the stress put on the camshaft and other components. Your average oil produced today provides enough protection for most cars used in normal operating conditions. Older classic automobiles, high performance engines and almost all non-roller cam-designed models need a more robust line of defense. That’s where zinc comes in.

High zinc oil or zinc oil additives deliver the extreme pressure wear protection to get the best performance and longevity out of your engine. It protects and eliminates wear problems with the cams, lifters and rocker arms. Zinc in oil also helps older engines start smoother in cold temperatures and maintain peak horsepower and fuel efficiency.

[Pfeil]

Zinc dialkyldithiophosphate (ZDDP) is the preponderance of zinc in Classic Car Motor Oil. This chemical was invented by Lubrizol in the early 1940’s to stabilize bearing corrosion when harder bearings than babbit came into use.

[West Peterson]

If you're going to use Zinc (ZDDP), never put it in as an additive. Use the oil that has been formulated with it, such as the Castrol that Pfeil posted above.

[Pfeil]

1 hour ago, West Peterson said:

If you're going to use Zinc (ZDDP), never put it in as an additive. Use the oil that has been formulated with it, such as the Castrol that Pfeil posted above.

When I called Castrol about their reduced rate of ZDDP for their straight weight 30 & 40 & 20-50W they told me it was acceptable to use 1/2 the amount per bottle of ZZDP for my VW's. The ZZDP bottle treated 5 quarts. For my Oldsmobile, one bottle was the prescribed amount. The Pontiac's with their 6 and & 7-quart pans required an additional bottle to be measured out for the proper amount.

I had already called ZZDP to see if it were a problem, but I wanted to make sure though that it was acceptable with Castrol which it was. Castrol's excuse at the time was they were being forced to reduce their additives in high pressure lubricants. Working for a major car manufacturer in engineering I already knew this was true due to problems with blowby gasses being reburned and having an effect on catalytic converters. The interesting thing is, my 1976 Oldsmobile never failed an emission test with its original complete exhaust system and still counting 117,000 miles and 47 years and a steady diet of ZZDP.

Edited July 25, 2023 by Pfeil (see edit history)

[Stude Light]

4 hours ago, Pfeil said:

Why Put Zinc in Oil for Old Engines?

Zinc or zinc dialkyl dithiophosphate (ZDDP) in motor oil creates a protective coating on metal surfaces in the engine so it can stand up to the stress put on the camshaft and other components. Your average oil produced today provides enough protection for most cars used in normal operating conditions. Older classic automobiles, high performance engines and almost all non-roller cam-designed models need a more robust line of defense. That’s where zinc comes in.

High zinc oil or zinc oil additives deliver the extreme pressure wear protection to get the best performance and longevity out of your engine. It protects and eliminates wear problems with the cams, lifters and rocker arms. Zinc in oil also helps older engines start smoother in cold temperatures and maintain peak horsepower and fuel efficiency.

Written by the people wanting to sell you their specialty products.
 

I would consider myself very well informed on this subject and have written many times on it. I use off the shelf oil in all my vintage cars (none of which are race cars) as there is plenty of zinc and phosphorus in today’s oils for my applications. But as @EmTee suggests….spending the extra dollars on specialty oils is fine too as it won’t be detrimental (as long as you don’t go adding supplements too).

 

[46 woodie]

 The auto part's store that I have been purchasing my part's from for ever, now has only one small shelf of conventional oil. All the other shelves are now synthetic oil. When I asked him about it he said that it's only a matter of time before he won't stock any conventional oil at all.  That Castrol looks promising if I can find it.

[Buffalowed Bill]

Ignoring the zinc and phosphorous additives that were added by oil companies during the early 50's is suicidal. The history of why it became essential is well documented. All manufacturers who were using overhead V8's with flat tappet cams, had their dealerships flooded with with cars requiring warranty work, for cam replacement. Some companies were more up front about the problem then others, but all overhead V8's suffered from the problem. 

 

The addition of z/p is not some snake oil added to  oil during the early 50's just to enhance sales. Laboratory testing, in the day, showed that the sacrificial film left by oil containing Z/P reduced much of the issue. The condition is as real today for our 1949-about 1970 cars as it was in the day. What has changed is the limited use of the Z/P used in most modern oils today because of potential damage to more modern cars which have catalytic converters. 

 

Prewar cars can get by without Z/P for obvious reasons. Your car your choice. 

[Stude Light]

17 hours ago, Buffalowed Bill said:

Ignoring the zinc and phosphorous additives that were added by oil companies during the early 50's is suicidal. The history of why it became essential is well documented. All manufacturers who were using overhead V8's with flat tappet cams, had their dealerships flooded with with cars requiring warranty work, for cam replacement. Some companies were more up front about the problem then others, but all overhead V8's suffered from the problem. 

 

The addition of z/p is not some snake oil added to  oil during the early 50's just to enhance sales. Laboratory testing, in the day, showed that the sacrificial film left by oil containing Z/P reduced much of the issue. The condition is as real today for our 1949-about 1970 cars as it was in the day. What has changed is the limited use of the Z/P used in most modern oils today because of potential damage to more modern cars which have catalytic converters. 

 

Prewar cars can get by without Z/P for obvious reasons. Your car your choice. 

Totally agree except for "limited use" statement. Not limited, reduced.

 

My point is there is still plenty of zddp in todays oils to protect most engines. You need a bit more for the extreme tappet pressures in a high revving race engine with high compression ratios, high cam lifts and high valve spring rates so, you should spend the extra money on specialty oils for those applications. The levels were reduced, not eliminated, to protect catalytic convertors (and pollutants) but still met all the SAE requirements to protect production flat tappet engines. Having read all the SAE test reports when the levels were reduced and having talked directly with the OEM oil experts, I educated myself from from the engineers of the oil companies and the OEMs (that sell the engines) and not from the internet oil sales companies, thus I don't needlessly overspend on specialty oils that are not needed in my applications. I just hate seeing a lot of our members get sucked into the disinformation created by suppliers of specialty oils and additives that all older flat tappet engines need to run higher levels of zinc and phosphorus or else their engines will suffer great harm. Total BS contained in their anecdotal stories that continues to be purported by those that have something to sell you.

 

For the OP......the '54 Special definitely doesn't require anything special. My assumption is you aren't racing the Invicta on weekends and pounding on the engine to redline. If you do like hammering on it, then I would go with the Castrol of VR1 for a bit more protection. 
 

Edit - adding one more thing, the reason you shouldn’t add a supplement to oils already containing ZDDP is that too much will also cause damage so, unless you have a way of measuring the levels of zinc and phosphorus, you become the chemist with no idea if you are in the safe zone. Better just to buy the specially formulated oils.

Edited July 26, 2023 by Stude Light (see edit history)

[Guest]

Larry you seem to have poked a hornets nest. . . just about like me and converting to 12v.  

 

Providing it's an honest question you never mentioned driving conditions.  There is a big difference between running 65 for a few hours across NV, getting it started at below 0 in ME, or just cruising on a perfect day to a car show.  

[Pfeil]

2 hours ago, Stude Light said:

Totally agree except for "limited use" statement. Not limited, reduced.

 

Edit - adding one more thing, the reason you shouldn’t add a supplement to oils already containing ZDDP is that too much will also cause damage so, unless you have a way of measuring the levels of zinc and phosphorus, you become the chemist with no idea if you are in the safe zone. Better just to buy the specially formulated oils.

That's why I said this;

   When I called Castrol about their reduced rate of ZDDP for their straight weight 30 & 40 & 20-50W they told me it was acceptable to use 1/2 the amount per bottle of ZZDP for my VW's. The ZZDP bottle treated 5 quarts. For my Oldsmobile, one bottle was the prescribed amount. The Pontiac's with their 6 and & 7-quart pans required an additional bottle to be measured out for the proper amount. Further they told me that today's oil has dropped beyond the threshold of 1,000ppm and are somewhere around 800ppm's. In the past engine manufacturers were building engines and oil suppliers were making the average motor oil with 1,400ppm ZZDP!

Edited July 26, 2023 by Pfeil (see edit history)

[Stude Light]

1 hour ago, swab said:

Larry you seem to have poked a hornets nest. . . just about like me and converting to 12v.  

 

Providing it's an honest question you never mentioned driving conditions.  There is a big difference between running 65 for a few hours across NV, getting it started at below 0 in ME, or just cruising on a perfect day to a car show.  

What??!!!  12 Volts!!!!  How could you? 

 

Yeah, sometimes I should just shut up about the oils as it comes across the wrong way at times. 😉

Scott

 

[Hemi Joel]

On 7/22/2023 at 8:01 PM, larryabbott said:

I have a '54 Special and a '62 Invicta.  I'm pretty sure the previous owners used dino or synthetic oil.  Should I switch to Valvoline VR-1 oil for both?  Or . . . ?  Thanks, Larry

 

I use VR1 in most of my old cars. It is not synthetic, and it is high zinc.  I have been able to get it for about $4 a quart when it is on sale or I have a coupon. 

 

The only reason I see to use synthetic, ever, is in a Diesel in the winter for it's low viscosity cold. It leaks more, costs more, and I see no advantage.  "Oh but Joel, you can go 15,000 miles on an oil change!" Nope, not me. False economy. The dirt needs to get flushed out more frequently.

[Stude Light]

Speaking of an Invicta, I thought Larry might like this video. 

It even shows the proper oil at 3:08 - gotta get the cardboard cans 😁

 

Pretty interesting, especially the refueling system.

[Frank DuVal]

11 hours ago, Stude Light said:

My point is there is still plenty of zddp in todays oils to protect most engines.

Yep! Emphasis on most. There are high spring load flat tappets that need all the phosphorus they can get. Yes, I did not mistype, it is the phosphorous in the zinc compound that is the anti-wear additive.

 

I use synthetic in most everything, but I do not go extended oil change intervals because of dirt and acid. Everything I have from the mid 90s up have reminders on the dash when to change the oil (except the Saturn). Al else I have to remember. Hmm maybe I do go extended.... Ha!😁

[Stude Light]

16 hours ago, Frank DuVal said:

Yep! Emphasis on most. There are high spring load flat tappets that need all the phosphorus they can get. Yes, I did not mistype, it is the phosphorous in the zinc compound that is the anti-wear additive.

Right, most - like not racing applications. And it is actually quite a bit more complicated than just ZDDP. While phosphorus is the primary anti-wear component there is also a significant interaction of the modern ashless antioxidants in today's oils that were not commercially available in the 1960s and early 70s that allows for less ZDDP.  And too much phosphorus is also bad. See below in a post where I go into detail and reference some of the SAE papers. I would encourage anyone interested to obtain copies, read them and draw your own conclusions. Side note - unfortunately, Carl (aka C Carl or Cadillac Carl), who I was replying to, is no longer with us.

 

Larry asked a simple question that has a complex answer but he probably went out and bought some Castrol GTX and is enjoying driving his car by now 👍.  Sorry for dragging out your post....my goal is to share knowledge.

 

 

[Terry Wiegand]

Someone is going to have to explain to all on here the connection between ZDDP in engine oil and catalytic converters.  I don't know about the rest of the readers on here but I do not put motor oil in the gasoline tank on my old Buick.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918  50+ Years

[edinmass]

4 hours ago, Terry Wiegand said:

Someone is going to have to explain to all on here the connection between ZDDP in engine oil and catalytic converters.  I don't know about the rest of the readers on here but I do not put motor oil in the gasoline tank on my old Buick.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918  50+ Years

 

 

Catalytic converters stores and release oxygen in the exhaust system. ZDDP coats the catalyst slowing down and making the reaction less efficient. 

[Terry Wiegand]

Ed,

Thank you for this explanation, however, unless the engine is an oil burner (poor rings and etc.) crankcase oil is way removed from the exhaust system.  I can understand this might be an issue with a more modern vehicle, but a pre-war vehicle?  This just doesn't make any sense to me at all.

 

Terry Wiegand

South Hutchinson, Kansas

AACA Life Member #947918

[Frank DuVal]

There is always some miniscule amount of oil that gets past rings, otherwise they would not be lubricated and fail quickly.

 

And of course the PCV system, where crankcase (where the oil is) vapors are sucked into the combustion chamber to burn the unburned hydrocarbons in the crankcase vapors.

[sagefinds]

It's my opinion that only vehicles that came out of the factory made for synthetic oil should use it. The molecules are so small that the gaskets can't keep it in. My nephew delivers fuel for a living,his company switched to synthetic in all their trucks but had so much leakage they went back to conventional. Incidently in the 1915 Cadillac we had,I used 15-40 diesel oil same as my duramax and will go back to it when I get another one of these put together.

[ted sweet]

any sn rated oil is synethic