Classic Car Gas and Oils

Q.

I just purchased a 1957 Ford Skyliner and have questions about correct gas and oil uses. It is unrestored and looks like it just rolled off the assembly line in Kansas City, where it was built, minus the 60-year-old normal wear and tear because it was not in a museum. My question is about gas and oil. It has the 312-c.i. Thunderbird Special engine. The seller bought it and a 1968 Chrysler 300 from his mechanics neighbor, whose husband passed away. He said he has been using unleaded gas for the short time he has owned it. Is that recommended or is there an additive to be used? Also, what kind of oil should be used for it?

A.

Gas and oil are certainly two topics that can start a lively conversation amongst car enthusiasts. Let’s take a look at gasoline first.

Tetraethyl lead was originally added to gasoline to cheaply boost the octane levels as opposed to further refining—although in high-performance applications, it also served as a buffer against micro-welds forming between the hot exhaust valves and their valve seats. Without the lead, these micro-welds occur when the valves are closed; when these valves reopen the micro-welds pull apart and leave the valves with a rough surface that abrade the valve seats, leading to valve recession. When lead was phased out of motor fuel, the automotive industry began specifying hardened valve seats and upgraded exhaust valve materials to prevent valve recession without lead. If you drive a vehicle conservatively that doesn’t have hardened seats and valves, you will likely not have any problems. However, if you sometimes use your car for performance driving (drag strip, road course, etc…) you should consider gasoline additives or having stainless exhaust valves and even hardened seats installed in your heads. There are a number of lead substitute additives on the market, and while I don’t believe they’re necessary for non-performance driving, they do give many classic car enthusiasts a degree of “peace of mind.”

Perhaps a bigger concern with modern fuels and classic cars is ethanol. The alcohol in modern fuels does cause it to burn cleaner, but it can be detrimental to older fuel systems. Vintage carb seals, fuel pumps, o-rings, fuel lines, fuel filter, and fuel level floats can all be damaged by ethanol. Most states allow distribution of non-oxygenated fuels for classic cars—ask around to locate a service station that carries it near you.

Most standard “off the shelf” oils at the local auto parts stores are not good choices for your classic car. Modern oils lack sufficient zinc (zinc dialkyldithiophosphate) to properly lubricate flat tappet cams and lifters, especially during startup. The zinc was removed from modern oils as it caused carbon to build up in the exhaust system, causing catalytic converters to prematurely fail. You have a couple of options: either use oil specifically blended for use with classic cars that still contains zinc, or adding a zinc additive to modern oils. Which one is best? That’s an argument I don’t want to get into, but here are a few options to consider:

Oils: Lucas Hot Rod & Classic Car Oil, Valvoline VR1 Racing, Amsoil Z-Rod, Brad Penn “Penn-Grade 1,” Royal Purple HPS, Shell Rotella Diesel Oil

Additives: Cam-Shield, ZddPlus, Edelbrock High Performance Zinc Additive, Eastwood ZDDP

I am sure there are dozens I left off this short list, but I’ll post this reply on the site and am certain we’ll hear fellow members share their thoughts as well.

Wrench Safe,
Mark

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37 Responses to “Classic Car Gas and Oils”

  1. Joel Evans

    What year did all this occur as to eliminating lead and zinc? The term "classic car" includes a broad range of model years, so how does one know if your classic car is "pre" or "post" lead and hardened valves? What year was zinc removed from oil?

  2. Edward Greenberg

    In Florida and other states in the south east, 100% gasoline - no ethanol - is available at various octane ratings. I have a 68 Cougar XR7 which runs fine on 87 or (better) on 89 unleaded. Occasionally I add a can of octane booster which has "anti ethanol" properties or Sta Bil. 133k on it, driven very often, no damage from ethanol BUT I can get 100% gas now close by and I use exclusively. Definitely better performance when doing high speed driving. Local stop and go driving is not affected at all either way

  3. Kenneth D Norman

    I recommend Amsoil Z-Rod formulated for classic cars. High zinc content and intended for winter storage. https://www.amsoil.com/p/z-rod-10w-30-synthetic-motor-oil-zrt/ https://www.amsoil.com/p/z-rod-10w-40-synthetic-motor-oil-zrd/ https://www.amsoil.com/p/z-rod-20w-50-synthetic-motor-oil-zrf/

  4. Michael Conner

    Excellent refresher on the lead and fuel in regards to the valve train. However I'd disagree with adding Zink solutions to Oil. This was information was given to me decades ago when Zink was removed However In a thread a few years ago there was a heated debate re adding Zink, which lead (no pun intended) to an embarrassing statement to a member who had emphatically wrote that all the ingredients in engine oils where blended carefully, at a heated temperature ,, etc.. was incorrect in a very Nasty statement. His reply was that He was in Fact a Petroleum Engineer with decades of experience,, etc.. etc .. I can add that I've had several friends that have had early Flat Lifers fail, common denominator being adding A Zinc additive themselves. One Very experience builder the Lifters failed on a Fresh engine build during the initial engine break in period. Oh, He's also a Perfectionist What Do the great company's that make these secondary additives , They emphatically State their products are perfect , research , blah blah blah. ME, I don't take any chances, and when I owned Flat tap lifters I always purchased Engine Oil that Contained Zinc,, why take the chance I only have one SBC but it's a GM performance ZZ4 crate engine with a Roller Cam assembly. The other 4 are LS engines and I onot utilize Synthetic engine oil it's just to Expensive and time consuming to take a chance Can I blend a perfect mix of Zinc, will it be perfect ?? Possibly but I choose to be in the cautious side I do recall much Rhetoric when, was it Corn based alcohol, was added and not much in the way of warning re old cars with Carbs etc,,, Most of use k is that and many leaned a nasty lesson when broke down in the road of often in the home garage after our Classic of Street Rod wouldn't start. Case in Point. Acid Rain ... Michael. EE / CE , never be short sighted and take the risk

  5. Steve Benson

    I live in England & am considering buying a 53 customline flathead v8 I would like to know the fuel and oil type to use over here please

  6. Mark W Clark

    I have a '62 Corvette, 47K miles, original engine (Never been apart). I have always run factory recommended 30w oil and would like to switch to a higher quality oil. What would you recommend? Multi weight? Synthetic?

  7. Scott

    I have a numbers matching 1970 Corvette 350/350 hp. Is it safe to use 110 octane leaded fuel in this car without having any problems?

  8. RICHARD

    I have a couple of cases of oil that is about 25 years old that has been stored in the garage where it does not get too hot or cold. Does the oil still break down if not being used? Should the oil be used or just taken to a recycler? Thanks!!!

  9. Gary Thieschafer

    You are correct that the current SN now SP rated oils zinc and Phosphorous may not protect your camshaft properly especially if there are new lifters, cam and springs. If you use an oil that has a rating on of SL only then they are allowed to have higher zinc and Phosphorous. Some people used non-detergent oils back in those days so you may want to pull a valve cover or use a scope to see how much sludge if any is there. You don't want to develop oil leaks if detergent oil cleans it up. Non detergent is tough to find but ISO 100 Compressor would work and it is a 30/40 wt. I use AMSOIL ZRod in my '70 Plymouth Cuda 340. You have a Very nice looking car. Don't forget the transmission and rear axle. Gear Oils today protect much better. Fuel without alcohol for sure and an lead replacement substitute or even 100 to 1 two cycle oil would help the valve guides.

  10. Paul Trivellini

    I contacted Mobil about oil in my 1950 Studebaker with 47000 original miles. Their engineer was really nice and informative. Mobil 1 European Car Formula has 1000 ppm of lead, and Mobil 1 Turbo Diesel Truck Formula has 1300 ppm of lead. They both are perfectly fine for older cars.