TR4/4A ZDDP in the Oil

Another question from the past. Do folks here still feel this is critical to add to the oil?

I use Valvoline VR-1 20w-50 and it has plenty of ZDDP, so adding more is unnecessary.

I add it but have no idea if it helps.

Maybe it's like the horseshoe Neils Bohr had hanging on the wall over his desk: "I'm told that it works even if I don't believe in it".

I and my mechanic use Collectors Choice 20W-50 from Moss Motors. It already has (ZDDP) mixed in it. it is made by HICKS OILS.

The specialty oils have this covered but I usually buy a year's worth of oil every November on 'Black Friday' at Pep Boys. Not to promote Manny, Moe & Jack -- but their Black Friday morning sale usually has some very low oil prices. Also very low ZDDP content so I add the usual stuff sold on eBay.

Fat_Dog_Garage said:

I use Valvoline VR-1 20w-50 and it has plenty of ZDDP, so adding more is unnecessary.

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Ditto.

I remain suspicious of additives; they don't always work. Makes a lot more sense to me to buy an oil that has been engineered as a package, rather than buying cheap oil and assuming that a "one size fits all" additive will turn it into a silk purse. BTW, O'Reillys also has occasional sales for very good prices.

Maybe on a new rebuilt for a while.After that the usual suspects like Valv., and Brad Penn should be fine

I use Brad Penn.....leaks out just as well as all the others!

Does ZDDP harm the cats?

Yeah, that's the reason they want to reduce the content in the oil; trying to extend the life of the cats. The goal is for the emissions control system to never need service during the life of the car.

I use Collectors Choice 20W-50 from Moss Motors in the summer and 10W-40 in winter.

Paul

I use Valvoline Racing Synthetic (VR-1) 20W50 in my Triumph TR4 and 1933 Chevrolet. It has a higher level of ZDDP for older flat tappet engines.

I have owned my 1933 Chevrolet for over 40 years and it over heated easily in warmer weather until I switched to the VR-1 synthetic oil. The oil must have reduced the friction enough to eliminate the over heating.

I have also heard ZDDP destroys Cats, so I use Valvoline SynPower (Synthetic) in my 1984 BWM.

I buy all my oil for a descent price from Amazon and get free shipping. No need to leave my house and I get the oil and filters in 2 or 3 days.

Like some of the others, I don't believe in additives either.

Vila
1933 Chevrolet
1962 Triumph TR4
1984 BMW 633 CSi

curley said:

Does ZDDP harm the cats?

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My cats never get thirsty enough to drink oil.

Years ago, before they started cutting back on ZDDP, one or our cats stuck his head under the car while I was changing the oil. He lapped up some of the used oil from the drain pan before I could shoo him away. It never affected him in the least. Years later he eventually died of abject stupidity.

BOBH

Several years ago I had to rebuild my TR6 engine after I purchased it. One of the reasons was a cam with three badly worn cam lobes. Around that same time there was a rash of cam problems with folks on this forum. I have no idea what oil was used in my engine before I purchased it.
But it was at that time that the ZDDP controversy came to light. The more that I read the more confusing it became. Since I was spending a considerable amount on my engine I decided to do diligent research on the subject. I scoured the internet and called oil companies to verify the amount of ZDDP in their product. I found varying amounts and that at least some companies were reducing the amount without letting consumers know. Even trusted diesel oils were reducing the amount. My research found that the recommended amount for our engines was a very narrow band of percentage. Too little was supposed to be harmful and too much could damage an engine. Because of the narrow range and the varying amount in different oils I decided it would be all but impossible for me to safely use an additive. I initially used an oil that I could source from a local wholesaler and a couple years ago I switched to what I feel is a better oil that has local resale outlets nearby.

In the end it is my engine and my money and time. Which is why I took the time to sort it out as best I could. Compared to a rebuild oil is cheap at any price.

O'reilly sells Valvoline 50 weight racing with plenty ZDDP. Straight 50. Good enough? Why bother with 20/50?

KVH said:

Why bother with 20/50?

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Because you probably start your engine from cold? I'm sure even Arizona gets cold sometimes, straight 50 is pretty darn thick around freezing.

I agree with Darrell

This is a little off the original topic, but this link https://www.widman.biz/English/Calculators/Graph.html takes you to a website that shows the actual viscosity of several grades of oils over a temperature range of 0 - 100C which is equivalent to 32 -212 Fahrenheit.

Multi-grade oils were developed back in the early 1960 so the oil would have a lower viscosity at starting temperature, verses single grade oils, to reduce engine wear on start up yet keep a higher viscosity at engine operating temperature. Modern multi-grade oils attempt to keep the viscosity more constant over the entire operating range of the engine, but even they have a higher viscosity at lower temperatures compared to engine operating temp.

Your refrigerator is probably in the vicinity 38 degrees F +/- a degree or two. Put a quart of straight 50 weight in your refrigerator next to the milk for a few hours and see how it pours when you take it out. Also try a quart of 20W50 and see the difference.

Vila
1933 Chevrolet
1962 triumph TR4
1984 BMW 633 CSi