Old car oil question

[rflnomad]

Hello all. We have the 389 out of the GTO and ready to send it to be freshened up. No mods, just tighten things up a bit.
I have been hearing the horror stories about newer oil not being compatable with flat tappet cams. ( we are not converting this to a roller cam!)The ZDDP based additived are supposed to be great. It isn't cheap, but this motor is the original and I do not want to risk anything causing a failure.

Anyone else having this conversation that has old cars? Our rebuilder STRONGLY mentions the ZDDP and I listen to him very closely. He knows 'real vintage Pontiac' motors and that is rare.

Just thought I would drop a line for some feedback. Thank you.

[ringadingh]

Im not sure about the ZDDP addidive you mention but GM used to have a oil addidive product in a 16oz can that was primarily for camshafts during motor rebuilds. I use to use it all the time in the 70's when I built motors. Strangely I can't remember the name of it anymore.

[AlabamaNomadRider]

Don, I never used the ZDDP but it does have a good reputation. I think you use like 4 ounces per 5 quarts. It can't hurt to use it. It is supposed to be good in older, classic cars with flat tappet cams. I used another product in my '70 GTO with the 400 cubic inch engine but that was a long time ago and I can't remember the name of the product. Of course it wasn't a classic at the time as I did buy it new. Got 60,000 miles out of it in four years before I sold it. Only replaced the timing chain and had to have the clutch replaced a couple of times. The engine was too powerful for the clutch.

[Sin City Stan]

Originally Posted by Ringadingh

Im not sure about the ZDDP addidive you mention but GM used to have a oil addidive product in a 16oz can that was primarily for camshafts during motor rebuilds. I use to use it all the time in the 70's when I built motors. Strangely I can't remember the name of it anymore.

It was EOS. Couldn't buy a GM camshaft without it. It was pretty much like STP oil treatment. It had the consistency of honey.

I had a 65 1/2 GTO with a 421 and three deuces. I knew small block Chevy's inside and out but I also knew the 389/421 block pretty well as I built engines for straight-line go-fast a long time ago and the 389/421 was one of them.

If I can be of help just let me know.

[Cajunrider]

Originally Posted by AlabamaNomadRider

Only replaced the timing chain and had to have the clutch replaced a couple of times. The engine was too powerful for the clutch.

That was probably caused by a short circuit between the steering wheel and clutch pedal.

[AlabamaNomadRider]

Mitch are you saying I was a short circuit. I did love to watch the smoke from the tires when I left a stip of rubber. Didn't take me long to figure out that that was very expensive the first time I had to buy tires. And yes getting the clutch and pressure plate rebuilt was also expensive.

[Cajunrider]

Yep......that's what I'm sayin Gene.

[ringadingh]

Your right Stan, the additive from GM was called EOS. I wonder if its still available.

[rflnomad]

Not an assembly lube, the ZDDP is a additive to replace the Zinc that the new oils have removed. Apparently, the older motors struggle with the newer oils.
It is avalible from Summit, Jegs and even the Joe Gibbs oil has it inside so I don't figure it to be a 'snake oil claim'.

[oldbikers]

It is probably great stuff Don but I have been running some type of hot rod for better than 40 years and have used Castrol GTX in every thing with no problems as long as you have hardened seats installed in your stock heads because of no lead in the gas you should be fine with any top of the line oil.