I have been reading about Z-Alt and Royal Purple oils for classic/muscle cars. Is there any need? I have run Castrol GTX but was told they have changed their formula and the modern oils are not good for older engines.

I don't know what to believe, so I thought I would ask and see what oils some of you use.

 

I'm not an expert, but I can suggest you peruse past threads on this popular topic. If you look at the very bottom of this page you'll see a section titled 'Simlar Threads'. The one with 'cutlassgal' as the thread starter is probably a good one to review.

 

I use Rotella T.

 

Here is one of the most recent in depth discussion of oil...
https://classicoldsmobile.com/forums...tml#post112663

 

If you want to get confused, just read about oil!!! I didn't realize there was so much involved with oil until everyone chimed in!! Lord!!!

 

The only 2 oils I trust now are Royal Purple and Amsoil. Both have zinc/phosphorus contents in the 1200/1300+ ppm range. Rotella just changed their formula so say goodbye to safe zinc levels there, as did Mobil 1. Just lost a flat tappet cam with 2nd oil change of Mobile 1, not knowing they just changed their formula and which now has less zinc. The only 2 oils that I KNOW have the required levels of zinc and phosphorus are RP and Amsoil. Buyer beware of anything else if you are using a flat tappet cam.

 

Whew! Now I'm really confused. After reading through alot of this I'm thinking about the zddp additive or Royal Purple.

Is it okay to switch an engine over to synthetic oil after using conventional oil?

 

You can always change from conventional to synthetic, the only exception being on a newly rebuilt motor, which should be run about 2,000 miles before changing over to a synthetic. I assume the ZDDP additive would be fine, not sure about everything that is in it. What I do KNOW is what is in Royal Purple and Amsoil and both of those are a sure fire way to go.

 

Valvoline VR1 has Zinc, I made the switch this past year. Any people here lose a lobe on a stock original engine?

 

I used to too on all my flat tappet stuff. But now my cam grinder says no to that, and just about any diesel oil, too many detergents.

Best so far is Valvoline VR-1 as mentioned or straight Castrol, Valvoline etc with an additive. Helluva way to go for the rest of the life of the engine, that's why I went roller.

 

Interesting. I think I am going to stick with Rotella T since I can get it so cheaply at Sam's Club. Plus, I think the type of oil you use is secondary to how often the oil is changed.

 

This oil issue is why I went full foller in my 455 in the 57 and will be going the same route in the 48's 455 that plus the hp gain made sense to me.

 

I use Brad Penn in my race car, tow truck and beater car. 2000 miles for break-in? With ring technology of today, no need for that much break-in.

 

A note regarding racing oils: They do not carry the detergent package of oils for street driven cars, and are formulated for cars whose engines are torn down and rebuilt after short periods of time (race cars). Racing oils are not formulated for cars that undergo street driving conditions. This information is from Hotrod magazine, Hemmings, Bob the oil guy, and other sources who are trying to help flat tappet cam users make informed choices about what oils to use. Of course, the most sure fire way of all is to do what some above have said, and that is to go roller...assuming you have the extra $800-$900 to do so.

 

I have used racing oil in both my Intrigue (90,000 miles)since it was new and my dually (tow truck) with 80,000 miles since I bought it. There has been no break downs, loss of pressure or consumption. The dually pulls an enclosed trailer so it gets quite a work out. If using it for short spurts in my race car........what do you think I put that oil through? OK I will answer my own question.....A LOT!!

 

I have decided to go with the Royal Purple.

 

I have a 425 with W30 cam and have just changed to Castrol GTX 10-40. I have added a 4oz bottle of ZDDPlus to the 5 quarts of oil as per instructions on the ZDDPlus bottle. According to the specs that ZDDPlus publishes in their pamphlet, this will give me 0.18% zinc and 0.15% phosphorous in my engine.
ZDDPlus has the following website http://www.zddplus.com/

I have no experience with this engine as yet but decided on the above after reading various posts.

Pat Mills