I've been reading many many post on here about what engine oil is recommended and find that 95% of recommendations are for Synthetic motor oils. Are the synthetic oils with ZDDP additive really good for a basically stock 60,000 mile 400 CID G block.
I'm kinda hesitant to use synthetic for fear of introducing oil leaks.
Here we go, What say you?
Thanks
Jerry

 

Synthetic oils have been found to cause leaks in older engines. I've used nothing but non-synthetic 10W40 in my '67 Delta's 425, and I've had no problems. These synthetics did not exist at the time these cars were new, and these cars ran just fine on the oils available back in the day.

I also add a container of STP Oil Treatment every time I change the oil to add the needed ZDDP.

 

Engine oils are backwards compatible so any oil meeting the API Service Classification (currently SN) is okay to use in a non-racing engine. One of the several engine tests is the Sequence IVA which evaluates cam and slipper follower wear. Any oil that carries the API "star burst" must pass the battery of tests used to qualify a lubricant. The use of additional additives is not necessary. Unless your engine is using oil, I would stay with the recommended viscosity grade (10W-30 for example). But if your engine is using oil it could be the result of wear so oil viscosity is not going to "fix" the issue. Unless you have a specific need for synthetic (extreme cold/hot temperature operating environment or fuel economy), conventional oil is just fine.

 

We have beaten the oil discussion to death. There are numerous threads with a lot of subjective info. 95% run with dino oil with a good friction package to include ZDDP.

 

Opinions on this differ.

Here's a good summary.

http://www.oldcarsweekly.com/restora...l_and_old_cars

 

Some of us have switched over to Accel oil(not the ignition company, it's made by Warren Distribution) and if SF Grade. Which is 1998 and earlier, and it contains 1100/1200 ppm of ZDDP. It's very reasonably priced too.

If you're worried about ZDDP, that's what It'd recommend. Currently seems to be only available on Amazon though. Used to be available locally and it isn't anymore. :/

 

The bottle says 1988 and earlier. $40.59 for a case of 12 with free shipping for Amazon Prime members. That's $3.33 per quart. Not bad.

https://www.amazon.com/Accel-22601-S.../dp/B0052KY9BY

 

Once synthetic oil has been used in an older engine, is it acceptable to go back to using conventional oil? I've "heard" that you should not do so.
What is the conventional wisdom on this.
After using synthetic oil in my Camaro engine(in which I had used conventional oil for many years with no leaks) I seem to have introduced oil leak at both the front cover and the rear main seal. I don't want the same leak issue with my 442

 

Yes you can go back to regular oil from synthetic.

 

I have gone back to regular dino oil (15/ 40 Rotela T) after using Mobil 1 for a couple times with no performance problems. I developed oil leaks soon after using the Mobil 1 and I believe the cause is the uses of cork gaskets in the older engines which are more porous than the newer rubber stuff found in todays engines.

All will work fine no matter which one you use but the synthetics will require a little paper training on your part.... Tedd

 

Sorry. That was a typo. I meant 1988. And true, $3.33 isn't bad. But it used to be $2.6x or something at Walmart. Not a big deal, just wish I could still source it locally. I don't want a case of 12. I can 5 qts, 10 qts, or 15qts. Ha.