Oil Weight for Bored 302?

My engine builder with 30+ years machine shop experience told us to only use this



because it is the only oil with zinc already in it, when we took delivery of the short block after a .030 bore and new pistons,etc.

Only use other oil and a zinc additive in a pinch.
My dad and I have a jillion years of combined experience and opinions and just shut up and did what Fred told us to.
It ran great as he drove it away when we sold it.

 

10w-30 is just fine for a flat-tappet cam. It is the original spec for V-8s from the 1970s, and I actually use 5w-30 in my car. I've never had a problem with cam wear. If you are running a flat-tappet cam with stiff, high performance valve springs, you're gonna want to use a zinc additive or VR-1 regardless of what viscosity rating the oil is.

 

Rotella also has reduced levels of zinc. Modern diesel engines now have catalytic converters, which get ruined by high levels of zinc.

 

20-50 is for race engines with looser tolerances and high-volume oil pumps. Running 20-50 in a tight street engine is pointless, and actually robs power.

 

ATF won't do anything that regular motor oil won't do... Been a old wives tale for probably the last 60+ years it has some mystical cleaning powers, no it doesn't... A fresh engine should not need cleaning, change the oil after just a few miles(or first 20-30 minute run in) to eliminate any wear metals, then again at 500 miles... After that drive it...

 

No it hasn't, most all the 15W-40(and Rotella 10W-30) diesel oils have approx same level of zinc as did passenger car oil before the reduction(1000-1200 ppm)... Passenger car oil limit now is 849 ppm for xW-20 & 30 weights... The xW-40 are exempt from the 849 limit but most seem to have approx same as the lighter oils... A exception is the 0W-40 Mobil 1 at 1100 ppm...

Not one of the oils in this list has less than 1000 ppm and most are mid 1100 to mid 1200 with Pep Boys in the lead at 1363 ppm...

http://www.pqiamerica.com/June 2014/consolidated HDEO 2015.html

 

I have been driving cars for more than 5 decades, never put any ATF in anything but a transmission. I think the oil companies have the knowledge and experience to make oil for all automotive purposes.

 

So did the Rotella previously have more zinc than it does now? I remember reading in car publications that it had reduced levels and was not recommended as a solution to premature flat-tappet cam wear.

 

I honestly dunno, but has been approx same for last five years or so...

I have the 10W-30 Rotella in my flat tappet 306...

 

Zinc additives won't hurt an engine whether it "needs it" or not, right? Was told all oils had them back in the day until EPA got their panties in a twist. Forgot to mention that the car has sat for a while ever since my grandfather passed on. Not like 3years straight or anything, but months at a time..I'm just concerned about any potential sludge buildup. Any treatments that would help clean the system right before I change it??

 

Forget the additives to clean, do a short 500-1000 mi oil change if it worries you... That'll SLOWLY dissolve any sludge which is the proper way to do it...

There's been oil analysis that stated too much zinc looses it's effectiveness(maybe someone with a agenda?)... I'd use the Rotella and forget the zinc as well...

 

Won't hurt the engine at all, but if your vehicle has a catalytic converter(s), it's bad for that. The zinc doesn't hurt the atmosphere, but if your cat isn't working properly, you're polluting more, which is why the EPA is involved.

 

at least he didn't tell you to run Quaker Sludge

 

Care to elaborate on that?

 

Old issue from the '70s that some won't let die... QS has been owned by SOPUS(Shell Oil Products US) for the last 25 years or more, sludge issues corrected prior to that... So it can be said if you recommend QS you're recommending Shell...