What weight oil are people running in the summer? The light for low oil pressure comes on after the car gets warm and I'm wondering if it's the weight oil in it. Just bought it Wednesday and based on the spare container in the car it looks like it has conventional 10W-40 in it. Any clues?

well discussed

20w/50 is best for these cars
and you do need a non SAE-API oil if you want to have the protection of no longer used zinc additives.

so brad penn is a dino oil that is the most common

all of the oils at your local auto parts stores meet now required emission regulations that take out the additives your engine needs to protect its cam shaft

brant

So nothing off the shelf local will work? Bummer.

some say the valvolene vr1 racing oil is ok
I would check the API starburst on the label
if it meets current emissions standards it won't protect your cam shaft and lifters...

if it is sold for "off road use" it might

some of the safe oils include:

-royal pursple HPS, and royal purple racing
(not the regular royal purple)

-redline

-brad penn

-jake raby's snake oil.

Joe Gibbs DT-50 and Lucas Oil Syntheitic Hot Rod High Zinc are what I have run. I would highly recommend either.

I've been running Brad Penn 10/30 in my 1911 all this year.
Its a low mile fully rebuilt engine and oil pressures are perfect except if the oil temp gets above 220.
I have to work pretty hard to get the oil that hot, and I only have the stock cooler, remotely mounted with no direct airflow.

So to recap:


I want to look for an oil that contains Zinc.


The following oils are acceptable:

Joe Gibbs DT-50
Lucas Oil Synthetic Hot Rod High Zinc
Royal Purple HPS,
Royal Purple Racing
Redline
Brad Penn
Jake Raby's Snake Oil


I'm looking for a weight of 20W-50 but 10W30 works as well


Additional oil questions:

Are these ok for the winter too?
What is the interval you are going for oil changes?
Are oil filters generally available?

Thanks everyone!!

10 w 30 DOES NOT work just as well as 20 w 50! At its thickest it's barely thicker than the thinnest 20 w 50 gets.

The Cap'n

and its more complicated than just "zinc"
its really a compound with zinc, phosphate, etc.

it used to be in all oils and was removed to meet catalytic converter life expectancies.

If the oil you find has a API code on the back that is street legal
such as "CJ, or SM" then it does not contain the additives you need.

look for the API codes (also called SAE certification starburst)


also the weight of oil makes some difference on the climate and state of tune or wear. So a tired motor with worn tolerances is going to allow a thinner oil to slip between those wear tolerances. the 30wt might work on a tight and fresh motor. but these motors run hot and especially a worn used motor will usually benefit from a thicker/heavier oil.

I am also here in colorado
I am up in longmont.

we get VERY hot in the summer
and due to altitude we have less efficient cooling than the most of the folks on the coast.

I would run 20w/50
in the winter on a tight motor if you are actually driving the car in below freezing you might go a little lighter.

I used to go to 10w/40 in heavy winter
then I realized that

1) I was rusting the car out
2) I had inadequate heat and unsafe defrost
3) I was just not comfortable beating the heck out of the car in year round driving, and I was more likely to get hit by some idiot.

so I quit driving it on below freezing days. If you use that same rational and drive on decent days you really don't have to change oil weights. just warm it up carefully and slowly on cool days.

20W50 it is.

So I'll avoid the CJ/SM stamps, is there a stamp I -should- be looking for or just make sure it doesn't have those?

Thanks for all the insight, did you have an oil change interval you could share? Also, about how many quarts do I need for a change?

I have recently noticed at Walmart, the QuakerState high mileage oil has a "high Zinc additives" bullet on the label. Looks like they are getting wise about engine wear issues.

Can someone fill us in about how a 911 and 914 cam/lifter is different from say my Toyota or Pontiac? Is it just solid vs hydraulic or another difference?

"Enquiring minds want to know."

It really isn't. Old motors are flat tappet. Almost all new motors are roller tappet of some sort.

From what I have heard if your motor is well broken in, or tired it may be too worn to care about the oil. It seems to be most important at break in.

I'm not taking any chances myself. Oil isn't that expensive. Rebuilding the Stroked Windsor motor in my dad's Fairlane because the cam went flat was...

I think all of the API certifications are now without the additives
so it is a lot more than just the 2 I mentioned
also all of the diesel oils are also without additives.

I would be careful about that quaker state
"high zinc" is great advertising
but if it still receives the API stamp of approval (and is legal to be sold for highway use) then it is probably not high enough..

the royal purple stuff I use does not have an API certification and is listed for "off road use"

so be careful.

What does that mean John?
If 10w30 didn't work well, the oil mfrs wouldn't bother making it.
The only issue of importance (outside of detergent and anti-wear additives) is that the oil protects the bearings from contacting the journals.
The range of seasonal temps for a particular vehicle is an important factor when deciding which oil to use.

As long as the oil reaches all the bearings and provides a layer of protection any extra viscosity wastes horsepower by loading up the oil pump.
In addition, oil which is too heavy may not reach all the bearings effectively.

Oil wt numbers represent viscosity at two temperatures.
The first number is for cold oil, the second is for hot oil.
I don't recall the specific temps but all oils are measured to the same standard.
However, the manner in which the oil is formulated to meet a specific standard varies with the type of base stock used, and how a particular oil behaves at temps outside the standard may vary widely.

There are 5 motor oil base stock groups, Group I and II are petroleum based (dino), III, IV and V are synthetic. Its almost impossible to know what a particular oil company uses for base stock unless they fully disclose their formulation or you read deeply into the data.
Regardless of the base stock and additive package, the numbers tell the most important story.
10w "winter" weight is plenty thick for cold operation in almost all engines in the continental US. In fact 20w is often too thick unless bearing clearances are intentionally high from race prep or worn from age.
30 hot weight is fine for engines with moderate bearing clearance up to reasonable oil temps.
Higher weight oils are only useful with high bearing clearances or high temps.
The only way to know which oil is best for your engine is to monitor oil pressure and temperature.

When I was using BP 20/50, the pressures were too high on startup, even in 75 degree temps. That's why I switched to 10/30.
My experience suggests the 30 hot weight isn't quite sufficient because occasionally my oil temps exceed 220F where the pressures go a little below my expection of 10psi/1000rpm.
Rather than changing oil viscosity with the seasons, more than likely, I'm going to settle on 10w40 for year round use.
The temp range I operate in is 20F to 100F air temps.
YMMV