First of all GM does not reccommend use of 0w-anything in their engines for a good reason...the stuff is just too thin !
They do recc. 5w30, which I find far too thin still.
I won't run ANYTHING thinner than 10w30 in ANYTHING including a LAWNMOWER, and in my LT1, which had over 265,000 original miles on an untouched LONG-BLOCK before it puked a head gasket, was ran exclusively on Red Line or Royal Purple 20w50 EVEN IN MICHIGAN WINTERS. Oil was changed roughly every 15,000 miles, of which generally 90% were long highway drives (over 50mi each way to work at the GM Tech Center where I am an engineer)
My 383 build will be using the same....I can't argue with 265,000 miles
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A/G
Ya must have completely missed this post.
Might want to read it!!!!!!!!
He is a GM engineer.

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Build ya an engine with 2.5-3.0 thou on the rods and 3-3.5 on the mains and put in some 0-10 weight(Royal Purple has it) and see where your OP is at any time.

That statement is without foundation and irrelevant. It is a foolish statement! It is missing the point.
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Try it one time and see where it gets ya with thin oil and OP. It is the same as trying to put 0 weight in a 100,000 mile engine.
With wear=more clearance.
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'm not asking to find out, I'm doing so to see if you know what it does. I'm not convinced you do. The ideal oil is one that does not energize the by-pass on a cold weather cold start, and increases it's adaption as the temp increases. That is the purpose for 0W(whatever).
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A 20 weight oil WILL NOT open the OP bypass at a cold start on a 70* day.
Ya thinking backwards or something. Must Be

 

You bet,and if they work on the bodies they got a pretty GOOD idea of what's going on with the engine dept or any other dept.

I have run 0/20 in some drag engines that I built to run it so convincing me is not an option. I don't believe in running it in a 2/3rd's worn out engine and letting the OP suffer--- which it does. Ya can tell everybody else how wonderful it is in a high mileage engine NOT built for it, but not me.
Real good way to cause an overhaul.

 

Is there a graph or anything stating proper oil temps vs oil weights?

I have a oil temp gauge and when cruising around town with the 4.10's and keeping the rpms no higher then 3k when shifting and a cruising rpm of 2k my oil temps can hit 220-240 is this too high? And will a thicker oil lower the temps?

Right now im running 0-30 castrol.

 

I run GC 0w-30 year round and I get great oil pressure. Always at 25-30psi when warm at idle, even after alot of WOT

 

No, but 0/30 GERMAN or whoever is damn close to the same thing.
Thinking backwards again.
Know some that know something about every facet of the operation.

AMAZE on there.

 

Did I see right that racerdude allowed 15k to roll by before a oil change just wondering if that was a typo or not...

 

Nope weren't me.

 

gotcha you quoted someone else... sorry

 

Nope.

That's to damn long in one of my engines,or my personal 'maro. Might work for some folks but not here.

 

Oil was changed roughly every 15,000 miles, of which generally 90% were long highway drives (over 50mi each way to work at the GM Tech Center where I am an engineer)


Who was you referring too?

 

The engineer who posted it in this thread. I was not or did not intend to say anything about the 15,000 mile change,(that's his deal)just that GM didn't recommend "0" weight.

 

Ya got most of it right. I ignore statements that do not suit the facts.

 

Sometimes it pays to keep um laughing-- makes um wonder what ya are up to,HUH.

 

So is mobil 1 a true synthetic and will I see any ill longterm effects from using M1 0w-40? And am I correct in assuming the only difference in thickness of 0w-40 vs 10w40 occurs before the engine is at operating temp? I know the wider viscosity range will affect durability of the oil, but I follow the old school ways of changing it every 3000 miles religiously. The reason I switched to that particular oil is all the reading I've done regarding how "thinner on startup is better", and the 40 weight operating temp rating seems to give me great oil pressure. With 0w-40 I see 40 psi on startup, 18-20 at warm idle and 40+ at WOT on a 72K mile stock engine. So this oil cant be "too thin" for me with those numbers, correct?

 

Wow ..thats all I can really say on that one...in reference to a 15k oilchange..