# oil question.. again



## Chris-Austria (Dec 23, 2010)

Hi!

I have to rebuild my engine again. This time I'll get a roller camshaft. The engine will be:

428cui with 4.25" stroke and 4.16" bore (rotating assembly from Butler), Ross Pistons 15cc dished, Eagle H-Beams 6.80", Edelbrock D-Port 72cc heads, Compcams 276HR hydraulic roller (224°/230°/110° LS), Pro Billet timing set, Tomahawk valley pan, Scorpion roller rockers 1.5, Holley Ultra Double Pumper 750cfm, Edelbrock Performer (matched), RobbMC fuel pump, MSD ignition (pro billet), new gaskets and bearings from Butler

What type of oil can I use with the roller cam? I want to use synthetic, maybe 5w40? or the 5w50 from Valvoline?

Chris


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## geeteeohguy (Feb 2, 2008)

If I lived in your climate, I wouldn't run anything heavier than 10w/30. And yes, you can pretty much run any modern engine oil with a roller valvetrain.....except racing oil.


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## Chris-Austria (Dec 23, 2010)

10w30 isnt available over here.. 10w40 (semi synth) or 5w30, 5w40, 5w50 (full synth).. so it's gonna be something with a 5 in front and full synth


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## 646904GTO (Feb 10, 2008)

Go with the 10-40 then. Stay away from the 5 stuff. Easy start ups and it will be just fine.


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## geeteeohguy (Feb 2, 2008)

I agree. Go with the 10w-40. The 5w oils are too thin.


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## Chris-Austria (Dec 23, 2010)

10w40 is semi synthetic and cheap, but if its better for the engine than a 5wXX then I'll use it instead. Why is the 5W too thin? Will it leak? I have a full roller valvetrain and all new gaskets, pistons and rings.. 
Dont want to doubt that the 10W fits better, just want to understand why 

A oil with a high number after the W will handle the heat better as far as I know.. is that a concern or is even a XXw30 "strong" enought normally?

edit:

I found a semi-synthetic Valvoline VR1 10w60.. what do you think of this oil? The data sheet sounds nice, just what I may need?!


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## geeteeohguy (Feb 2, 2008)

No reason to run 60 wt oil in anything but an old worn out tractor.


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## Chris-Austria (Dec 23, 2010)

Where I buy the oil they also sell the 10w30 but they call the 10w30 tractor oil (mineral oil). That's why I never bought it.. on the other side they call the 10w60 a high performance semi-synthetic oil for high performance cars and ralley cars.

I trust the Valvoline oils.. they have a standardn 10w40 (DuraBlend) or the high performance VR1 10w60 if I want a 10wXX oil. So better use the 10w40 over the 10w60? The manufacturer says the VR1 is better at handling heat and heavy duty use.

Maybe I think too much about the oil but I once had a oil go thick because of heat.. don't want this to happen to the GTO.


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## Lemans guy (Oct 14, 2014)

Chris; Pardon if you know this but the Society of Automotive Engineers SAE motor oil ratings of 5w-30 or 10W-40 are temperatures in Farenheit degrees where the oil will flow the best.

So the 10 in 10W-40 means 10 degrees farenheit for the Average low;

The W means "Winter" in all motor oil designations, it has never meant "Weight"

The 40 is again degees in Farenheit...as in 40 degrees as the average high

5 Degree Winter oil flows better in colder weather, because it has a thinner viscosity....

10 Degree Winter flows less better in extreme colder climate'

10Winter-40 is a thicker viscosity that 5W-30.

All that said these cars we love are older technology that was built generally around rcommended oils of 10W-30 or 40'

Newer fuel injected cars and trucks with now very tight tolerances and computer efficiency demand a freer flowing 5W-30.

Watch your oil pressure gauge when the car is cold and oil is thick, high pressures once fully wamed lower pressures as it flows easier...

I like what the gang said these big powerful 60's engine a 10W-30 (what i use, Valvoline) or a 10W-40 for all that muscle you have would seem right.

In the old days folks would run a 10W40 in summer and a 10W30 in winter or some other highe lower combo.:rofl::rofl::rofl::rofl:


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## Lemans guy (Oct 14, 2014)

PS and that 60 Winter oil, like GEETEE said an old tractor....I would just add an old tractor operating in the sahara desert............it may be the only place you could get that tar to flow!


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## Koppster (Jul 27, 2008)

Lemans Guy,

Not to argue but my understanding is a bit different. 

The numbers in a multi-grade oil refer to the viscosity at certain temperatures. The first number, i.e. 10W is a designation of the oil's viscosity at cold temperatures (testing temp varies....0W, 5W, 10W, 15W, 20W, or 25W); the second number is the viscosity rating at 100 degrees.

Probably a bit more complex than that but I believe that is closer to the correct answer about multi-weight ratings.

Rick


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## Lemans guy (Oct 14, 2014)

Rick, yes thanks I think we are saying the same thing different ways...

The 6 or half a dozen

The o,5,10 temperatures are Farenheit.........and are a used for how it flows in cold weather........

They certainly create that temp to test the flow for Winter conditions.....

The 30 or 40 is also Farenheit..... For warmer temperatures

People do not only drive at 5 degrees Winter ....so the guide as I understand it is that the lower temp would be used in more severe winter conditions....and as you correctly say how good it flows at a specific temp, here 5 degrees...as a guide to be used for Winter driving.

If your average temp are even colder the first number goes lower....

W is not weight......it is for winter.....

You are correct, temperatures Farenheit and flow, it allows drivers to choose the best oil for there average driving conditions....hope that explains my comments better ....


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## Lemans guy (Oct 14, 2014)

Ps I saw your comment on testing at 100 degrees for viscosity flow......don't disagree that it is a measure of flow and temperature for summer driving thanks!


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## geeteeohguy (Feb 2, 2008)

For all you never wanted to know about oil, check out bobistheoilguy. All the info you'll ever need. Being in the automotive industry for over 35 years now, It's amazing that the myth of "racing oil" and "20-50" being needed still persists. This was dirt track thinking from the 1950's, and has nothing whatever to do with our more modern engines and lubricants. If you need a thick oil, your engine is worn out or was built with very loose clearances. My 100 year old Model T Ford calls for 20 weight oil....and it's basically a tractor engine. 60 weight? For what, a gearbox?


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## Lemans guy (Oct 14, 2014)

right, I think Koppster is more right though than I am on it....

they are using certain testing temp...like 100C to see the flow at the oil for summer operation and a completely different temp test for flow at the colder temps for winter

two different tests on the multi grade oil....Koppster is right on the flow for viscosity.....

Amsoil also has a good in depth explanation....

but we all agree it is about temperature hot and cold and which oil flows better in your climate and engine perameters.....


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## Lemans guy (Oct 14, 2014)

SINCE WE ARE ON TEMPERATURES, ANY preferred themostat on a 326? I have a 180 I believe just wondering if a 160 might be better


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## geeteeohguy (Feb 2, 2008)

I've always run 160 'stats in sunny and hot CA. 180 would be fine, though.


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## Lemans guy (Oct 14, 2014)

Thanks Gee,

the factory manual says 190,

I think 180 is in it and I am just going to go with that...........


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## Chris-Austria (Dec 23, 2010)

I read a lot about oils now... I learned that every multi-viscosity oil should have about the same thickness at operating temperature. So you can't say a 5w40 is too thin if you say a 10w40 isn't too thin. Every oil is too thick when cold, but a 5w40 isn't as thick as a 10w40 when cold. When hot both are the same.

So I don't really see why I shouldn't run a 5w30 or 5w40 full synthetic oil in the rebuild engine. The other option is a 10w40 semi-synthetic but like every non-full synthetic it has components that age because of time or temperature, that's one reason why a full synthetic oil is "better".. 

A full synthetic oil will be thinner when cold and it can handle more heat until it gets too thin to lubricate good enough. You can read those numbers on the sheets from the manufacturer.

for example: (viscosity mm²/s at 40 and 100° Celsius)

1. Valvoline Dura Blend 10w40 = 95 at 40° and 14.1 at 100°
2. Valvoline Syn Power 5w40 = 83.9 at 40° and 14.1 at 100°
3. Valvoline VR1 20w50 = 186 at 40° and 20.5 at 100°
4. Valvoline Syn Power 5w30 = 68 at 40° and 11.8 at 100°

As you can see the number 4 is genarally thinner than all the others. Maybe it's too thin for the GTO engine.. but the 20w50 is too thick all of the time. The best choice seems to be the number 2, full synthetic 5w40.. more stable than mineral, not too thick, not too thin (if 10w40 isn't too thin you can't argue that the 5w40 is too thin I guess).

What do you think? Am I wrong?

I'm still not sure if it will be the semi synthetic 10w40 or the full synthetic 5w40... just because of the fact that one is fully synthetic I like that one more.

And I agree now... 10w60 is wrong for the GTO, 5w50 is false as well. They both are too thick at operating temperature. Maybe a race car that runs at 300° F can use this oil, our engines should run at some degree above the cooling temps, so 210 to 250° F seems right, that's why the viscosity at 100° C is very important.. and the flow at room temperature is very important as well because most engine wear occurs as long as the oil is cold.. so the better it flows at low temperatures the better... and every oil flows too less when cold! (it's just the question how much too less)

Another thought is... if 10w30 is good than the 5w30 should be good as well, because they flow the same at operating temperature.. about 11-12 probably. The xW40 oils are a little thicker at this point.. I can't tell if the 40 or 30 would be a better choice, maybe this can be checked by watching the pressure gauge.. if it makes enough psi with the 30 I think the 5w30 is best, if the pressure is better with the 40 I think 5w40 is the way to go. (if you don't have to care about ZDDP with a roller cam).


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