[wakesupremo]

I'm sure this has been asked several times. What oil is recommended for a newly built motor with modern spec parts and tolerances? Im sure with roller cam etc its not necessary for a high zinc content oil but with small tolerances on the bearings etc can I run a more modern , thinner oil such as 10/40 fully synthetic?

[lust4speed]

All depends on bearing tolerances. I had old school clearances in the drag engine and ran 20w50 racing. My street GTO with tight tolerances I run 5w30 Valvoline Conventional (translation = old fashion) oil. This gives me 70 pounds cold start up in cooler weather and 65 pounds with engine at operating temperature at 1,900 cruising RPM. The 10w30 I started out with was 80 pounds cold so I dropped the cold side down a bit. If I found that running temp oil pressures were a little low I would have went with 5w40.

In short, use an accurate gauge and respond with viscosity changes to what it is telling you.

Also don't have anything against synthetics and just haven't made the move.

[Dragncar]

Sure you can. Street car, the most important thing about oil is regular changes. Few engines does it matter a hill of beans what brand or type of oil is in it as long as it has needed additives for a flat tappet if you have one.
Just don't run thick oil if it gets cold where you live. Most over talked about thing there is, oil.

[steve25]

To break in a new motor and not wash the break in lube off the Cam , lifters and whatever else, you want to run a non detergent 30w oil like you do in your lawn mower and also a break in additive.

There’s zero need for fancy expensive break in oil as the factory never used such, and I think they know a thing or two about getting cars out the door with motors done right, don’t you when you think about it!

[Cliff R]

Considering how much oil "floods" the lifters when the engine is running I doubt if any type of lubricant supplied with or used for "break-in" is there very long. The key to success with flat tappet cams is using real USA made lifters, not re-boxed junk from China or South of the border. I've never had a single issue once with flat cams and lifters, but was also lucky back when shortages of USA made lifters caused the market to get flooded with low quality imported varieties I was using Rhoads at that time and never "scrubbed" a lobe.

I actually saw a "fresh" Olds 455 engine built by a good friend and very experienced engine builder wipe over half the lobes right off a Comp XE cam before it had an hours run time on it. He used the recommended springs from Comp at the correct height, their cam, lifters, PLENTY of break-in lube, and the engine was static times and carb (I supplied it) filled with fuel so the engine roared to life instantly and was ran at a fast idle for over 15 minutes. It started to get a little noisy after about 10 minutes of "run-in", and when they finally allowed it to idle down it sounded like a thrashing machine! It pumped so much metal thru the engine it required another complete rebuild and the crank had to be ground another .010".

I also don't run nearly as much spring pressure as we typically see others using nor do I use cams with "short seat timing" and super-quick opening/closing ramps.

It is my opinion that combination of high spring pressures, imported lifters and fast-ramp cams are a death sentence for the lobes and missing tiny trace elements of zinc in the oil have really nothing to do with that sort of thing, at least early in the life of the engine.....FWIW.....

[78w72]

what exactly are "modern" specs & tolerances? if this was built as a "street" engine & not bigger drag race type clearances, a 10/30 oil is probably best, but as mentioned see what kind of pressures you get, if they are good then use a thinner oil, especially in a colder climate. yes modern thicker synthetics like 20/50 can be used & some here use them on street cars but most are in warmer climates or have looser bearing specs. a thicker oil has no real benefit in a street engine.

but the best advice to seek is that of the machine shop that built the engine, ask them what you should use based on how it was built.

[Don 79 TA]

don't be fooled into thinking just because you have a roller cam you dont need good quality oil
some of the roller profiles are aggressive and some people have had wipe out issues
LG motorsports had this we some rollers in LS engines and once they swapped to the good quality oils they didn't have failures

i've been using Motul ester oil which comes in a 2qt cans
i dont know life of it as i dont drive much and change it once a year
another positive is esters dont seem to weep like other Synthetic oils do
the motul oil is a base V stock i believe

[Kenth]

Use the correct viscousity for the running temperature of the engine.
The normal running temperature for most classic GM V8 engines is 195°F to 220°F and here is were the recommended 10w30 protects the engine.
Ram Air or S.D. engines with somewhat looser tolerances and no oil shields on valve springs require 10w40.
Mineral oil is fine for regular oilchange intervals, synthetic oil is optional for longer intervals.
For break in with a flat tappet cam use GM E.O.S. the first couple of oil changes.
After that oils with 1000-1200 ppm zink is just fine. Over 1800 ppm you can expect added wear and residue inside engine surfaces.

JMHO from 40+ years maintainance on my Pontiacs.

[wakesupremo]

Thanks everyone for the info.

[taff2]

You wouldn't go far wrong with Valvoline VR1 20-50 imo. I've used it for years in everything from my race cars, camper van, my Jag road cars, wif'e Toyota, even my sons 4 stroke dirt bikes.

[Kenth]

20w50 is fine if your engine is preheated before start and runs at 250°F.
Or, if you have a preheated NASCAR engine running large bearing clearances with full throttle for 3 hours between oil changes.

FWIW

[78w72]

Originally Posted by taff2

You wouldn't go far wrong with Valvoline VR1 20-50 imo. I've used it for years in everything from my race cars, camper van, my Jag road cars, wif'e Toyota, even my sons 4 stroke dirt bikes.

20/50 in a toyota? what year & model is that & what weight does toyota recommend to use? never heard of 20/50 in any modern toyota, usually 5/30.

[78w72]

Originally Posted by wakesupremo

Thanks everyone for the info.

are you able to answer any of the questions asked about the engine?

did you ask your engine builder what oil they recommend?

[wakesupremo]

Thanks again. Yes i asked my engine builder, He suggested modern 10/30 fully synthetic because of the crank tolerances and the fact that it has a roller cam. Afterwards though, just in conversation with a very good friend and very knowledgable racer, when I mentioned this he said that he would never use modern fully synthetic in an old motor, stick with Kendall 20/40 or similar. Thats the reason for my question. And, as this post proves, there are several conflicting answers.

[Kenth]

Your engine builder is correct, and he should know since he built the engine.
It was long time since i took advice from "racers", they tend to break parts all the time and in retrospective i have found why.

[padgett]

"The normal running temperature for most classic GM V8 engines is 195°F to 220°F" - true at that temp it does not require much tuning and cats may light off quicker so the factory likes for warranty periods. OTOH I keep cars for decades and run non-computer cars at 160-180F and computer cars at 180-190F (have to reprogram fans) for years and find that EVERYTHING under the hood lasts longer.

[Dragncar]

BS. The OP can run 10-30, he can run 20-50. It does not matter a hill of beans. Over thinking at its finest.
I race. Have run 20-50 with roller cam and rockers. Never hurt a engine in my life. Ran 10-30 for awhile, did not hurt anything. Went back to 20-50.
The OP can run straight 30WT for all that matters.
The most important thing about oil is selecting a high grade oil and changing it regularly.
Have you ever looked at the clearances of dead stock Pontiacs ? They can run .001 clearances all over and those engines ran straight 30WT.
And no one sets up their performance Pontiac at .001 these days. Even if the engine builder says "run this oil". Does not matter unless its really, really cold or hot where you live.
All this stuff against 20-50 is cr@p. Its all thin once your engine is hot.

[Dragncar]

Originally Posted by 78w72

20/50 in a toyota? what year & model is that & what weight does toyota recommend to use? never heard of 20/50 in any modern toyota, usually 5/30.

The biggest reason car companies today all say to run WATER for oil in NOT about these incredibly tight tolerances of today's modern engines !. Its because if you run super thin oil over a entire fleet of cars they will get a tiny bit better fuel economy, thats it.
Same reason they have a freaking computer drop a cylinder, or cut of charging your alternator while at highway speeds. Its gets a tiny, minuscule better gas mileage.
Over complicate things and give less protection in the name of fuel economy.

[78w72]

Originally Posted by Dragncar

The biggest reason car companies today all say to run WATER for oil in NOT about these incredibly tight tolerances of today's modern engines !. Its because if you run super thin oil over a entire fleet of cars they will get a tiny bit better fuel economy, thats it.
Same reason they have a freaking computer drop a cylinder, or cut of charging your alternator while at highway speeds. Its gets a tiny, minuscule better gas mileage.
Over complicate things and give less protection in the name of fuel economy.

not entirely true, there is a lot more to using different oil weights for different applications than just mpg. 10/30 is not "water" & no consumer has a "fleet" of vehicles. the economy features on modern vehicles do a lot more than get minuscule better gas mileage, some vehicles that cut half the cylinders get pretty big increases in mpg. the question was simply asking what toyota uses 20/50 or why someone would use that oil in a modern toyota. there is absolutely no reason or benefit to using that thick of oil in a modern vehicle. especially a small 4 or 6 cylinder toyota.

Originally Posted by Dragncar

BS. The OP can run 10-30, he can run 20-50. It does not matter a hill of beans. Over thinking at its finest.
I race. Have run 20-50 with roller cam and rockers. Never hurt a engine in my life. Ran 10-30 for awhile, did not hurt anything. Went back to 20-50.
The OP can run straight 30WT for all that matters.
The most important thing about oil is selecting a high grade oil and changing it regularly.
Have you ever looked at the clearances of dead stock Pontiacs ? They can run .001 clearances all over and those engines ran straight 30WT.
And no one sets up their performance Pontiac at .001 these days. Even if the engine builder says "run this oil". Does not matter unless its really, really cold or hot where you live.
All this stuff against 20-50 is cr@p. Its all thin once your engine is hot.

yes he can run any weight he wants & 20/50 probably wont make the engine blow up, the point is that there is no benefit at all to using that thick of oil in a motor built to tighter street type clearances. there is a lot more to oil viscosity than what you claim in your post. if you race, chances are the engine was built for that purpose & not regular/daily driving in a wide range of temps. thicker oil doesnt lubricate at cold start up as well as a thinner weight oil for the application does, it also doesnt flow through bearings & cool as well. so yes 20/50 will "work" especially some of the thinner synthetics of today, but a thinner weight that gives good oil psi will work better in these types of engines. what is the benefit or reason to run an overly thick oil in a motor that doesnt need it?

& what stock pontiac ran a straight 30w oil? late 60's & all 70's pontiacs use a multi viscosity oil, usually 10/30 or 10/40, with the exception of the 80/81 turbo t/a's that used a 30w due to coking in the turbo, but that was 40 some years ago & modern oils are improved so much over oil back then that its not needed now.

nobody is "against" 20/50, just saying there are better options for an engine that doesnt really need a thick oil.

[promptcritical]

Modern engines run few hundred thousand miles on a diet of the recommended 5 or 0W30, so it doesn’t appear that the light oil hurts anything and parts are pretty well protected. That being said, the builder of my 455 recommended Brad Penn 20W50, so that’s what I use. My newer cars and my Formula seem to be fine using those weights in Phoenix weather year round.