Which oil? Mineral vs Synthetic

66 Sat

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Just wondering what everyone is using for engine oil? Mineral, Semi-Synthetic or Full Synthetic?

After the first rebuild of my poly I was told by a number of knowledgeable people here in Australia to run Penrite HPR 30: https://penriteoil.com.au/products/hpr-30-20w-60-mineral

The engine builder who recently did my poly stroker build recomended a thicker oil again:
HPR 40 25W-70 (Mineral) | Penrite Oil

Then I came across this article in the "similar threads" below:
What I Learned Today — Bearing Clearances vs. Oil Viscosities

I have no issue with using either oil or something different, but was just wondering the thought process behind what folk here use. My engine has a solid lifter camshaft with presumably reasonably tight bearing clearances being a fresh build, and is run on the street and occasionally the track in a climate similar to Miami Florida.

I will ask the engine builder next time I'm passing his shop as I'm curious why he told me to use such a heavy oil. Both recommendations were for a Mineral oil as well, not anything synthetic.
20221004_104457.jpg
 

66 Sat

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Picture is very blurry, hard to read. Is it Full Synthetic? Both the Penrite oils I use are full zinc protection but are mineral oils.
Oils seem to be a very personal subject where people have their favorites but I'm wondering why? Is it just a case of 'well I've always used this and had no failures so it must be good" or "my father always swore by it".
I'm open to using any oil, but I'm keen to know the reasoning behind people's choices.
 

69L48Z27

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25w-70? Is that metric or something?

Here in the US we have lots to chose from. Personally I run 15w-40 diesel oil in anything with stock valve train. If I have high spring rates and want the assurance of high zinc it’s the VR-1 10w-30. I’ve used Brad Penn oils too for high zinc.

As far as I know they’re all dino juice.
 

demonram

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In the newer vehicles I use Castro full synthetic, 5W20. The reason for Castrol? About 25 years ago I had an 85 D350 crew cab dually I built from an ex paddy wagon I bought from the county auction in 92. I built the 360, about 350 horse, used mopar performance valve covers. I pulled out one morning from the house (I didn’t drive it everyday). Had mechanical gauges for backup. Got about a mile and a half from the house, looked down and had no oil pressure. I pulled over, thought a bit and said well could be time for a big block. Drove it home. Never made a sound as far as a tick. Got home, checked the oil, none on the stick. Found the right valve cover had a crack. Fixed it, filled it with oil, never had an issue. In the car I run high zinc 10/40 Amzoil. In the D150, I use 10/40 Castrol, high mileage oil. Worried about leaks with synthetic and old gaskets, currently no leaks , knock on wood.
 

1967coronet

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Everyone has their favorite , Myself I am all for synthetic oils in the newer late model engines that are built with tight clearances.
The old 6s and V8s that are built loose compared to the newer ones I like a good brand of 10 - 40 or 15 - 40 mineral oil with zinc.
And yes synthetic will find your leaks for you. Lol.
 

Photon440

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The only thing I've seen that uses close to 70W is a top fuel engine with loose bearing clearances. Or a hot running Harley using 20w-60 in desert use only. That's too thick for a regular street engine.
 

Mopar Hunter

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Picture is very blurry, hard to read. Is it Full Synthetic? Both the Penrite oils I use are full zinc protection but are mineral oils.
Oils seem to be a very personal subject where people have their favorites but I'm wondering why? Is it just a case of 'well I've always used this and had no failures so it must be good" or "my father always swore by it".
I'm open to using any oil, but I'm keen to know the reasoning behind people's choices.
Not the synthetic, mineral oil.

95A9B8BD-F6C9-4343-9548-4B073991F72C.jpeg
 

Geoff 2

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66 Sat,
If the engine is newly rebuilt, you should use Penrite break in oil for 500 miles. Then, the same again for 1500 miles. After that any oil you like. I would use full syn oil because it withstands higher temps before it breaks down. I use Penrite 10-10ths. Full syn oil, 10w/60 grade. Has you covered at both ends of the temp spectrum. 25-70 oil is for high mileage engines, & builder must be a real dope to suggest that for a re-built engine.

Street Commodore magazine compared a lot of big name engine oils a few years back, using the Timken OK bearing test. Penrite full syn & Royal Purple got equal first place. Some big name full syn oils did badly: Mobil 1, Shell Helix, Fuchs, motul, Castrol R, Redline.
 

66 Sat

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66 Sat,
If the engine is newly rebuilt, you should use Penrite break in oil for 500 miles. Then, the same again for 1500 miles. After that any oil you like. I would use full syn oil because it withstands higher temps before it breaks down. I use Penrite 10-10ths. Full syn oil, 10w/60 grade. Has you covered at both ends of the temp spectrum. 25-70 oil is for high mileage engines, & builder must be a real dope to suggest that for a re-built engine.

Street Commodore magazine compared a lot of big name engine oils a few years back, using the Timken OK bearing test. Penrite full syn & Royal Purple got equal first place. Some big name full syn oils did badly: Mobil 1, Shell Helix, Fuchs, motul, Castrol R, Redline.
He's definitely no dope, very respected engine builder in SE Qld, races cars in the replica touring class, build street engines, circuit race engines, drag engines etc. I've emailed to ask him his reasoning. The HPR30 (20W-60) & HPR40 (25W-60) bothhave the same description:
HPR 30 is a premium high performance mineral, SAE 20W-60, non-friction modified engine oil. It features a DOUBLE LAYER of engine wear protection with FULL ZINC (approx. 1600 ppm levels) and Penrites advanced EXTRA TEN technology. Protects against corrosion, oil oxidation and sludge under all operating conditions.


HPR 30 is recommended for use in vehicles where SAE 20W-40, SAE 30 or 20W-50 were originally recommended by the manufacturer.


Application​


HPR 30 is designed for use in 4, 6 & 8+ cylinder naturally aspirated, supercharged and turbocharged petrol, LPG and diesel engines. It is also suitable for use in older Rotary engines. It is particularly suited for use under high load conditions such as towing and competition or where ambient temperatures are high.


So you're saying the Penrite Full Synthetic 10W-60 is better than the Penrite HPR30 20W-60 Mineral Oil?

I'll email Penrite Tech Dept. and ask their opinion. Will be interesting what they say.

Cheers
 

66 Sat

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Well I've emailed Penrite tech dept. so I'll let you know what they say. The engine builder got back to me, he wanted 25W-70 for first 1,000kms to help seat the rings. After that he says 20W-50 is fine. Glad I cleared that one up.

Interestingly:
Valvoline VR1 Mineral 10W-30 or 20W-50 have high zinc 1,400 ppm
Valvoline VR1 Synthetic 10W-30 or 20W-50 have high zinc 1,400 ppm
Penrite HPR30 Mineral 20W-60 has high zinc 1,600 ppm
Penrite Premium 10 Tenths Full Synthetic 10W-60 has high zinc 1,800 ppm
Penrite Racing 10 Tenths Full Synthetic 20W-60 has high zinc 2,200 ppm

Do the Full Synthetic oils need more zinc for some reason? In Penrite's case it looks like the case, but not Valvolines. Is there an amount of zinc that is adequate, and then is more better? So if 1,400 ppm is good, is 1,600 ppm better? What about 2,200 ppm? Can you have too much zinc?
If you look at Penrite's website descriptions the oils are pretty much the same, except the HPR oils have some magical Double Layer of protection with full zinc plus the "extra 10" (which just changes a 10W-30 oil to a 10W-40 for instance i.e. extra 10 on the second number - sounds like marketing bullshxt).

Anyway, my head is spinning with all these numbers, and I'm still trying to ascertain why some folks like mineral oil and some like synthetic. Hopefully the oil manufacturer provides a definitive answer.
 

Photon440

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Short answer, yes you can have too much zinc in oil (ZDDP actually), as it will cause the oil to become acidic and start to add wear to bearings cams and bushings.
 

RemCharger

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I would absolutely go with the builders advice. Engines are expensive.
If something goes south(bad) with a different oil, what do you think the builder is going to say when you go back to him?
That being said, I run 20w50 conventional in my cars and customer builds. Never an issue.
If you are concerned about the oil breaking down, you need an "oil breakdown tester".
 

Dennis H

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Amsoil. Everything I own. 10-30 in the 440. High Zinc.
 

Black_Sheep

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Mobil 1 in my daily and dino oil in my fun stuff. 10w30 in my 454 Chevy and straight 30w in my 440. Both also get a bottle of break in additive at every oil change.
 

Runcharger

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Interesting. That seems like a really thick viscosity on the warm end. They must measure them differently or use a 250f thermostat.
 

Budnicks

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Climate has a huge effect on oils too
thinner viscosities for colder climates
& thicker viscosities for hotter climates
(of either mineral or synthetic)

I have a buddy, fellow drag racer Doug B.
he used to do destructive oil testing on all brands, before he retired
at Richmond CRC, Chevron Research facilities after 40 years 'expert'
on his recommendations & testing

I run a high mileage or a Race Oil Torco Synthetic TR-1
10w-40 for cooler temp or 20w-50 for hotter temps
in all my special engines, viscosity usually to me
all depends on clearances
& what style of camshaft or rings (even bearings in some cases)
but still the same oils/brands

in my Daily Driver 99 Dakota SLT 4x4 5.2ltr/318 Magnum roller engine,
has 1.7:1 HS Rollers too, since doing that switch
I used 10w-40 Synthetic Royal Purple, since like 2007
in fact everything is Royal Purple synthetic 'that used/uses fluids on that truck'
so far so good, after nearly 16 years now...

allegedly
Amsoil & Redline full synthetics are the best for wear
in unbiased testing
I used to use both at different times of racing
Until I got my Torco sponsorship &
I never had any failures due to oil even in harshest of racing conditions
for over 25+ years I used their products
so I've stuck with them 'like the loyal dog I am'
for 35+ years now

Torco Racing Oil Professional Series TR-1-20w50.jpg
 
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66 Sat

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Interesting. That seems like a really thick viscosity on the warm end. They must measure them differently or use a 250f thermostat.
It seems like the "extra ten" "double layer protection" is at play here. The Penrite HPR30 that a lot of us use here is really a 20W-50 high zinc mineral oil but this "extra 10" that they market pushes it to a 20w-60.
I don't know if it's some special technology or if it's merely a 20w-60 oil to begin with...
 

gtx6970

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I was told by the engine builder to use a straight 30 weight in mine. ( basically stock street hemi with mild solid lifter cam/lifter pkg )
So it gets Rotella 30 with a bottle of Lucas ZDDP zinc additive at each oil change
 

Budnicks

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also I should have added
many of the newer engines use very light viscosity oil
0w-5, 0w-10, 0w-20, 5w-20 etc. etc. etc.
much tighter clearances/tolerances in machining
& hydr. roller cams & roller bearings in valvetrain trunions
tighter oil-pump clearances & higher volumes/pressures of oil going thru,
with better/good oil pumps, worlks well with thin oils/lower viscosity

With a lot more tech stuff, sensors everywhere
EFI & dry intake manifolds DPI (direct port injection),
computer-controlled everything
less washing down rings, far more sensitive to it too
less dilution & less carbon, for the emissions system 'to sniff out' too,
with synthetics
 
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