Anyone running 0W20, 30, or 40 in a 10W30 engine?

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I’d like to know, would I benefit in switching to an 0W oil in my Mustang’s 351W pushrod motor. It’s just a standard older 351W pushrod motor. 10W30 was what was always recommend back then. Car is hardly driven. Maybe once or twice a month.
 
Since you are in CA I am assuming brutal cold starts are off the table, so I would say NONE benefit wise. Unless you just want to use a real high quality full syn...it won't hurt anything either.
 
The real advantage of a 0W motor oil would be in below lets sat -30*f so no but run the oil anyway 0W-40 Mobil 1 Is a great oil
 
Originally Posted By: Nicasio
I’d like to know, would I benefit in switching to an 0W oil in my Mustang’s 351W pushrod motor. It’s just a standard older 351W pushrod motor. 10W30 was what was always recommend back then. Car is hardly driven. Maybe once or twice a month.

Depends on the 0w.

For example: If you pick a fuel economy oriented 0w-30 (e.g. Mobil 1 Advanced Fuel Economy 0w-30), it'll flow better on a cold start, even in a warm climate. However, being a modern synthetic that meets modern API and ILSAC specs, it should still protect better and last longer than an old 10w-30.

On the other hand, some 0w-30 and 0w-40 oils are formulated for tough long-drain Euro specs (e.g. Castrol Edge 0w-30, Mobil 1 FS 0w-40). Those are thicker overall, so they won't be much better than those old 10w-30s on a cold start in a warm climate -- but they'll protect and last WAY better.

If you go with a 0w-20, it'll flow WAY better on a cold start, and cool your engine better. Technically it won't be as thick as an old 10w-30 when brand new, but being a synthetic it'll hold up much better, so it might not be much worse by the end of an OCI. Hard to say how well it'd protect, though I wouldn't be shocked if it worked just fine.

Then there are those weirdo low-ash Euro 0w oils, like Mobil 1 ESP X1 or Pennzoil Platinum Euro LX. They meet really tough wear control specs and tend to have the best base oils, but they also have low-ash additive packs -- great for deposit control and catalytic converter health, good for wear, not good for OCI length.
 
What year is this engine? If it's old and has been running 10w all its life I would be leary of running a 0w in it. You don't have cold winters in your location. I would stay with what has been working all along.
 
Originally Posted By: d00df00d

If you go with a 0w-20, it'll flow WAY better on a cold start, and cool your engine better...


Only at temps well below 0 deg F. It might not cool any better. And the thinner viscosity might be a detriment to your engine bearings without knowing more about this particular 351. For a factory original engine with plenty of miles and specced for 30 grade there'd be no 20 grade for me.

Considering your typical year round starting ambient temp is in the 30-100 degF range, any of the 0/5/10W oils will flow approx the same at startup. If it were me, I'd stick with the 5/10w-30/40 oils for your Mustang. The 10w-30 is still a good recommendation...especially from April-September. An A3/B4 0w-30/40 oil could still work well for you even if there's no real benefit to the 0w. If that supercharger is an add on, that could change things.

I note that Rocklin, CA hasn't made any new monthly temperature highs since 1988! It would appear there's no global warming in Rocklin.
 
Rocklin can get down to 20* on some day/nights. I have a new to me 351 also and I will be trying 0W-40 Mobil 1 Euro formula to see if I can get it to work ... Engine has 83K and is still modestly tight, so I'm hoping that I won't have too many drain-off issues as the truck will sit for up to a week at a time ...

If it's noisy and clattery on cold start after sitting, it'll get swapped out for some Delo 400 15W-30 (on hand) or 15W-40 (readily available) and I'll move the 0W-40 to something else. I don't tolerate noisy cold starts. Mobil 1 has a spotty record in my various vehicles for cold start noise. But I know it's good oil, so I always give it a try
smile.gif


Plus I have stock in XOM, so I like to support the firm if I can
laugh.gif
 
Something like M1 0w-30 AFE might give you a tick higher fuel economy, which you'll never measure, much less notice. Other than that, I can't think of much. Now, if you're already putting synthetic in there, M1 0w-30 AFE won't cost extra.
 
Flat tappet cam? Most of the passenger car oils have been watered down. I would not run 0W30.

Rotella 15W40 is what you want. Delo 15W30 or Rotella 10W30 are also good choices.
 
It’s got a COMP hydraulic roller cam set up, Brodix aluminum heads, 11psi Vortech, BBK long tube headers, & Magnaflow high flow catalytic converters. I believe it’s gotta be an early to mid 90’s short block. Like in the Ford Trucks/Lightnings. Dynoed 498hp/491tq to back tires at 5800 rpms. Makes 400lb tq at 2750 rpms. Been using M1 10w30 in it. I don’t drive it much at all so I change the oil yearly. Winters are frosty here in Rocklin sometimes. Summers are in the 100’s... For my set up, what would y’all try to better the M1 10W30?
 
Originally Posted By: d00df00d
For example: If you pick a fuel economy oriented 0w-30 (e.g. Mobil 1 Advanced Fuel Economy 0w-30), it'll flow better on a cold start, even in a warm climate. However, being a modern synthetic that meets modern API and ILSAC specs, it should still protect better and last longer than an old 10w-30.


OK, where's your evidence for this old chestnut ?

It's not true, no matter how many people repeat it.
 
Those hydraulic roller lifters are sensitive to oil viscosity. Go too thin and they'll bleed down and go flat. Go too thick and they won't pump up. If you switch to 0W-20 you stand a good chance of getting iron soup.
 
Originally Posted By: Merkava_4
Those hydraulic roller lifters are sensitive to oil viscosity. Go too thin and they'll bleed down and go flat. Go too thick and they won't pump up. If you switch to 0W-20 you stand a good chance of getting iron soup.


Whoa! Now that’s scary! So 0W-20 is no go
 
Originally Posted By: PimTac
Sounds like a HDEO would work fine here. Delo, Delva, Rotella, whichever brand you prefer


I thought I read something about the HDEO oils being bad for catalytic converters? Otherwise I wouldn’t mind dumping some Rotella in it. I’ve used Rotella in my motorcycles & they all ran awesome!
 
Originally Posted By: Nicasio
Originally Posted By: PimTac
Sounds like a HDEO would work fine here. Delo, Delva, Rotella, whichever brand you prefer


I thought I read something about the HDEO oils being bad for catalytic converters? Otherwise I wouldn’t mind dumping some Rotella in it. I’ve used Rotella in my motorcycles & they all ran awesome!


That would largely depend on how much oil the engine is burning. In all honesty if an engine is burning a lot of oil that in and of itself isn't good for the catalytic converter.
 
Originally Posted By: Shannow
Originally Posted By: d00df00d
For example: If you pick a fuel economy oriented 0w-30 (e.g. Mobil 1 Advanced Fuel Economy 0w-30), it'll flow better on a cold start, even in a warm climate. However, being a modern synthetic that meets modern API and ILSAC specs, it should still protect better and last longer than an old 10w-30.


OK, where's your evidence for this old chestnut ?

It's not true, no matter how many people repeat it.


Per my point...the differences are all at the extreme ends of the pumpability spectrum. Have wheeled this out too many times to count


When the oil is in the pumpable range, there's no difference...

Here's some new to my library pieces...on European engine testing. First is a chart clearly indicating that the thicker oils take longer to both build oil pressure and reach the rocker arms.


Note however that the viscosity is in Poise...Whole numbers of Poise...not Centipoise.

600 Poise is 60,000Cp, which is the limiting viscosity (give or take) for each of the SAE J300 "W" bands.

Rough as gutz (because density changes the number by about 20-25%), substitute the CSt of your favourite oil for Cp...then divide by 100 to get Poise...then look at the chart, and see where they sit with regards to the 3 bar oil pressure, and the RAOT...

Pick an "even in a warm climate" temperature for your 0W20 and 10W30, lets say freezing, and draw a dot on each line where they sit in comparison to each otehr.


Authors developed a correlation...and again, it's based on the entire spectrum of very thick, nearly pumpable oils tested, not at "warm climate' temperatures.



Remember to convert to whole poise before using ... again for the test engine in question.
 
To simplify the above, take the delta Cst between the two oils, and multiply by 0.001 (or divide by 1,000) to get the number of seconds difference in "flow" between them...again, in the particular European test engine in question.
 
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