Oil for older B&S engines

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Jul 14, 2020
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The Briggs manuals recommend straight 30 weight for their older engines, but it is getting harder to find. I have looked at Supertech, Rotella, or even just using 10w-30. What do you use or recommend in this case?
 
Rotella 15W-40 may also a good choice. But to say any 10W-30 is "fine" may not be correct. The HTHS (viscosity at high temp) of 10W-30 oils can fall far short of straight 30. I lost 2 Honda water pump engines due to XW-30 conventional oils. I simply switched to Mobil 1, 15W-50 and the problem was solved.

The issue became clear when I understood that XW-30 oils may not be designed to have adequate viscosity at the operating temperatures of some air cooled engines.

SAE082807.jpg
 
I seem to remember B&S saying that 10W-30 is not a good substitue for 30 weight. I, too, would go thicker.
 
I was helping someone put together a brand new mower (I think it was an MTD with a B & S engine) and it recommended using 10W30. If you strictly want an SAE30, you might have to go to a small engine store (or any outdoor/landscaping equipment store).
 
I understood that XW-30 oils may not be designed to have adequate viscosity

I have a CHonda generator I bought recently. The manual says I can use SAE30, 5w-30 full syn, or 10W-30 depending on temp. I broke it in with SAE30 but switched now to 5w-30 full syn. I am rethinking switching back to SAE30 based on cujets post? Thoughts? Its not used much - for emergency purposes. I start it monthly is about all? Unlikely I would ever use it under 40F here in South Carolina.

B&S markets their own SAE30 oil - likely made by Warren - sold at Walmart: https://www.walmart.com/ip/Briggs-Stratton-4-Cycle-48-oz-Small-Engine-Oil-SAE-30W/16778644

1662466006547.jpg
 
Rotella 15W-40 may also a good choice. But to say any 10W-30 is "fine" may not be correct. The HTHS (viscosity at high temp) of 10W-30 oils can fall far short of straight 30. I lost 2 Honda water pump engines due to XW-30 conventional oils. I simply switched to Mobil 1, 15W-50 and the problem was solved.

The issue became clear when I understood that XW-30 oils may not be designed to have adequate viscosity at the operating temperatures of some air cooled engines.

SAE082807.jpg
Cujet, is that illustration from an aviation publication? TBO Advisor by chance? Anyhow, I have been looking for that article for years now. My memory isn’t what it was.. I seem to recall it was a Mercedes Benz and Shell study?
 
Rotella 15W-40 may also a good choice. But to say any 10W-30 is "fine" may not be correct. The HTHS (viscosity at high temp) of 10W-30 oils can fall far short of straight 30. I lost 2 Honda water pump engines due to XW-30 conventional oils. I simply switched to Mobil 1, 15W-50 and the problem was solved.

The issue became clear when I understood that XW-30 oils may not be designed to have adequate viscosity at the operating temperatures of some air cooled engines.

SAE082807.jpg
@Cujet your chart is labeled as data from passenger car diesel engines.
That is about as far away from small, gasoline powered utility engines as it gets.
Different engine design, duty cycle, oil requirements/specs, cooling system design, etc ...
How do you reasonably apply the information you've posted to OP's question at hand?
 
I have a CHonda generator I bought recently. The manual says I can use SAE30, 5w-30 full syn, or 10W-30 depending on temp. I broke it in with SAE30 but switched now to 5w-30 full syn. I am rethinking switching back to SAE30 based on cujets post? Thoughts? Its not used much - for emergency purposes. I start it monthly is about all?
@Cujet 's chart is plotting data for diesel powered passenger cars.
I'm not sure why anyone would expect it to apply to small utility engine designs.

Making changes based on this info is a stretch at best.
 
I have a bunch of PYB 10W30 that I use im my mower and I have no problems with using it.
 
I have a bunch of PYB 10W30 that I use im my mower and I have no problems with using it.
You really shouldn't have any issues. Briggs and Stratton states that 10w30 might have more burn off than SAE 30 in their manuals, but that doesn't mean you shouldn't use it. I have a customer that runs 5w20 in all of his lawn equipment and has done so for years because he feels he uses less fuel. I really don't think it makes much difference, but he has never had any issues since he checks the oil frequently. I find 15w40 to be very similar to SAE 30, and more readily available, so that is usually what I use/recommend for my small engine customers and my own equipment. The answer for "what oil?" in a small engine is usually "whatever is oil and is kept full".

I see lots of blown up engines every year, most are due to low oil/no oil and also other problems like mouse nests causing overheating.
 
You really shouldn't have any issues. Briggs and Stratton states that 10w30 might have more burn off than SAE 30 in their manuals, but that doesn't mean you shouldn't use it. I have a customer that runs 5w20 in all of his lawn equipment and has done so for years because he feels he uses less fuel. I really don't think it makes much difference, but he has never had any issues since he checks the oil frequently. I find 15w40 to be very similar to SAE 30, and more readily available, so that is usually what I use/recommend for my small engine customers and my own equipment. The answer for "what oil?" in a small engine is usually "whatever is oil and is kept full".

I see lots of blown up engines every year, most are due to low oil/no oil and also other problems like mouse nests causing overheating.
I've probably run that oil on and off in OPE for over 40 years w/o issue. It works quite well in fact.
 
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