Oil consumption

[Simplicity_728]

The 8hp Briggs in my 728 is a short block with aprox 100 hours on it. Last summer I used Pennzoil SAE 30 with no problems and no consumtion. This summer I switched to synthetic. I am using Mobil 1 10W-30 and when not under heavy load it doesnt use and oil. When under heavy load it used 1/16 of an inch every hour and a half. No smoke and anything and runs like a swiss watch. Is this normal with Briggs engine to use a little oil when under heavy load?

[D-17_Dave]

No usage of oil should occur if the engine isn't worn. That said, it's likely the rings can't properly seat against the aluminium bore with the better viscosity of the synthetic oil. The synthetic oil does have added properties that provide a better, longer lasting cohesion to the metals. So in effect it's so slick that it's passing oil like a worn engine. Synthetic based oils can outlast natural oil due to the heat resistant properties and does provide some mildly better lubrication in some cases due to additives. The biggest reason to change oil in an engine unless it's been abused is due to contamination from combustion by-products. On most small engines this contamination is more than most automotive applications. So if your wanting to get more life out of the oil between changes, but your watching the darkness of the oil you'll likely see your not gaining anything except that your using higher priced oil.

[Simplicity_728]

this one has a cast iron sleeve (shortblock is an I/C model) and with SAE 30 I had no consumption and with the synthetic its only when under heavy load it uses alittle. Normal load it uses none

[Storm7012]

Go back to the old oil.

[DMedal]

1/16" every hour and a half. When the smoke interferes with your visibility it is time to be concerned. For now, live with it. I guess you need to check the oil every 10 hrs or so at that rate. After 25 hrs you have to drain it all anyway. I'm told in WWII the mechanics would have to rebuild an engine if it DIDN'T use oil. (as it was too tight) Or as Storm said, you already know it doesn't burn with the old oil. So that's a good option, although I think I'd stick with the synthetic myself. You still have to keep checking the oil anyway, even if it doesn't burn. I don't want to say how I know that, it is embarrassing.

[Brettw]

quote:

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When the smoke interferes with your visibility it is time to be concerned

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Or when the windows are open in the house, and it sets off the smoke detector. Trust me, this can happen. New rebuild kit just arrived today. 8D

[Simplicity_728]

It will sometimes smoke for a few seconds when the PTO is engaged

[DMedal]

another 900 hrs and you'll need a ring job

[Simplicity_728]

I'm changing back to SAE 30/10W-40

[IronPony]

With my AC712 I knew it was time to work on the old Kohler because I had to change my cloths after blowing snow for an hour or so. Dan

[Storm7012]

I hate to even get into the oil thing again. My though on it is, if the old SAE 30 got some of my engines through 30 plus years of service it's good enough for me.

[Simplicity_728]

Im done with synthetics! She's getting changed to Mobil Clean 5000 10W-30 this afternoon

[427435]

First, a 1/16" in an hour and a half of heavy load isn't bad at all. Second, if you would like to have the advantage of high temp oil stability (not a bad thing in an air-cooled engine) that a good synthetic oil provides, use a 15w-40 or 15w-50. Both will reduce oil consumption, but especially the 15w-50 (available in Mobil 1).

[Simplicity_728]

Changed it to Mobil Clean 5000 conventional 10W-30 and mowed the neighboors 6" really thick grass (Fuel pump went bad in his Craftsman) for 2 hours to give her a good work out and she didn't use a drop:) I figure every 50 hours I'll change it as the OM says to do. Also the air cleaner cover says Summer: SAE 30, 10W-30, 10W-40 Winter: SAE 5W-30 or 10W-30 I noticed that 1988 and prior engines say multigrade is acceptable for summer but 1989 and newer say not to use multigrade in summer. The air cleaner cover on this is off of a 1986 8hp Briggs and the sticker on the 1987 12hp I/C I have says the same as above.

[Al]

Hi, Sae ..30 is more resistant to heat than 10-30. The areas around the exhaust valve in the cylinder where the valves are siamesed is where the oil is breaking down as this little triangle in the cylinder wall behind the exhaust valve is where the oil can't stand the heat. The OHVS have solved this problem. I have never been in a service school where on the L head engines they didn't REALLY stress telling people ONLY straight 30 om the summer. It is tougher under heat than the multi-grades. Al Eden

[427435]

quote:

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Originally posted by Al
Hi, Sae ..30 is more resistant to heat than 10-30. The areas around the exhaust valve in the cylinder where the valves are siamesed is where the oil is breaking down as this little triangle in the cylinder wall behind the exhaust valve is where the oil can't stand the heat. The OHVS have solved this problem. I have never been in a service school where on the L head engines they didn't REALLY stress telling people ONLY straight 30 om the summer. It is tougher under heat than the multi-grades. Al Eden

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While this is certainly true with dino oils, a good synthetic oil will be even better. I use either Mobil 1 15w-50 or 0w-40 in my air-cooled engines. That includes a Kohler MV20 that has something north of 2000 hours on it spinning a 72" deck on a commercial lawn mower.