piston ring break-in

[Marc P. Cyr]

I was wondering how long does it take in hours run time for new rings to break-in. I've been running the engine speed fast, and driving the tractor but not in high gear,with some Marvel Mystery Oil mixed with the gas. The rings are standard (not chrome) and the cylinder has been honed. The 9 horse Briggs smokes until it warms up now and I have about 3 hours total run time on the engine.

[BLT]

Well leave out the oil in the gas and then observe your engine smoking. Generally speaking, there is no break-in on air cooled engines. The harder you can work it, the quicker the rings will seat in.

[B.Ikard]

Marc, There are as many ideas on "break in" from folks than you can number. I've built many engines, mostly larger and have never noticed much oil smoking after it(assembly oil) burned out of the exhaust after initial startup. After initial startup, I usually run one unloaded around 1800-2000 for an hour and then use normally. Most of the time smoking in an overhauled engine is due to something that "didnt go back together right" or somebody hoping a set of chrome rings will cure a worn bore,etc Ike

[mowerman1193]

quote:

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Originally posted by B.Ikard
Marc, There are as many ideas on "break in" from folks than you can number. I've built many engines, mostly larger and have never noticed much oil smoking after it(assembly oil) burned out of the exhaust after initial startup. After initial startup, I usually run one unloaded around 1800-2000 for an hour and then use normally. Most of the time smoking in an overhauled engine is due to something that "didnt go back together right" or somebody hoping a set of chrome rings will cure a worn bore,etc Ike

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I have to agree on this from my experiance as well...although I have never rebuilt a small air cooled engine yet...Also the oil you are adding to the gas would cause some smoke so I would not mix it and see what it does then...

[PMax4041]

It May Be Possible that you have some ring end gaps that aligned themselves. Did you stagger your ring end gaps far enough when you assembled it? when I stagger my end gaps I usually go at 11:00 1:00 & 6:00 with the piston wrist pin at 3:00 & 9:00 I Have Been told By a Briggs And Stratton Service School Tech That it is possible for the rings to align while it is running if the end gaps are to close to one another