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johnmonkey

Ring Gap

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johnmonkey
I finally got some oversize rings (.010 over) for my model 19 magnamatic. The piston size is 2.981, the old rings had a ring gap of .057 1" down the cylinder and the new set of rings has a .029 -.030 1" down the cylinder. The B&S manual says that the reject size is .030". Question; do I need a set of rings .020" over OR Should I bore the cylinder and get a new piston & rings? There are a set (3) of small thin rings- what are they for? Thanks in advance for your help. John H PS why do some of the threads read on my computer 1 mile long and I have to shrink the text (microsize) or toggle back & forth with the cursor?? So many question so little time!!!!!

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arjr111
John, just redid my kohler. There has been alot of discussion about whether to buy a piston and bore to size, or bore to specs and use the factory piston. Anyhoo, first thing I would do is measure the cylinder bore and see if it is within standard specs. (if you are not boring and using an oversize). If it is then, IMO you should use the standard size piston. Then simply buy whatever size rings will work even if you must grind the gap to size, (if the bore is within specs standard size rings should have the correct gap, but measure to be sure).....Art

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HubbardRA
John, If you go with that it will probably work just fine. I hava a 10 Hp B/S that has had stock size rings(no oversize) put in it twice. First time because of stuck rings, second time because of overheating because of lack of oil. Never even measured cylinder or ring gap. Runs great with no smoke. Remember, the tolerances on these parts are for new or rebuilt engines. Many older engines are still rinning fine, but are outside the specs. When you rebuild one, the goal is to put it back like new. Only thing I have seen with the rebuild rules that I constantly bend is, that the closer to the ideal factory condition - the longer it will last. Maybe you won't get thirty years on this engine, but you will probably get five to ten. Just bored a scored 14 Hp Kohler. $75 to buy the block only, $50 to bore .020 oversize and $125 for piston and rings. Two days before I was to pick this one up, a guy offered me a complete running 14 Hp Kohler for $250. Bought it. Installed it. Still haven't assembled the bored engine. Question? Do you spend a lot now for a complete rebuild now, or go with what you have, to put the rebuild off for several years? By the way, are you still looking for a 10 Hp Carb? Rod H.

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