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Old 08-08-2010, 09:41 AM   #28
Special Coupe Frank
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Join Date: May 2010
Location: Northeast Penna
Posts: 2,108
Default Re: Marvelous Mystery Oil?

I would just add that TOO much MMO ( or other oil in the fuel ) will turn to ash & carbon, and gunk and develop undesireable deposits, as well as un-necessary blue smoke.

As for sticking valves in the previously mentioned Gravely tractors ( the ones with the Gravely engines), this was a chronic headache with the per-1958 engines, and had to do with steel valve guides and inadequate lubrication.
In 1958 ( or so) Gravely revised the lubrication system on the engine, and replaced the spring-loaded valve-shields with a cast box with a little cover for adjustment, and oil-passages to the crankcase, and switched to bronze valve guides.
The exhaust valves tended to stick less after this revision.

My experience with the Gravely was that the pre-'58 machines would tend for the exhaust valve to stick open while running at high-speeds, during heavy use, after the machine had been running for a hour or so. Made it tough for me to get my grass-cutting jobs done in a timely fashion when I was in high-school.

With the post-'58 machines the if the e-valve stuck open, it was usually after sitting overnight...

And this was back in the days of leaded-gasoline, by the way... so much for the theory of lead keeping the valves lubricated...

At any rate, I like MMO... "Honestly so..." since, 1907 ?
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