K301 Stellite Exhaust Valve

[Anglo Traction 761]

I need some from you Veteran Kohler Engine Re-builders/users.

I have a 1981 Kohler 12hp which is stripped out ready for a Re-Bore and Crank Re-grind.

It is from a Triple Gang Ransomes (Reel) Mower. It has a Stellite Exhaust Valve with a Rotator. The Valve has a narrowed Waist in the Stem just below the Mushroom Head, presumably to reduce 'Gas Flow interference.

My first question is, was this type of valve fitted to engines for a specific 'Hot Running' applications where the engine was more 'Enclosed' and a close fitting Muffler with tight bends in the pipe?.

My second question is, I will be replacing the Valve and I normally comply with the Spec of the Engine when replacing parts, but as this is going into an open sided Tractor, would it be ok to use the Standard Kohler Valve?.

The other reason I ask this is because a Kohler Stellite Valve over here will set me back the equivalent of $74.00US.

Any help will be much appreciated.

Thanks, Regards.

[TT-(Moderator) 1,162]

The Stellite coating is used to prevent excess erosion of the exhaust valve from the hot gases and has absolutely nothing to do with the engine application.

A Stellite-coated valve will probably last two to three times longer than a non-coated valve. If you add up the cost of another "cheap" valve, a head gasket, breather gaskets, and the time to replace the "plain" valve, the additional cost of the Stellite valve becomes reasonable in a hurry.

[Anglo Traction 761]

Thanks for that Terry!. I'll probably go for the Stellite Valve and obtain one from your side of the Pond along with a list of other bits (may be cheaper in the long run).

Just can't seem to understand why Kohler didn't use them in all Model Specs, or what their reasoning was to specify which Engines should have them?.

Thanks.

Regards

[shorts 182]

back before the days of green everything and the enviromental people gasoline had lead in it to lubricate and help cool the exhaust casses and internal engine parts, the stellite valves and sodium filled valvestems were usually only needed/used in industrial and heavy truck engines, with the advent of unleaded fuels with different addatives and leaner fuel mixtures resulting in higher exhaust temperatures has caused the need for improved materials for internal engine parts. Kohlers change from the K engine to the Magnum waas mostly emissions driven and consisted of electronic ignition and fixed main jets in the carb if my memory hasen't gone completely. I'm sure that the valve, piston, rings and probably rod bearing materials got respecified aling with the valve seats.