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ChadS
06-09-2005 07:27:51
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Re: M Head Shaving in reply to JBF203, 06-06-2005 12:34:06
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You must have an origianl 248 ci M! It has to be a kerosine engine, with a low compression head. Junk that old head and get one from a super M-450, youll find that your $$ spent will go a little farther in the long run. You could mill the old head down, but for maybe 40-42 hp, I agree with FB, turn up the rpms when its on the dyno, if its not reaching above 540, before you pull the engine down on the dyno, your not getting anything just yet to accuratly tune the engine. a good rpm # to shoot for for no load rpms is 600-625, then pull it down to 540 pto rpm, read it from there. You will see a difference in HP, cause the governor is now opening up the carb more. As far as how much to mill off the head,, you first need to measure how thick the head plate is. You can measure it from the triangle water ports and get a rough idea on how thick it is. Keep the plate thickness no thinner than .300 have the head checked for cracks first,,, you mite have a crack hiding there and not find it till you start milling. anything beyond .300 can be removed safely. Your dealing with 50 year old parts, and cracks are likely in some cases. CHadS
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