Small Engines (Lawn Mowers, etc.): Kohler M20 Engine, iron pig, m20 engine

Question
I have a Kohler M20 Engine and am rebuilding it. The engine (cylinders) are before Serial #1917809296 which are 45 degree angle valves. The replacement valves and seats are 30 degree, can I use the 30 degree valves and seats and use the 45 degree valve clearance (the clearances don't overlap there is a .002 difference or I would have used that overlap point) or do I have to replace the cam and lifters at a huge cost? There are no 45 degree seats or valves stocked. I can't get a straight answer from anyone on this. Stumped everyone on this one!

Answer
Dale, Dale, Dale. You are thinking way to hard.

You can cut the seats to any angle you want.  The machine shop  I use at work charges a whopping 2.00 a grind.  Take the valves with you and the machine shop will match the grind to the valves.


Valve clearance in this old cast iron pig is so non- critical it's ridiculous.  I'd go .008-.010 on the exhaust and .006-.008 on the intake.

You do have a machine shop that bored your cylinders, right?  You need to bore this  pig's jugs .030 over or you wasted a rebuild.  It will need to go .030 over to take out the taper and out of round.

FYI... if you buy a new cam and tappets you are nuts.  You do however need to grind the divot out of the top of the old lifter to get an  accurate valve adjustment.