On Tuesday, August 6, 2013 12:10:47 AM UTC-4, Terry Coombs wrote:
Anybody here have any experience with hoppin' up the engines ? I've been

asked to mill .045" of one from and OHV motor , don't know the brand . One

thing O found after I clamped it to the mill table , the area over by the

pushrod area is about .005 down from the area around the piston . No obvious

difference in the appearance of the original milling looks like about a 10

or 12 inch face mill on the surface .

If this guy likes my work , there are 4 or 5 more who want the same thing

done . I guess you could call this redneck racin' in it's most basic form .



--

Snag

A loooong time ago we'd mill the heads on Continental (single-cylinder/four cycle) engines for quarter-midget race cars.

A Burke #4 horizontal mill did a fine job of it. In fact, I've still got that mill now almost 50 years later.

Clamped through the spark plug hole for some reason that I no longer recall.

That, and we'd make thin head gaskets from copper sheet.

Another trick was to make offset woodruff keys for the flywheel.
Changes (we advanced) the timing with magneto ignition.

Yet another cheat was to trick the cam profile with a fast & high intake pop up.

Of course, all of the above was NOT legal for the class we raced in.
But a challenge teardown was always possible if we got too fast.

Good times, hadn't thought about it for quite awhile.
We had a ball, hope you do too.

--
PaulS