Making of new screw-in valve guides
for the 1½ & 3 hp type "M"engines

Since I had a head with broken off "spring towers"
I decided to make these new screw-in valve guides for
 the one & half and the three horse type "M" engines.

After machining the new
screw-in guide, I milling
two flats at the top
for use of a wrench.

Here the guide with the
new "spring tower" in
one piece. Ready to
screw-in the head.

Milling the old
"spring towers" off.

Drilled the holes for
9/16" UNC thread.
At the right, how it
looks when screwed in.

Made a boring tool for boring the valve
seats. There was 7 degrees difference
between the ceramic insert and the 45
degrees for the seats, so I drilled the
hole at 52 degrees ( far left ).

Both screw-in valve guides are mounted in the head,
I smeared some thin JB-Weld on the threads and
fasten them very well with a wrench at the flat milled
top of the guide. Let it stay for a day to harden the
JB-Weld.
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For the final stage I clamped the head at the mill
table by means of four pieces round stock under the
nut faces of the head and align it out with some shims.
The next step is to align the mill spindle exactly in the
center of the seat, when done I bored the seat, drilled
the guide hole and reamed it to fit the new valve stem.
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THIS HAS TO BE DONE IN ONE TIME WITHOUT
MOVING THE PIECE OF WORK.
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Finally I milled the flats off on top of the guides to
the actual size of the "spring towers".