Also, Be sure to check out the
drawing and explanation for the Bovaird & Seyfang...
Here are the timing gears that will need to have a lot of machine work done on
them. They are gears made by Browning that I ordered from a gear house in
Rochester, NY. The small 40th gear is steel and the larger 80th gear is cast....
This photo shows the original 40th gear still on the crank shaft with all the
teeth warn down. I have to remove this and get the crank shaft ready for the
These 2 photos show the main valve guide and seat part ready to be pressed into
the piece of heavy wall tubing, and welded in place, that will start to form the
valve chest assembly. I was going to machine the material out in this part on my
vertical mill but thought this would be an ideal job for a wire EDM machine. We
have a few of these at work and I asked a friend of mine if he could fit in a "G"
job. Well you can see the results in these 2 photos. The EDM machine did a great
job. As the valve chest takes shape I think how things work will become
If you look close in this photo I am putting a nice 45 deg. chamfer on the O.D.
here that will be for welding on the inside of the valve chest...
Next, I used the die grinder and just knocked off the sharp edges on the valve
stem guide. There will be air and fuel mixer flowing by the valve guide support
Here in these 2 photos I am pressing the seat and guide support into the heavy
wall tubing. The second photo is of the seat and guide support pressed into
position and ready for welding...
Now we're all ready to weld the seat and valve guide support in place. It will
be welded here on top in the "V" groove and also on the inside. where the previous
chamfer was cut...
With the seat and valve pressed in I then proceded to weld it in place. In the
first photo I welded the inside of the seat and valve guide, after tacking it
on the outside. Then I flipped the part over and finished welding the outside
I had to let the valve chest cool off before I could put it in the lathe so I
decided to work on getting the timing gear off the crank shaft. I drilled a series
of holes right above the key and was able to spread the gear enough so it now
would slip on the crank shaft. The second photo shows the old gear moved away
from the through. Now I need to remove the flywheel and slip the old gear off and
the new gear on in its place. I will wait to do this till I have the new gear
ready to install...
These next 3 photos are interesting. In the first photo you can see a hole in the
crank shaft where the key was for driving the 40th timing gear. Now in the second photo
you can see what the key looks like installed on the crank shaft. In the third
photo is key all by itself. What a great idea this is not to have to cut a keyway
into the crank shaft. I will have to keep this one in the memory banks for future
With the valve chest cooled down I chucked it in the lathe and started to take a
few rough passes. It is finally starting to take some shape and look like something.
In the second photo I still have about .120 to remove but I am going to wait and
do this when all the welding on the valve chest is completed. Then I will be able
to complete and finish turn all the surfaces...
Here I pressed a 1" diameter shaft into the gear so I would have something to
hold onto while cutting the hub off and facing the gear to the 1" thickness
it needs to be...
This is a photo of the gear in the lathe, all indicated and ready to start making
The first photo here shows the gear hub all removed and the second photo shows the
gear faced down to the final thickness of 1". Now to bore the center out to fit
the crank shaft...
Here I am setting the 40th gear up in the four jaw chuck for boring the 3 1/4
diameter hole that will be an interference fit with the crank shaft. In the
second photo you can see the bored hole is getting larger and now I need to get
the crank shaft cleaned up so I can measure it and bore the hole in the gear
to the proper diameter...
Now I needed to remove the flywheel to be able to remove the old 40th gear and
put the new one on. Also I need to clean the crank shaft and measure the crank
shaft where the new gear will mount. Then I can bore the hole in the gear to the
proper diameter. You can see in the second photo that I have a lot of cleaning
to do on the crank shaft...
Here in this photo I have the crank shaft all cleaned up where the new 40th timing
gear will go. It will mount all the way back by the through...
This photo shows the gear all bored out and ready to go onto the crank shaft.
The ID of the gear is .002 under the crank shaft diameter and will be heated
up and shrunk onto the crank shaft...
Now to heat the gear up almost cherry red with the tourch (rose-bud)...
After the gear was heated I picked it up with a large pair of channel locks
and slipped the gear onto the crank shaft. I had a piece of 4" pipe ready if I
had to press the gear on, but with it so hot it slipped right on. In the first
photo you can see I left the pipe on the crank shaft to hold the gear in place
up against the through till the gear cooled a little bit. In the second photo
you can see the gear all cooled and in place...