Another Internal Combustion Engine
- Thread starter Rdean33422
- Start date
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I wrote thread #20 yesterday but I forgot to post it so two for today
Thanks Danuzzo
Cutting out the cam shaft supports.
Hot off the mill.
The cam shaft drive gears can be either helical or bevel gears. The helical gears are more compact but much more expensive and a 2to1 ratio is also rare. I will be using the bevel gears but there are still problems with size. In order to get the pinion gear big enough so I could mount it on the crankshaft I had to go to Mod 1.5 which has good sized teeth on it and that makes the driven gear quite large.
Here is a shot of how I modified the pinion gear to fit a 12mm shaft and shorten it up as much as possible. There isn't much meat left on the inside hole. I was able to shorten the length of the gear considerably but that meant most of the original set screw holes were cut away. I pressed a brass collar over the gear and drilled and tapped through that for the set screw.
The driven gear was reduced in diameter by 1/2" which meant cutting away the outside 1/4"of the teeth. I didn't need the full length teeth for this application anyway.
I mounted the cam supports on the engine and there was just enough room.
The driven gear is only about 0.050 away from the engine base and I now have 0.950 of shaft left for the flywheel.
Quite happy with how things turned out. (maybe I should make my crankshafts longer in the future)
I was turning the engine over with the drill when I realized I had another big problem. Even at 250 rpms the engine wants to leave the shop. I will work on that issue next.
Thanks for looking
Ray
Thanks Danuzzo
Cutting out the cam shaft supports.
Hot off the mill.
The cam shaft drive gears can be either helical or bevel gears. The helical gears are more compact but much more expensive and a 2to1 ratio is also rare. I will be using the bevel gears but there are still problems with size. In order to get the pinion gear big enough so I could mount it on the crankshaft I had to go to Mod 1.5 which has good sized teeth on it and that makes the driven gear quite large.
Here is a shot of how I modified the pinion gear to fit a 12mm shaft and shorten it up as much as possible. There isn't much meat left on the inside hole. I was able to shorten the length of the gear considerably but that meant most of the original set screw holes were cut away. I pressed a brass collar over the gear and drilled and tapped through that for the set screw.
The driven gear was reduced in diameter by 1/2" which meant cutting away the outside 1/4"of the teeth. I didn't need the full length teeth for this application anyway.
I mounted the cam supports on the engine and there was just enough room.
The driven gear is only about 0.050 away from the engine base and I now have 0.950 of shaft left for the flywheel.
Quite happy with how things turned out. (maybe I should make my crankshafts longer in the future)
I was turning the engine over with the drill when I realized I had another big problem. Even at 250 rpms the engine wants to leave the shop. I will work on that issue next.
Thanks for looking
Ray
Maybe you need a big block of concrete to bolt the engine to haha. I suppose the flywheels will help.
Add some balance weights to the crank.
I weighted the connecting rod, piston, and the rod journal bearing together and they came out to almost 5 oz. Now after much deliberation and concentrated thought using several data pages and checking the phase of the moon I came up with the size of the counter weights that I needed to make.
(Really I just guessed)
Cutting the counter weights from some 1/2" thick bronze.
As long as I had the material mounted on the mill I cut out the cam also.
The two weights together are 4.4ozs but they are mounted out further on the crank webbing so it should all even out.
A test at 1000 rpms proved to be very satisfactory.
Thanks for looking
Ray
(Really I just guessed)
Cutting the counter weights from some 1/2" thick bronze.
As long as I had the material mounted on the mill I cut out the cam also.
The two weights together are 4.4ozs but they are mounted out further on the crank webbing so it should all even out.
A test at 1000 rpms proved to be very satisfactory.
Thanks for looking
Ray
