Now we all know that adding a header, aircleaner and governor removal would help a three horse motor out and add some horsepower and help the little motor out, but what if you want more, alot more? well your very limited on what you can do, and if it is done it would be an extreme amount of work, and the true horsepower gains unclear,
During my recent teardown of the new 5 horse block that im going to build up, I decided to drag out the 3 horse that sits under my block, its a cute small motor that's been gathering dust for many years and probably hasnt run in more, and adding my burned valves and old piston from the 5 horse, I noticed some interesting possibility's.....
First, the block size is extremely different, BUT, things are seemingly compatible. ( five horse on the left)
Now looking at the small valves in the 3 horse, I noticed that with new seats and a little work, the 5 horse larger diameter valves seem to be able to fit, not only do they fit, they will permit more flow, and no the valves are not to long
Next we look at the piston, the three horse, obviously smaller but the 5 horse piston fits within the head bolt pattern....
Now we look over at the ports and the spring chamber,
the springs fit, meaning I can use 5 horse springs to get heavier springs in, and the port sizes are extremely close if not the same as the 5 horse,
and this allows for a smaller diameter (possibly a .960 inch inner diameter header) but it also allows use of this....
So, my final verdict is, I can make the displacement and flow of a 3 horse larger, and more flow, yielding more horsepower when properly jetted, I could also cut the head, or a dual plug head, and if money permitting have dyno cut me a cam, and grab a billet flywheel
The downsize is I doubt the motor would last very long, how ever for scrap parts, ( the only thing id need is valves and seats) It would be an interesting experiment to see what I could pull out of the little motor, even if I does grenade. So one day, when I have a few dollars to spend, I may have to play around
in this new realm
If anything I hope its some inspiration for someone out there!
During my recent teardown of the new 5 horse block that im going to build up, I decided to drag out the 3 horse that sits under my block, its a cute small motor that's been gathering dust for many years and probably hasnt run in more, and adding my burned valves and old piston from the 5 horse, I noticed some interesting possibility's.....
First, the block size is extremely different, BUT, things are seemingly compatible. ( five horse on the left)
Now looking at the small valves in the 3 horse, I noticed that with new seats and a little work, the 5 horse larger diameter valves seem to be able to fit, not only do they fit, they will permit more flow, and no the valves are not to long
Next we look at the piston, the three horse, obviously smaller but the 5 horse piston fits within the head bolt pattern....
Now we look over at the ports and the spring chamber,
the springs fit, meaning I can use 5 horse springs to get heavier springs in, and the port sizes are extremely close if not the same as the 5 horse,
and this allows for a smaller diameter (possibly a .960 inch inner diameter header) but it also allows use of this....
So, my final verdict is, I can make the displacement and flow of a 3 horse larger, and more flow, yielding more horsepower when properly jetted, I could also cut the head, or a dual plug head, and if money permitting have dyno cut me a cam, and grab a billet flywheel
The downsize is I doubt the motor would last very long, how ever for scrap parts, ( the only thing id need is valves and seats) It would be an interesting experiment to see what I could pull out of the little motor, even if I does grenade. So one day, when I have a few dollars to spend, I may have to play around
in this new realm
If anything I hope its some inspiration for someone out there!
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