Rebuild Updates: 1941 Johnson HD-20

[1946Zephyr]

SO, today I decided to pick away at this project a little more. I took the front half of the crank case out of the chem-dip and cleaned it all up. I installed the pistons and the crank too and everything is in good shape. Here are a couple pics if this little booger. It's funny seeing an engine so damned small I set a quarter in the cylinder there, so you can see what I mean. I should take a pic of it, setting next to a Ford 460 block, which will be my next project.

 

[yorab]

Re: Rebuild Updates: 1941 Johnson HD-20

Wow! It took me a moment to get my brain wrapped around the fact that is a real quarter. The picture says that the motor is tiny but my brain says that must be some kind of illusion. How much horsepower is it?

 

[1946Zephyr]

Re: Rebuild Updates: 1941 Johnson HD-20

2 1/2 hp

 

[Mas]

Re: Rebuild Updates: 1941 Johnson HD-20

Here are a couple pics if this little booger. It's funny seeing an engine so damned small.

Double that & you've got a four cylinder zepher.

Mas

 

[1946Zephyr]

Re: Rebuild Updates: 1941 Johnson HD-20

Yea, exactly. I think this old HD-20 is about the smallest twin produced and the Zephyr would have to be the smallest quad ever built. The Zephyr 1/4" bigger on the bore though. The HD-20/25 is 1 3/8" and 1 3/8" stroke and the Zephyr is 1 1/2" on the bore. Same stroke though. One thing that cracks me up about this HD, is how tiny the block is. It stands only about 5" tall.