Horizontal Twin

[rdean]

I was doing some shop cleanup and organizing the other day and ran across this crank shaft that I had made close to 3 years ago. At that time I had built a flat twin engine that did run but not very well. After a lot of fiddling around and some disappointments I decided to use some of the parts off that engine for my 90 degree v-twin engine. That engine turned out to be very reliable and a good runner.

I thought maybe I should take another shot at building a horizontal twin engine I can't just throw the crank away.

I found a pair of piston and rod assembles that I had made for a different engine at some time and remade the connecting rod bearings to fit this crank.

This might be a good time to experiment on a bolt-together engine. No castings or large lumps of aluminum just flat plates screwed together in a simple way.
Since the crank, rods, and pistons are already made I will have to build around these parts.
I started with a couple of 1/2" aluminum plates and installed a ball bearing in each.


So here is the starting point.
1" bore and 1" stroke.


Thanks for looking
Ray

 

[Eddyde]

Are you figuring out the design as you build?

 

[rdean]

Yes Eddy that's what I'm doing but it can cause many design changes along the way and some bad moments.

I had some 3/8" aluminum plate to make the sides from as I wanted the sides to be stiff for the cylinders to mount to.


I added a couple of main rails for mounting the engine to a wood base.


It looks like I could have made the bearing end plates an inch shorter and still had plenty of room for the crank. I usually don't have enough room and now I have more room than I need. On well it gives it more stability.

Thanks for looking
Ray

 

[rwm]

Will this be a 4 stroke?

 

[Ben17484]

I’m looking forward to this. I enjoy following your build threads. Lots of pictures please


Sent from my iPhone using Tapatalk

 

[rdean]

Yes Robert it will be a 4 stroke with maybe some features I haven't done before.

Thank you Ben glad to have you along and yes pictures.

Ray

 

[rdean]

I took the frame apart, cleaned it up and even gave it a polish.


Drilled and bored for the cylinders and spotted the holes for the cylinder mounting bolts.




The next logical thing for me to do would be to start on the cylinders but the 4ft long piece of 1 7/8" aluminum rod I had is not 6061. I don't know what it is but it does not machine well. Even sanding it doesn't help much so since I need a nice finish inside and out I ordered a piece of 2".
It will be several days for the aluminum to arrive so I will see what other parts I can work on for now.

Thanks for looking
Ray

 

[Firstram]

Looks great polished, now you have to use all polished stainless hardware to match!

 

[rdean]

Sorry I don't have any stainless hardware Firstram.

I did find a flywheel in my "maybe I will use it sometime" drawer that should work.
I also made a new split bushing for the flywheel to fit the crankshaft size.





Thanks for looking
Ray

 

[rwm]

That is a damn nice flywheel! What is it made from? I don't have such a drawer? Which manufacturers offer that?