Upshur's twin opposed cyl. engine

[michaelr]

Thanks for the update on the inline twin. watching with interest on the Upsur's build.

Mike.

[Brian Rupnow]

I know what I'm going to do tomorrow. I won't actually cut to the layout lines. All positioning will be done with my X and Y dro's on the milling machine. The layout lines and punch marks are only there to keep me from dialing in something wildly wrong.

[Brian Rupnow]

Today was connecting rod day. I thought I might have time to do something else, but I worked right up to supper time on these connecting rods. They turned out okay, but there were a lot of different set ups required.  Thought I would pin the crankshaft today, but unless I get a surge of energy between now and bedtime, that will get done tomorrow.

[Brian Rupnow]

I actually did find enough energy to drill and pin the crankshaft last night before I went to bed. This afternoon when the Loctite has set up good, I filed the exposed ends  off of the pins and brought them down flush with the outside of the throws. I searched around in my odds and ends box, and came up with material to build a flywheel. There are two sheets of 1/4" brass Loctited and vice gripped together in the picture, and a hub that is complete except for the center hole. I'm lazy today, and don't plan on doing much more in my shop today.

[Brian Rupnow]

I'm about to do something new, that I haven't done before. I found the "silver lead free solder" recommended for soldering the cylinder assemblies to the platework in the crankcase. It is 96% tin and 4% silver solder and is sold by Oatey, product number 48319. The recommendation is that both surfaces to be soldered should first be "Tinned" before soldering. I had to look this up on the internet, as I haven't "tinned" anything before soldering it. The flux that I bought with this small "kit" contains "#95 tinning paste", and according to the internet I heat up the pieces to be soldered and use the brush from the kit to spread some of this "tinning paste" onto the joint before actually trying to solder it. Okay, sounds easy enough.--I will let you know how things worked out.

[crueby]

I'm about to do something new, that I haven't done before. I found the "silver lead free solder" recommended for soldering the cylinder assemblies to the platework in the crankcase. It is 96% tin and 4% silver solder and is sold by Oatey, product number 48319. The recommendation is that both surfaces to be soldered should first be "Tinned" before soldering. I had to look this up on the internet, as I haven't "tinned" anything before soldering it. The flux that I bought with this small "kit" contains "#95 tinning paste", and according to the internet I heat up the pieces to be soldered and use the brush from the kit to spread some of this "tinning paste" onto the joint before actually trying to solder it. Okay, sounds easy enough.--I will let you know how things worked out.

I have some of that - works well, but if overheated it smokes/stinks pretty bad, some kind of wax component to it. Fine as long as its heated just enough to flow, then the residue cleaned off. I think its formulated for use with a soldering iron, and its temperatures. It does let you coat a larger surface well before mating on another large part. Being a soft solder its no where near as strong as the usual high temperature silver solder - wish that the industry had settled on names that were not so similar for such different products!

[Brian Rupnow]

Hi Chris---Nice to hear from you. I'm all set up to use this solder tomorrow, and will do it out in my main garage with the big doors open. I haven't used this type of solder before, so it will be interesting.

[Jasonb]

Tinning is quite a common way to solder parts together, I was first shown how to do it at school. Basically it is the application of a thin layer of solder to both parts so that you can see they are fully coated before assembly. It does need to be thin, just enough to put a film on the surfaces. Tinning should ensure that the whole of the mating surfaces are soldered and you are not just hoping that the solder has fully flowed into the joint this is why it is often used for larger areas than this particular joint where the solder may need to flow some distance.



Flux and apply solder to the part and then wipe off excess solder with a cloth (not man made fibre), assemble the parts with flux and "sweat" them together this means bringing them upto the temp that the solder melts at, apply a little more solder if needed.



Fluxed split bearings ready to be sweated together

[Jasonb]

Just be aware that the solder you say you have got is not 4% silver / 96% Tin as spec'd on the drawings. Looking at the Harris website they make a big point of their 4/96 having a high tensile strength, upto twice that of some of their other lead free offerings.

Up to you if you want to change it now or risk joint failure at a later date.

[Brian Rupnow]

This morning bright and early I got up and cut the crankshaft to give it's final shape. The con rods and their caps were installed, and they went in with no problems. I emailed Andrew Whale in the U.K. about application of the special solder to the cylinders where they attach to the crankcase plates and he answered my question.  I think that will be my next job.

[Brian Rupnow]

So, here we are. The parts to be soldered were heated up and coated with tinning paste. Then they were assembled in the correct relationship to each other and a 1/2" bolt put thru each cylinder to hold the cylinder portion tight against the plate it gets soldered to. The solder was cut into 16  short pieces about 1/8" long and 8 were arrayed around each cylinder, right where I wanted the joint to be. Then I used my torch to heat from underneath the aluminum set-up bar. I haven't done this before, but it worked--the solder began to flow, and it sucked into the joint all around the cylinder. The second picture shows the resulting joint. I am waiting for things to cool down, and then will clean up the joints. I'm happy.--Learned something new today!!!

[Brian Rupnow]

And this is how I got the 0.156" thick plate that the plans call for under the cylinders. I used 3/16" plate, and after everything was soldered together I set it up in my lathe and machined 0.030" off the face of the plate.

[Brian Rupnow]

So, today I reached a milestone with the Upshur opposed twin cylinder engine. I have assembled all of the major components and everything goes round and round and up and down like it is supposed to. This engine is very small, having a 3/4" cylinder bore, and it will be my first engine with a distributor. The sides of the connecting rod do interfere with the bottom of the cylinders, preventing a full 360 degrees of rotation. This was solved by putting a large 30 degree chamfer on the bottom of the cylinders. Tomorrow I will probably make the cylinder heads.

<a href="https://www.youtube.com/watch?v=cOvtRnUNYbY" target="_blank">http://www.youtube.com/watch?v=cOvtRnUNYbY</a>

[Brian Rupnow]

Today I didn't accomplish much. I made both cylinder heads, but I had to go across town and buy a slitting saw to cut the fins into the heads. I did have the correct slitting saw in my shop, but it had dulled from a lot of use, and it costs as much to have it resharpened as it does to buy a new one.

[dudeface]

This is going to be a neat engine