V-TWIN--MAYBE V4

[Brian Rupnow]

The valves, springs, retainers and cross pins are finished and the heads are now completely finished. I will bolt on all of the rocker tower supports, axle pins, and rockers next. You will see that I had to move a set of tapped holes where the intake manifold connects to the heads. I had a pair of tapped holes interfering with one of the head bolts, so I moved the tapped holes and updated the drawings.

[Brian Rupnow]

Well, so far, so good.

[crueby]

This is going to be a very good looking engine!   

[Brian Rupnow]

Today things slowed down a little. I wasn't getting enough clearance between the head of the valve at "fully open" and the top of the piston at tdc. I didn't plan on having one of those zero clearance engines, where if it jumps time then the valve goes thru the piston. This issue was solved by putting a 0.100" thick spacer between the bottom of the cylinder and the crankcase. I took a quick look at my bin of mystery metals, found something close to the right size, and didn't realize until I was machining it that it was 303 stainless. That's okay---almost any metal would have worked. I also machined a starter hub. Right now I have both cam shaft supports removed to give me better access to the bolts which hold the cylinders to the crankcase.

[Brian Rupnow]

This is where I'm off to next. The carburetor is a purchased carburetor. The fan and fan shaft are supported by two 3/16" i.d. x 3/8" o.d. sealed ball bearings which are sold as router guide bearings. The center part is turned from brass. The trick of course will be to purchase and bend the two curved pieces. PartSource Automotive sell a metal brakeline that has the same inner and outer diameter as I have used, and I have a reasonably good tubing bender that accepts that diameter of tubing. The part I'm not sure about is what radius my bender makes.--I'll know tomorrow when PartSource opens.

[Brian Rupnow]

What did I do on the engine today?--Not that much. I took two grandsons swimming at a nearby lake. Geez the water was cold. I bought a new 1/8" carbide end mill and cleared some obstructions out of the cylinder heads where the head bolts go thru. I bought a length of rigid brakeline to make the two bent intake manifold pipes. I redesigned the gear guards into something that will be a little easier to make, and I spent some time making changes on the fan mechanism because the 1/8" ball bearings that I used originally are no longer easily available.

[Brian Rupnow]

I haven't had stellar results bending my intake manifold tubes. I bought a length of steel brake line from PartSource, my local auto parts store. This is what I generally use to make bent tube assemblies from. The one on the right was a total failure using the red tube bender beside it. It kinked and that was that. The one on the left was bent using one of those wound spring bending devices, and although it didn't kink, it flattened out considerably in the bend area. I'm too cheap to buy a container of Ceramet which is a very low melting point metal which melts in hot water, can be poured into the tube, where it rapidly solidifies and then you can bend the tube without it kinking or flattening out, then just heat the tube in hot water and pour the liquified Ceramet out. I've bent these brake lines before with no trouble, so I will have to go down to PartSource tomorrow and see if there is a different grade of brake line that is more bendable. I was in a hurry today, and they had moved the stuff I generally buy to a different part of the store, so I may have picked up the wrong kind of brake line.

[RReid]

Annealed brass tubing bends easily and well with the kind of bender you have (the red one).

[Brian Rupnow]

Okay---as I thought, I had purchased the wrong type of rigid brake line first time around. This morning I went back to PartSource and bought a length of copper nickel line. I bent two pieces on the right with the red mechanical tubing bender, and although they bent without kinking, the bends were very lumpy looking. Then I bent up a second pair of tubes with the silver coil spring tubing bender. This gave a very satisfactory bend with no kinking and very little flattening.

[Brian Rupnow]

I've changed my mind three or four times about what to do for a gear guard. Gear guards on these little engines do more than protect fingers---they cut down a lot of the noise created by the gears. Yesterday I finalized the design of the gear guard, and this morning I bought a piece of aluminum to make it from. We spent part of today returning a visiting grandson to Orangeville, and I got a good start on my guard this afternoon.  I have the final shape laid out, but won't finish machining it until tomorrow. I'm trial fitting this part as I go along, because the finished engine always has minor differences from the engineering drawing. So far, it's fitting the way I had planned.

[Brian Rupnow]

And Presto!!!---We have a beautiful new gear guard. Lot of work in that puppy, but it looks good.

[Brian Rupnow]

Starting to run out of things to make--and that's a good thing. This afternoon I made the main brass turning for the intake manifold---in fact, I made it twice. First try was with some of the mystery metal I bought last week. As I was turning it, I realized that it was bronze, not brass. I don't even know if you can silver solder bronze, but I was willing to try. Then I found that I had misread my own drawing and I had one of the turned down areas too long. At that point I thru it in the can and started over with something I knew was brass.

[crueby]

Brian, bronze does take silver solder just fine, for future reference.

 

[Brian Rupnow]

Chris--thank you so much. That is good to know.---Brian

[Brian Rupnow]

Todays offering to the Machine Gods is a cooling fan.  The discoloration is from the heat of silver soldering. I wish I had a small sandblaster, but I don't. This fan has been pickled in Citric acid, scrubbed with an old toothbrush and polished a bit with silver polish on a Q-tip. I may just pint it flat black.