Thumper--a new 1 3/8" bore i.c. engine

[Brian Rupnow]

I just tried to upload a video to YouTube.---It loads to about 34% and just hangs there. Anybody know if YouTube is having a problem?

[Art K]

Brian,
Good looking crank. I don't know about you tube but Post Image gave me a "Server is under maintenance, sorry for inconvenience. ETA ~1 day" message so who knows. Maybe its time to sit back relax and have a cold one.
Art

[Brian Rupnow]

This morning I test fitted the rings into the cylinder. The rings have a stepped gap, however when I had a ring pressed into the cylinder and held it up to a bright light, there was still clearance for the ring gap to close a little bit more if it expands with heat. I was satisfied with the fit of both rings. I set my piston up in the lathe 3 jaw chuck and very carefully opened up the 0.086" wide gap to about 0.095" to accept the 0.094 thick rings. Any time I cut a groove in aluminum, it raises a shoulder on each side of the groove. Not much of a shoulder, but enough to keep an already tight fitting piston from sliding into the cylinder. Knowing that, and knowing that a few people were alarmed at the thought of a tight fitting aluminum piston in a cast iron cylinder, I walked a piece of 220 grit garnet paper back and forth on the piston to knock down the shoulders and take about 0.0005" off the overall piston diameter. the rings went onto the pistons with no problem. I had the cylinder off the engine, so  set it up in my 3 jaw and machined a 15 degree "lead" taper into the bottom to aid in installing the rings. everything went together fine. In about 15 minutes I'm going to make a head gasket and install it, and  then the  engine will be finished except for the flywheels.

[Brian Rupnow]

The engine is finished---except for flywheels. There may  a significant time span before I get the flywheels finished. I am now turning my attention to the flywheels, which will very probably be fabricated with my new TIG welder. Thank you, to those who have followed this thread, which was started 32 days ago.

[crueby]

Looking forward to seeing how the welding goes. Have you had experience/classes in TIG welding? Something I'd like to learn, will likely take classes at the local welding shop someday - they have a large classroom building behind their store.

[Brian Rupnow]

Very little experience with TIG. Many, many years of experience with stick, oxy-acetylene, and MIG.

[crueby]

Brian, I got hold of a bottle of the Loctite 638 as you use, I like it! Much thicker than the 603, great for spots that have a little more gap. Thanks!
 

[Brian Rupnow]

And this is how I spent the last two days. My welding cart which previously held only the mig has been widened about 9" and now holds both the mig and the tig. I hardly ever get to actually fabricate things any more, so I enjoyed doing it.

[Johnmcc69]

 
 Nice setup!

 Looking forward to see how those flywheel turn out!

 John

[Brian Rupnow]

I woke up this morning thinking about how to fixture the hubs of the flywheels to cut the 45 degree slots in them. Sometimes if I model what I am thinking about, it helps to clarify things. It looks to me that if I make the yellow fixture, I can hold it in my vice and just crank the mill table back and forth in the X axis to cut the slots. I will have to drill a set of holes in the face of the hubs to register them on the yellow fixture so that they don't move while being cut.

[Brian Rupnow]

And that, my friends, is slicker than whale poop!! Here you see one of the finished hubs by itself, and with a nice blade array using a bunch of my parallels. I just wish I had a 1/8" wide slitting sawblade. This was made using a 1/16" saw blade, but I had to go around once to make the slots 1/16", then around once with the blade offset 1/32" then again with the sawblade offset the other way by 1/32". This was far less work than I anticipated. I will make the second hub tomorrow.

[crueby]

While I will take your word for it on how slick whale poop is (dont want to know how you know  ) that is a very slick setup for the hub!

[Art K]

Brian,
Can't sleep so I am perusing the mem site. I have to say the hub turned out pretty slick, pun intended. Looks like it should pull some air across  the engine. And will be a great test for the new welder.
Art

[Jasonb]

I just wish I had a 1/8" wide slitting sawblade.

If you had turned your fixture on it's side you could have used an 1/8" milling cutter,

[Brian Rupnow]

This morning I put on my mask ,Purelled my hands, and drove to my metal suppliers who had set my material outside their door. Collected my material, Purelled my hands again, wiped down my trucks steering wheel with antiseptic wipes, and drove home again. Got home, washed my hands for 30 seconds with warm water and dishsoap. My hands have never been this clean. I look goofy wearing a mask. The 1" x 1/8" cold rolled flatbar is exactly what I asked for. The tube is 6" o.d. but the wall is only 7/16", not the 9/16" that I had wanted, but it will do. I could die of old age before my bandsaw would cut thru that pipe, so I will part off "rings" of material 3/4" long. I think I will weld a flatbar across one end with a hole for a live center and hold the other end in my lathe chuck with reversed jaws. You can't cut all the way thru in the lathe or bad things will happen. DAMHIKT. You can however, cut almost thru and then complete the cut on the bandsaw. This was the last material I will require to build this engine, and by the time I buy a set of ignition points and a condenser, it's going to get very close to the $200 mark. The steady-rest is which came with my lathe is way too small to use--looks like it will only open up enough to take 3" diameter stock.