Author Topic: T head engine by Brian  (Read 2830 times)

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #30 on: July 17, 2021, 05:57:22 PM »
Here I am, waling away on a piece of 2 1/2" diameter hot rolled to make the 50 tooth gears from. The o.d. of those gears is 2.166" x 1/4" thick plus 7/8" diameter hub on one side.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #31 on: July 18, 2021, 08:59:54 PM »
Got up nice and early this morning and cut both 50 tooth gears. Everything worked out nice, no extra teeth. Maybe I'll do the 25 teeth gears tomorrow. It has been a lovely day here, had a family birthday party for my daughter and I  out in my backyard. There are twelve of us now in the family. I'm the oldest at 75, Davy's the youngest at 1 1/2 years.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #32 on: July 19, 2021, 01:26:56 AM »
Holy Gas Tank, Batman---Were going to try something a little different. I've made about two dozen gas tanks. Many had the end plates silver soldered in place. A roll of silver solder costs about $100 here.  Then I found out that I can J.B. Weld the endplates in and they never leak, but you have to be aware of your construction procedure and have any other soldering or welding finished before you use the J.B. Weld. Tomorrow, I am going to Tig weld the endplates into this tank. Of course there will be a bit of prep work first, probably a counterbore in each end of the pipe, and endplates made with a decent chamfer for the weld to fill. I'll let you know how that turns out.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #33 on: July 19, 2021, 04:43:46 PM »
Damn, I just lost an entire post.---Here we go again. The tig welding turned out very nice. No, it's not the perfectly overlapping "fish scale" pattern that a professional welder would lay down, but it works for me. A bit of clean-up on the lathe and it should be a beautiful thing. I simply can not afford the $$$ for brass, so I will be painting the gas tank and the flywheels in some complimentary colour.


Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #34 on: July 19, 2021, 05:35:56 PM »
And it's a lovely thing, what a bit of lathe and file work will do to finish off a welded gas tank.

Offline bent

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Re: T head engine by Brian
« Reply #35 on: July 19, 2021, 06:09:20 PM »
My Tig skills are about on a par with yours, Brian.  And I agree, it's amazing what a little bit of filing and machining does to smooth up the welds.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #36 on: July 20, 2021, 04:06:52 PM »
The outer diameter of the crankshaft bearings have been coated with J.B. Weld and located in their bores. Before it has had any chance to set-up, a 1/2" diameter cold rolled shaft has been ran thru both bearings, and the two halves of the crankcase have been reassembled with locating pins and bolts. The two 25 tooth gears were finished this morning and then slid over the ends of the shaft to make sure that they mounted and meshed properly with the camshaft gears.---They do!!!

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #37 on: July 21, 2021, 11:12:13 PM »
Things are going to slow down for a little while. One of my old customers has come foreword with a request for some new welding fixtures for one of the big three automotive companies. It's design only stuff. Fabrication will be done elsewhere. I'm not sure just how much work there will be, but probably not much.---It would be nice if there was a couple of weeks work---that would buy me a new metal cutting bandsaw. My current bandsaw is an old woodcutting saw that I modified to cut metal. It works, but it is painfully slow.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #38 on: July 22, 2021, 08:54:50 PM »
The welding fixture is completely designed and sent to my customer, who has to go to his customer for "design review". After that has happened I will complete it and make detail drawings.---Now--Back to my own stuff. I finished the welding fixture design about noon today, and spent the rest of the day machining valve cages. In a perfect world, they would be a press fit into the head. In the real world, you can't press them too hard because they are made of brass. So, they are coated with #638 Loctite and lightly pressed into place with my shop vice. After they set up for 24 hours or more I will drill the intake and exhaust port thru the cylinder head and the valve cages at the same time. I have not used my special valve guide cutting tool yet to prepare the seats to mate with the valves. That is just about the only thing left to do to the valve cages. I will make the valves later today or perhaps tomorrow. I did stop by my metal suppliers today and picked up a foot of 1 1/2" diameter "stress-proof steel to machine a one piece crankshaft from.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #39 on: July 23, 2021, 07:45:23 PM »
Todays nifty trick was to machine a pair of tappet guides. They set between the 50 tooth gears and the sides of the engine frame. They have a 7/8" clearance hole on center to clear the cams, and there will be a 5/16" i.d. sintered bronze bushing pressed into the hole in the top of them to guide the tappets which ride on the cam. The cam is attached to the side of the 50 tooth gear.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #40 on: July 24, 2021, 09:30:46 PM »
I had to take my chainsaw over to my oldest son's place and play "Johnny Lumberjack" this morning and take out a couple of big trees for him. This left me with a bad case of "lazyitis" this afternoon, so I made two parts for my engine that didn't require a lot of thought. The brass part is the adapter for the Traxxas carburetor, the aluminum piece is the exhaust.

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #41 on: July 24, 2021, 10:35:38 PM »
Ah Heck---I couldn't wait to see how they looked on the engine, so I tapped the cylinder head and installed them!!!

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #42 on: July 25, 2021, 03:10:40 PM »
I ran into something a bit strange yesterday. When I threaded the ends of the exhaust and carb adapter for the engine yesterday, the parts were held in the lathe chuck and the die was held in a collet in the tailstock chuck. No problems were encountered, I even ran a standard 3/8"-16 nut up the thread to ensure that everything was Kosher. When the cylinder head was tapped 3/8"-16 it was held in the milling machine vice and threaded by hand with a tap and standard handle. After screwing things together yesterday afternoon, they were crooked!! It doesn't show in the picture I posted, but they were quite visually crooked. I didn't want the Loctite to set up, so I disassembled things. This morning I held the cylinder head in my mill vice and a tap in the milling machine spindle and turned the spindle by hand, and the tap was cutting metal. I ran the tap in until it bottomed out, removed it, and cleaned up the ends of the cylinder head. I then held the inlet (carb adapter) in the chuck of the milling machine, applied a bit more Loctite and turned the spindle until the shoulders on both pieces were touching each other. I must have had the tap turned at an angle when I first threaded these parts. I would stand and deny that I would make such a dumb mistake, but I can't figure out what else it could have been.

Online crueby

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Re: T head engine by Brian
« Reply #43 on: July 25, 2021, 04:10:11 PM »
Blame it on the shop elves. Usually works for me.....

Offline Brian Rupnow

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Re: T head engine by Brian
« Reply #44 on: July 25, 2021, 06:29:32 PM »
It hasn't been a horrible morning, but it sure as heck hasn't been productive. I have one valve to show for it. Beside the valve sets a piece with a 0.1875" hole reamed thru it to check the valve stem for when it is exactly the right size. I can't even begin to tell you why it took so long, but suffice it to say, I've never sanded on anything in my life as much as that valve stem to bring it down to size. I did use a live center in the tailstock to keep the outboard end from flexing while the valve was machined. Maybe tomorrow I'll get lucky and make another valve.