Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Another day, another morning opportunity to do work before vision goes out of focus for the day. So I donned my trusty lighted magnifying visor over my super strong reading glasses, and spliced a 6mm wide GT2 belt.

The transmission design has no belt tension adjustment, instead relying on a custom made to length belt.  My splicing method has evolved.  Once cut to length and trial fitted with a painters tape splice, applying very little tension while trial fitting, a permanent splice is made consisting of about 1 1/2 inches of cotton, waterproof bandage tape, what we used to call adhesive tape, on the sandpaper scuffed back side, pressed between a piece of wood with a matching piece of belt attached, and a second piece of wood, clamped for an hour or so, insuring maximum adhesion.  Then, while oriented in a fixture, in a vise, I sewed the joint with a spiderweb of locked stitches using 4-0 silk suture, then coated the whole splice with a very thin coat of thick CA glue, worked into the silk sutures and tape surface with a small wooden spatula to insure the silk is reinforced and nailed down to the tape.  I’ve used nylon sutures in the past, but they make undesirably big knots and don’t benefit from the glue. My son, who is a doctor, tried to dissuade me from using silk as it’s not really strong, until I said it’d be soaked in superglue after application.  Then  it’s amazingly strong, yet retains the flat profile. A dab of marker to dye the splice, and it’s reasonably disguised.

Twisting the engine by hand, the transmission engages and stays in gear perfectly, and slips as designed when out of gear.  It’ll do.

Lucas asked if changing the website to eliminate the drill start option would satisfy me. Yeah, ok. Erase the evidence and silence the victims. Sounds about right. I’m telling you. They lack any sense of a contract sealed at time of sale. They negotiate even after delivery.

Your belt looks pretty seamless to me! Nice work!

Really surprised that they wouldn’t send you the drill start adapter; I mean, at least 1 (or probably at least 2) existed… we saw the pic! Haha

Your belt looks pretty seamless to me! Nice work!

Really surprised that they wouldn’t send you the drill start adapter; I mean, at least 1 (or probably at least 2) existed… we saw the pic! Haha

Your results are encouraging. I keep seeing in my mind’s eye, an old guy I knew who flew a four stroke is on gas.  Crank once around while choked, switch on ignition, and flip the prop.  One time and it ran, about a 22 inch wood prop, bare hand flip.  I had a G 38 about the same. As boring as electric, so reliable.  I think these can get there, especially after a bit of breakin and familiarization with tuning.  It’s a classic design.

Quote from: gamma13r on April 12, 2022, 09:28:57 pm

Your belt looks pretty seamless to me! Nice work!

Really surprised that they wouldn’t send you the drill start adapter; I mean, at least 1 (or probably at least 2) existed… we saw the pic! Haha

Just listen for any pinging when running fast or under load.  If it sounds funny or seems to run overly hot, advance the timing a little.  The breaker cam is on the camshaft, not the crank. That means ten degrees deflection of the timing lever is actually five degrees of timing advance or retard. If you’re pointed left visibly, say ten degrees, that’s maybe five degrees before TDC

That’s incorrect. Brain misfired. The camshaft, including our breaker cam, turns half of crankshaft speed. So for each degree of crankshaft or piston movement, the cam moves half a degree.  If your lever is pointed say five degrees left, that’s ten degrees of advance compared to straight up.  In other words, what looks like a little is a lot.

Upload the video to your YouTube channel, then put a link here.  Glad it’s running well. Points I’d be keeping an eye on would include the ignition cam for some kind of light grease lube, maybe fishing reel or gun grease. Just enough to insure the cam isn’t dry.  Also the valve lifters where they pop up out of the block definitely should be wet with oil. If they’re not glowing, give ‘em a drip of oil from the outside.  Overall, I suspect these will be robust engines that want to run.

Jon, I got my parts!  Looks like they made the oil pan from sheet stock. Probably couldn’t locate any leftovers. No powder coat finish. Not that it matters on the bottom.

Question.  How did you know which wires to use to connect the points? The goofy instructions, such as they are, simply say to hook it up.  There  are three wires though, and unlike earlier CDI boxes, no need for a ground to the engine block.  I had a clue when you mentioned the plug firing without touching the block, the braided shield on the plug wire is the ignition ground.  But the three wires on the hall switch had me going.  So I looked the company up, and sure enough, RCEXL is CH ignition.  They’re old school. They actually publish a phone number and a real person with technical knowledge answers. Use black and white, ignore red, or so he said.  That’s what I’ve done, 
so far I’ve got oil pan installed, engine mounted, oil in the crankcase, breaker wires attached, cooling system plumbed, and the battery/ignition box laid out.

I just dragged out my baby table saw, so I can cut square 1/8” ply. Battery box pieces much easier than any other way.  Since my downstairs neighbors are away, I can run said noisy saw this evening, and with any luck, turn gasoline into noise tomorrow.

Well that sucks.  Just thinking since the crank is single ended, we would drain oil, remove oil pan, remove flywheel, partially remove crankshaft bearing housing, taking crankshaft with, until the crank pin is free of the rod big end, and if you feel froggy, chase through the dipper hole, through the bushing.  Ought to get away without pulling the gear case and crank auxiliary side, if you can drill the bushing with the piston and rod in the bore.  If you get away with it, then I’d just blast away with WD40 as a rinse, and slap it back together. If you don’t disturb the gear case, timing remains intact, etc. you’re simply plugging the crank pin into the whole back half. Deburring  the hole in the bushing after you drill it might get interesting. Then again, drill with a handheld pin vise, and you can control breakthrough and not leave a burr worth worrying about.