Opposed twin Onan engine in half scale

[ignator]

Some may question the rotary table? I was given a 97 tooth gear about 30 years ago. What can you do with a 97 tooth gear? It is mild steel, I counted the teeth on a Holden ringgear 135, cut 15 out and carefully pulled it in and welded it, giving me 120 teeth which can be divided by numerous numbers. Turned part of the 97 teeth away, fitted the ringgear, had a worm wheel that fitted, onto that I can fit any combination of lathe change wheels or drive it with a motor. Drilled holes and threaded 3/8 W

I do not see where you partially removed the 97 teeth, and slipped on the modified ring gear. That must have taken some doing to keep the 'shrunken' ring gear from getting a kink vs a round gear.
I guess I cheated by buying a H/V rotary table. Vertex brand made in Taiwan. I mounted a 10 inch 3 jaw chuck on it's 12 inch table. Very heavy and have to use the overhead shop bridge crane to put it on the milling table.

 

[ignator]

Another day on the Onan opposed twin half scale. Photo 1 I have set up the crankcase on a spigot to turn true bolted the timing case on and bored through for the crankshaft, faced back the case ready to fit the Lifan Chinese ignition coils and flywheel, photo 2 turning the seal seat inside the timing case.
Ted from down under

Interesting setup to start the machining of the timing case spigot. I assume you supported this with the tailstock. Did you 'carve' out the internals of the timing cover all on the lathe?
For size reference how big is the 3 jaw on your lathe? Appears to be 12 inch diameter.

 

[teeleevs]

The chuck is 10 inch, I cast the timing cover from lost foam, photo 1 in the green sand ready for the next box, 2 shows the internal shape, 3 the outer shape, 4/5 it came out very rough but it is cleaning up OK. The ringgear I slowly bent in the vice until it nearly metup then I clamped it in place using several clamps then welded the join and a few tacks around, all went well.

 

[teeleevs]

The crankshaft? Most weed eaters have a single shaft through 2 bearings then a plate with an open crankpin, much like the model aero engine, some motorcycle crankshafts are made up with roller bearings and all pressed together, even multiple cylinder ones, the Suzuki 3 cylinder 2 stroke Jeep engine the same, but they have better equipment and jigs than I have.

 

[teeleevs]

Todays progress on the Onan opposed twin half scale engine. Photo 1 fitting the Lifan Chinese magnito, 2 machining the base for the magnito on the timing cover, 3 how to get it all the right shape, this photo more detail of the rotery table can be seen, 4, 5, & 6 travel stops on the old lathe. 4 each number represents 1/4 millimeter approx 10 thou 0.010". 5 each mark approx 2thou 0.002 on a 10x1.5mm booker rod thread. The spring presses a ball bearing on the thread to prevent unwanted movement. 6 final cuts for the seal seat.
Ted

 

[ignator]

Todays progress on the Onan opposed twin half scale engine. Photo 1 fitting the Lifan Chinese magnito, 2 machining the base for the magnito on the timing cover, 3 how to get it all the right shape, this photo more detail of the rotery table can be seen, 4, 5, & 6 travel stops on the old lathe. 4 each number represents 1/4 millimeter approx 10 thou 0.010". 5 each mark approx 2thou 0.002 on a 10x1.5mm booker rod thread. The spring presses a ball bearing on the thread to prevent unwanted movement. 6 final cuts for the seal seat.
Ted

Ted, I had to look up Booker Rod. Appears to be different spelling of Brooker (internet say's Booker is Australian and German spelling). But in the States, it's called All Thread rod, or local colloquial as Redi Rod.
That's an interesting feed control method. Is the cross feed screw worn out so you don't trust it on the lathe? I guess I'm spoiled as I have DRO's on all the machines in the shop. But I still find I have to measure twice, as you don't always get the feed you want. So if I don't want scrap, I have to sneak up on it.
I do work in both Metric and Imperial (SAE), as I measure in the units that thing I'm fixing was made in. That said most digital measuring tools, use Metric scales, and convert to inch, loosing some resolution.
So your magneto appears to be an alternator, and not the type that controls spark to the high voltage coil. Unless that one coil that has wrapped insulation is the high voltage source. If not, There must be a rectifier, feeding the ignition. So I assume there is an ignition system, where shaft location sensor controls spark timing. Unless you have points in this somewhere. I know that Onan fired both spark plugs simultaneously, as the high voltage coil was in series with both of them, and engine block closed that secondary coil circuit through the airgap of the plugs.

 

[haakonpe]

Where did you get the plans for this?

 

[ignator]

The crankshaft? Most weed eaters have a single shaft through 2 bearings then a plate with an open crankpin, much like the model aero engine, some motorcycle crankshafts are made up with roller bearings and all pressed together, even multiple cylinder ones, the Suzuki 3 cylinder 2 stroke Jeep engine the same, but they have better equipment and jigs than I have.

Yes, I've seen some 2 strokes have pressed cranks. and they are high RPM types, which surprises me.
My previous two autos were based on the Suzuki 3 cylinder 1 liter engines. The first one got 57MPG, it was made in Japan, but sold by Chevrolet as a Sprint ER model, that was a 1987, then next one was a 1998 Chevy Metro, but only got 40MPG, as they went from carburetor to throttle body fuel injection, and they added 800 lbs to the chassis weight to make it crash worthy. And as always they worry more about the odd emissions and controlling them, then the emissions per mile, so fuel efficiency suffers.

 

[teeleevs]

Hi ignator, yes I thought that "Booker rod" would cause some comments, My 1890s lathe has a 6TPI Cross feed screw and the marks (if they can be seen) represent 0.017 off the diameter, not counting backlash, not very useful. The Lifan setup is an alternator with a magnetic pickup for the ignition so battery and starter are on the drawing board, I have been able to get all, rectifier, CDI unit, on eBay, I have a twin lead coil from an early Honda bike so lost spark ignition should not be a problem.
The 2 rebadged Suzuki cars you mention would be 4 stroke and have auto type shell bearings on the crankshaft but my Suzuki tractor is 2 stroke so is all different, will have to add a post from my computer about the tractor (Type in Articulated tractor homemade ) you will find it among the thousand or so that Google will bring up.
Hi haakonpe, I have drawn some 2d drawings in TurboCAD (no expert ) but mostly I have to adjust things as I go along and avoiding having 2 bolts occupying the same small piece of metal has become a game of hide and seek. Google is a Godsend and I found a lot of parts of the full sized machine to copy or get ideas from. I have worked in the bush (sticks) and made do with whatever is at hand during my working life so I continue on in retirement. I can put my drawings on this page if it will help.
Ted from down under

 

[teeleevs]

Hi guys, This is the Youtube item for my tractor
Since then my friend and I gave it a full makeover. It will mow grass at 12 KPH, The Suzuki engine is facing backwards, 2 gearboxes are running backwards and the 2 diffs are upsidown so it runs forward. There are forty speeds 14 of them reverse, if game (stupid) it can do 60 KPH but I have blocked out Reverse in Gearbox 1 and blocked our top gear in both gearboxes which leaves me with a manageable selection of speeds. I think that is enough for this time.
Ted

 

[ignator]

Hi guys, This is the Youtube item for my tractor
Since then my friend and I gave it a full makeover. It will mow grass at 12 KPH, The Suzuki engine is facing backwards, 2 gearboxes are running backwards and the 2 diffs are upsidown so it runs forward. There are forty speeds 14 of them reverse, if game (stupid) it can do 60 KPH but I have blocked out Reverse in Gearbox 1 and blocked our top gear in both gearboxes which leaves me with a manageable selection of speeds. I think that is enough for this time.
Ted

Ted, your video was entertaining (Gilson kept the 'play by play'). So what did this Suzuki engine power originally? I'm guessing you modified an existing hobby farm tractor. I saw a hydraulic pump, looks like power steering.
I do the same thing with scrap. I just hauled in 727 lbs. of lead acid batteries. I got US$0.17/lb. They needed to go years ago.

 

[teeleevs]

Ted, your video was entertaining (Gilson kept the 'play by play'). So what did this Suzuki engine power originally? I'm guessing you modified an existing hobby farm tractor. I saw a hydraulic pump, looks like power steering.
I do the same thing with scrap. I just hauled in 727 lbs. of lead acid batteries. I got US$0.17/lb. They needed to go years ago.

The engine was from an LJ50 Jeep these came out from Japan in 1974, my brother bought one of the first to arrive here, they were very small 540 cc so they were probably never seen in the US. this one had an oil leak in the feed to centre cylinder so little end bearing went, there was no way to replace the rod so I finished up with the engine and a whole lot of other bits, it still ran but rattled a bit, he used to put a new wrist pin bearing in every now and again, I later finished with a whole used crankshaft. I built up the whole tractor from parts scrounged from work or scrap yards, in the 80s one could wander through a scrap yard and load up a trailer paying scrap price on the way out, those days are gone. The power steering came from a Holden V8 about 1962 model, the Toyota Crown axles were cut down to fit in a 6x4 garden trailer, an extra Toyota gearbox between the Suzi gearbox and the Suzi transfer box, have to get some photos, I have it at my friend Gil's place at the moment, one trouble to address is when steered to end of travel it rips into the power steering belt so need to devise stops on the steering wheel to prevent it being held hard against the end of travel.

 

[teeleevs]

Not a lot happened today, photo 1 I fitted a spacer and bored out the timing gear, drilled a hole to drop in a 1/8th ball locking the timing gear to the shaft, 2 turned the spacer/seal surface for gear to flywheel. Tried out an upside down parting tool made from a tungsten carbide tooth saw blade, it worked magic. Can't put the video on here.

 

[ignator]

Not a lot happened today, photo 1 I fitted a spacer and bored out the timing gear, drilled a hole to drop in a 1/8th ball locking the timing gear to the shaft, 2 turned the spacer/seal surface for gear to flywheel. Tried out an upside down parting tool made from a tungsten carbide tooth saw blade, it worked magic. Can't put the video on here.

You can post your video like the Suzuki tractor on YouTube or some other video hosting site, and post a link here.
Interesting way to key the gear to the shaft. Is the ball removable without much effort?

 

[Shopgeezer]

Have you got a picture of the saw parting blade? I have often thought about something like that.

 

[teeleevs]

Another day in the shop, some of my pictures have split the points and taken another track. Picture 1 drilling the crankshaft for the flywheel, 2 fitting the Lifan Chinese magnito, 3 the flywheel, 4 the fan & ringgear will fit over the flywheel. Missing pix, 5 marking out the positions of the magnito bolts 6 the seat for the magnito/alternator, 7 mag in place. Merry Christmas to you all from Ted from down under

 

[jdurnya]

WOW that is great !!! I restore John Deere Garden tractors and love the old Onan engines !!! following closely !!

Joe

 

[ignator]

Another day in the shop, some of my pictures have split the points and taken another track. Picture 1 drilling the crankshaft for the flywheel, 2 fitting the Lifan Chinese magnito, 3 the flywheel, 4 the fan & ringgear will fit over the flywheel. Missing pix, 5 marking out the positions of the magnito bolts 6 the seat for the magnito/alternator, 7 mag in place. Merry Christmas to you all from Ted from down under
View attachment 121575

This looks like your spark timing generator. I'm not familiar with this sort. Proximity sensor type. So does this drive a CDI that adjusts advance to the spark automatically?

 

[teeleevs]

Yes Ignator, i have a new CDI box and wired it up according to the information I gleaned from YouTube but no joy. I was given parts from a wrecked Lifan motorcycle so now I guess the reason the bike is off the road is failure of the ignition system. EBay have listed all the ignition parts for Lifan for less than Au$50 so I haven't done all this work for nothing. Someone asked for pix of the upsiddown parting tool, the single tooth one works best, the metal curls away down out of the way, but the adjustable multiple tooth blocks up when in deep.

 

[ignator]

Yes Ignator, i have a new CDI box and wired it up according to the information I gleaned from YouTube but no joy. I was given parts from a wrecked Lifan motorcycle so now I guess the reason the bike is off the road is failure of the ignition system. EBay have listed all the ignition parts for Lifan for less than Au$50 so I haven't done all this work for nothing. Someone asked for pix of the upsiddown parting tool, the single tooth one works best, the metal curls away down out of the way, but the adjustable multiple tooth blocks up when in deep.

I've been seeing a repeated post about a spring tool (goose neck), for a parting blade holder. Very old idea from the start of the previous century. But the upside down parting blade mimics this same behavior, as when the cutting edge grabs the material, the tool post flexes back and away from the cutoff operation, instead of digging in further with conventional tool post mount. From my read, this parting operation requires a very robust lathe. Hobbyists have light duty lathes, and fight this operation. I've had my 10x24 bench lathe 'dancing' on the floor, when the lathe goes into harmonic oscillation. My fix was to procure a 2 inch thick piece of hot rolled steel and mount the lathe bolt down locations to this, and the sheet metal cabinet to the floor. This fixed all my problems.
.
I assume you're waiting on a new alternator to continue the build. Any idea what failed in your used one? I have a neighbor that repairs motocross bikes, and had an electric problem with one. I used my oscilloscope to see if the alternator was putting out 'juice'. I could capture the sine oscillations from the alternator. This went to a rectifier, and then the CDI module. In the end, he had replaced the kill switch with a normally open contact, and it required a normally closed.