Engine for Rumely model F oil pull tractor

[rutzen]

Hi everyone,
I am trying to draw up a 1/8th scale engine for a Rumely oil pull model F [ single cylinder] project. I am thinking of building the engine first then if it runs ok I will build the rest of the tractor. I have got so far using the few pictures I have and by watching online videos. I have no access to the original and live in Ireland so there are none locally that I know of. I would like to ask if anyone else has ever drawn one of these or could help with details of the original . Thank you.

 

[rutzen]

Hi Everyone, I've got the engine built and got it to run yesterday for the first time! Here is a photo of the engine and chassis with the radiator. Does anyone have any ideas about the carburettor? It's a copy of ET Westbury's design for his road roller scaled up. It has to lift the fuel because there is no float chamber. However it won't tick over and does not seem to be speed controllable.

 

[rutzen]

Here is a short video of it running. Sorry about the quality, I'll have to get a better camera!
MVI 7332 Rumely Oil Pull model engine running. - YouTube

 

[ShopShoe]

Congratulations on finishing a successful project. It lools and sounds good, despite the video issues.

Thank You for posting,

--ShopShoe

 

[Brian Rupnow]

Irish--That works great. Congratulations.

 

[bobden72]

Here is a short video of it running. Sorry about the quality, I'll have to get a better camera!
MVI 7332 Rumely Oil Pull model engine running. - YouTube

Nice job sounds good.

 

[rutzen]

Thanks everybody. The running isn't right yet, it dies if I open the throttle. Any ideas as to why that could be please?

 

[bobden72]

Weak fuel mixture.

 

[Gordon]

I don't know about the speed but you seem to have a rather high ratio of oil in the fuel. There is quite a bit of smoke. That makes it look authentic but it will also quickly foul the plug.

I have completed the engine on my 1/8 scale Rumely and have had it running briefly but decided to complete some of the other tractor parts before concentrating on getting the engine to run well. I have the wheels done and mounted and I am trying to figure out a clutch and gear train. I have made the cooling radiator but I am not happy with it so I will probably redo it.

Gordon

 

[rutzen]

Thanks guys, I think it's burning oil from the crankcase. I used an O ring seal on the piston but I suppose the first one could have become worn by the bore not being polished enough. It seemed to give a perfect vacuum seal when I tried it. I can easily enrich the fuel, I'll try that.

 

[rutzen]

Hi Folks, here's a video I made showing the details of my tractor engine.
It's better quality than the last one because I got myself an action camera. The editing is more difficult than I thought though.

 

[Willyb]

Thanks everybody. The running isn't right yet, it dies if I open the throttle. Any ideas as to why that could be please?

Possibly getting to much air when the throttles opened. Do you have anyway of closing down the inlet of the carburetor a little? Allot of flywheel type engines have a way of adjusting the inlet restrition along with the mixture adjustment.
The round part with the lever at the bottom of the carburetor by the mixture screw, what is this for?
Cheers
Willy

 

[rutzen]

Hi Willy, thanks for the reply, The round part with the lever is a slide which covers the air inlet holes to provide a choke for starting. Westbury says most people make the inlet too large. The inlet passages into the cylinder are only 8mm . I've now made another throttle slide with holes only 4 mm in it but it still doesn't seem controllable. I all makes me wonder how internal combustion engines got developed at all. Steam engines are so controllable and at the time the steam manufacturers must have seen internal combustion engines as a joke.

 

[rutzen]

Hi Everyone, I've got the tractor more or less finished. Here's a video of the first run this week.

 

[ShopShoe]

That's a great model. It gives a good scale representation of what these full sized machines look like and sound like running.

For some reason, I like it in just the metal, without paint.

Congratulations.

thank You for posting,

--ShopShoe

 

[rutzen]

Thanks Shopshoe. I rather like it unpainted as well. The problem with painting it would be it's too shiny and un-tractor like, also I can't get the Rumely decals from anywhere.

 

[rutzen]

Here is a photo of the gearing under the engine.

 

[rutzen]

Some explanation;- The upper of the two shafts you can see has two pinions on it both of which can slide. In the position shown the engine is in neutral. The two brass pieces are the selector forks and are moved by the two gear levers. If the right hand gear is slid to the left it engages with the differential gear [ it's behind these gears so you can't see it]. If the left hand gear is slid to the right [after moving the RH pinion back to neutral it engages reverse. The large pinion in the foreground is in mesh with the differential gear. Hope that makes sense!

 

[kuhncw]

You've done a very nice job on your Oil Pull. I like the unpainted look also.

Chuck

 

[rutzen]