Webster Engine

[Coomba]

I pulled up my set of Webster drawings to double check my memory.

Everything is symmetrical on the Webster so it will run in either direction equally well. Your preference as to the direction of rotation. As the Webster is a low-speed engine cam timing will not be extremely critical. I checked the Webster cam drawing and the flanks are 125° of crankshaft rotation apart. For starters, I would set the cam for the exhaust opening starting at 25° before bottom dead center and an fully closed at 10° after top dead center. In practice, you won't have quite the full 125° of operation because of the necessary few degrees of tappet clearance. Just split the difference and you will be fine.

The ignition cam will also have to be set depending on your rotation preference. For starters I would just set the cam so the points start to open about 5° before top dead center on the compression stroke. Really, on a low-speed engine all you really need to do is make sure that you are slightly before top dead center and not after top dead center.

These are not optimized settings but are settings that should make the engine run okay. After you have the the engine running satisfactorily you can tweak these settings but I think you will find that you can vary quite a bit from them without making a significant difference in performance. Low-speed engines with atmospheric valves are not very demanding of the settings.

Gail in NM

Hey Guys, I have been having trouble getting my Webster to run also. I think I have a lot less hair now then I did before I began. I was just about to post a help thread, then found this one. Maybe I found the answer here?
Gail in NM says the points should be opening at 5 degrees before top dead center. I have the points closing on the flat. I'm I setting them backwards?:wall:

 

[GailInNM]

Coomba,
As you rotate the engine in the direction of normal operation the points will close significantly before you reach top dead center. This allows current to flow into the coil and energy is stored magnetically in the core of the coil. This is not where the spark occurs. As you continue to rotate the engine the points will open. This should be about 5° before top dead center. The magnetic field collapses in the core of the coil at this point and that is when the spark is generated.
Gail in NM

 

[Coomba]

Thank you so much for that answer! I was under the ideal that the coil collapsed when the contact points closed. Is there a set value as to how wide the points need to be set open? I can't wait to give this a try. But yesterday I strained my back, so I,m a little laid up. I'm confident now that it will run. I will report back.

 

[Brian Rupnow]

A good value to use is .030" to .045" at full opening. This depends a lot on the configuration of your ignition cam. Opening more won't really hurt anything. Be sure you use a condenser with the points if you are using old style conventional ignition.

 

[Coomba]

Today I got the chance to work on my Webster; I made the changes that were suggested. It did improve, but it still won’t run.I know there must be ignition, I can hear it popping, the exhaust, cylinder and head get hot. The throttle arm is in about 25% open. When I close it down I can feel the engine kick back on the drill I’m using to start it. I have adjusted the low speed mixture, and the idle screw, back and forth to their full range several times, using 1/4 turn increments. The carb. I'm using is a TRX Pro .15 . Also I did put a small amount of oil in the fuel. Suggestions please

 

[Brian Rupnow]

If you are certain of the ignition timing, and the valve timing, and you are turning it in the right direction, first try a lighter spring on the intake valve. If you have cast iron rings, or even if you are using a Viton ring, your engine probably is leaking compression at the valves. Put a pulley on your crankshaft, mount it on a bench, and drive it at about 600 rpm with a larger electric motor using a v-belt. Make sure that there is about a 2% oil mix with your fuel, turn the ignition on, open the carburetor wide open and turn on the electric motor and let it run for an hour, making sure you oil all friction points on your engine with a squirt oil can. If it fires at all, which is what you want, each time it fires will seat the valves better and better, until they begin to seal enough to boost the internal compression. If your ring or rings are cast iron, this "running in" will also help seat the rings to boost the compression. Ideally, if everything is set up correctly, your engine will begin to fire consistently right along with the electric motor eventually. If this doesn't work then you have to disassemble your engine and relap the valves. These engines simply will not start and keep running if the compression is too low due to leaky valves or piston rings.---Brian

 

[Coomba]

If you are certain of the ignition timing, and the valve timing, and you are turning it in the right direction, first try a lighter spring on the intake valve. If you have cast iron rings, or even if you are using a Viton ring, your engine probably is leaking compression at the valves. Put a pulley on your crankshaft, mount it on a bench, and drive it at about 600 rpm with a larger electric motor using a v-belt. Make sure that there is about a 2% oil mix with your fuel, turn the ignition on, open the carburetor wide open and turn on the electric motor and let it run for an hour, making sure you oil all friction points on your engine with a squirt oil can. If it fires at all, which is what you want, each time it fires will seat the valves better and better, until they begin to seal enough to boost the internal compression. If your ring or rings are cast iron, this "running in" will also help seat the rings to boost the compression. Ideally, if everything is set up correctly, your engine will begin to fire consistently right along with the electric motor eventually. If this doesn't work then you have to disassemble your engine and relap the valves. These engines simply will not start and keep running if the compression is too low due to leaky valves or piston rings.---Brian

Brian
I'll give that a try, and yes I do have cast iron rings. I'm looking at it facing the ignition cam and the points, turning in a clockwise rotation. And no at this point I'm not really sure of anything. I just have to assume that because I can hear it put, and things are getting hot, that it is timed correctly, maybe not. Would the amount of oil in the fuel be a concern? I mixed it 40-1. Is it normal to have some black liquid splash out from behind the piston? I was thinking that the compression was good because, when I was trying to start it, if I reduced the throttle setting I could feel the engine kick back.

 

[Brian Rupnow]

Your oil mix is okay. Cast iron rings hardly ever seal enough right "out of the box". They should be "run in" using the method I described for one to two hours. If you want me to call you and discuss it, send your phone number and name to [email protected]. It doesn't cost me anything to call you.

 

[65arboc]

Hot tubes have always fascinated me mostly 'cause I haven't really studied
how they work. I would be very interested in your re-build of one.

See, we do read your posts!! And your engine was made 2 years before me.

Pete

Pete,

Some pics of the Myrick hot tube I'm restoring now. Has a 5-1/4" dia. piston!

 

[10K Pete]

I went off and read up on the hot tube thing. Most interesting!! Way before
spark plugs or fuels like gasoline. Natural gas and large displacements. Maintaining
the exact heat on the tube and the exact position of the heat line on the tube
was the big trick. All of which seemed to change with speed, load and fuel.
Wow, real hands on operation.

Your engine is a small one from what I was reading!! Please post pics as your
rebuild progresses.

Thanks,
Pete

 

[65arboc]

Pete,


First pic is cylinder head with carb, pushrod guide and governor weights all redone. I used ceramic disc brake caliper paint on the cylinder head.

Second pic is the cylinder with governor hold up finger still attached, paint stripped.

Last pic is crankcase with original primer paint still inside case.

More later,

Jim

 

[deverett]

Very interesting project - your Myrick rebuild.

As the subject matter has strayed away from the original Webster theme, would it be possible to put Myrick into a new thread?

No criticism intended. Think positive - if someone wants to read about Myrick in the future, why would they look under Webster?

Dave
The Emerald Isle

 

[65arboc]

Very interesting project - your Myrick rebuild.

As the subject matter has strayed away from the original Webster theme, would it be possible to put Myrick into a new thread?

No criticism intended. Think positive - if someone wants to read about Myrick in the future, why would they look under Webster?

Dave
The Emerald Isle

I was only answering Petes request for more pics of the project. Move it to a new thread if you want. I don't know how. No criticism taken. Besides, I don't think there are many on here who ever heard of a Myrick so why would anyone type that in? I thought it may spur someone on to build a model of one but whatever.

 

[deverett]

There is (or was) a member on this forum who went by the name of Myrickman, so I guess there are others who know about them.

Dave
The Emerald Isle

 

[10K Pete]

Ya know, having a thread for your hot tube would be a good idea, Jim. I don't
know what the title would be....
I'd love to see more posts as you work on that engine.

I'll see if I can get the attention of an Admin to set this up or move it or
whatever needs to happen..

Thanks,
Pete

 

[65arboc]

Hi Pete,

This is a hot TUBE engine which is a little different than a hot bulb engine I believe. If someone wanted to build a scale model of one like I have I don't think it would be too difficult. It is a very simple design and needs no spark, mag or battery to run, just heat. I am no engineer but I would be happy to take measurements and pictures for any one who wanted to model this engine. It has a very simple governor system that holds the exhaust valve open when rpm gets too high. I may try to model it myself some day. We could call the thread: Model this Myrick?? or some thing like that.

Jim

 

[10K Pete]

Ooops. Yep it's a hot tube. That bulb just sneaked out of my fingers.
It might be kinda fun to build a model like that. Do you think the hot tube
concept would scale??

Pete

 

[Brian Rupnow]

I believe that Chuck Fellows tried to make a model hot tube engine and didn't have a lot of success with hot tube ignition on a small scale. I could be wrong about that, it was a while ago. He started with a horizontal "oil-field" pumping engine, which was a conversion from steam powered to gasoline powered. He eventually got it to run, but I think he ended up going with spark ignition.

 

[Barnbikes]

My father tried to make a 3 hp Briggs into a hot air engine a couple years ago. It ran but just not consistently.

 

[65arboc]

I believe that Chuck Fellows tried to make a model hot tube engine and didn't have a lot of success with hot tube ignition on a small scale. I could be wrong about that, it was a while ago. He started with a horizontal "oil-field" pumping engine, which was a conversion from steam powered to gasoline powered. He eventually got it to run, but I think he ended up going with spark ignition.

Brian,

You are always looking for something different to build so here ya go. I think you could do it! There's a lot of info on Smokstak.com and I even found schematics of a couple different ones. It does involve propane to heat the tube red hot but I think with very small orifices to feed the hot tube and the engine it could be done. All it needs for the hot tube is a stainless tube capped at the top end and sealed into the cylinder head. You need a metal cylinder around the tube to protect it from drafts. The valving system is very similar to the webster. The more I talk about it the more I am tempted to try to build one! I may need more experience tho:

Jim