Resurecting my Webster IC project

[chucketn]

As often happens with me, my Webster project got put on the shelf while I worked on something else. Probably shelved due to lack of material, or some other problem. That happens often.
The new threads on building the Webster spurred me to get it down, dust it off and try to continue.
When laying the Webster out in my mind. and making a few basic parts, I had the brilliant idea to use a weed eater coil and flywheel. I had several defunct weed eaters lying around, so I stripped them down and gathered some parts. I ended up with cranks, flywheels, coils, bearings, and a few pounds of aluminum for casting.
I had completed the base, bearing standards, crankshaft, cylinder, piston and con rod, and the head. I was trying to figure out how to mount the weed eater coil to be near the flywheel when I stopped.
Today, I made a simple mounting plate for the coil and set the gap between the flywheel and coil to about 20 thou.
I have attached a couple pictures of where it's at.
Am I correct in thinking with the weed eater flywheel and coil, I wont need the points and gear system? Am I full of @%#$?

Edit: Yes, I Am I full of @%#$! I just realized I need the cam shaft and lobes and gears to work the valves...

 

[aka9950202]

Make sure you have the kill switch wired correctly. Some of the weed wackers need the switch closed to run while others need the switch open.

I was caught out with the switch closed to make it run when troubleshooting the weed wacker.

Cheers
Andrew in Melbourne

 

[chucketn]

I am using a weed eater flywheel and coil. I have been researching how to hook it up. One important bit of info I founs is the weed eater ignition needs the flywheel spun at a minimum of 250 rpm to make enough spark to start. I'll use a cordless drill to spin the crankshaft to start it
I don't have a schematic of the actual weed eater so don't know if the kill switch was open to run or closed to run. That should be easily determined by experimentation. I found a generic circuit diagram during my Google searches. I am assuming the mounting bolts through the laminations of the coil provide ground to the coil as shown in the diagram.
I think the only problem I will have will be timing and air gap between the flywheel and coil. I found differing values for the air gap from .006" t0 .030". I cut the flywheel end of the crank off and drilled it to fit on the end of the Webster crank, and added 2 set screws to allow adjusting position for timing. We'll see if it works...

 

[chucketn]

I need to make the flat rocker arm spring for my Webster build. I have never made such springs before. For material, I have a frame saw or coping saw blade that is 6" long, .235" wide and .016" thick. Can I use it for the spring? Do I have to anneal it to bend it and drill the hole, then re-temper it?
The saw blade was in tools that my Dad had and is probably 40 years old or older, so I suspect it is not bi-metal.

 

[Brian Rupnow]

Use the recoil spring out of the weedeater. You will probably have to use a carbide endmill to put a hole thru it.

 

[chucketn]

Thanks, Brian. I hope I saved the recoil spring!
To get that tight bend, do I need to anneal it and then re-harden and temper?

 

[Brian Rupnow]

Chuck--That will be very much a "try it and see" kind of thing. I think that once you heat one of those flat springs enough to easily bend it, you will never be able to bring it back to what it was before you heated it.

 

[chucketn]

Yes, I've heard that about spring making. I'll dig through my "I might need that someday..." box to see if I saved the re-wind spring, I 'm almost sure I did.
Thanks again.

 

[aka9950202]

I used a hacksaw blade for the flat spring. First aneal the blade. I left might in dry sand overnight which was overkill. Shaped and drilled the soft blade. Heated it to red to bend then quenched in oil. I used a toaster oven to temper it then polished it.

Cheers,
Andrew in Melbourne

 

[bill70j]

If you have some, you might consider using strapping tape from a packing carton. It cuts easily, bends easily, and works fine on my Webster rocker arm.

 

[chucketn]

bill70j, I haven't seen metal strapping tape for about 10 years... All I see is plastic.

 

[bill70j]

bill70j, I haven't seen metal strapping tape for about 10 years... All I see is plastic.

I got a whole bunch when my they strapped the skid and crate together when they shipped my lathe. I can easily mail you a piece, if you like - just pm me your address.

 

[chucketn]

Thanks, Bill, but no need to go to that expense. I am sure I have the pull starter recoil spring in my junk box. If not, I'll let you know.
Chuck

 

[kwoodhands]

bill70j, I haven't seen metal strapping tape for about 10 years... All I see is plastic.

If you have a commercial building site near you , often 1" wide strapping would be found for free. Often used for safety rails between columns and around stair and elevator shafts . Sometimes an entire perimeter is strapped. Also sometimes lumber yards still strap their framing lumber with steel .
mike

 

[kquiggle]

Another alternative is to use a torsion spring, which you can wind yourself from spring wire:

https://www.homemodelenginemachinist.com/threads/water-cooled-webster.23224/page-10

Look here for other Webster build links (scroll to bottom of page):

https://sites.google.com/site/lagadoacademy/machining---lathes-mills-etc/build---webster-engine

P.S.

If you go to the link above, you will see that I started a Webster build in 2014. Since then I moved and had to relocate my shop, and a few other things have slowed my progress. I still plan to finish it though! As the saying goes, "Life is what happens while you are making other plans."

 

[ZebDog]

Not a good pic but I used a spring from a pen on my Webster

 

[chucketn]

I have the valve blocks doe, and I'm getting setup to turn the valve guides from brass.
Looking at the drawing, I see the top part is tapered. What is the purpose of this taper, and is it really necessary?
I'm trying to figure out how to make these on my lathe. I think I should start with the large diameter end toward the tailstock.

 

[Brian Rupnow]

They don't need to be tapered. They were originally designed that way so they wouldn't rub on the spring. Make them with parallel sides--They will still work fine.---Brian

 

[chucketn]

I kinda thought that was the reason. How about 12L14 for the valves? I have several rods salvaged from printers that I think are 12L14.
Chuck

 

[Brian Rupnow]

Chuck--that is really a "try it and see" situation. I have always used cold rolled 1018 steel for my valves. About the only thing I have been warned on about 12L14 is that it doesn't weld very good at all.--Brian