Author Topic: AOG's version of Elmer's No 50 "The Educational"  (Read 5602 times)

Online AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #30 on: February 01, 2017, 02:23:44 PM »
Here is a quick update. I got the flywheel turned and painted but I still couldn't put a piece of paper between the flywheel and the base. I ended up making some brass spacers per Bill's suggestion.



I was in the process of setting my throws when the cam frame broke. It turns out the the Locktite wasn't strong enough to take the loads. I went back and silver soldered the frame and after some clean up it appears to be working. To answer zee's question the cam set up so that it holds the valve open for the full length of the stroke. Now for the real question. Anyone have any ideas on how to set the valve timing? Elmer's "adjust cam until the engine runs well" wasn't particularly useful. Because of the shape of the cam, I don't think I can advance the timing 90 degrees like I would for an eccentric.

Tony


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« Last Edit: February 01, 2017, 03:46:06 PM by AOG »

Offline b.lindsey

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #31 on: February 01, 2017, 02:59:03 PM »
The spacers look fine Tony and the contrast of the brass and aluminum add just another focal point as well. This is going to be a large engine based on that last picture. Sorry I can't help with the timing question, but will have a look at the plans and see if anything springs to mind. That flywheel should have plenty of clearance now though.

Bill

Offline Mike Bondarczuk

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #32 on: February 01, 2017, 03:35:35 PM »
Hi Tony,

When I cam to make the cam frames I decided to mill them from a solid piece of brass which resulted in a matched pair of frames with no gluing or brazing to make things go out of shape, and the wastage was quite small, but the end result worth it.

I also had questions about the cam timing as the copies of the drawings I had are very blurred and impossible to make out the comments so Jo, who is on this site as well, was good enough to forward me a photo version of the relevant page and I am assuming that the engine runs anti-clockwise when viewed from the side with the cylinder nearest the viewer.

1: with the con rod fully forwards, meaning piston at the top of the stroke, the widest part of the cam should be up pointing at 12 o'clock and should also be centred in the frames.

2: with the con rid fully backwards, meaning piston at the bottom of the stoke, the narrowest part of the cam should be pointing upwards at 12 o'clock and should also be centred in the frames.

3: when the cam drive rod knuckle is going towards fully up the cam should be turning anti-clockwise and pulling the frame back towards the flywheel.

4: when the cam drive rod knuckle is going towards fully down the cam should be turning anti-clockwise and pushing the frame forwards away from the flywheel.

If anyone else has built this engine and had it running perhaps they could comment on my interpretation of the cam timing so that we can at least try to get these two engines to run.

Mike
"Everything I can't find is in a totally secure place"

Online AOG

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Re: AOG's version of Elmer's No 50 "The Educational"
« Reply #33 on: February 02, 2017, 10:27:19 PM »
Thanks Mike that's what I needed. She's a runner.  :whoohoo: :pinkelephant: pics and a video in the showcase at the following location:

http://www.modelenginemaker.com/index.php/topic,6851.msg140616/topicseen.html#new

Tony
« Last Edit: February 02, 2017, 10:41:38 PM by AOG »