Pressing Cam Gears

Builders,

One of the other tasks today was pressing new cam gears on our cams for Group 1100 cam kits. T learn more, get a coffee and read this link: 1100-WW Camshaft Group. This is a really good look at the issue of thrust washers being correctly installed, you can look at the dated photos and see I have been beating this drum for 12 years. This is why you don’t just go to anyone to instal a cam gear. I also wrote this update in 2017: Update notes to 2014 manual, 1100 – Camshaft group

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There are a lot of small elements to get right with the camshaft group, but almost all builders just get the full group 1100 kit from us. http://shop.flycorvair.com/product/1100-cam-shaft-kit/ is the link to the products page.

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“The press that launched a thousand cam gears”. The cam fits through the 1.5″ hole in the steel plate. if you want to have a new respect for Lennox bi-metal hole saws, the hole in the inch thick plate was bored by one in less than 5 minutes. 250 rpm in a drill press and lots of oil, and the hole saw wasn’t even dulled. The aluminum horse shoe is a 7/8 inch thick slab of 7075 alloy. It supports the cam just behind the first journal. I carefully cut it so the cam will gimbal under the press and self align under the press. The press itself has a cup shaped head because the very end of a Corvair cam protrudes 3/32″ past the gear when fully seated, and you can’t send it ‘home’ with a flat pressing face. I heat the gear very carefully on a glass grill for 30 minutes to saturate it at 300F.  It goes on with mounting pressure, once it bottoms I actually drive it to 6 tons. If you give it 10 minutes to cool, the pressure will drop off to 4.5-5 tons. If you don’t do this the thrust washer will not be tight when it cools. If the cam gear is too cool, it will gall, if it is too hot it is soft and will distort under pressure. Typing the 3 sentences above cost about 40 cam gears to learn and perfect my technique 20 years ago, when I could ill afford the $1,600 learning curve, but I spent it anyway.

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The sticker is a 2003 graphic designed by Gus Warren to express how well our Corvairs work on Zenith aircraft. We has hats and shirts also, today they are collectors items. Last year Sebastien Heintz had a photo of a very attractive passenger  wearing a tee shirt, airborne in the factory Zenith Cruiser on his FB page. They turn up every now and then in nice settings.

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Above, the Craftsman screwdriver (classic, not a made in China one) is pointing to the cam’s thrust washer. It is part of the design, because the Corvair uses a sophisticated angled gear tooth design that smooths the operation of the valve train.  The gears I use are made in the USA billets from California Corvairs. they are about $70 by themselves, a very well made part. The little green square on the face of the gear is a small patch of zinc chromate primer I apply before heating the gears. I check the temperature with an infa-red meter, which will not read accurately on any glossy or shiny surface like the cam gear. I just aim it at the flat paint mark and it works like a charm. I have verified this method many times with very accurate Fluke contact thermometers I have.

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Turn off the TV and Computer, now go have a productive night.

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Wewjr.

About William Wynne
I have been continuously building, testing and flying Corvair engines since 1989. Information, parts and components that we developed and tested are now flying on several hundred Corvair powered aircraft. I earned a Bachelor of Science in Professional Aeronautics and an A&P license from Embry-Riddle Aeronautical University, and have a proven 20 year track record of effectively teaching homebuilders how to create and fly their own Corvair powered planes. Much of this is chronicled at www.FlyCorvair.com and in more than 50 magazine articles.

One Response to Pressing Cam Gears

  1. Bruce Culver says:

    What always impresses the heck out of me is how beautiful your machined parts are, just as physical objects, and that goes double for the wonderful billet crank Dan supplies – just physically beautiful examples of industrial products that can be appreciated in looking at them and also appreciated for the job they will do in your engine once it’s flying. Bravo!

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