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    • CommentAuthordavid
    • CommentTimeDec 20th 2008
    I have seen some single cylinder engines with a single cam and Yoke that toggles to operate the intake and exhaust valves.
    Does anyone have an example of how this is done and set up? Even photos of a engine, detailing this set up, to operate the valves would help.
    David Kerzel
    What type of engine did you see this setup on? Given some more detail we may be able to aid in the search.
    • CommentAuthordavid
    • CommentTimeDec 21st 2008
    There aren’t any in the gallery and I have not had time to search the show photos.
    The engine is a single cylinder, 4 cycle, overhead valve. Possibly European style.
    There is one cam lobe centered in the yoke which is normally level allowing both valves to be closed.
    With the cam rotating clockwise, exhaust full open is at cam 45 degrees before top, causes the yoke to toggle clockwise and open the valve.
    When the cam is at the top the yoke returns to the neutral position closing the exhaust valve.
    As the cam continues to 45 degrees past the top, the yoke rotates counter clockwise and the intake valve is full open.
    The advantages are one cam, so it is smaller and the yoke spreads the push rods left and right of the can shaft.
    • CommentAuthordavid
    • CommentTimeDec 23rd 2008
    I found the design in a book finally.
    Turns out it is not a yoke but 2 pivoting arms that follow a single cam and convert the cam action at + and – 45 degrees to vertical operation.
    I have spent hours trying to make a single yoke work in CAD. I get close but to many parts end up line to line. With 2 arms it is a no brainer.
    I will post details when I get it put together in the next few days.
    Have you looked at the "Tandem Double-Acting Engine" plans and article in Home Shop Machinist. This covers the plans for a "Snow" engine. Similiar to the one we have at Florida Flywheelers in Ft. Meade.
    • CommentAuthordavid
    • CommentTimeDec 24th 2008
    I remember reading the issues with the Snow Engine and will try to find it.
    Thanks for the tip.
    First Snow article was in May/June 2004 issue of Home Shop Machinist and the plans and build articles started in the November/December 2006 issue. This engine uses a single cam that drives both the intake and exhaust valves.
    I have reviewed the prints of the 400 HP Snow engine at Flywheelers park and it also uses a single cam that drives both the intake and exhaust valves.

    Come and visit the engine at Flywheelers Park. Show dates are Jan 14-17 and February 25-28.
    • CommentAuthordavid
    • CommentTimeDec 27th 2008
    Thanks for posting the note about the Flywheelers Show.
    The first time I met Bob Sores face to face an saw a running model engine was at Flywheelers Park during a show.
    I think posting a note about local events relating to engines is a great way to get model builders to see the real thing and talk with people who know the history.
    • CommentAuthordavid
    • CommentTimeDec 29th 2008
    I spent some time sketching then I went to 3D CAD and got the 2 independent cam followers designed and fit to a cam.
    The lift is .07, the cam is .62 diameter

    As I see the small size I am starting to drift to a flat head design.
    • CommentAuthorjay rich
    • CommentTimeJan 16th 2009
    the engine that has this is honda ive worked on so many of them the single cam has 2 off set cam arms if i get a chance ill rip the head off my honda and take some pics i got a ? about cams to the cam cutter design that steve made i dont get it on the cutter fram wont it hit the lathe tool ? and can some one e mail me the plans on the origanl cam cutter and steves ive got some i deas but as you all know my math is realy bad as for the honda engine just look up hondas 5 hp ohc or over head cam engines pluse you guys will lol the cam is pvc and like a rubber band belt good running engine thoug ....jay
    Hello Jay!

    I had no problems with the tool hitting the frame. Once the fixture was assembled, I had to provide clearance for the tool on the right side between the cam and the degree disk. I also moved the locking screw from the top to the side so the tooling would not interfere.

    What original cam cutter are you refering to?

    If you have ideas, spill em! The camshaft article was an idea I had. I plopped it on paper and mailed it to 5 or 6 guys who are very good thinkers as well as builders. I took all there suggestions and now there is some help for anybody who needs it. David was one of them.
    • CommentAuthorjay rich
    • CommentTimeJan 16th 2009
    hi steve i mean as bob shores do you have those plans i would like to try his and yours the reason is i was going to try to think of a way to make a cam grinder where you load up the size you want and grind it out then move the set over and just copy i sent david the honda pics and a small video i hope this helps ive been thinking of trying this single cam i dea to from what i rember i think indian had something like this to oh yes i hope david posts the video i want to tell you guys on honda little secret look closely at the video then ill tell ok ill give you a hint exuhast side to your right in the video and steve can you e mail me the plans i would like to try it your way my math realy sucks ....have fun cause i am going nuts here ....jay
    I can send you plans for the fixture but you did not register your email address in your profile. The fixture is very much like Bobs.
    • CommentAuthorjay rich
    • CommentTimeJan 18th 2009
    oh sorry my goof ok ill do this rite now thank steve
    I am sending the drawings for my fixture. The only difference between mine and Bob's is, his had a riser on the end with a pin in it. The pin was to index the degree wheel depending on which cylinder you are working on. Using the cut table, there is no longer a need for the locating pin.
    • CommentAuthorjay rich
    • CommentTimeJan 19th 2009
    steve one more thing do you have the degree wheel so i can print it out and paste it to the disc thanks for the e mail on the plans ....jay
    My email is down right now. I will send over the one I got from MEB magazine website.
    • CommentAuthorjay rich
    • CommentTimeFeb 15th 2009
    steve i would like to thank you for the cam cutter plans they realy made the difference i would like to say the westbury 4 cylinder engine cams and mine are the same i found the cam section of the 15cc 4 cylinder engeine and used them on my a.r. engine
    I'm glad it helped. How long did it take to complete the shaft?

    Where did you find the information for the ETW seal?

    • CommentAuthorjay rich
    • CommentTimeFeb 15th 2009
    the info on the seal i dont rember i wish i did rember but the cut depth is great and the angles are like comp cams angles after making the fixture it was a breeze 15 mins to make the cams oh the depth is 0.078 oh yes i think geroge hunt helped me with the seal info i think i am not sure dont realy rember i can ask david if i can email all the info i have to post it here i think it would help all of us but the cam cutter and angles are great it makes the ar engine realy breath ....jay
    • CommentAuthordavid
    • CommentTimeFeb 16th 2009
    I got the pages of the Westbury engines you sent. They look like they are from a book or magazine so I suspect they are copyrighted so I cannot post them on the site.
    Copyright rules stop public sharing or copies being sold. Making a copy for your own use is OK. Using a part of a article in a new larger article is also OK if credit is given.
    I would recommend people who are interested contact you by e-mail.
    For those who are interested the article is complete drawings and machining instructions for a Seal 15cc 4 cylinder 4 cycle engine.
    • CommentTimeFeb 16th 2009
    Wasent Me, I dont have anything on the seal. I have helped You out with other stuff though.
    Cant wate to see the video of the ar engine running!
    George Hunt
    • CommentAuthorjay rich
    • CommentTimeFeb 17th 2009
    wow i am getting old my memory is bad well any way i gave the pdfs to david to post for all of us ....jay