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1910 Model 20 Hupmobile timing marks on camshaft gear


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Hi- Well, I'm finally starting to put my side cover with camshaft back on my Model 20.  The instructions say that there is a mark on the gear, which would line up with punch marks on the mounting surface of the magneto. Problem is, this is a new gear with no marks.  A cast in place camshaft, so it's hung out in air while babbitt is poured for bearings, what a nightmare but it's done.


Does anyone have their plate off, so that you could tell me exactly where camshaft gear should be marked, that is, when marks are at correct spot and line up on side cover, what position is camshaft at that point?


I'm going to raise all valves at once to make it easy to install side cover, but don't want to have to do it by trial and error!


I've seen the instructions on TDC and #4 exhaust valve opening, but to me that's still a lot of teeth which I can be off, as "opening" can be defined as first contact, significant movement, and so on.


Any help appreciated.  Thanks David C.

Side plate one.jpg

side plate two.jpg

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The instructions in the manual show marks, but my new gear wasn't marked unfortunately when replaced.


The instructions I've see a few time are:


TDC on the fly wheel 10mm to the right of the line of punch marks on the front of the cylinder block, looking from the front of the engine. With No.1 piston at the top of its compression stroke, the exhaust valve on No.4 cylinder will already be starting to open."


Thinking through that, if #1 piston is at top of stroke, so is #4, and it doesn't make sense that exhaust starts OPENING at TDC.  It could start opening on #2 or #3.  Correct?


Is this supposed to read "the exhaust valve on No. 4 cylinder will already be closing"??????????


Ken, I have the old side plate you sent  me, but it seems every fifth tooth on the cam gear has a mark on it, so that's little help!  But do appreciate having it in hand.

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