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Valve rod question

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dvensel1
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2017/06/17 20:56:50 (permalink)
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Valve rod question

I had a customer bring me in a bunch of parts for a 17.5 HP Briggs that he'd torn down for a bad head gasket.  The problem I'm having is that there's 2 different push rods.  One is steel and the other is aluminum.  He can't remember where they go.  Frankly, I've never torn one of these down and don't know either.
It's a 17.5HP, Model 31C707-0230-E1.
Can anyone out there tell me which is which?
 
Thanks!
 

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    Mikel1
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    Re: Valve rod question 2017/06/17 22:39:06 (permalink)
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    Intake has the aluminum pushrod, exhaust steel pushrod.
    dvensel1
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    Re: Valve rod question 2017/06/18 09:21:35 (permalink)
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    Mikel1
    Intake has the aluminum pushrod, exhaust steel pushrod.



    Thanks!  I figured this was it but I appreciate your input to be sure.
    Regards.......
    Doug
    dvensel1
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    Re: Valve rod question 2017/06/19 10:05:17 (permalink)
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    I appreciate the help.
    I have another question.  I have it almost assembled but I notice that the intake valve hardly opens.  Is this normal?  The exhaust if fine and opens to what I would expect, but the intake just opens a small amount.  Again, I'm not familiar with this overhead valve engine so I'm ignorant on a couple of things.  I hate to tear the whole thing down searching for a bad cam and I've never seen one go bad, so I'm appealing to the masses once again.
    I've assured proper seating in the lifter off the cam and adjusted clearances properly but it doesn't help.  Is it normal to have these engines open so little?
    Thanks once again.  I truly appreciate it.
    Again: it's a 31C707-0230 E1.  17.5 HP Vertical.
    Doug....
     
    dvensel1
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    Re: Valve rod question 2017/06/19 11:34:30 (permalink)
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    FOLLOW UP:
    Curiosity got the better of me and I knew I had to see it for myself.  I took the engine off the mower and tore it down.  Much to my surprise, the intake cam lobe was worn right off!  I have NEVER seen an engine do this, especially since the intake cam lobe is nearest the oil sump and would have more than ample lube.  How could this happen?  The owner is very good about oil changes and keeping the machine up but it came to this anyway.
    Also, in the cylinder there's a spiral scratch.  It's very odd. I've seen scoring on the stroke of the piston but I've never seen scoring in a spiral design that looks like someone took something and screwed it into the cylinder.  It's not honing marks either because the scoring goes around the cylinder half way and at a distance of about 1" from TDC to maybe 1.5" down, spiraling as if it was screwed in clockwise.  I don't have an answer, but the guy doesn't want to put the money into it and he bought a new machine.
    I'm relating this to everyone in case they come up against this themselves.  Very odd failure indeed.  It's a shame.  The rest of the machine is in good condition.  I may fix it myself and sell it.  Cams are around $85 so it's not too bad.
    dvensel1
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    Re: Valve rod question 2017/06/19 11:38:24 (permalink)
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    ANOTHER UPDATE:
    I just found a crack in the head on this thing.  Wow.  Bad engine.  Yet, he was still using it when it lost power and called me.  It's a wonder it started at all.
    $150 in a head, $85 in a cam, another $25 in gaskets.  He'll have over $450 in it.  A new engine is around $600.
    Mikel1
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    Re: Valve rod question 2017/06/20 18:38:37 (permalink)
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    Those cams go bad more than you may think, also some of the acr's break. We were trying to help a member on another forum, the rpms would not rise even though throttle was full speed, ended up being bad cam.
    Not sure on the spiral, doesn't look like a screw does it?
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