<VV> uneven vacuum

Keith Hammett keith.hammett at stainlessfab.com
Wed Feb 14 10:36:05 EST 2018

I thought it was axial movement of the push rod.  Shop manual gives a way to do this with just finding top dead center on two cylinders and the corresponding other valves that can be done at the same time.

Keith Hammett | Senior Design Engineer | STAINLESS FABRICATION, INC. | 417-865-5696
Visit our website at www.stainlessfab.com

-----Original Message-----
From: VirtualVairs [mailto:virtualvairs-bounces at corvair.org] On Behalf Of Michael Kovacs via VirtualVairs
Sent: Wednesday, February 14, 2018 8:45 AM
To: Hugo Miller via VirtualVairs <virtualvairs at corvair.org>
Subject: Re: <VV> uneven vacuum

 ...when does a pushrod become 'tight' to turn?). But I've never heard of valves running under pre-load?...    Back off the rocker arm adjustment till the push rod can be easily twisted. Then slowly tighten up the rocker arm with a socket wrench, you use the other hand to grip the push rod between your thumb and opposing finger and twist the push rod.

 There will be a point when you can no longer twist the push rod. Back off the rocker adjustment till the push rod can barely be twisted with your fingers. Then just tighten up the rocker adjustment 1/2 turn.
 With no preload on the hydraulic lifter, they may clatter like an old typewriter.

    On Wednesday, February 14, 2018, 6:42:43 AM EST, Hugo Miller via VirtualVairs <virtualvairs at corvair.org> wrote:  
 Is that correct? I speak as a Brit and a total newcomer to these engines - I have seen such a procedure described for TIMING camshafts (and I find it hopelessly inaccurate - when does a pushrod become 'tight' to turn?). But I've never heard of valves running under pre-load?

Joe - The cold adjustment involves setting the engine to TDC (at the end of the compression stroke) for each cylinder and go through the firing order. 
1-4-5-2-3-6. When the cylinder is at TDC, you back off the valve adjusters
(both) until you can easily spin the pushrods between your fingers (Thumb and pointer). Then tighten them down until you take out the slack. The pushrod will be hard to turn. Then give it your pre-determined preload, often 1/2 a turn. Do both the intake and the exhaust, then move to the next cylinder. That is it.

Please advise standard cold valve adjustment procedure.


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