[Healeys] Cam and crank gear timing update

[warthodson at aol.com]

Mike,
Your description refers to #4 cylinder being at the end of the exhaust stroke
& at TDC both of #4's valves will be partially open.
But Bill's message refers to #4 cylinder being on the compression stroke &
neither of #4's valves are open.
In your scenario, we would be adjusting the valves on #1 cylinder. In Bill's
scenario we would be adjusting the valves on #4 cylinder.
I thought the discussion was about setting the cam timing!
Gary


-----Original Message-----
From: Michael Salter <michaelsalter at gmail.com>
To: warthodson <warthodson at aol.com>
Cc: healeys <healeys at autox.team.net>
Sent: Sun, Nov 11, 2012 8:19 am
Subject: Re: [Healeys] Cam and crank gear timing update


Bill's message is missing a bit of information I think.
When #4 cylinder is "on the rock" you set the clearances on #1 cylinder...
In most 4 stroke engines, at the end of the exhaust stroke the inlet valve
opens before TDC and the exhaust valve closes after TDC .
that means that at TDC at the end of the exhaust stroke both valves are open,
at least partially.
As you move the engine back and forth past that TDC point the valve rockers
for #4 cylinder will "rock" i.e. one will open as the other closes hence the
term "on the rock".
When that is the case when #4 is "on the rock" #1 cylinder is at the top of
its compression stroke. At that point the cams (on the camshaft) for #1
cylinder are both pointing away from the lifters for the valves of #1 cylinder
which is where they need to be for setting the clearances.

Michael Salter

I have body panels check here




On Sun, Nov 11, 2012 at 8:59 AM,  <warthodson at aol.com> wrote:

I understand the statement below, but I am not familiar with the term "on the
rock". Does anyone know the origin & exactly what does it refer to?
Gary Hodson


-----Original Message-----
From: WILLIAM B LAWRENCE <ynotink at msn.com>
Subject: Re: [Healeys] Cam and crank gear timing update

A point of clarification: when you set the camshaft to "on the rock" on the
number four cylinder you are setting it so that both of  the valves on number
four are closed. In other words you are setting it so that number four
cylinder is on the compression stroke.
Bill Lawrence
BN1 #554
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--
Michael Salter

                         I have BJ8 water pump kits!!