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I'm referring to the measuring lift, not max lift. IE measure at
0.010 or measure at 0.050.<br><br>
Tony<br><br>
At 12:55 PM 12/23/2016, Ken Suhre wrote:<br>
<blockquote type=cite class=cite cite="">" I'm pretty sure that
<br>
an intake normally opens before top dead center, so if it was <br>
supposed to open to 0.050 lift at 20 degrees before top dead
center,"<br><br>
Tony, didn't you want to say 0.500 lift?<br><br>
<br>
<br>
<font size=2><b>From:</b> Tony Drews via Fot
<fot@autox.team.net><br>
<b>To:</b> jerryvv@roadrunner.com; Duncan Charlton
<duncan.charlton54@gmail.com> <br>
<b>Cc:</b> Duncan Charlton via Fot <fot@autox.team.net><br>
<b>Sent:</b> Friday, December 23, 2016 11:33 AM<br>
<b>Subject:</b> Re: [Fot] Kastner F cam<br>
</font><br>
If you are putting in 4 degrees of advance, you want the valve <br>
opening 4 degrees of crankshaft rotation earlier than whatever spec <br>
you're following (0.010 lift or 0.050 lift or whatever). The
degrees <br>
are confusing because you have the "Before" and
"After" degrees (BTDC <br>
- Before Top Dead Center and ATDC - After Top Dead Center) - for one
<br>
you add the 4 degrees, for the other you subtract it. I always
spend <br>
about 5 minutes figuring out which way to go. I'm pretty sure that
<br>
an intake normally opens before top dead center, so if it was <br>
supposed to open to 0.050 lift at 20 degrees before top dead center,
<br>
4 degrees of advance would have it opening at 24 degrees before top <br>
dead center. It would also close 4 degrees earlier. If close
is <br>
supposed to be 50 degrees ATDC, 4 degrees early would be 46 degrees <br>
ATDC (no one would close the intake that early I'm pretty sure). I
<br>
guess you add the advance to the "before" and subtract from the
<br>
"after" settings.<br><br>
When I degree a cam, I measure both the open and close events. If
<br>
the cam isn't ground PERFECTLY to spec, if you only measure opening <br>
you may end up with more or less advance than you expected. So
<br>
average the open / close to get the centerline in the right spot.
If <br>
close is 4 degrees early when open is on spec, you really have 2 <br>
degrees of advance already. I have a hard time explaining it so
it's <br>
clear - but it's clear in my head... :)<br><br>
Tony Drews<br><br>
At 08:46 AM 12/23/2016, Jerry Van Vlack via Fot wrote:<br>
>Friends, can someone explain installing a cam with xx advance, <br>
>somewhere I saw a reference to doing a cam installation with a 4
<br>
>degree advance. Does that mean that if the valve opens at xx degrees
<br>
>that it should be set to open at xx minus 4 degrees and what purpose
<br>
>does that serve? Is this the same as using .010 or some other <br>
>checking clearance. Seems that these two variables are related and
<br>
>one should use one or the other method but not both. Thanks, I'd
<br>
>like to learn more about this stuff. JVV<br><br>
<br>
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