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<p>Um,, no. If you rotated the distributor rotor 360 degrees, you
were at the same stroke. Remember, the crankshaft turns twice as
fast as the camshaft, but despite the Corvair actually driving the
distributor off the crankshaft, instead of like most every other
engine out there in which the distributor is driven off the
camshaft, the Corvair distributor , like all 4 stroke
distributors, turns half crankshaft speed, so 360 degrees of rotor
is the same stroke of the cylinder's piston. i.e. when the rotor
points to #1 spark plug tower, it is always going to fire the #1
sprk plug on the compression stroke.</p>
<p>You need to turn the crankshaft 360 degrees to get the two
different strokes (end of compression and exhaust).</p>
<p>Frank DuVal<br>
</p>
<div class="moz-cite-prefix">On 3/3/2017 2:47 PM, Dan Weiss via
Novacc-list wrote:<br>
</div>
<blockquote cite="mid:rZNT1u00y4cttDi01ZNZLx" type="cite"><font
face="Arial, Helvetica, sans-serif" color="black" size="2">Ran
leak test again. First time at 60 % leakage. Rotated rotor 360
degrees. Second time read 66% leakage. Air flow out exhaust.
<div><br>
</div>
<div>Would the 60% indicate the compression stroke, and the 66%
the exhaust stroke?<br>
<br>
<br>
<div
style="font-family:arial,helvetica;font-size:10pt;color:black">-----Original
Message-----<br>
From: Dan Weiss via Novacc-list
<a class="moz-txt-link-rfc2396E" href="mailto:novacc-list@corvair.org"><novacc-list@corvair.org></a><br>
To: novacc-list <a class="moz-txt-link-rfc2396E" href="mailto:novacc-list@corvair.org"><novacc-list@corvair.org></a><br>
Cc: Dan Weiss <a class="moz-txt-link-rfc2396E" href="mailto:dkakd@aol.com"><dkakd@aol.com></a>; bryan
<a class="moz-txt-link-rfc2396E" href="mailto:bryan@skiblack.com"><bryan@skiblack.com></a><br>
Sent: Fri, Mar 3, 2017 1:09 pm<br>
Subject: Re: [NoVa-Corvairs] Noob May Need a Good Used Head<br>
<br>
<div
id="AOLMsgPart_1.2_c882b6f6-692d-44e4-96e4-c365385ab44e">
<div class="aolReplacedBody"><font face="Arial, Helvetica,
sans-serif" color="black" size="2">Bryan,
<div><br>
</div>
<div>Thank you for your input. </div>
<div><br>
</div>
<div>If I understand your first point, I may need to
rotate the nut on the harmonic balancer until the
rotor comes back around to the position for the
second cylinder. Had not thought of that. I have
been turning the nut clockwise. Should manual
advancing of the crank be done in only one direction
regardless of which one? I read somewhere that if
you go over where you want timing marks to meet, you
should not go backward, but make another rotation. I
know that the timing marks are only for cyl #1.</div>
<div><br>
</div>
<div>Yes, it has electronic ignition. Everything in
your middle point flew over my head ;-}, but the
above is pretty much all moot as to diagnostics in
this instance but great for my edification on
corvairs. </div>
<div><br>
</div>
<div>I would be reluctant to go through all the work
with one of "unknown history." Clarks quoted $150
for good used heads, which several have said is
really high. Any idea what it should cost to
rebuild a head and where to go? One vendor quoted
$1500 to rebuild both heads. Does "if it ain't
broke, don't fix it" apply to the other head, or
should both be rebuilt at the same time?</div>
<div><br>
</div>
<div>Apologies for all the questions, but really at
the start of the learning curve with this.</div>
<div><br>
</div>
<div>Dan</div>
<div><br>
</div>
<div><br>
<br>
<br>
<div
style="font-family:arial,helvetica;font-size:10pt;color:black">-----Original
Message-----<br>
From: Bryan Blackwell via Novacc-list <novacc-<a
moz-do-not-send="true"
href="mailto:list@corvair.org">list@corvair.org</a>><br>
To: Northern Va Corvair Club <novacc-<a
moz-do-not-send="true"
href="mailto:list@corvair.org">list@corvair.org</a>><br>
Cc: Bryan Blackwell <<a moz-do-not-send="true"
href="mailto:bryan@skiblack.com">bryan@skiblack.com</a>><br>
Sent: Fri, Mar 3, 2017 12:21 pm<br>
Subject: Re: [NoVa-Corvairs] Noob May Need a Good
Used Head<br>
<br>
Hi Dan,<br>
<br>
A couple of thoughts:<br>
<br>
First, you're right, the head has to come off. The
compression check shows zero. On the leakdown
test, it may just be you had it on the overlap
instead of compression, don't forget it's two
engine revolutions per cycle.<br>
<br>
One other bit - as I recall you have an electronic
ignition. On those you don't want to pull plug
wires for the test, it's better to sneak a probe
down the boot on each distributor wire and ground
the cylinders one at a time.<br>
<br>
Finally, I've reached the point that I don't trust
used unknown history heads. IMHO, if the head is
coming off, I want to put a rebuilt one with fresh
seats in it's place. In any case, you should
verify which casting numbers are on the engine so
both sides match.<br>
<br>
--Bryan<br>
<br>
> On Mar 3, 2017, at 12:04 AM, Dan Weiss via
Novacc-list <novacc-<a moz-do-not-send="true"
target="_blank" rel="noopener noreferrer"
href="mailto:list@corvair.org">list@corvair.org</a>>
wrote:<br>
> <br>
> Pulling one plug wire at a time, removing the
wire for #2 Cyl produced no difference, so it
seemed the problem was the same cylinder the Ranch
found in need of some attention.<br>
> <br>
> Compression test was done on each cylinder.
First test was without having throttle open
(forgot about that); second test was with throttle
open for each cylinder. Open throttle produced a
range of 2 to 7 additional PSI of compression.<br>
> <br>
> Here are readings:<br>
> <br>
> CYLINDER FIRST TEST SECOND TEST<br>
> 2 0 0<br>
> 4 143 145<br>
> 6 150 157<br>
> 1 140 143<br>
> 3 157 164 <br>
> 5 151 156<br>
> <br>
> Onto the leak down test.<br>
> <br>
> Did the best I could to get cyl #2 to TDC by
aligning the rotor under the cap with the #2
contact. First attempts read close to 100%.
Further adjustment seemed to tighten things up and
tests consistently read right on the yellow and
red section divider at about 71% cylinder leakage.
I made sure to turn the regulator so the gauge
read 0% before connecting it to the cylinder. The
gauge immediately read 71% leakage and stayed
right there. I turned the regulator clockwise to
allow for airflow from the compressor, and the air
was flowing out the exhaust pipe. What surprised
me was that if I did achieve TDC, with the air
leaking out the exhaust, I thought the rocker arm
in the pic would have been with the exhaust valve,
but as you all already know, that is the intake
valve.<br>
> <br>
> Does it seem that the leak down test was done
correctly? <br>
> <br>
> Obviously, regardless of the leak down test,
the head has to come off to be replaced or
repaired. I plan to pull the valve cover off to
see what may be going on under there tomorrow or
Saturday..<br>
> <br>
<br>
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