[FC] Vacuum advance issue -

[Bruce Gwyther]

It sounds like you have the distributor vacuum hose connected to the wrong 
port.  The correct one is the vertical pipe fairly close to the idle 
adjustment screw. below that is a horizontal pipe (same size) that should 
have a short hose going to the choke pull-off.  The distributor gets ported 
vacuum depending on engine speed.  The choke pull-off gets manifold vacuum. 
If distributor gets manifold vacuum it will advance the spark at idle and 
may even be the cause of low vacuum at idle.  Only the carb on the passenger 
side goes to the distributor (the carb port on the drivers side is to be 
plugged off).
The choke ports must be either plugged off or connected to properly working 
choke pull-offs.
                      Bruce Gwyther
                      Bonneville Corvair Club of Utah

----- Original Message ----- 
From: "Jeff Brylow" <jeffbrylow at gmail.com>
To: <corvanatics at corvair.org>
Sent: Wednesday, August 29, 2012 11:11 AM
Subject: [FC] Vacuum advance issue -


> Folks - First issue - I've been attempting to dial in the engine in my '64
> Greenbrier for some time now and have an issue that has me stumped. Quite
> simply the vacuum advance seems to be performing too well! I'm 
> experiencing
> hesitation on take off and I believe excess spark advance may be the 
> issue.
>
> With the vacuum line disconnected, as is called for during the normal
> timing procedure, I can time the engine, vehicle in drive, right at 13
> btdc.  Then when I hook up the vacuum advance line from the carb, I
> immediately get at least 10 degrees of advance at idle. I've tried  three
> different advance units all with the same results.
>
> Some facts to help with any offers of help  -
>
> Engine  code- "ZB"  '61 - '62  80 hp
>
> carb codes - left bank 7020101 / right bank 7019110
>
> distributor - # 1110272 / vacuum advance #951
>
> head # 3786588.
>
> Second issue (related to first issue?)  - I'm only seeing 5-7 in. hg at 
> the
> carbs with my vaccum gauge and the truck actually seems to run quite well
> here. This is with the curb idle set at 1-1/2 turns in per factory 
> setting.
> Many sources state we should see 14-18 in hg.
> .
> Third  issue (question) - I ran a compression test recently - results  as
> follows - #1 - 140# , #2- 145# , #3 - 142# , #4 - 141# , #5 - 157# , #6 -
> 140#. These numbers seem a bit high to me. Are these numbers normal for a
> 80 hp. engine?
>
> Thanks,
>
> Jeff B. - Wisconsin
>
> '64 Monza sedan
>
> '64 Greenbrier
>
> '62 Greenbrier Deluxe (running parts car)
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