<VV> Help - Convention Attendance at Risk!

Wed Jul 11 10:17:09 EDT 2012

Jeff,

I had a very similar problem as yours with my '66 Monza 110/pg.  It would
run fine until it got warmed up, then it would cough and bog when I tried
to accelerate.  The bogging occurred when I was traveling at speeds in the
40+ range.  If I accelerated gingerly (eg 1/2 throttle or less), everything
was fine.  Everything was also fine when just cruising around town.  Like
you, I replaced everything (well, maybe not quite as much as you).  In the
end, the problem turned out to be electrical.  It was the plug wires that I
thought I'd replaced, but found still stashed away in the Clark's box they
came in.

Please don't interpret this as saying it's your plug wires, but look for a
possible electrical cause (don't give up on fuel related possibilities).
 My best diagnosis of my situation is that the wires (they were original)
began "leaking" when warm or they opened up.  I should have, but did not,
raise the engine lid on a dark night after the car was warmed up and the
problem appeared.  This might have revealed a corona around the leaking
area.  Of course the leaking could have been occurring under the top shroud
or the internal resistance could have gone way up.  Give the dark night
test a try and see what you find.  Have a friend rev the engine while you
watch.

If you don't see anything, have a Corona (w/lime) and think of a different
approach.

Dave Keillor

On Wed, Jul 11, 2012 at 6:55 AM, Jeffrey B. Aronson <jrh at foxislands.net>wrote:

> Sorry in advance for this long email, also a post on the Corvair
> Center/Corvair Forum!
>
> I'm having a long stretch of continued running problems with my '66
> Monza 110/4; now it's making my attendance at the Convention questionable.
>
> The core symptoms are that the car will start and run quite well for
> approximately 15 minutes - nice idle, smooth acceleration, good power -
> and then cease to accelerate. Pressing the throttle to the floor will
> result in a tremendous "bogging."
>
> The only way to pick up and hold speed is to feather the accelerator to
> slowly build speed. The car doesn't just slow down, it wants to die off
> the side of the road. Unless the car sits for a few hours it will not
> run well again. It will tootle about town fine - it only manifests
> itself when it's under load at speed. When it has died, it will sputter
> to a stop. Then it will start again. A mechanic on the roadside has seen
> the carbs shoot gas when punching the accelerator - so have I.
>
> The car has 129,000 miles on it. I've had the car since 2007 and have
> put about 15,000 miles on it since its purchase. It did not exhibit
> these symptoms until the past year.
>
> A leak-down test yesterday revealed no cylinder blowby in any cylinder.
> All the plugs looked the same - dry and a bit black from running around
> town too often - both to me and more experienced Corvair enthusiasts
> [thank you Dirigo Corvairs].
>
> I've tried to tackle this in sequence to diagnose the problem
> effectively, to determine whether the problem is fuel or spark, or some
> combination of the two. Here's what's been replaced [so far to no avail]:
>
> -New spark plug/coil wire set [Clarks]
> -New coil [Clarks]
> -Rebuilt distributor [Clarks]
> -New points, cap, rotor, condenser (replaced twice) [Clarks]
> -New engine wiring harness [Clarks]
> -Rebuilt carbs [Clarks]
> -New fuel lines from sending unit to carbs
> -New filter sock
> -In line fuel filter
> -New fuel lines in engine compartment
> -Replaced Facet electric fuel pump twice, then removed the pump altogether
> -Replaced mechanical fuel pump twice, now running only on mechanical pump
> -Gas tank drained examined with scope and pronounced clean
> -Filter stones completely clean
> -Carbs balanced and synchronized by an experienced tuner and confirmed
> by a Unisyn.
> -Exhaust "doors" open when the car is warmed up
> -Placing my hand over each carb throat when running results in the same
> drop in rpm.
> -Running the car at speed without a gas cap does not change the running
> problems.
> -Balance tubes, vacuum hose and PCV pipe are fine and the PCV pipe has a
> tiny orifice at the vacuum hose end. It runs the same with and without
> that orifice.
>
> Since the car starts and fires I can confirm that I have spark, low
> tension and high tension. On the side of the road the car will restart.
> Cracking a fuel line at the carb shows that I do have fuel pressure in
> the lines.
>
> The coil is in the stock location and has been there since I purchased
> the car. The coil's been replaced twice with no change in running
> condition. The coil was hot to the touch yesterday when I experienced
> the problem again - but it's always been hot after running. When last
> tested it had the correct voltage when running.
>
> The car does run around town without these symptoms - the problems seem
> to be when the car is running warm [> 10 minutes] and under highway
> speed load.
>
> The car needs to earn its keep as a work vehicle [4 hours of driving
> once a week] and I want to keep my reservation and registration at the
> Convention. Has anyone else experienced this problem and discovered a
> solution not on my list?
>
> Thanks for your advice,
>
> Jeff Aronson
> Vinalhaven, ME 04863
> www.landroverwriter.com
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-- 
Dave Keillor
Technology Concepts
507-529-2955 (direct)
507-254-6390 (cell)