<VV> update and review- engine hesitation (was accel pump adjust and many others)

Ramon Rodriguez III corvairgrymm at gmail.com
Fri Nov 18 17:51:11 EST 2011


Alright, after installing the richer jets last night the car still had the
hesitation this morning.

Today when Missy got home I pulled the car in to try something else... I
couldn't remember exactly where I had set the timing so I decided to check
it and make sure I was on the high side of spec, and found that the timing
was WAY advanced at idle... pulled off the vacuum hose and it was still WAY
high....   I had set the timing just yesterday and ALWAYS check it after I
tighten the nut.  This lead me to check the dwell/points gap which I also
set yesterday.... dwell was VERY low (around 20deg.).  Apparently it
adjusted itself.... meaning I didn't tighten down the screw enough I
suppose.  I'd had this problem with this car before but it was a different
engine and a different distributor and a different points plate!!!!

Anyway, since swapping the electronic out for the points day before
yesterday did not change things at all I decided to reinstall the Ignitor I
instead of set dwell again.  The car is running fabulously right now...
just like new, we'll see if it is still that way tomorrow since the trend
has been that after I think I have it fixed it acts up in the mornings when
Missy goes to work but I'm pretty confident this time.

Now for those following this for their own information:  The only changes
I've made since it was hesitating badly WITH the Ignitor are changing the
vacuum advance unit (the one on it didn't start coming in until 8 inches
vacuum, I installed another that starts moving at around 5), and changing
back from the 49 jets to the 52's that were in it before.

I'm pretty confident (assuming it STAYS fixed this time) that the change
that made the difference was the jets.


Now for the full review:

The car would not idle at a nice low RPM and was hard starting.  I removed
the 52 jets and installed the 49's that it had from the factory (though
these are 65 up carbs and it was a 63 engine).  I also adjusted all
linkages etc. on the carbs to factory spec (many were way off). I don't
think I made any other changes at that point.  The following day the car
had a low battery and wouldn't start.  I jumped it and got it started, left
home and drove it a very short distance until it started performing poorly
and pinging badly as soon as the chokes started opening.  Stopped the car
to let it cool a bit so I could get it back to the house (only about 2
miles) and it died before I even hit the key.  The car was then VERY hard
starting.  It cranked very slowly, presumably a bad battery.  Tried jumping
it and it was still very hard to start.  Once it was running it would
always die instantly upon putting it in drive.

Towed it home and got a new battery.  Started tinkering and it wouldn't
idle below near 1000 RPM in drive plus died most of the time when dropped
into gear.  Did lots of testing, replaced nearly the entire ignition system
with on hand parts plus bought a coil and an Ignitor I and installed that.
Problem persisted.  I did a bunch of testing and found that the left bank
was making only about 6 inches of vacuum at idle vs. 16 or so on the right
bank.  Did compression test and discovered ~ 90lbs compression left bank
vs. 150 right bank.  Decided to swap in the engine from my 62 which I have
not yet driven but idled beautifully and made good vacuum.

After the engine swap the car started and idled beautifully (with the same
set of carbs as before the engine swap) but had a very bad hesitation
(often stalled) when accelerating from a light or stop sign.  Observed that
the car ran fine on choke and adjusted chokes to stay on longer.  Car still
hesititated/stalled on acceleration once the chokes opened up.  Recalled
that all this trouble started when I changed to leaner jets and associated
that with the fact that the car ran well on choke and decided the car
wanted more fuel where I originally thought it wanted less (and thus went
to smaller jets).  Still wondered about ignition so swapped points back in
with no change.  Observed that when accelerating if I floored the pedal
really fast and let it up (accel pump squirt) then accelerated normally the
car drove great... considered this confirmation it was running too lean.

That brings us to yesterday.  Installed the bigger (52) jets again and test
drove it (still on points installed and adjusted the day before).  It drove
pretty well when I pulled it out of the shop for a test drive.  This
morning Missy took it to work and it stalled on her 3 times at stop signs.
When she got home I pulled it into the shop to check it out.  Based on
something someone on VV said I checked the vacuum advance and it was not
responding quite as quckly as it should (not moving till 8 or so inches
vacuum).  Didn't think it very likely this could cause such a bad
hesitation and stalling but swapped it out for a better one.  Before
pulling the car out I checked the base timing and found it advanced way off
the scale... which was crazy considering I set dwell and timing yesterday
before installing the smaller jets.  Checked dwell (with meter) and found
it was very short (20 deg.).  Checked the plate and found the screw was not
quite as tight as it should have been and I guess just loose enough for it
to move after a bit.  Removed points plate and installed Ignitor I to solve
the dwell problem rather than adjusting dwell again.

Test drove, ran absolutely perfect.  I think the key was changing to richer
jets, and this mornings stalls etc. were caused by the dwell self
adjusting.  The real test will be tomorrow morning.

Hope this helps someone else in the future!
-- 
Ray "Grymm" Rodriguez
Lake Ariel, PA


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