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

Larry Forman larry at forman.net
Fri Nov 18 22:01:30 EST 2011


Ramon,
The vacuum advance unit you pulled out was working better than the one 
you replaced.   The one that pulls in at 5 inches of vacuum has a very 
tired internal spring.   It can be fixed by removing it and dimpling the 
metal area around the vacuum nipple with a 9/16" deep socket drive.  You 
should replace the one that pulls in at 8 inches of vacuum as it is 
working closer to how it should work.

Larry Forman

On 11/18/2011 2:51 PM, Ramon Rodriguez III wrote:
> 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!



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