First, car always ran smooth, problem was getting it started, sometimes to the floor and it would start, sometimes not......just so frustrating, so...contacted a member of our Corvair Club, they checked timing and put new plugs, next day I it started right up took it out but ran rough and by the time I shifted into third gear it began to buck. Got it home, guy and came, took carbs off, did find some stuff in one of them but very, very little, cleaned them, rebuilt them, put in new points, new distributor cap, put new gas filter on, checked gas from tank..all clean, got it started, ran rough and often backfired through exhaust. Came back today, did change the condenser, checked timing and dwell again, checked compression (ok), got it started, still ran rough but noticed when you pulled vacuum tube off vacuum advance it smoothed out! So, we put hose on, took it out for a drive (finally) and still began to buck now in most gears.........but at least ran. So....going to get a new vacuum valve since it might be leaking (what role that plays in the cars performance I do not know), did backfire once and am just lost, completely lost as to how a car that ran so smooth and only had a starting issue now starts ok but runs rough and bucks.
Any ideas as to what we are missing? Have no problem replacing the vacuum advance and would have no issue replacing the plug wires but it just seems strange that these things would show up out of know where as a possible cause. Know there are some good car people out there that might offer some insight...love to hear from you.

 

I don't know what you mean by vacuum valve, but, if you are referring to the EGR valve, yes, I think that would be something I would check, as it could be restricting your exhaust. Along with that, and this is in general as it's been a long time since I have had my head under the hood of a Corvair, there is probably a port through the intake manifold, where the exhaust is diverted, which could be plugged. Depending on how bad it is, sometimes you can get it out by hand, or it may need to be hot tanked, as long as the composition of the manifold allows it.

 

Thanks for responding, referring to the vacuum valve, I meant to say the "vacuum advance", it is attached to the side of the distributor. Not sure why when the hose is pulled off it runs smoother nor do I know that if in fact the advance is not working correctlly whether it could cause the car to buck, just lost. It would have been different if the car had run poorly before and did not start correctly but it always ran smooth! Just trying to search for some advice and feed back....there has to be a reason and some still say that the bucking and or backfire can be tied to timing but....maybe that vacuum advance by not working right is affecting the settings.....just do not know.

 

I just corrected the description of the valve in my post to...vacuum advance.

 

A 1963 car does not have an EGR valve.

 

If you haven't changed the plug wires, it would almost be imperative. They were carbon string wires and were notorious for breakdown. The vacuum advance changes the dwell angle as you increase the vacuum while driving, thereby changing the timing slightly to compensate for TDC error at speed.

'Cause you started "messing" with it. Those older engines only required fuel, air and spark, unlike today's engines. If you get all three in the same synchronization, it will run. Do the wires and let us know.

 

Know that, it has a vacuum advance which is attached to the distributor, not sure where you got the EGR valve from.

 

Chandler......you know that was the only thing that was not touched where the wires but for some reason felt that if they were part of the problem, then why did the car run sooooo great and so smooth when the starting was the only issue. Well, someone did say that one of the wires could in fact have failed...then of c ourse my thought was "is there a way of checking to see if one of the wires had crapped the bed and may have been causing an issue. But, since the car finally got the starting issue fixed and only the car running rough and bucking, that wire issue seemed to lose a point of conversation. That being said, I think it is a good idea to change the wires because they are the carbon filled and do not know ow long they have been in there but they sure do not look worn or old.

 

I have found these problems in ignition systems;
Point cam lobes worn so bad they barely open points
Points incorrectly adjusted
Bad condenser
Condenser not fully grounded
Rotor burned through and leaking fire
Cap cracked causing misfire
Vacuum advance not working
Vacuum advance with hole in diaphragm
Point plate losing ground when vacuum advance operates
Point plate worn so bad points go out of adjustment when vacuum advance operates
Distributor not grounding properly
Distributor shaft bushings worn so bad that point adjustment can't be maintained
And many more!
Check everything related to ignition system and repair as needed.
I don't have a '63 Corvair to look at, but it will be similar to systems I do remember.

RR

 

Rough Rooster. Thanks....we have replaced distributor cap, did replace points and condenser, plugs and checked distributor parts to make sure there were no worn rotor etc. In doing so we got the car running but rough and then found it ran better when the vacuum hose was removed from the vacuum advance which in itself could be part of the problem and have ordered a new one. The other thing that we are not sure of is whether one of the spark cables may not be doing its job, they are the mag filled, not sure how old they are and not sure if there is a way to check each of the cables to see if there is an issue with one of them.......so, may just get news ones. So frustrating to have all this happen when as I said, it ran so good, so smooth when it ran, just had lots of trouble starting it. Got to be one of those things you mentioned, just makes sense. Car never bucked before, never backfired before thru the exhaust so something is messing up the firing...I guess. Will let you know how we make out, thanks for the tips.

 

if it started to run rough after changing plugs possibly could have a bad plug with cracked insulator or one that isn't gapped correctly might want to pull them out again and inspect them.

 

Thanks for the response but the car actually ran rough after we put the rebuild carbs on and checked the timing etc. Then we replaced the plugs and the points and it still ran rough, put a new condenser in, it did run better but still not as smooth as before and found it did smooth out if the vacuum hose was removed from the vacuum advance...........then someone replied that it could have been the problem since a hole might be in the diaphram so, a new one is ordered and we will see what happens. We are also going to replace the spark wires since they are some 15 years old and they are the mag type which often crack.
Hopefully this will correct the problem..........just baffles me I go from a smooth running engine with only a starting problem to one that now starts but runs horrible.

 

When you set the timing, did you have the vacuum advance unhooked? It needs to be unhooked and plugged to set the initial timing. After it is set, you reconnect the vacuum advance. The reason for this is most engines run fine with around 30 deg of advance. However, they will not start with that much so the manufacturers set a static distributor advance of 0-8 de roughly depending on the motor. Once the car starts and produces vacuum, the advance diaphragm pulls the points plate slightly and advances the timing to where it runs good. When the engine rpm's come up, the vacuum signal drops and the mechanical advance kicks in and does the same thing. It is possible that the advance weights may be sticking in either the advanced position or not moving and allowing advance to happen. If the advance weights are sticking in the advance position then the initial timing will be way of. Where in NY are you?

 

Interesting you mentioned that and am not sure if hose was removed before timing was done but when he returns will ask. After the latest tinkering we did find the roughness almost disappeared when the hose was removed. So, that might be the culpret...maybe a hole in diaphram or as u mention something is sticking...so a new is ordered and also ordered new plug wires since there seems to be a feeling they are over 15 years old. Have my fingers crossed
From the Rochester area.

 

Smoothing out when you pull vac hose would lead me to look for a broken or bare wire inside dist.

 

Or a severely out of adjustment carb

 

Add an s on to carb......................

 

When you change vacuum advance make sure the primary wire to points is not cracked or brittle. Apply vacuum while cap is off and make sure plate on disturber moves smoothly. Owned 2 of these in the day one was a station wagon, Only wagon I have ever seen.

 

Thanks for the input, been a frustrating time....go from a car that ran perfect, just hard to start, to a car that did not run, misfired etc, replaced plugs, points, condenser distributor cap and wires....then found the vacuum advance was not good and after a few Corvair people from the club trying to help, found that at some point and haven't a clue the distributor was off a notch (or whatever you call it) and finally, fianally got it running, just had the idle adjusted yesterday and what a treat to finally drive it again. Only issue I still find is that as smooth as the engine is running, you can still feel periodic bucking.......no backfire or any tone that would suggest a misfire and now am baffled as to what might be causing that...could a clutch out of adjustment be the reason?
Thought it just needed to be driven and engine sounds good, runs good at all speeds but just feel this bucking.

 

Thanks for the help, we did get the new vacuum advance in along with new wires, plugs, points, condenser and found in the process someone we think had put the distributor in one tooth off setting the wiring diagram out of wack but, we got that squared away......car started fine, guy from the Corvair Club had to leave but took it out for a drive for the first time in two months and it seemed to run well other than the idle was way high, stopped at his house and he adjusted it, have taken the car out for the last two days and found this...idle has crept up again but, kick the gas petal and it drops; car jerks/bucks especially at 35-40, you can feel it at all speeds but very slight at like 55-60. First, never thought it was idling smooth, secondly there is not sound that suggests something is misfiring, what it feels like is it is starving for something....any ideas as to what might be the issue? Carbs were rebuilt, the club member did put a gauge on each and they were in sinc but, something still is not right and am lost.
Any feedback or ideas would be very much appreciated.

 

Do Corvair have hydraulic lifters? If not, a valve adjustment would be called for, and a cylinder leakdown test to see if there's any problem with burnt valves...

Did the same guy that put the dizzy in wrong also rebuild the carbs? hmmmm...

 

Not sure what you mean my dizzy.....if it is the distributor, we now think it was the prior owner and with it one tooth off, and wired then accordinly (not by spec) it would have run fine, but since we where doing changing the wires and hooking to the distributor by spec, that is how we found the problem.
Now, idle is an easy fix but we now wonder if the fuel pump might be the cause.....the fuel pumps over the years had issues and most carried an extra just in case. Not sure how old this one is but we are going to change it and who knows, it might hve been the cause of the problem to begin with because.....the way the car jerks.hesitates, it just feels like something is not getting enough of something! Just got back from a corvair meeting and everyone put in their two cents, some think it is still tied to the timing &advance but each time that was checked it was per spec. We will see.

 

as someone else mentioned did you check the timing to see how much total advance the engine is getting as it could be over advancing the timing helps to use a timing light with an advance wheel so you can dial it back to tdc and read the dial.
with the high idle issues maybe still have a carb problem is the chokes opening up when the engine is warm?

 

Yes, it is.

With it being only one tooth off, you would not have had to move the plug wires around, you should have had enough adjustment to just twist the dist a little bit to get the timing on the mark. And if it ran that way for a while, that wasn't the problem.

I presume you've owned the car for some time?

 

Two years, never had issues until starting became an issue, then such things as points, plugs, condenser, even plug wires were questioned as to when changed and i did not know so felt it would be wise to do it. As worked progressed, it either ran rough or really bucked, then with tweaking got better but still runs rough and still feel hesitation or jerking. Some still feel it is a result of too far advance setting........just so frustrating.

 

Have you tried adjusting the timing by ear? Sometimes on worn or rebuilt engines using a timing light doesn't get it right.

 

Good point and I will talk about that when we address the issue again this week. Going to take the car out today just to get the feel with what is happeing again so I can better talk about it. Hopefully the club will drive the car before puttering with it.

 

If the carbs aren't balanced correctly you will have a hesitation. And if anyone has accelerated the engine by grabbing the levers on either carb they are out of balance. You pull the rod coming from the front end that operates both carbs. It would take me forever to type the procedure to adj the carbs maybe you can google it.