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Missing and getting worse

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Dadandson

Dadandson

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It started a while back and only when the motor was cold. I would accelerate and the motor hesitates. I dismissed this as a cold motor. Now it is getting much worse when I accelerate. The funny thing though, at high RPM's such as the freeway at 60 MPH, no problem. I checked the feul pump and fuel filter and they are okay.I am thinking Carbs but would like to have a knowledge in my pocket before I start repairing the anything. Opinions please?
 
I went through this a few months ago with my Bugeye and went through a lot of parts before it was fixed. Look at your points, condenser, distributor cap/rotor and plugs & wires. I changed all of these things and it wound up being a small hole in the plug wire boot (the wires were only a year old too) and I was getting some arcing between the wire and engine block. It too seemed to drive OK at higher RPM's, but stumbled terribly around town.

It is also possible the carbs are giving you problems too. I replaced mine due to worn out throttle shafts and it drives so much better now. However, the carbs were not what was causing my problems.......it was the plug wires, so again.....look at everything electric in the ignition and go from there. It might not be a bad idea to replace the points & condenser anyway.....they're cheap enough to do.
 
Question, does it miss when you rev it up when stopped? If so is it one particular cyclinder or is it random? If it misses every time you rev then you need to determine this. If its random then check points and condenser area. If it is one particular cylinder then check plug wires, replace the plug and see if that helps. If not and it keeps missing it might be a valve. A cracked valve will miss at an idle and in a pull but tend to smooth out at higher rpms depending on the size of the crack, because the compression can't leak past the crack as fast at high rpms becasue it doesn't have as much time to leak out and the cylinder does fire a bit but not well.
 
I will examine the points and condenser. I have been toying with the idea of a Pertronix Flamethrower Dizzy. Now might be the time. I have never changed a dizzy. Is there any step by step instructions available?
 
Just as a matter of course, I'd change the plugs, points and condensor. And look inside your distributor cap for any obvious carbon paths.

And, as was mentioned, look at your plug and coil (high tension) wires carefully.

A good way to spot high voltage "leakage" from plug wire is the following:

Park the car in a dark area at night with the hood open and engine running. Use a spray-mist bottle (like a Windex bottle) filled with water to 'mist" over the engine. If there are high voltage paths leaking current, you'll proably see them this way...it may even light up like a Christmas tree (sometimes, having an assistant rev up the engine will make this more obvious).
 
If you haven't already read it, there is a very good step-by-step on possible sources of a stumble or miss, in this month's Practical Classics. All of the above suspects (and more) are discussed.
 
Do you have the correct amount of damping oil in the carbs?
 
Something to keep in mind. 90% of electrical problems are really fuel problems and 90% of fuel delivery problems are electrical. Since it SEEMS like an electrical problem, i'd be looking at the carbs. Tims CHECKING THE DAMPER OIL is the first place to look. Then the floats. THEN the CAP and Rotor. Always assume the easiest and cheapest thing to fix is the problem, and work your way up to the complex and expensive parts. Changing the Dizzy would probably be among the LAST things to examine, UNLESS you just WANT a new one. For that you don't need the excuse of fixing a miss!!!
 
The damping oil is okay. I will check the points, condenser, rotor, cap and wires. I will also check the floats. I have tested the fuel pump and filter using a glass jar and they are okay. I don't subscribe to Practical Classics, not that I don't want to, it's that I did not know about the magazine. And yes, I want a new electronic dizzy. Thanks for everyones help.
 
Dadandson said:
And yes, I want a new electronic dizzy. Thanks for everyones help.
Click to expand...

Fix the prob before the new dizz. Save yourself some frustration (been there).

This sounds like it could also be a bad condensor.
 
Although rare, I practically tore a GT6 engine apart trying to solve a missing problem.

After about two days of work, I finally discovered an almost imperceptible hairline crack in the distributor cap.

That was it! New cap, no problem.

Good luck, let us know . . .
 
I would replace points, plugs, wires, rotor, cap, and condencer before I did anything else.
 
Could be the coil. Moisture time heat it could be failing.
Could be a crack at the high tension side thats jumping to the low.I would try the Misting with water in the dark.
Its a great way to find Ingtion Leaks as stated above.
 
I checked the point and somehow the clamp screw came loose and I had little or no gap. Re-gaped and it appears to have fixed the problem.
 
AHA,.. the CHEAPEST thing is the first place to look. Zero cost repairs are the best kind.. Still gonna buy that DIZZY? No more loose screws!.. ..

So your options for the electronics are...in order of cost.

Pertronix points replacements doo-dah.
Crane Unit
Pertronix DIZZY
123 DIZZY

Keep us informed about your decision.
 
Took the car out last night. Started out great but then the miss slowly started again. I will check the points today. I tightened the snot out of that little screw. Flamethrower is really becoming an option.
 
Did you set the points on the bench or in the car? It can be a real pain in the neck (back) to try to do it leaning over the fender, but it's easy as out of the car. you can also get the little screw a little tighter, or maybe use a dab of BLUE LOC-TITE?

But oh yeah, you WANT the Flamethrower Dizzy! Be SURE you have a 3 ohm coil to go with it. Pertronix makes a at least two differently rated coils (not counting black or chrome).. but you'll HAVE TO HAVE the THREE OHM. Same if you decide to go with a CRANE unit.
 
Did you lubricate the cam with a touch of distributor grease? If not you could be wearing the rubbing block of the points quickly.
 
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