64 Gal misses while at cruise speed

My 64 Gal misses at cruising speeds. I've replaced points, condensor, spark plugs and wires, rotor cap and roter. At idle in Park, it purrs like a kitten even at higher RPMs. Any help with this would be great.

 

I'd check for a vacuum leak first. Then check the dwell of the points.

 

Gapped the points at .018 and Autolite 46 spark plugs at .035. Just wanted to add those details. THanks.

 

What's the best way to check for vacuum leaks? Thanks.

 

Use a can of break clean and spray along the base of the carb,intake and any hose that is hooked to a vacuum. If the motor stumbles after you spray a certain area there's your leak.

 

Factory riser between the carb and intake that has a problem with cracking. I have also had the base of the factory carbs crack. Both caused what you are talking about (intake leak). I'd check there first like Master said. Good luck.

 

If that's a factory Ford distributor, it's probably dwell changing. (advance plate is NOT centrifugally mounted on those, it is pinned from a point off-center; when changing RPM, dwell changes.)
I read that you set your points at .018". Dwell would be marginally low at that setting, so

1) Put a dwell gauge on it and adjust to idle at 28-30 degrees cam dwell angle.

2) If no dwell meter is available, reset points to .015"-.016". A "happy medium" is within grasp.

 

thanks a bundle guys...just damn irritating! I check what ya'll are talking about. When I rebuilt the carb (autolite 4100) I didn't notice a crack of any sort or crack at the riser. I will check again though. THe carb does leak a little gas at the base but I thought it would be just the gasket not seated in all the way. I'll spray around it while the car is running to see if I get a stumble.

 

It's often the vacuum advance as mentioned.
At idle, use a vacuum pump or a line from manifold vacuum and go full vacuum advance. See how many degrees it advances AND how much the dwell changes.

 

fuel filter? mine did something similar, then i found a bunch of junk from a disintegrating hose clogging up the fuel filter at the carb.

 

crank it up at night, look under hood with no light, see if anything is arcing on block

 

Is it surge? Stumbling when at speed with the pedal held down just slightly? Does it go away when accelerating? What carb?

 

Thanks again fellas....

jobbless: yes, it's stumbling when pedal is held down slightly and yes it goes away when accelerating. It's the original carb that came with it: Autolite 4100. It's been rebuilt about several months ago. Thanks.

 

O.k...I performed a couple tests from this thread...

The visual arching test at night: all wires and spark plugs are arching...I'm assuming this is good? Although some dimmer than others

Spraying brake cleaner around the base of the carb and around vacuum lines: While spraying around the base of the carb, I did have an rise in rpm. When I sprayed around the vacuum line on the back of the carb, I experienced a HUGE stumble.

So, what do I do now the young newbie ask?

 

Pull the hoses off plug the port on the carb and check again.

 

If it still does it with all the vac ports plugged then the gasket or spacer are leaking. If it foesnot do it anymore the hoses are bad.

 

Check for play in the breaker plate ( what the points attach to). It should have no side to side play. Mine was doing same thing last year right before the it quit all together. I had about .010 play and point gap was all over the place. Vacuum advance makes it worse.

 

Are you talking just watching, not pulling them off? BAD, they should not 'leak' any current!

Big vacuum leaks, others have told you how to pin it down and fix.

 

If the suggestions don't fix the problem, it is time for a compression check.

 

Alright just plugged up the vacuum port on the carb and sprayed again around the base of the carb....it still bogs...time for new gaskets. Funny thing is that I replaced the gaskets between the riser and intake and the one between carb and riser. What kind of gasket should I find to replace them with? Cork, rubber?

RodStRace, I'm just watching them flicker and dance away...Bad huh...what should I do? I even see the spark plug wires glowing as well...purty. Also, when I sprayed around the base of the carb, the RPM went up. Not good either? I know when the RPMs stumbles it bad. again...first car ever to work on.

 

Buy a good set of wires.

 

So my wires are bad and that's the reason I'm getting the arching? Damn, those are new as well. there ACCEL brand from Autozone. How about my spark plugs glowing arching as well? THose are new Autolite 46s. Maybe I don't have them tightened enough?

 

Go careful torquing plugs- go to correct torque spec, don't overdo it guessing.

I've just gone thru this exact problem with my Cleveland. I'd caught the condenser lead wire in the dizzy cap at some time & exposed the wire. New condenser- now it's running good.

 

How well do the boots fit over the plugs, if the boot is high on the plug more towards the end it will leak as juice takes the easiest path, the boot on the wire should go down on the plug and fit tight.

Some of this might help too..

http://www.permatex.com/products/au...e/auto_Permatex_Dielectric_Tune-Up_Grease.htm

 

So just to make sure I understand: I should be seeing anything lighting up? When all lights are off and am looking at the engine block where the spark plugs are, I see a flickering light and I also see electrical current traveling through the spark plug wire. THis is not good right? So in a nut shell, I should buy new spark plug wires? Just to make sure that I understand.

 

Are you seeing arcing around the plugs?? you can see the voltage going thru the wire? cool.

you shouldn't see any arcing around the plugs, that is a voltage leak

 

Yes, I'm seeing arcing around the plugs and seeing voltage going through the wires especially when they're touched by hand. Is the seeing voltage traveling through the wires a normal thing? How can I fix this?

 

When you put the new plugs in, were your hands greasy and dirty? You want to make sure that the ceramic on the spark plug is clean, and also that the plug wire is pushed firmly onto the spark plug.

Also sounds like you have a bad vacuum hose and a leak under the base of the carb.

 

I can check to see if their dirty...shouldn't be.
Questions then I'll be done with this thread:
1. Knowing that I have a vacuum leak under the carb, what type of gasket do I use to fix it?
2. Is it normal to see electrical current traveling through spark plug wires at night?
3. I get that it's not good to see spark around the spark plugs at night while at idle. How do I fix this issue?
Thanks!

 

NO, you should not see spark anywhere under the hood at night! Replace your wires, tighten spark plugs to torque spec, make sure plug wires are all the way on the cap and plug.
The carb gaskets I use are like a paper material. Any auto parts store should be able to get you the right ones.