Technical 1946 59AB - Intermittent Stumbling Under Load

Closing the choke will richen the mixture to help cold starting. Doing so with the engine at operating temperatures will cause flooding, poor driveability and stalling. After opening the choke back up it can be difficult to restart and maybe take a bit of driving to dry out the fuel soaked spark plugs. If severely flooded it may be advisable to remove the plugs and crank the engine over a few times to help drying out the cylinders.

It's not necessarily a fuel only problem. You might still have some other ignition or mechanical issues to consider if your problems persist.

 

Stick with the Holley! Providing it was properly rebuilt it runs just as well.
A misfire can blow a perfectly good power valve.
Fuel pressure!
Get a cheap pressure gauge at harbor freight and check your pressure before changing your fuel pump. Check it at different rpm ranges. 1-1-1/2 to 2-1/2 pounds max.

 

So I have my distributor apart and the points as well as the inside of the cap were very corroded. The rotor was very brittle and broke in two. I’ve ordered some new parts - A new cap, as well as a crab style cap, as some have said it’s easier to deal with. Crab rotor too. I have take the spring and plunger out of the vacuum brake to determine if this is part of the problem. I also have removed the plate that the brake made contact with, as this was recommended by several folks as a potential fix. Are there sources for replacement contact plates? Mine seems to be ok, but when re assembled, the cam is fairly difficult to spin by hand and feels kind of bound. That said, I’m not sure whether it should spin freely by hand or not. So….now I wait until the parts arrive Saturday to put it back in and set timing, etc. hopefully I can get it running smooth again.

 

Aha. . . . 90% of your fuel problems are ignition related

 

Did you at least file the points if you didn't replace them when you did the condenser?

 

Here’s a pic of my old cap. A couple of questions for the group: Should I be able to freely spin the distributor when assembled, mine is super tight once I put the retaining clip in. 2. Can I use the same spark plug wires if I switch to the crab cap? Lastly, if I elect to use my replacement standard cap, any pointers on how to easily get those spark plug wires back into the cap. With little slack, it seems to be obvious why people go to the crab.

 

The only thing holding the distributor shaft back is the rubbing of the point blocks, and the vacuum brake. Loosen the big nut of the vac brake and pull it out. Then you will just have the slight drag of the points. At least that’s what you “should” have.

 

Having just done the conversion from the later round style to the crab I can say do the crab conversion and don't look back. Also I chased an issue for months that ended up being plug wires that looked brand new but upon closer inspection were junk, just go with new wires so you know they are good.

 

There definitely is “slight drag” before I put the retaining clip in. Afterwards, it is difficult to turn by hand.

 

I still think that if the problem is ignition related, it's usually consistently bad. Not intermittent. Good to get the ignition system up to snuff. But I suspect you have debris floating around in the carburetor bowl, plugging the jets whenever they feel like it.

I did have an intermittent ignition problem once. The insulation was worn on the wire going through the body of the distributor. And it was intermittently grounding out.

 

Don't forget you need the proper dist cap clips when changing to the crab cap. Yes you can re-use your plug wires.

Dave

 

Distributor is installed with new crab cap, points and condenser. Now I have no spark.... it just cranks, but won't fire. Pulled plug wire and not getting any spark. Not sure what went wrong. Now to remove and troubleshoot.

 

You didn't mention rotor. The crap cap has a different rotor than the later round style cap. Hopefully your issue is something that simple.

 

Rotor was replaced also with correct crab version.

 

Tell us how you set up the distributor. On a machine? Static fixture? Straight edge method? If points are dialed, I would be looking at condenser. I put one on the other day that was included in a coil conversion kit for a coil on distributor for a friend. It popped and such and then would not fire at all. I got out my box of condensers, closed my eyes and grabbed one and installed. Lit right off and ran as it should.

 

I used the straight edge method. It was my first time doing this, so I’m fully prepared for it to be my error. I did change the condenser previously and it started to run like a dog turd. That’s when I decided to replace points, and now the cap, etc. I’ve just returned from a weeks vacation. I’ll be taking everything apart to try again…..

 

I also forgot to mention that I did take out the vacuum brake and the plate inside. I may need a pointer on how to plug the port.

 

I took it all apart. Did everything all over. Put it all back. It started right up! Now for a test drive.

 

Ran pretty good. Definitely no hesitation or choking out like before. Idles nice with no skips. That said, when accelerating, it did sound a little different. Perhaps a little bit like the timing needs to be adjusted. It just didn’t feel or sound as smooth as at idle. Again, I’m no mechanic, so my non technical description is pretty useless. Just glad she’s running again. So far with no problems.

 

Took out, but then replaced, right?

 

I did not replace the vacuum brake plunger and spring, based upon several sources stating that taking it out, as well as the internal plate which the brake's leather pad pressed against, solved their intermittent timing fluctuation.

 

I guess that’s hot rodding. Much smarter than Henry Ford. You are in uncharted waters now, unless those two guys who recommended that mod can give you advice.

I actually think the vac brake does the opposite. By reason it will provide a more consistent resistance and should smooth the system.

 

Time will tell. I plan to give the vehicle a longer test this evening. Hopefully some higher rpm than just putting around the neighborhood.

 

Ran the car last evening. Started well and ran pretty good with no hesitations or sputtering like before. I ran for about 20 minutes, in the range of 25-45 mph. That said, as expected, without the vacuum brake installed it did get warm faster than usual. Temp gauge never went past the center of normal range, but it rose much faster than usual. I plan on putting it back together with the plunger and spring in place. I could use a tip on how to fashion a new pad for the plunger, as mine is worn (in multiple directions, so it must have been rotated several times) and the pad is fairly hard. What should the consistency be? Is anyone making these?

 

Found a new plunger on eBay. It showed up. Hard as a rock. Just like the one I took off. The new one is on the left. The old one is VERY hard. Nearly brittle. Diameter is same but the old one is taller. Anyone know of the height makes a difference? Obviously, the adjustment will differ, but just wondering which is “correct”. I’ll try to soak them in leather conditioner to soften and try.

 

The height doesn’t make much difference, just be sure the leather will hold the plunger away from the disk.

 

Carefully check the plug wires in the dark. If there's any leakage outside the conduits, you will see it. It could be leakage inside the conduits. Running plug wires bunched together and inside a pipe is asking for trouble. Not one of Ford's better ideas. Pulling a load puts more stress on the ignition plug wires and leakage does just what you are experiencing. Also double check the actual fuel level, not the float level, in the carb with the engine running. Top of the fuel needs to be 11/16" below the top of the fuel bowl with no gasket. It takes a special tool to set this, which I have described in previous posts, and how to make one yourself. They can't be bought. The carb kits they sell for these are one size fits everything but they're more proper for the Holley 2100 series carbs. The float gauge in the kits is confusing and pretty useless in my opinion. If you would like to make a fuel level tool, leave me a private message for help.

 

Installed the vacuum brake and disk. Idles decent. It immediately started to miss and vibrate with any throttle raising the rpms. Just like before. The brake is fully adjusted out. Super annoying. Is the plunger too loose, causing the misfiring?

 

The way to set the plunger is to go about 35-40 mph in second, then stomp on it. If you get pings, tighten the top bolt in a bit (half turn?) and try again. Stop adjusting when the pinging stops.