Drivability problem

[SnowCanyon]

Newbie A owner here, glad to have found this forum. 1930 Cabriolet 68B inherited from my dad, who passed away several years ago. Only recently trailered from his home to mine in southern Utah.

After being on blocks & not having been started for about 8 years, got it running after flushing the fuel delivery system & new underdash fuel valve with stainless steel screen intake. Replaced Tillotson carb with original Zenith as it didn't want to start on the Tillotson.

Car starts & runs OK for a while, maybe 15-20 minutes or 5-10 miles, then loses most of its power and starts to backfire and may die entirely. Changes to spark advance, mixture control, or idle throttle setting don't seem to make much difference. Coolant temp stays in the 180-200 range.

Any suggestions, ideas, or thoughts will be very much appreciated.

[John Stone]

It could be the gas cap vent is clogged. Another possibility is the coil is breaking down with heat.

[newshirt]

Maybe there is an intake manifold leak that widens as the manifold heats up. That would explain the backfiring as it heats up. It could be worth pulling the manifolds and replacing the gaskets.

[harleyjj]

condenser???

[JBohannon]

I am another newbie but this is an interesting problem for me. Keep us posted as you figure it out. I had much the same problem and mine was a dirty tank. But I never got up to 10 miles without problem. It seems to me if your was fuel flow it would not go that long without acting up.

[harleyjj]

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some one on here can probably tell you for sure but I believe if you remove the stock condensor and attach a modern type condensor to one of the posts on the coil it should work and will tell you if indeed it is a bad condensor

[Jim Parker Toronto]

Sounds like a simple problem, take all of the above advise. It would be nice to see some pictures if you have them. Those 68 abc's are nice cars... In my opinion, the most desirable A

[Purdy Swoft]

Here is how I mounted the condenser on my 29 fun car. If you are running original style wireing harnesses , you will connect the pigtail to the switch side of the coil, this will be the red wire. Good ground is necessary at the mounting tab of the condenser. The Briggs fordor cowl used on mine has lots of wood , I worried about ground , so I ran a wire from under the mounting tab on the condenser to the side water inlet on the engine. Some later and repro coil brackets have a mounting place for a condenser.

I use the common condenser that is used with the modern Ford points conversion but not the points. I have never tried running this setup with the condenser still in the distributor. It may work with both condensers, I just havent rried it that way and always removed the original condenser first.

[Brentwood Bob]

Go slow, and do one thing at a time to eliminate possibilities. If you do all the above at one time you may muddy the water. You want to be deliberate and systematic. That way you learn from your efforts. Keep us posted on your progress.
Some guys will throw new parts at the problem and its double hard to backtrack.
Bob

[Purdy Swoft]

In many cases with the model A, you can have multiple problems. I'm leaning toward the condenser but I would also check points gap. Anything from .018 to .022 will work. I prefer a gap of .022 . As the rubbing block on the points wears, the points gap closes. As points gap decreases you lose power and run warmer.

[Mike in NRN IN]

I would start with fuel and fuel delivery. Drain the tank CAREFULLY into approved containers. This is a good time to check flow by disconnecting the line AT THE CARB and diverting the line to an empty gas can.

Is there a steady flow or is it weak. Should come out pretty fast and steady.

I had nearly identical problem and found that tiny flakes / crud were blocking the flow to the carb.

Flushed the tank with Kerosene (5 gallons at a time) and drained it directly from the tank using a set of brass plumbing parts. The key was to have a direct drain OUT of the tank.

I could have removed the tank, but that would have required repainting, etc. I'm too cheap.

I'm putting my money on fuel and fuel delivery.

[Elcastor]

As you can see, you will get lots of suggestions...... For what it is worth, I would replace the condenser first (because it is a cheap item) and try it. If you still have the problem, then I would replace the coil (my guess is that is the real problem) and try it again. Keep trying things one at a time, until you figure it out. Good luck! Let us know what the solution was.

[ctlikon0712]

I agree with Purdy Soft, check the points gap and clean it. I.E. file and regap.