Won't run

[2935ford]

Hi All,

Just wondering if some of you might have the answer.

A friend just purchase a 1930 Deluxe Roadster and we are having one heck of a time getting it to stay running.

Symptoms:
When cold engine runs and sounds great. Lots of power.
The minute it gets up to temp.......backfires, jerks, hops then quits running.
Can restart but backfires, jerks and hops then quits running.
Repeat until I manage to get back to the garage.

What has been done:
I have replaced the carb with a known good carb along with replacing the distributor with a known good distributor and replaced the coil with a known good coil.
New spark plugs have been installed.
Timing has been checked.
Fresh fuel.

This should rule out a bad carb, distributor, condenser and coil?
It has good fuel flow to the carb.
GAV is 1/3 turn.

Ideas?

[J Franklin]

Check the compression. you might have a warped valve, or a valve with too little clearance that doesn't close properly or when warm.

[2935ford]

^^^
J Franklin, thanks.

[Big hammer]

MMO in the gas, 4oz per 10 gallons for normal operation, I would double that amount, it may smoke at little, MMO will help freeing a sticky valve

[2935ford]

^^^
Big Hammer, thanks.

[2935ford]

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After looking things over a bit closer, one thing I notice is a lot of the wire connections are rusty or green corroded?
Hmmmmmm, that can't be good!

[1crosscut]

Try running it without the gas cap. Might have a plugged vent and it creates a vacuum about the same time as it gets warmed up.
Or you can run it without taking the cap off and then once it warms up, acts up and dies take the cap off and listen for air to whoosh in.

[Gene F]

It is likely something not all that involved.

Please let us know how you are progressing.

[Rob Doe]

2935ford,

You don't by chance have a second condenser hanging on the firewall next to the coil do ya?

When the car is running good while cold, jiggle the ignition key in every direction, up down, in out etc.

Check all wire connections from the battery ground at the frame to the terminal box up to the ammeter and back down to the coil and on to the switch for loose, frayed or corroded wires.

If you have a safety fuse mounted at the starter, replace the fuse first and consider moving the wire back to the starter stud temporarily. The ends of the fuse holder that the wires are attached to can become loose at their rivets.

Good luck.

[2935ford]

Thank everyone.

There is not a lot of history on this A but it has sat for a very long time and the wiring is sketchy. It has the wrong ammeter which I plan to replace with original. I will replace all the ignition wiring to get it back to stock form. Check all the grounds etc etc.
We replaced the throw out bearing, clutch, pressure plate and had the pan off to look at the babbitt to discover it's good (yay) but whoever was in there used nails as cotter pins in the mains (ugh)!

We will find the cause I'm sure of that and will let you know what we found.
I just hope the new owner has the patience and hangs in there with us.
He's a newbie to this world.

[2935ford]

Just wondering if there is suppose to be excessive oil on the distributor shaft and oil on the bottom plate and below?
If not....cause?

[Chuck Sea/Tac]

Does it have a drilled upper shaft (under the rotor)? If so then probably over oiling it.

[ModelA29]

Originally Posted by 2935ford

.... oil on the bottom plate and below?

Does it have a wireless lower plate? Could the oil be interfering with the internal grounding of the distributor?

[ArtimusGordon]

Long shot BUTtry removing the RED wire from the coil and providing a JUMPER wire to the distribution from the coil. I had a problem with an ignition switch that had a intermittent open!

[2935ford]

No drilled upper shaft.
No wireless lower plate.
The long shaft is rusted but pretty tight in the bushings.
I have cleaned everything in there up and reassembled.
Further investigation, all of the wiring is suspect so I will rewire the whole car.
Process of elimination, I guess!

[sequim]

Make sure the coil to distributor wire is fully up in the coil and fully down in the distributor. I chased an issue like this.

[2935ford]

sequim: thank you.

[gdmn852]

Hello, as post 9 said , check ignition switch, some of the reproduced ones were noted for problems, originals sometimes short out inside the cable , the wire connecting the lower plate with upper can develop a short also . Please let us know what you find out.

[Rob Doe]

2935ford, here are some of my early morning thoughts:

Your initial comment: "The minute it gets up to temp.......backfires, jerks, hops then quits running." leads me to suspect a slow starvation of fuel.

To test this, when the popping and jerking starts, turn the engine and fuel valve off, remove the fuel line at the carb and loosen the line at the filter, then rotate the line up so that you can blow back through the line to clear any sediment that has migrated into the top of the fuel valve at the bottom of the tank. Use and air gun or add a piece of clean hose to the line and use your lung power. If its a quiet area, you should hear the bubbling in the tank. I'd do this outdoors with a fire extinguisher handy.

Do you have a pencil filter in the top of the valve?

My speculation: Backfires come in two flavors??? A backfire in the exhaust system is sometimes referred to as afterfire and backfire through the carb air horn is a backfire. Intermittent electrical problems can create both types, but backfires via the carb alone are usually a lean condition.

Test the fuel flow by opening the valve and running fuel into a jar or bottle. It should shoot out a full stream a couple inches and fill several ounces in a few seconds if not restricted.

[2935ford]

gdmn852 and Rob Doe....thank you for your responses.

The pencil filter is an unknown at this point.

Lower plate wire to upper plate is good.

As I have mentioned all of the wiring is suspect. The plan is to rewire the entire car to stock.
Get and install a good original ammeter and replace the ignition switch. This gets us back to "original" setup and rids us of the old brittle wiring.

There is good fuel flow when we tested that. There is however a rigged fuel filter from the valve inside the car and does not completely eliminate possible clogging.

The gas tank is suspect and will need further investigation.
The plan is also to install a new float as the old is presumed saturated and sinks so as to not register fuel level.