1930 ford backfires after climbing hill

Bobant

Bobant

Member
I just bought a 1930 Ford roadster. I rebuilt the carb, timed it, cleaned out the gas tank to the best of my ability without removing it, and it runs great almost. I have a steep hill close to my house. If I don't go up the hill no issues. Last night I was feeling brave and went up it. Have to shift to 1st gear to get to the top. When I reached the top it started backfiring about 5 or 6 times, almost stopped, but settled down without stalling and ran good from then on. Gas tank was a 1/4 or less full.
I have heard stories that people used to back up steep hills because of gas related problems. Is there any truth to this or folklore?

I was /am going to check my float in the carb and maybe lower the valve by adding a washer to get the level in the bowl lower. I have also bought a tube screen to put on the end of the intake tube inside the gas tank to make sure the intake in not getting blocked because I know I did not get the tank 100% clean. There are still flecks of rust , but not stuff that looked like decayed leaves when I started.

I don't think the car is overheating but since I am new to all of this I am not sure of that either. Lots to learn.

Any feedback is greatly appreciated.

thanks
Bob A.
 
Folklore goes back to the Model T and due to the gas tanks position relative to the carb. This backfiring happened after you managed to find 1rst gear? Did she pop out of the carb or the exhaust? Can you see any leaks around the intak/exhaust manifolds?
 
Did you say your tank was 1/4 full, 3/4 empty or 3/4 full, 1/4 empty... I keep at least 1/2 full tank
 
It did not happen when I got it in first gear. It happened after I got to the top and was going to 2nd after I got on the level and then went away.

When I first got the car the bolts were loose on the carb but after rebuilding the carb and using a new gasket I tightened it pretty good. I will check this though as maybe it did come loose again.

As far as I can tell there are no leaks or evidence of leaks on the intake or exhaust manifold. The backfires are pretty loud and I think it is coming out the exhaust. They so loud that people in my neighborhood come looking to see if someone is shooting up the neighborhood or maybe to get a look at my nice car- not sure.
 
It could be the level of gas in your tank. I know the old Model T's had problems in this area but one time when I had a very low level of gas in my Model A coupe's tank, I tried to go up a hill toward our place and it quit on me. So the small amount of gas, depending on how much you have in the tank, can go to the rear of the tank and cause it to quit. I filled tank with more gas and had no problem starting and going home. Not saying this is your problem, but it could be.
 
The idea of backing Model T's up a hill is hard to buy. Not sayin some didn't. I am no "front end guy" but they way a model T is set up is akin to a bicycle. They can get away from you in a hurry, think of riding a bicycle backwards. The better bet is to put tubing on the gas cap and it you run out of steam...blow. I have even seen articles about using exhaust gases to pressurize the gas tank.
Now back to your problem..
 
As Farrell said, the Model T's with the tank under the driver's seat might have the fuel lower than the carb if the tank is low and the car is climbing a steep hill. Driving backwards would put the gas in the tank higher than the carb, so the engine would't starve for gas.
 
Try again with more fuel. If it tries to pop open the GAV and see what happens. Also try it with the fuel cap loose [or off].
 
A backfire out the exhaust pipe that sounds like a gun shot is caused by excess unburned fuel collecting in the exhaust pipe and muffler, and then being ignited by the engine running.

When climbing the hill in 1st gear, where is your spark lever and where do you have the GAV positioned?

That must be a very steep hill to require 1st gear to climb it. I can climb pretty much anything I encounter in 2nd. It does not sound like you have "normal" power.

I know you just got the car. What do you know about the condition of the points and the age of the condenser? The condensers do go bad with heat and age.

Have you checked the initial ignition timing?
 
I checked the ditrbutor cap and points last night. The contact points in the cap itself looked mushroomed and the gap between 3 of them was way to big and the other one was almost touching. The actual timing points themselves are not hitting flush against one another, it's like they're off aim with no visual way to align them. I ordered a new distributor cap, points, rotor, plugs, and condenser. Maybe this will make my issues go away.
 
on the original style you can align the points contact by tweaking the holdown with a screwdriver.. i have done it many times
 
You are using more gas than the gravity feed can supply, and your gas level in carb is getting low as you plough up hill in second and causing a lean mixture.

First gear is using less gas.

Check your flow at carb .
 
Next time it happens, stop and pour a bottle of water on the carb and see if that makes things better. The bowl gets hot and boils all the fuel out of the carb.
 
The reason you need first gear for the hill is because it is a very steep hill. It is in my neighborhood and you can only go about 20 miles per hour at the bottom. I have nothing to compare the power to as I have never been in an old car like this before. I am a newbie and I do want to thank everyone for the suggestions and help as I take each comment and see how it compares to my particular problem.
 
Do the simplest, easiest, cheapest thing first....go fill it up with gas and try it again.
THEN, if it does the same thing, start looking other places in the fuel delivery.
You could still have ignition problems, but typically electricity flows the same whether its going uphill or down.
Good Luck:)
 
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