Bang in the exhaust

[Oberfranke]

There is a pop in the exhaust when shifting gears and reducing the gas. The ignition should not be the problem. Everything is well adjusted here. What could be the cause?
Greetings from Bavaria

 

[J Franklin]

Rich fuel mixture and air leaks in the exhaust system can cause that. It is not uncommon.

 

[old31]

Where do you have your gav turned to? 1/4, 1/2, 1?

 

[Y-Blockhead]

You're a little on the lean side, open the GAV a little.

 

[J Franklin]

A lean mix usually pops in the carb not the exhaust in my experience. But anything is worth a try.

 

[Oberfranke]

The GAV is 1/4 open. I will see if there is a leak at the manifold or exhaust. I think with flush water or with a bird feather I can detect a leak.

 

[CatMan1]

This explains what I'm seeing, or hearing as well. I have exhaust leaks around the manifold and where the exhaust pipe clamps on. I also get this popping sometimes when I'm going downhill and letting off the gas.

 

[Ed in Maine]

Get a sleeve that mounts between the exhaust pipe and the manifold to stop air leaks into the exhaust system. Ed

 

[old31]

Remove your fan belt and start the car. It will be easier to hear and see leaks.

 

[Werner]

Mageres Gemisch + zu später ZZP fördern Auspuffpatschen.

 

[DRG-ler]

I have the glitch too, but my manifold and exhaust are definitely tight (re-sealed). Is the consumption of 18 liters so little that the mixture is too lean? GAV stands at 1/4. I would also argue that it tends to run too fat.

Greetings from Berlin

Andy

 

[Oberfranke]

I have not had a backfire since I opened the GAV to about 3/4. The exhaust seems to be tight. If not, oil would probably leak out. I will now also give more early ignition.
But why didn't I have this problem before?

 

[Y-Blockhead]

You're a little on the lean side, open the GAV a little.

A lean mix usually pops in the carb not the exhaust in my experience.

I have not had a backfire since I opened the GAV to about 3/4. The exhaust seems to be tight. If not, oil would probably leak out. I will now also give more early ignition.

As I posted in post #4. I am happy that worked out for you. My Town Sedan did the same when I had my Zenith on if the GAV was closed a little too much.