1930 82b

[Jim/GA]

I have not used a timing light on it.
6 Volts Pos ground
Yes, coil Has + -
Small popping Exhaust
Nu-rex modern upper plate
I didn't do a compression test

Could it be Exhaust to manifold brass Muffler Clamp Exhaust Seal ?

I have ss exhaust and was told I didn't need it? I am just re-thinking this thing out could that be it?

Carefully trace the wire that is attached to the + post of the coil. It should go to the distributor and the points. It might go there directly or it might go there through the ignition switch. Because you have the battery connected with positive ground, you need to have that + post on the coil go to the points.

What do you know about that coil? Is it a true 6 volt coil? If you have a coil meant for 12 volts (with an internal resistor built in) and use it on 6 volts, it will give a very weak spark.

If you have an ohmmeter, read between the two posts on the coil with no wires connected. It should be closer to 1.5 ohms than it is to 3 ohms (12 volt coil).

There is nothing wrong with the Nu-rex modern points style upper plate.

Did you use the "gland rings" on the exhaust manifold when you installed it? They are a common source of vacuum leak.

 

[FLEETVDO]

No more popping!

I installed the brass exhaust seal and advanced the timing and is running pretty good.

I am still running with the GAV 3/4 out and running ethanol fuel (93 Super).

Thanks for the help everyone!

 

[SteveB31]

Intake vacuum leak

 

[Purdy Swoft]

Generally exhaust backfiring is caused by a lean mixture and retarded timing. First step is to just get everything set to factory specs. When I was in high school a classmate bragged that his friend's Model A would "pop 40 times going down a hill!". The trick to get those backfires was to throw the timing lever all the way up and close the GAV as you let off the gas at the top of the hill.

Remember, ethanol fuel has the effect of leaning the air/fuel ratio so you need to open the GAV some more to compensate if you're running that stuff.

I agree 100% ! retarded is correct !!! I accidently typed advanced in post number 19 but went back and corrected my mistake . Senior moment , I guess .