Pissed off with motor, want to change

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No problem. I have learned a ton on this sight, and am learning something new all of the time. It's all about getting a better understanding of how these old cars function. Disagreement and challenge is good, it promotes learning.
 
moper said:
Anything that causes unburnt fuel in the exh can cause popping. So yeah, the carb could be the culprit.
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I agree. Many others have suspected the ignition system for causing the exhaust pops. Sounds likely though I have never experienced it from ignition problems.

Re the carb, if overly rich, unburnt fuel can get to the exhaust. It usually ignites since most cylinders are still firing. An overly lean charge can cause misfire, which also puts unburnt fuel in the exhaust. This is often seen when decelerating with the throttle closed. I played with a Ninja 250R motorcycle carb recently. It has a "decel enrichment" valve (forgot exact name) which adds fuel during high vacuum decel to eliminate popping. If all cylinders are running lean and not burning, you probably need a hot exhaust to ignite the charge.

I have a Holley Projection TBI on my Newport. I think the injectors leak since if it sits ~30 min and I start it, I get an exhaust bang (I think, though could be an intake backfire). I can avoid by pressing the throttle wide open ("clear flood" mode) then turn on (so no pre-spray), then crank and pull the throttle up quick. The controller got in a bad mode once on the highway where the engine became real sluggish, then "boom" and blew the seam on my sheet-metal muffler. I imagine it went real rich. After crimping the muffer back, it did it again a week later, at exactly the same over-pass 4 miles from home. They were doing construction, so I wondered if a radio transmitter messed up my controller. I then installed a glass-pack muffler so it will blow back at any tailgaters if it recurs. BTW, does anyone know the correct way to install a glass-pack? I oriented so the small cupped openings face into the flow. Perhaps more drag, but seems like should be quieter that way. No arrow on the muffer, instructions on the box or website.
 
Mopar to Ya, I can tell you a very simple way to determine if you have ignition problems - without tools and in less than 5 minutes:

Have someone crank the car "cold" while you're standing by the engine. Then, as soon as the car lights off, quickly touch the backside of your fingers to the pipes, near the cylinder head one at a time, to verify whether or not you have good spark.

Any cylinder that is missing, or not firing, will feel significanly colder than the other cylinders, and yes, the firing cylinders do get hot very quickly, so you only need to quickly contact them to know if they are firing.

Any cold cylinder can (95% of the time) be traced to an ignition issue (plugs, wires, cap, etc.).

I hope this helps as I've used this method many times over the years and it's proven reliable for me. Also, if you're not comfortable touching the tubes, a temperature gun/probe (Fluke sells such attachments for their multi-meters, as do others) will tell you the same thing and save you a lot of guess work.

Southernman
 
Southernman said:
Mopar to Ya, I can tell you a very simple way to determine if you have ignition problems - without tools and in less than 5 minutes:

Have someone crank the car "cold" while you're standing by the engine. Then, as soon as the car lights off, quickly touch the backside of your fingers to the pipes, near the cylinder head one at a time, to verify whether or not you have good spark.

Any cylinder that is missing, or not firing, will feel significanly colder than the other cylinders, and yes, the firing cylinders do get hot very quickly, so you only need to quickly contact them to know if they are firing.

Any cold cylinder can (95% of the time) be traced to an ignition issue (plugs, wires, cap, etc.).

I hope this helps as I've used this method many times over the years and it's proven reliable for me. Also, if you're not comfortable touching the tubes, a temperature gun/probe (Fluke sells such attachments for their multi-meters, as do others) will tell you the same thing and save you a lot of guess work.

Southernman
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Good tip if it has headers
 
Heres how you really do this.....
If you have headers, you need to just run the motor for a minute or two.....THEN while still running and using a screwdriver handle... run/drag the plastic handle across each primary tube near the flange...A good firing cylinder will have the handle sliding on the tube like butter on a skillet......A dead non firing cylinder will have the handle sticking as you try to slide it around.

But if you really want to burn yourself...go ahead ;)
 
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