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Making pop-corn with the 322 - Backfiring / poping -Suspect crossfire, looking for anything special about the 322....


Treozen
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Hello all-

 

I have quite a bit of experience with the venerable small block Chevy, and even the Jaguar XK, but zip as it relates to the Buick 322.  My car is a '55 special, but the engine was replaced with a 322 from a 1956, has a two-barrel carb, and.....there are pops and small backfires that occur, and become more frequent, as the engine warms up.  By the time its been running for say 2 - 5 minutes, these exhaust pops are very frequent and start to impact running stability.  The engine starts just fine - instantly actually, choke is non-functional, but open.  Sounds great at first, then starts to pop, runs rich, popping becomes more frequent over time.

 

The car has not been on the road for about 8 years, the engine was rebuilt in 2010. I plan to start with the usual suspects - plugs, wires, cap, rotor, new coil, check timing, check carburetor - points have been replaced with pertronix (which I like, and use in most everything I have).  I haven't touched a thing yet, and don't expect that it should run smoothly without a little tinkering, but I wanted to check for any Buick-specific issues or likely causes, since I've not worked with a 322 before. 

 

It sounds to me like several plugs are firing, again, at the wrong time - crossfire style - or that its running so rich there's enough eat to ignite in the manifolds - tends to smooth out with some throttle, but not entirely.  If this were a Chevy, I'd suspect plugs 5 and 7 were crossfiring, or creating an inductive charge.  Sounds to me like more than one plug is being naughty.

 

Thanks,

Allan.

 

 

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(1)After engine shutdown, remove the small plug on the driver side of the carburetor and see if fuel spills out, if more than just a little dribble, the float is sticking or set too high.

(2) Recheck firing order and wire routing.

(3) Compression check is always advised.

Edited by TexasJohn55 (see edit history)
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Does it have the spark plug covers on it?  If so, there is a recommended routing of the wires under the covers in order to avoid crossfiring.  And if not, I would not be surprised if you still have cross firing.  I had a new set of wires on my car for a few short years and they started to leak around the grommets in the spark plug wire brackets.  Also I presume you used dielectric grease on the plug boots?   

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For some reason, which I am yet to explain, my car did a similar thing and used to pop and carry on. Spit dark soot out the exhaust but smooth out with higher rpm. Stopped after I purchased NOS non-resistor plugs. Not saying that is a fix for you but sure sounds similar.

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2 hours ago, TexasJohn55 said:

(1)After engine shutdown, remove the small plug on the driver side of the carburetor and see if fuel spills out, if more than just a little dribble, the float is sticking or set too high.

 

 

Ok - I'll add that to my list. I believe the carb may needs rebuilt. It was done 10 years ago with few miles since, but given gas sitting in there, probably needs redone.

 

 

2 hours ago, JohnD1956 said:

Does it have the spark plug covers on it?  If so, there is a recommended routing of the wires under the covers in order to avoid crossfiring.  And if not, I would not be surprised if you still have cross firing.  I had a new set of wires on my car for a few short years and they started to leak around the grommets in the spark plug wire brackets.  Also I presume you used dielectric grease on the plug boots?   

Yes, it does  - so that's a great tip. Hopefully this is the cause, because it would be easy to resolve.  I do use dielectric grease, yes, but who knows what the prior owner did - I'll use it when I change the wires /plugs.

 

26 minutes ago, 56 Buick said:

For some reason, which I am yet to explain, my car did a similar thing and used to pop and carry on. Spit dark soot out the exhaust but smooth out with higher rpm. Stopped after I purchased NOS non-resistor plugs. Not saying that is a fix for you but sure sounds similar.

 

Yes- I also have the black soot. Plugs are in the plan of course, Autolite 85 is what I picked.

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8 hours ago, Treozen said:

 

 

 

 

  

 

 

Yes- I also have the black soot. Plugs are in the plan of course, Autolite 85 is what I picked.

Soot doesn't indicate rings worn, check compression with plugs all out, number and mark plugs for reference by appearance.

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