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

[Treozen]

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.

 

 

[TexasJohn55]

(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 June 14, 2021 by TexasJohn55 (see edit history)

[JohnD1956]

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?   

[Bill Stoneberg]

Check the firing order and don’t forget #1 is on the passenger side.

[old-tank]

Coil   wires  plugs  valve guides  firing order   Pertronix

 

 

 

 

[56 Buick]

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.

[Treozen]

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.

[TexasJohn55]

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.