There is a big temperature difference from the left bank at +400 degrees to the right bank at 297 degrees. The measurement was taken with the '56 Ford 312  warmed up and running.
 I pointed the infrared thermometer at the very end of the exhaust header, closest to the fire wall, on both banks and got the imbalanced readings of +400 degrees left and 297 to 300 degrees right bank.
Why is this happening or is it normal ????
Let me know what you think,
Thanks,
Tim Quinn
Florida

Some left cylinders running a bit lean ?
Same Spark plugs all around? Same gap?


1936 Ford 3W Coupe : 56 T-Bird 312, 47 Packard 3 speed, 40 juice brakes.
1968 Merc Cyclone FB GT 390, Getting a better front clip!
1977 Ford F-250 Supercab RWD Explorer Long box.
1976 Chev Camaro RS LT
Future rebuild : 1949 Ford F-1

All spark plugs are E3's and the whole left bank is hotter that the right bank.
Idle is a 700 rpm, temperature gauge (after market ) sits a 180 all day.
One thing, have a Summit 600 cfm and have the two idle screws closed, can't get the car to run well with the idle circuit screws open. Have to advance the throttle advance screw to keep engine from stalling when the idle circuit screws a opened two turns. So I close them and the engine runs smooth but hot on the right bank.
Why is it running lean on only one bank?
Let me know what you think,
Tim
Hot 'n Humid, Florida 33706

If you have to close the idle mixture screws to keep the engine running, then I think you may have a carb issue. Maybe a blown power valve, or float to high. Retarded timing will cause high EGT's
A lean mixture can cause a low EGT, and a rich mixture can cause a high EGT. Also a collapsed exhaust can cause high EGT's. I've seen collapsed exhaust systems glow red.
Some things to look at or consider.

Dave

Dave ,
Thanks for your evaluation. I'll check the power valve.
Tim 
Florida.

The engine should stall with only one idle screw turned in.  If the engine still idles with both idle screws turned in, then you do have a fuel problem.  In addition to the power valve and floats, having the throttle open too far at idle will cause fuel to be pulled from the boosters, in addition to or possibly instead of the idle circuit.  You can check this by looking down the carburetor with a mirror while the engine is running.  It could also be too much pressure from the fuel pump.  700rpm is a high idle for a stock and even more mildly modified engines.  If your cam does not require that, then it could be a clue to the problem.  A vacuum leak or retarded timing will require the throttle to be farther open in an attempt to compensate.  If the cam is large enough that 700rpm is justified, then then you may need to close the primaries and open the secondaries in order to achieve the correct idle speed while ensuring that the idle circuit functions correctly.


Lawrenceville, GA

Charlie,
All good info, but, why is only one bank hotter ?
Also, the throttle screw is back as far as it can go, it is not engaged at all.
What if I open the idle screws 2.5 turns to let more fuel flow.
Because it is LEAN, that means it needs more fuel...right ?
Now with the idle screws open, I have to turn the throttle screw in
to prevent the engine from stalling and this gives more fuel
What are you thoughts ?
Tim
Florida

I don't know why one bank is hotter.

If the throttle speed adjust screw is backed all the way off and it still idles at 700rpm, then some possibilities are:
The throttle is hanging open, maybe caught on the gasket, maybe stuck in the throttle bores of the intake or spacer.
The secondary throttle is adjusted too far open.
Vacuum port without a cap
Vacuum leak.
Some other means of getting air into the intake.

Since the engine runs with the mixture screws all the way in, you need to fix that.  Anything else will be only a bandaid on the problem, which could lead to far more expensive problems, fuel washing the cylinder walls, oil dilution, etc.

Fix the idle speed problem and idle mixture problem and then move on.  Maybe they are the actual issue, too.

Another thing is that your '56 312 requires a '57 or newer distributor to work with the Summit carburetor.  I don't think that would cause the hot bank issue, though and it would not cause the idle speed and mixture problem.


Lawrenceville, GA

Thanks,
I have a modern electronic distributor and coil to go with the Summit carb.
I'll work on the problems at had and get back to you later on.
Again,
BIG THANKS FROM HOT 'N HUMID TIM IN FLORIDA

Hey Charlie,
About vacuum leaks..........i have a PCV hooked up to the exhaust tube and connected to the back port on the carb. That would be a vacuum leak into the crank case...RIGHT ?
Could the PCV be installed backwards ?  
Tim, Florida