Fouled plugs on the right bank

[6 pac]

I keep getting a couple of fouled plugs on start up on the right bank of a 340 six pack t/a. It happens on cold start up and if I clean them it will run fine. Everything is stock but I have the revnnator box and have the vac advance disconnected. The motor is all rebuilt and runs perfect other than that. Can anyone help?

 

[AUSTA]

Sounds like too much fuel on startup or idle.
I have found the new Champions RC12YC seem to foul a lot easier & wont clear unless cleaned than the old ones
The NGK plugs seem to work longer with over fueling.

 

[moparleo]

How long have you been running this six-pack set-up? Why do you have the vacuum advance disconnected ? Who balanced and adjusted your carbs ?

 

[Adam]

Could the intake gasket on that side allow oil to be sucked in from the lifter valley

 

[moparleo]

Didn't say if the fouling is oil or fuel. Black or blue/grey smoke ?

 

[6 pac]

The plugs are black fouled. And only at start up. I can clean them and they work fine. And only when the car sits and it's a cold start up. I'm wondering if that heat exchanger has something to do with it. The plugs are super clean after it warms up it's fine but only that start up

 

[6 pac]

Everything has been restored on this car, carbs, heat exchanger, everything and is in perfect working order but this fouling issue.

 

[Steve340]

The standard spark plug for iron heads is Champion N9Y

 

[moparleo]

If it is just one bank that does it, it has to ben carb related. Take out the metering block on the center carb and after removing the power valve and mixture screws, blow it out with an air hose and reinstall it. Readjust the idle mixture screws and see what happens.

 

[aussiemark]

If the heads are not a matched pair the RH one may have excessive valve guide clearance or no/worn stem seals allowing oil into the chamber when shut down and fouling those plugs on start up.

 

[moparleo]

He says they are "black" fouled.. More than likely excess fuel not oil, Seals normally a puff of grey/blue smoke at start up and will clear up quickly. Guides will smoke constantly.
Pull the dipstick and sniff it. Any fuel smell ?

 

[AUSTA]

Try removing the air cleaner slowly open the butterflies before you start it & have a look with a torch to see if there is wet fuel sitting in the bottom of the manifold
The carby may have the float level a bit to high or there is fuel leaking when the car is stationery
Do you need to pump the pedal to start or does it start instantly with black smoke could also be the choke set a bit too closed when cold.

 

[cudabob496]

leaking valve guides

 

[moparleo]

For us North Americans, when AUSTA says to use a "torch" to look down the carb with, He is talking about a "flash light". Just FYI.

 

[AUSTA]

That's the one we don't want to set the vehicle alight.