Running Hot?

[JohnZ]

My only reason for leaving the tubes in place is the 30 degree countersink under the tube - the tube seat seals that, then the flat nail head seals the top of the tube.

That's why I use the #10 x 1/2" flat head machine screws - they have a flat top, and a 30-degree taper on the bottom that matches the countersink in the manifold that would normally be sealed by the tube nut.

[Vince]

I wanted to thank all you guys once again for your responses and help.  I am taking things one step at a time.  I think it has been narrowed down to a fuel percolation problem with excessive heat being produced from the exhaust manifolds due to the AIR pump pumping air all the time, due to a broken diaphragm in the diverter valve, plus a vacuum leak from the same cause.  The cooling system checks out fine.  The timing checks out fine.  I'm still looking for a racing gas distributor in my local area. 
What do you guys think about Joe Gibbs Driven Carb Defender Fuel Additive, for counteracting the ethanol in gas, possible help or waste of money?

[Vince]

I finally got the AIR system inactivated.  Checked for a vacuum leak around the carb and couldn't find any.  Car seems to hold an idle now without slowly going down and dying.  One thing I have noticed since I have been doing a lot of work with the air cleaner off is that after the car has idled awhile, though still not anywhere near hot, after I shut the engine off a vapor or mist almost as thick as smoke comes out of the carb throat.  The carb is still cold to the touch when this occurs.  What is causing this? 

[JohnZ]

I finally got the AIR system inactivated.  Checked for a vacuum leak around the carb and couldn't find any.  Car seems to hold an idle now without slowly going down and dying.  One thing I have noticed since I have been doing a lot of work with the air cleaner off is that after the car has idled awhile, though still not anywhere near hot, after I shut the engine off a vapor or mist almost as thick as smoke comes out of the carb throat.  The carb is still cold to the touch when this occurs.  What is causing this? 

Crankcase vapors - if you had the air cleaner and PCV hoses connected, you wouldn't see it.

[Vince]

Thank you John.  Glad to hear it is something as simple as you described.   

[BULLITT65]

I finally got the AIR system inactivated.  Checked for a vacuum leak around the carb and couldn't find any.  Car seems to hold an idle now without slowly going down and dying.  One thing I have noticed since I have been doing a lot of work with the air cleaner off is that after the car has idled awhile, though still not anywhere near hot, after I shut the engine off a vapor or mist almost as thick as smoke comes out of the carb throat.  The carb is still cold to the touch when this occurs.  What is causing this? 

Crankcase vapors - if you had the air cleaner and PCV hoses connected, you wouldn't see it.

shoot, you close the hood and you won't see it....

[melav8r]

De-vane the pump - the rotor spins, but doesn't pump air, obviously. Block the vacuum tube for the divertor valve.

You can use roofing nails (galvanized) in the extension tubes - seals off the extension tubes, flat surface to seal on. Drop them in, tighten the tube fitting and you're all set.

My opinion - others ?

Regards -

Hi z28z11,

Old thread but I just devaned the smog pump on a ‘67 327 Malibu and now moving on to the smog tubes. At this point I’d rather not remove the exhaust manifolds so I’m interested in using galvanized nails to seal the tubes off.
I just want to confirm I drop the pointed end of the the roofing nail into the extension tube in the exhaust manifold so when I reattach the smog tube fitting it’s riding against the top of the nail head?
What size roofing nails do I use?
Should I apply any hi-temp RTV to the top of the nail head before reinstalling the smog tube fitting?

Thanks,
Mel