Fried Valve, anyone?

[32 Chevy]

A while back I posted photos of Son-in-Law Joey's Mustang II with the dual quad tunnel ram sticking out of the hood. He has been having a ball driving the car to work and whatever, annoying the ricers but not doing any serious racing.

The engine is (was) a wrecking yard 302 with a ton of miles on it, slightly warmed over with cam, headers and the aforementioned dual quad tunnel ram.

So yesterday it was not a real surprise when on a freeway on ramp the engine suddenly started making a hell of a knocking and blue smoke came out the back. The motor still ran so he drove it 4 miles to work with a blue smokescreen behind. Pulled the motor today and found that a valve had come loose and  the valve head was jammed sideways in the seat. Kind a cool, really. Too bad it's too big to make a paperweight from it.

Something else I noticed, though; at the opposite end of the engine the valves look burned even the rest of the valves including the broiken one show decent color. As we are now going to install a better block with the same setup I want your opinion of if there is a problem with carburetion, or if the discoloration may have been caused by running the motor for 4 miles (!) with a broken valve.

Cheers,

Dave R

[Bib_Overalls]

I'm in over my head trying to answer this.  But I notice the exhaust valves get progresively lighter in color as they march from front to back.  

My guess is that one of the carbs is reunning lean.  Or not working in sync with the other.  

Seems like a lot of intake for a near stock motor.  Any chance one of the carbs is set up just for looks?

[32 Chevy]

Both carbs are linked together. The primaries operate simultaneously, and the secondaries are progressive. So basically it is always operating on 4 barrels, two from each carburetor.

Dave

[entodad]

Even so, unless the manifold is a 2 plane, the back four cylinders are mostly operating from the rear carb, and it may be lean. or it may need to operate richer due to some quirk in the breathing system.
I know that big chevys on 2-4's are sometimes jetted quite differently depending on what cylinder that each barrel is closest to.
Doug

Both carbs are linked together. The primaries operate simultaneously, and the secondaries are progressive. So basically it is always operating on 4 barrels, two from each carburetor.

Dave

[Crosley.In.AZ]

lean or mean....... that one valve ain't spose to be sideways!

Some of my best running motors were simple freshens on a used engine.  Maybe a crank kit and fresh rings on the OE pistons.  I would use a DA sander to clean the decks on the block & heads.  Lap the valves a bit.  

I had a 454 in a 57 Chevy truck that would run very strong!