Manifold Heat Riser

[davidyavidy]

What's the best way to repair this thing short of replacing the manifold on my friend's '56 Century 322 V8? Frozen solid. Heat and penetrating oil haven't budged it.

[D Yaros]

Separate the exhaust pipe from the manifold. Remove the butterfly valve/flapper. It is not needed unless you drive in cold weather, and even then only needed until engine is warmed.

[beerczar1976]

Concur. I had a spare one sit in a molasses soak for about 3 months over the winter. Surface rust was removed but that dang butterfly valve wouldn't budge even a mm. When trying to free mine up, all I ended up doing was snapping the tack welds that hold the butterfly to the shaft. I'll probably end up just cutting the butterfly off the shaft at this point or tack welding back in the open position. At least from the outside, it'd look stock, plus mechanically I won't have the fear that it's causing the manifold to overheat. Gasses will flow freely by.

[D Yaros]

I see little-to-no reason to tack weld the valve open. I would just as soon move the restriction in the exhaust pipe the valve creates?

[bhambulldog]

Take the butterfly valve out and throw it away.

It's function is to speed warm ups.

It'll warm up fast enough without it.

And you don't have to worry about it seizing while closed.