heat riser install

[oldcarlover]

Looked up tech tips for heat riser valve. Counterweight should be 12 oclock

when valve is open but where is 12oclock on the counterweight?

[55 Fargo]

The counter weight will be on top, then when the engine warms up, and the bi-metallic strip contracts, the weight moves toward the front of the engine.

The weight assists in this action, by pulling forward and downward, whcih keeps the heat riser plate closed, in order to let hot exhaust gases to flow directly out the exhaust outlet.

The opposite occurs when the engine and heat riser mechanism is cold, warm exhaust gas flows upward into the intake manifold chamber, and warms this area, allowing fuel to be warmed up quicker on cold starts.

Not sure if this helps or not.

Once it is back together, start your engine, rev it up, and when the engine is revved, it will move the counter weight forward, this allows a good flow for exhaust, in the event the engine is revved up, while the heat riser is still in the cold position.........Fred

[TodFitch]

The counter weight will be on top, then when the engine warms up, and the bi-metallic strip contracts, the weight moves toward the front of the engine. ...snip...

I think it is just a thermally sensitive spring that gets weaker as it gets warmer. When the spring warm (weak) the counterweight can pull the flap to the hot position. When it is cold it is strong enough to close the flap (except when there is high flow from the from the exhaust of the front cylinders which will tend to force the flap to the hot position too).

[DonaldSmith]

It's a bimetallic spring. The two metals expand at different rates. That makes the spring tighter or looser.

I used the spring from a yard thermometer to fix my heat riser valve.