When it started to swell I cut back the flow and barely cracked one exhaust valve.

The valve timing was changed with the exhaust valves opening earlier and closing later.

Similarly, the exhaust valves are opened after combustion to remove waste products.

The exhaust valves of the main engine also saw attention many times during the trip.

One of the exhaust valves burned and had to be replaced.

There were also problems with exhaust valves and valve guides on the engine.

Helmets have an exhaust valve which is spring closed and allows the air to leave the helmet.

It was a simplified version of the Series 53 that did not have exhaust valves.

The exhaust valve was a little red in colour but quite good; it would not even need re-facing.

I opened one exhaust valve a crack and touched helmets.