cant get my head around headers

[JET BUG]

howzit guys
i cant understand all the abbreviations/termanology used some times in your country so here goes.What is the difference between a t-valve and a gate-valve from what i understand the gate-valve regulates the flow of water through a set of O.T headers HOW??????.I asume it must be linked to the accelerator somehow,where can i find out what the working principals are or maybe how i can import one to S.A.By the way figured out the t-valve issue same as t-piece maybe,having a set of ot headers made localy so all info will be put to good use
cheers
J.B.
ps (we dont have any laws regulating the amount of beautiful music extracted from a motor on our water ,but can you live with a non water silenced system on a long term basis.is water silencing the only option)
cheers again

[mister460]

They have a spring and a ball in them. They're set so that they start flowing water at a certain pressure, i.e. rpm. Water flowing through the exhaust also helps your headers last longer and the rear end of the boat cooler.

[froggystyle]

The "T" valve I think you are describing is also called a "Bassett" valve, as the company that makes the best ones is Bassett racing in Anaheim, CA. What it is, is a tee, with a ball/spring valve in it. The spring pushes the ball against a seat, until the jet produces enough pressure (through accelleration) to overcome the spring pressure, and "opens" the valve. This is to prevent your headers from getting water below 1500-2000 rpm and setting up for possible reversion. This is commonly installed after the water exits the engine, but still allows cooling water to bypass it at low rpms.
The gate valve you speak of is to regulate overall flow going to your engine. The faster you go, the more pressure the pump puts out, and the more cooling water that is given to the engine. This system is inefficient at best, but does the trick. The wider the gate valve is open, the cooler the engine runs. The higher the engine speed, the more water goes to the headers (only to a certain point though). Just make sure you don't shut down your engine at 4000 rpms, or the valve will stay open, and revert water quickly.
Best of luck to you

[timitunnel]

A gate valve is a valve used by most plumbers to shut off water in a building. jet-boaters use it to limit the amount of water coming to the motor from the pump just like a faucet. The t-valve is a presure valve that shuts off water when idling to the headers and hopfully saves the valves in your motor. Tim.