[chuckski190]

i have a 1978 Hallett 19' sport/ski v/drive old style gale banks twin turbo 468 BBC set up. what is the best way to slow the water flow through the block, heads and exhaust? the boat never reaches normal operating temp.

mahalo's!

 

[steveo143]

Thermostat from Rex Marine.

 

[chuckski190]

mahalo's for the reply. my engine is plumed as follows. water pump driven off the front of the camshaft. straight into the block. out the t/stat housing where it is Y to feed both banks of the exhaust system and out the exhaust. i am concerned that the exhaust will not get water soon enough.

 

[steveo143]

My Race Arrow turbo is plumbed differently. Waterpump 2 exhaust logs 2 engine exit thermostat housing to thruhull exhaust. No thermostat and 180 + water temp. Heating the water thru the exhaust logs before the engine works best imo. If you use a thermostat you can drill a small bypass hole 1/8-3/16.

 

[chuckski190]

Aurite! man, i have been fighting this damn thing for years. it makes perfect sense! i have had 2 separate incidents so far. both from an exhaust valve hanging up in the valve guide banging a piston. i will re-plum the water into the exhaust first. mahalos big time for your help. i paid big dollars for a professional to rig my boat and look what i have gone through. if you are ever in kauai look me up and i will show you around!

aloha

 

[JWM]

There are a number of ways to plumb your engine. First you need to know how you’re going to use your boat! ¼ mile race boat, play boat, ski race boat and last of all what size boat.
Drag boats can use higher block water temp because they run and shut off. Play boats on the other hand run at lower rpm most of the time and then when the Jet Ski comes by they build boost and see if the can keep the Jet Ski in sight. Last is the all out ski race boat. Most of these boats make boost for long periods of time.
One thing to keep in mind when you want to make max HP. OIL TEMP is more important than water temp. The most important thing water does is transfer chamber and block temp overboard. Oil Temp makes HP.
There are 2 Common ways to plumb your engine. 1. Water pump to block and then to the exhaust manifolds. 2. Water pump to exhaust manifolds and then to the block.
Another way to cool you engine is the reverse cooling method.
Water pump to the thermostat housing out the block to the exhaust manifolds.
In all plumbing application I would recommend a water crossover at the other end of the intake manifold. I like to run 2 -6 hoses to a -8 tee then a line overboard.
Remember to check your system at WOT for proper water pressure. 20 lbs. min at WOT.
I hope this helps you.

JW