Running Temp? / Grey Motor

[Thommo]

Thanks for all the input guys
The gear pump has grease caps, where you give a turn on the caps, it adds grease.

Is a rubber impeller pump able to be overidden by water pressure at higher speeds? (making it not so much postive displacement)
Or does a rubber impeller running pump running too slowly (too big a pump pulley) create a restriction?

My ski boat, V8 holden, uses two gate valves, one from each head to regulate temp from side to side.
Could I run an impeller pump and the same system as Bauchy's beautifully simple set up, and use a gate valve to
regulate flow/heat? (with a small pump pulley)
That just looks to easy

[Thommo]

what are those pumps used for normally?

It just an industrial pump, usually coupled to an electric motor to
pump whatever liquid you want.

Dave D has been running around with this setup when it was his boat,
It works, I assume its been good for him.

I doubt If I could build up a dangerous pressure in the engine block,
as it is an open system that currently dumps into the exhaust.
As long as the exit pipes are no smaller than the inlet pipe.

Cheers
Jeff

[Alan]

Jeff,
as long as you check pressure the first time you go out all is well but most welch plugs and head gaskets don't like more than 40psi. Just got to make sure the pulley size is OK and don't forget the water gets bigger when it gets hotter. I have seen a boat pull over 80psi (without a pump) because of the pick up size (and speed).

The rubber vanes will flex (non positive), Here is a pic of a grey with a home made "tap" on the engine outlet the tap (bolt) has a tapper ground on the end.

Alan.

Watertap.jpg (30.66 KiB) Viewed 3536 times

[screwit]

Thommo, the problem with this pump is lube between the gears, the metal gears will have constant contact with each other and water is not a lubricant, They will wear on gear tooth surfaces and body surfaces of the housing without lubrication, the other thing with both types of pumps is that they are only designed to run slow, as Allan said, pulley size should match the engine speed you can reach in the boat.
Ross

[Thommo]

Thanks for all the great info guys, much appreciated

I will change to a rubber impeller pump.

I have also just read the Hollow Log Vol4 Issue1 Jan 04 It has an excellent article called "Hotting up the Holden for Marine Use"
It shows using the three welsh plugs on the block as water inlets.
This allows the spreading of cold water evenly along the block.
If I also utilize the two outlets on the top of the head (Heater hose & Temp sender in a car)
I should be able to create a bottom to top flow through the motor with an more even temperture along all cylinders.
Add in a valve to control outlet flow/temperture to around 80c/175f.

Sounds like a plan

Thanks everyone for your input

It sounds like a water pressure gauge is a good idea to check initial setup.

Cheers
Jeff