Running Temp? / Grey Motor

[Thommo]

Hi Guys
I am researching for the right Temp Gauge.
What temperture (roughly) does a grey motor run at in a boat?
In a car you have a sealed pressurised radiator which raises the boiling point.
In a boat it has a constant supply of cold water.

Cheers
Thommo

[tommo]

G'day Thommo Acording to the info i have on 138 grey motors the thermostat opens at 160 degrees Farenheight hope this helps cheers tommo

[Doc]

Thommo,
Water should be pre-heated via exhaust manifold before entering block. Water pump size & pulley size has alot to do with temperature reading. A car water pump circulates the water. A boat pump draws & pumps the water , hence a rubber impeller .
Doc.

[Thommo]

Ok, Thanks so far guys

I should let you know more about my set up I have, and what I plan to do.
The motor does not have a thermostat, or housing to run one.
The pump, is a gear pump.


And I plan to use a dry manifold with exhaust straight up & out the engine bay.

I had planned to modify this unit and use the wedges under the carbs.

Does anyone run a set up like this?
Do you really need a marine manifold?

Cheers
Jeff

[screwit]

Thommo, the gear pump you have to my understanding is for oil base fluid- cutting oil for lathe or machine type use. I may be wrong but there would be no lube in the pump if used with straight water, that why the pumps used in boats have rubber impeller in them.
Ross

[bootlegger]

Thommo I think you will find it will be hard to get the engine up to temp. usually you will find the engine will run alomost stone cold even if you pre heat the water through the manifold.
You can run that type of inlet manifold no problems especially on a skiff. Usually the water manfolds are used to keep the heat down in the engine bay.

[bauchy]

hey tommo
on my holden 6 i ran it the same way you are talking about. my set up ran the water from the pump, thru the head and engine and then it just dumped into the exhuast after the manifold. my manifold was not cooled at all and we had no dramas. it got up to tempreture no problems and never ran hot. i found it very simple and reliable. i think you wont have any dramas but not sure about the pump you are using. ill find a pic of my 6 without a water cooled manifold

[bauchy]

http://i264.photobucket.com/albums/ii18 ... GP2790.jpg

http://i264.photobucket.com/albums/ii18 ... GP2789.jpg

http://i264.photobucket.com/albums/ii18 ... GP2794.jpg

[Alan]

Thommo,
You would be surprised at what actually works that just shouldn't, and of course you can make some things work if you really try hard.
Some thoughts,
Water pump, like Ross said it's better for other things, having said that have used them before, but be careful because it is a positive displacement, and you can build some dangerous pressure.

Water temp, you should aim to get at least 80c so that things have grown to around the right size/clearance. Usually you restrict flow to get temp right but that may be tricky with the pump above.

The inlet manifold, like Dave said the exhaust is usually cooled to reduce heat inside the boat, and the non heated inlet is less of a problem in a boat that uses more throttle to cruise that a car.
Alan.

[bauchy]

what are those pumps used for normally?