Raw water cooling

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rayza1
Posts: 1574
Joined: 12 Jul 2009, 20:24

Raw water cooling

Postby rayza1 » 22 Jan 2010, 09:46

Hi guys, i'm finally getting to the pointy end of my little project and seek information on setting up my cooling system. I have a standard 186 holden sitting in a 15ft bondwood, it has 2 water inlets in the bottom of the boat from there i'm a bit stuffed. Motor has a water cooled sump as well as the usual watercooled manifold. What sequence do i use to direct water around the engine? My guess is water pump first (jabsco), block second, sump third, intake manifold next then out the exhaust. Am i heating or cooling the intake manifold? Also i have seen pictures of a gate valve in the sytem, is this to control the speed the water travels through the system? I figure that somewhere in the cooling system i need a fitting to run a water hose so i can flush or run the boat out of water. Sorry about the long winded question but i really dont have any experience with this. cheers. Ray (when i can work out how to put some pics up i will give it it's first public airing..dont expect too much!)

bauchy
Posts: 535
Joined: 11 Mar 2009, 20:34

Re: Raw water cooling

Postby bauchy » 23 Jan 2010, 09:05

hey rayza
with my 202 i ditched the water cooled manifold and made my own cast one. i thought it would get allot hotter then it does but when ya in the boat without an engine cover you dont even feel the heat from the exhuast.

i set mine up pretty simple. i went from the pickups to the pump, from there i have copper pipe that splits into two, one goes into the head and one goes into the block where the water pump was mounted when the engine was in a car. at the other end of the block i tapped a thread and put a fitting in so the water can escape out of the engine, from there the water was tapped into the exhuast where it exits the boat.

with yours id go from pick ups to pump, from pump thru the sump then into a split pipe which would then go into the head and engine, tap a fitting into the other end of the head so the water can get out, from there plump that into ya water cooled manifold or into ya exhuast to escape.
the idea of the water going thru the sump is so that you are not just pumping cold river water into a hot engine like im doing with mine, the oil in the sump will heat the water and stop that cold water doing any damage. i havnt had any dramas with mine taking in the cold water and it runs at a great tempreture all the time.

have a look in my post that is title " is anyone good with holleys on 202s" which shows a couple of pics with the plumbing i set up, hope it helps ya abit
brian

rayza1
Posts: 1574
Joined: 12 Jul 2009, 20:24

Re: Raw water cooling

Postby rayza1 » 23 Jan 2010, 09:28

Cheers Brian, the way you have set that up makes sense, by going though the sump first will take the chill off the water, what was your reasoning for spitting the water between the head and the block? My motor has a full rolco marinising kit fitted so there appears to be 2 inlets, one in the head, the other in the block directly below but only one outlet which has a temp. sender fitted and points toward the manifold. Can you tell me what hose size you used, my fittings all look half inch.
One more thing that i'm not sure of, do you run 2 lines into the sump then 2 out or do you run 1 in and loop around the end and back out the other side. Sorry for the questions hope there not stupid !! I am starting from a very low base here.

rayza1
Posts: 1574
Joined: 12 Jul 2009, 20:24

Re: Raw water cooling

Postby rayza1 » 23 Jan 2010, 09:43

Just had a look for the post you mentioned with the piccy's and i cant find it ! How old is it?

Alan
Posts: 977
Joined: 04 Mar 2009, 22:24

Re: Raw water cooling

Postby Alan » 25 Jan 2010, 23:29

Ray,
the standard approach is to go form the pump to the sump, the manifold, then the engine. The sump is not always used (and may not be needed depending on application), also as has been said the water should not be cold straight into the block, but even more important you get much better results cooling the water cooled manifold with water from the pump/sump than from the head outlet.

If you have a standard head gasket the hole sizes are arranged to force most of the water from the block pump inlet to the back (flywheel) before going into the head then out the thermo (front), so in a boat you may need to add some water at the front of the head as well as the block. Just remember if you put two in then two must come out at the back of the head, two 1/2" hoses are OK but if you go back to one hose in the system then it must be able to cope with the flow from both hoses. Sometimes a valve is used in one of the hoses after the head to adjust the temp and is usually set fully open till you can run it in and then run flat out to adjust it.

sorry about the long winded answer
Alan

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Sunbeam11
Posts: 80
Joined: 11 Mar 2009, 21:05
Location: Canberra

Re: Raw water cooling

Postby Sunbeam11 » 27 Jan 2010, 20:50

Hi Rayza,
my 2 cents worth here.......in regards to the hose attachment when wanting to flush motor/run motor out of the water......dont do what was done on my sons boat(302 Windsor).....a garden hose attachment on engine side of water pump :roll: What was happening here is, the engine was driving the pump but never geting hose water through it, as it was pushing water away from it through the motor.(as its meant to do :D )
This was causing overheating of the rubber impellors and bearings (jabsco pump) etc because no water was going through it.
I got rid of that setup by T junction a garden hose fitting with a tap between the raw water pickups and the pump. But when doing this, I put another inline tap/gatevalve to stop the hose water from running out the raw water pickups.
So now its a matter of connect hose, turn on tap valve, turn off raw water valve(to stop water runing straight out the raw water pickups)
When done.....remebering to shut of hose tap and open the "in line" tap to allow raw water to run through to the pump when launched.......it sounds untidy, but if done properly it works and looks fine.
probably had my 50 cents worth here....sorry

rayza1
Posts: 1574
Joined: 12 Jul 2009, 20:24

Re: Raw water cooling

Postby rayza1 » 27 Jan 2010, 23:25

Hi Guys, thanks heaps for your replies, its all starting to make sense how it should go together. A while ago i purchased a small non return valve off ebay, i was thinkink of using this between the pickups and the flushing arangement thinking this might eliminate the valve that stops the water backflowing out the intakes, would this work? Also while i'm in the questioning phase has anyone had experience with rubber exhaust pipe, it seems like a contradiction that you could direct hot gas through a rubber hose but it does claim to be heatproof. I have a problem in that my manifold is on the right side of the motor and the exit through the transom is on the left but because i've built a metal engine frame (chassis) there is not really anywhere for the exhaust to cross over, not without some fancy pipe work anyway. I was thinking this rubber hose might be able to conform to the gap that i have under the frame. Any thoughts welcome. Ray

Alan
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Joined: 04 Mar 2009, 22:24

Re: Raw water cooling

Postby Alan » 28 Jan 2010, 00:09

Ray,
there is a hose made for marine use with a high temp inner lining available from most engineering suppliers, it is sometimes made with a blue (spiral) stripe and a wire spring reinforcing. The spring can make it hard to use if you want to go around corners, the last boat (EFI V8) I put together I just used standard water hose it's a lot softer,(and heaps cheaper) and has done over three years and is still good. The water going trough the hose keeps the temp down.

Regards,
Alan.

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nool
Posts: 162
Joined: 12 Mar 2009, 08:39
Location: Sydney

Re: Raw water cooling

Postby nool » 28 Jan 2010, 08:54

Hi Ray,
I'll chuck in a couple of cents too...
I don't think anyone has mentioned yet (although maybe I missed it). You might want to consider running a filter somewhere in the pickup side of the pump. Depending on how clean the water you usually run in is it might save you the pain of trying to find the blockage somewhere in your system. Probably helps the pump impeller last a bit longer too...
The setup in Mystress goes from 2 pickups, tee together into 1 3/4 inch hose into a shutoff tap. Then into the filter. Then into a tee fitting with garden hose adapter. Then into the water pump and on to the rest of the setup...
In practice I find this setup works really well as if you are running in any weedy areas you know exactly where the filter is (easy to get at hopefully!). The shutoff tap also serves as a safety valve if you ever have the boat parked in the water for an extended period of time it eliminates the risk of your boat sinking if a leak develops anywhere else in the system. I also find that with the filter at that point, when you stop the engine after flushing the water from the garden hose is forced back through the pickups, backwashing the filter meaning its usually clean enough to go next time....

Cheers!

Neil

rayza1
Posts: 1574
Joined: 12 Jul 2009, 20:24

Re: Raw water cooling

Postby rayza1 » 29 Jan 2010, 20:28

Thanks guys for your help with this, i have enough information to tackle this phase of the project. I am really keen to get her finished or at least useable, my friends have a running bet that i will sell before it's finished...... not gonna happen!! Till the next lot of questions, cheers!


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