Plumbing a calorifier - HELP

[Gubbo]

I am trying to connect-up a calorifier to a BMC 1.5 in a narrow-boat with skin cooling. The problem is, I really cannot see an obvious place to make the connections with the engine. There is a blanked-off outlet on the exhaust manifold/heat exchanger, but no other "return" connection. If I were to put the calorifier in-line with the engine cooling outlet pipe, then I am concerned that the reduction in bore will cause overheating. If I were to T off this pipe then perhaps no worthwhile flow will find it's way to the calorifier. I'm sorry if this seems really basic, but I really would appreciate some advice from someone who has a working installation to pont me in the right direction. (An e-mailable sketch would be magic)
Cheers
Rich G.

For details of my boat see www.sailpast.co.uk

 

[tr7v8]

1st question is it diesel or petrol?
Certainly on the petrol the heater output when it is in a road vehicle is on the back of the head adjacent to the rocker cover, from memory the other one is close to the water pump/thermostat housing.

Jim
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[Col]

Is there not a blanked off one on the circulation (engine water pump) housing ?

 

[Guest]

Should be quite easy, the basic rule is hot water out from engine into lower parts of calorifier out of cal back into lower parts of engine, on the basis of hot water rising theory, on the bmc there are 3/8 bsp plugs in the cylinder head for the out pipe 1/2 bore heater hose will do, then you need to return to the engine somewhere near the water pump or lower engine block., it will need bleeding to get the water to flow because of the water already pumping around the keel /side tanks, you could try and T into the existing ones to see what happens, I have seen it done, you will get quicker heating as well.

Paul js.