cooling ideas?

[aztec]

hi, the choice is buy header tank/exhaust manifold/heat exchanger for about 350 quid.

or

buy a tube heat exchanger, keep cast exhaust manifold, fit expansion tank from a car for about 140 quid.

am i missing something or could i save myself a few quids, or are there associated problems with tube coolers that i'm not aware of (yet) most of my mates use them in fishing boats??

whadda ya fink?

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[tr7v8]

Assuming these are car exhaust manifolds they are going to be B!!!dy hot, like cherry red and a definite fire hazard (right up your street). I think for higher performance engines you may struggle with keel cooling as it's generally used for raggies and slow canal boats. You'll also need oil coolers on petrols fitted in a power boat as otherwise the oil fries. So you you'll be needing to get rid of a fair bit of heat. The Volvo 140 2.1litre heat exchangers are about the size of half a biscuit tin and they once slightly fouled up are marginal.
Personally I'd go for heat exchangers and header tanks from a car. You'll probably find some s/h if you shop around.

Jim
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[spannerman]

If the manifolds are not water cooled they will need to be, as there is no cooling air blasting through the engine bay as there is in a car. Two things will happen, as Tr7v8 pionted out its a high fire risk, also you won't get the performance out of the engines as if there is an excess of warm air in the engine room the engines will suffer from fuel boiling off, hard starting when warm, and reduced power. This will be the case if you rely on air to cool the manifolds.
I would invest in the water cooled manifolds, buy a heat exchanger, and a header tank from a car, I know this works as I am too tight to buy a pukka Mercruiser kit so made up a kit for my V8, I used an expansion tank from a Volvo 340, as this has a bleed which you need from the highest point on the motor to get rid of any air pockets. You may need to play around with thermostats as you will need to drill a couple of bypass holes in the stat flange so that there is 'some' circulation before the stat opens.

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[aztec]

sorry boys, misleading post!

i'm using 1600 diesel engines. running at 3000 rpm tops. the ventilation into the engine bay is'nt a problem as there is to be vents in the quarters. the air into the engines will be from an external supply via remote filters (noise more than poo)

can't bring myself to part with loads of cash if i don't need to!

cheers for the replies so far tho'

steve.

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