vt ecotec v6

[al J83]

I'm looking at running a heat exchanger to cool the engine and also exhaust manifolds, (complete closed system) would running coolant out of the heater outlet to manifolds then to HX then back to heater return work?

[Paul]

Yes, it would work.
If you want to do manifolds too, it will need to be a large\oversize HX (maybe twice the size), than what would normally be needed to do that size engine - lots of heat in exhaust gas.
You'll probably need to put some water down the pipes, otherwise you'll burn up the exhaust rubbers.

[JR]

I'm looking at running a heat exchanger to cool the engine and also exhaust manifolds, (complete closed system) would running coolant out of the heater outlet to manifolds then to HX then back to heater return work?

As a rule of thumb with a water/water cooling system is this... Engine water is cooled from your unit and then to you heat exchanger then to an outlet through your manifolds... And if i read your post rite you run a heater? If so this is what i would do.. ... From jet unit to heat exchanger to heater to manifolds... IE cool the engine then use the warm water to the heater then to the manifolds.... Make sure your engine gets cooled first... Cheers JR

[al J83]

Thanks Paul the HX is off a 350 chev so is bigger than would normally be needed for the v6, so should work ok. yes will exit raw water out after risers.

JR, not running a heater but using the old heater outlet pipe from engine (water pump) to supply coolant to manifolds. I'll be running raw water thru hx then it will exit after the risers both manifolds and risers will be cooled by the closed cooling system.

I'm making up some manifolds and risers for it now.
Boat will run in saltwater hence the closed cooling system.
Boat is a HJ83 there is a post in the project section of the rebuild.
Cheers