Jet drive pickup

[Vievire]

Hi so this is my jet drive that i am going to fit to a 17 ft speed boat with a 1.9 td VW engine if I am assuming correctly the pipe I have circled is the water pickup. My plan to water cool the engine is to use a gas boiler heat exchanger Link. Any advise would be appreciated.

 

[Beachbummer]

If that's the pickup tube, the inside of the jet should have some holes for the water to go through. that would be a good way to confirm. Any chance its possibly part of the mechanism to control the gate instead?

 

[Weasel]

Sounds like a fun project. I assume you plan to run the VW as a closed loop cooling system hence the need for a heat exchanger. Using a boiler heat exchanger could work but may end up quite a bit larger than a purpose built heat exchanger. You may want to investigate the various configurations from Sea-Doo PWC. Look for something in the same hp range as the VW or larger so that you have enough cooling capacity. I think you are correct, the tube circled is the cooling water supply.

 

[Weasel]

Also consider when selecting a heat exchanger, the water flow through the engine needs to be quite a bit more than the fresh water flow. The boiler plate and frame heat exchanger would likely restrict the water flow on the secondary (engine) side. Notice for reference this one has 3/4 in ports on the primary side and 1 in ports for the secondary and was intended to be used with a PWC engine. Taking a wild guess, the VW cooling system was probably designed to operate at quite a bit more flow than any PWC engine but more research is due. https://www.minijetboatbuilder.com/store/heat-exchanger-for-seadoo

 

[Liveto99]

Are you around NY? I have a diesel Jetta I’ll give you for parts.
Yes it runs im just a nice guy

 

[Vievire]

Thanks for the reply's
There is a hole at the bottom of the tube inside stator housing.
Yes I am planning to do a closed loop. Hadn't thought about the restriction of the tubes but I did think of the cooling capacity as water should be able to carry 4 times more heat away than the radiator. So i could either use two and get the pipe split equally as to not constrict the flow or buy a purpose built cooler.
Im from Northern Ireland ive already got a golf AAZ engine so just pull the cable and it runs. cheers anyways.

Edit: The heat the engine produces at max torque 150 Nm at 2000 rpm produces 31 kW of heat which would be the cooling power of one plate heat exchanger. So if two where used they would more than likely suffice.