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slant six chrystler cooling q's

J

jsheldon81

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Alright so i started on this boat with a seized slant 6 in it. its a 74 chrystler with volvo outdrive. ive got it to the poin now where the motor is running perfect. questions i have now are about the cooling system. Its got a sherwood dul impellor pump run by belt from motor. Im not familiar with systems like this there is a valve on a hose going to the bottom of intake manifold from a union supplied by the water pickup hose that when shut allows water to pump up through the pump but when its open it stops pumping.also motor has been overheating and i cannot for the life of me figure it out, theres no blockages in any of the hoses or manifolds. seems like pump is picking up water fine with that valve shut but not circulating through the motor. seems to me like possible backward hose or something but i have no idea how its all supposed to be routed. i know this is a long post any advice is appreciated.
 
Toise dual pocket pumps are a misery alright. Here's what (little) I know about them:

A "normal" circulating pump is a centrifugal design that can almost be 'stalled' when the thermostat is closed without a problem. That makes the warm up cycle much simpler: The flow is held back as the motor warms up, then increases as the t-stat opens, and away you go.

Not so the infamous dual pocket pump, for this is a positive displacement pumpo that doesn't like being throttled. To prevent the belts from slipping (which is what happens if the flow is shut off), a bypass of sorts--with an orifice in it--allows the water to keep moving around (but not through) the motor. The problem is that the water keeps moving AROUND the motor instead of through it! And even when the thermostat is wide open.

I suspect that this is what is happening to you. The solution is to install a gate valve in the bypass line and gradually close down on it to limit the bypass flow. That will force more water THROUGH the engine instead of AROUND it. You'll have to take your time and dial it in gradually: too much and the belts will slip at full throttle; too little and the motor will overheat.

Jeff

PS: Once you get this magic adjustment, wire the valve handle in place so it won't...you know.
 
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Alright that actually helps alot now i know how its supposed to work. i just need to figure out now if all my hoses are routed correctly. Anyone possibly gotta diagram i could look at?
 
Alright so i dropped it back in the harbor and i messed with the valve a bit. Ive got it to the point where i can sit at an idle at approximately 140-150 degrees all day long but as soon as i throttle up even a little it overheats really fast. im still not sure if all the hoses are routed correctly or not. Theres 2 hoses that go from the top ports of water pump to exhaust manifold by the exhaust outlet that stay cold but the rest of the hoses get to the point where they are too hot to touch. Any more ideas for this problem?
 
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