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Discussion Starter #1
Well, it seems that the newer intake manifolds do not have a water passage at the center or rear. The new Power Plus units seem to have a hole at the rear on both sides. You can put a nipple in each and connect a hose across if you so desire. But all of this begs the question, what is the direction of circulation in the water system? I used to believe that the number eight cylinder was always hotter than any other because of the circulation pattern. Now I am confused. Is there very little circulation in the actual heads them selves?

hr41pearl :cool: :confused:
 

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What motor are we talking about?

If we are talking about old small block chevys water flows in the front of the block, goes back, enters the head at varrious points, travels forward and out the front of the intake manifold. Gen II motors (LT1) reversed the coolant path going to the heads first.
 

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Discussion Starter #3
So you are saying that the water is pushed from the pump into the block and then flows up into each head and out to the radiator from the thermostat housing in the intake manifold? So, there really is no need to put cross over passages in the intake manifold, except at the front? But then why is cylinder 8 always the hottest cylinder in the V8?

hr41pearl :cool:
PS. Thanks for taking the time to answer.
 

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It is the hottest because the water has already been heated up a great deal by the time it gets to the back of the motor.


edit - I misunderstood the context of your question, my bad.
 

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I think part of the problem is that it doesn't get much flow past it. This is because of the multiple points that the water can take to get from the block to the head. This is why the water holes in a head gasket are smaller then the holes in the head or block.
 

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Discussion Starter #6
OK. The back of the motor should be hotter, but why cylinder 8 verses cylinder 7? Passenger side is hotter than drivers side? The reason I am asking, is just to make my self feel better about using newer intake manifolds that do not use cross-over tubes. Thanks for the answers.

hr41pearl :cool:
 

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Smokey Yunic observed that because of turbulance that coolant flow was more bank to bank then a constant flow thru both banks. In order to fix this he blocked off the intake crossover in the front of the intake manifold (that leads to the t-stat) and tapped the front of the heads and made a Y-pipe to help smooth out the flow. Of course he wasn't able to use a t-stat with that setup so it might not be the best setup to use on the street.

I bet that some of the newer 'brand name' intakes have looked into this and designed around it.
 
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