Big Hole and small hole in Tee

While reassembling my '68 289 Ford (Interceptor) I have discovered the T in the cooling water plumbing system (see top red circle in pic) has a small diameter (restricted) outlet opening on one side and a larger diameter outlet opening (no restriction)on the other side. (I have repainted the T blue as you can see in the bottom of the pic.) I assume the restricted end couples to the port side exhaust manifold to prevent most of the cooling water from being pumped directly into the exhaust manifold. Does anyone know if I am right or wrong? (I am guessing.)

hmmm. just remember the thermostat is an outlet, there should be no water entering the engine from that direction; I'm not saying that changes your conclusions, but something to consider

I will take your word for it Woody. It's too confusing for me. It seems to me that when the thermostat opens the engine circulating pump and the raw water pump will be working against each other. This is what made me think perhaps, I have it wrong and I should have put the small hole towards the thermostat (starboard).

Thanks all...

My '66 Mustang has the same piece in the same place. That's why I notice more water coming out one exhaust than the other. Remember, the water pump on the block pushes water into the motor, water goes out at the thermostat, not in. On mine, the smaller end is toward the thermostat, I guess to keep it from getting too cool on the back side,which would make it stay closed all the time, you know that water needs to cool the exhaust manifolds all the time regardless it the thermostat is open or closed. And it passes across the thermostat to get to the exhaust on the driver side.

The hose entering the front of the T comes from the raw water pump.

The raw water pump sends water to the large inlet pipe on the circulating pump AND to the T on the top I have pictured. (There is another T on the outlet of the raw water pump for this.)

Unless someone is definatly sure TimD is incorrect I will now flip my T over and position the small hole towards the thermostat. What I expext from this is my starboard manifold will not flow much water until the thermostat opens.

None of us want to burn up an engine or a manifold. BTW, the differences in hole sizes is not appearant when you pull the T off if you leave the old hoses connected to the T. I later yanked the hoses off and began buffing the old T on a wire wheel when I noticed the different hole sizes. (Too late). There is an arrow cast into the T that indicates flow but I have no reference material to tell me which way the arrow is supposed to point. The arrow is probably cast into your T and is plainly visable Tim. Beware CC engine rebuilders. Thanks all again!!!

I vote Tim D is all wet and doesn't have it correct. My money is on Woody who happens to be a very knowledgable Correct Craft employee for those that don't know what he does.

I'm off next week and I'll check mine to see which way it is but I know it (T)looks like Jim's.

Tim D I guess if the t-stat is put in backwards that would be an issue but since the part that acually opens the t-stat is on the opposite side of the cold water it will not effect it. It all boils down to flow and volume and mounting it the way you suggest is creating an un equal flow and restricting the flow to the engine which is the worst thing you can do so mount it any way you please I'm not riding it and don't care to.

If you think water goes in the motor at the thermostat I don't want you near my boat either. This T he refers to has nothing to do with water going in the motor. If you take the water pump off and look on the timing chain cover, those two holes is where water goes in the motor.

Not trying to be argumentative, but here's what I've experienced with my boats....

Another way to plumb the "T" is with the smaller port to the sea water pump. This would balance the flow to either exhaust manifold and would allow the block to have more of the cool water at higher RPM's since the restriction would send more water to the block. Even at high RPM's the exhaust still get's all the water directly from the sea water pump and from the thermostat discharge.

The thermostat valve cannot be pumped into after opening. The greater pressure needed to pump into the engine would force the valve to close.

The engine has more water pressure inside the block than outside the block/thermostat so again, and sorry to be repetitive, but water will not enter the block through the thermostat. In the block, the sea water pump and engine recirc pump pressures are additive...they work together. Outside the block on the thermostat side there is only sea water pump pressure which is less....especially it has the restriction to the pump.

End of discussion. I got my engine running last night. I placed the T according to Woody. Water flows and my engine cools correctly. It appears that an equal amount of water flows from each exhaust before and after the t-stat opens. Thanks all for taking the time to post. What a great forum!

I meant to say the main flow should feed the engine not the exhaust. Of course the exhaust needs cooling water at all times.

I am glad Jim got it sorted and all is well.