Benefits of 4-port water bypass on a SBC?

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Re: Benefits of 4-port water bypass on a SBC?

Post by cjperformance »

16407479504846436636314686968137.jpg
The gaskets pictured are small block chev top, ford cleveland bottom.

You can see the sbc, parallel flow, has similar sized coolant holes along its length(extra under center exhaust ports) but relatively uniform front to rear.

The ford cleveland , series flow, shows far smaller holes along the deck line for token flow in particular areas and air/steam exit from the block. (Not all of these holes are drilled in the block/heads either and some cooling tweeks are made here but thats for another controversial thread 🤣) . Marked in yellow you can see the odd shape large hole at the rear of the block for majority coolant transfer to the head and then the round hole at the front to exit coolant from the head and toward the thermostat.
The bbc and ford small block works the same but the front hole is not in the gasket as the coolant(like the sbc) exits the intake face of the head into the thermostat so.
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Re: Benefits of 4-port water bypass on a SBC?

Post by fabr »

Thank you.
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Re: Benefits of 4-port water bypass on a SBC?

Post by frnkeore »

A more graphic example, is the Ford FE head gasket.
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Re: Benefits of 4-port water bypass on a SBC?

Post by ChopperScott »

sbchead1.jpeg
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Re: Benefits of 4-port water bypass on a SBC?

Post by RCJ »

Very interesting ,any pics of the other half.
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Re: Benefits of 4-port water bypass on a SBC?

Post by ChopperScott »

RCJ wrote: Wed Jan 05, 2022 3:07 pm Very interesting ,any pics of the other half.
Unfortunately, no.
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Re: Benefits of 4-port water bypass on a SBC?

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SBCWP32.jpeg
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Re: Benefits of 4-port water bypass on a SBC?

Post by SchmidtMotorWorks »

Here are some images of two CFD runs on a head I did recently, showing velocity, one with 1 outlet and one with 2.
The sectioned images are the same simulations, just sectioned to see the velocity inside the water flow.
The difference is not much where it matters along the Ex side of the head.
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Re: Benefits of 4-port water bypass on a SBC?

Post by FC-Pilot »

Thanks for showing that. I love when data proves our thinking wrong. When facts prove our theory wrong, it is time for us to come up with a different theory. Seeing those CFD images helps put things into perspective.
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Re: Benefits of 4-port water bypass on a SBC?

Post by cjperformance »

SchmidtMotorWorks wrote: Sun Jan 09, 2022 11:20 pm Here are some images of two CFD runs on a head I did recently, showing velocity, one with 1 outlet and one with 2.
The sectioned images are the same simulations, just sectioned to see the velocity inside the water flow.
The difference is not much where it matters along the Ex side of the head.
What heads are these Jon ? Are you able to show/highlight the coolant passages from block to head that are in the gasket of your simulation?
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Re: Benefits of 4-port water bypass on a SBC?

Post by Rick! »

What?! No boundary layer refinement with 3 layers of hexes? That’s CFD sacrilege. Just funnin’ ya. :) Maybe folks will see that the head gasket controls the flow in the head and external plumbing after the fact has minimal effect. I used to design heat exchangers using clear prototypes and FCD - Food Coloring Dynamics. When the long side flow met the short side flow at the exit at the same time, I was done.
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Re: Benefits of 4-port water bypass on a SBC?

Post by xxdabroxx »

Am I reading that correctly that there is minimal flow/ velocity at the back of the head with one exit and more equal flow/ velocity with two?
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Re: Benefits of 4-port water bypass on a SBC?

Post by fabr »

SMW,please educate me. I see what I think is a basically constant velocity along the ex side of head whether single or dual outlets. In that regard, I assume there is no advantage to the second / rear outlet related to exhaust valve/seat cooling ?? Am I safe further assuming that the flow volume would need to be nearly equal at all of those places to accomplish a consistent temperature along the head? The head you show is unlike a SBC with siamesed center ex ports. How does that effect the temperature spread along the head in relation to the velocity /flow? Damn this is so far over my head I hope I'm not asking stupid stuff. :lol: :oops:
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Re: Benefits of 4-port water bypass on a SBC?

Post by SchmidtMotorWorks »

That project was for a canted valve head for a Cadillac 500 engine.

The main takeaway for this is that the gasket controls the water flow for the most part.

I just made a simple block with holes in it for the cylinders, changing the block portion won't change what goes on in the head significantly.

One thing to keep in mind is that with a single outlet, the pressure is highest at the rear of the head.
So when you add a port to the rear, the flow will be even greater than the front port neglecting for drag in the plumbing.

Regarding the difference to SBC style heads.
Even SBC style heads are so different from one manufacturer to another there is no reliable general rule.

I don't know of anyone in the performance aftermarket that is doing CFD of cooling passages, OEMS have been doing it for decades.
Actually it is even rare that anyone in the performance aftermarket does CFD on the ports, they just don't employ people that know how and don't have the software or budget. That said, given the choice between CFD and a Flow Bench, I'll take CFD every time.
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Re: Benefits of 4-port water bypass on a SBC?

Post by RCJ »

Isn't the pressure being higher a good thing. Anything I did that increased the boiling point seemed to be a positive. While keeping the Temps under control was a goal, the main thing was to stop the water from boiling and create hot pockets. Once the boiling steam pockets start forming the next thing you need to see is the checkered flag,other wise it's going to be an expensive night.
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