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'73 Camaro NETO/N
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Discussion Starter · #81 ·
Very interesting. That's only part of the picture on a different head, though. The whole picture would include CFD of both the sbc block and heads together, with both standard and performance head gaskets, with and without the bypass.

 

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Very interesting. That's only part of the picture on a different head, though. The whole picture would include CFD of both the sbc block and heads together, with both standard and performance head gaskets, with and without the bypass.

Where is the head water jacket in that video?
Without it, it mean nothing.

Next time you have 5 seconds to spare, write all you know about CFD and casting design.
 

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Enough to know that fluid flow in a Cadillac 500 is not going to display the same as a small block Chevy. I do appreciate you sharing, sir.
Not really much difference in how the water flows.
Anyone that puts in a reasonable effort in a water core design will get a good result.
The port layout sequential vs mirrored doesn't matter much.
I have developed many of both.
 

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Chopper Scott,

Just curious, what is your goal?

Cooling, keeping center exhaust cooler, consistency,...

I have a 355 short block that I probably need to disassemble since it's been together for a while. I was going to use the bypass hoses since the intake has provisions for it, but that was 10+ years ago! Now I'm not sure if needed or any benefit.

If I ever get off my ass and assemble it I'm thinking air bleeds. They probably aren't needed as well..

I'm also just a backyard builder that does my own engines.

Best of luck with your project.
 

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I have cut open hundreds of aluminum heads, both new and used.
The most common undiscovered problem in after-market aluminum heads is that water cores crack during the casting pour and then fins are formed that block the flow partially or entirely.
With the profit on engine castings being as low as it is, no one is checking for open passages on most heads.
An interesting thing to know is that on aluminum heads, the heat distributes amazingly well even when there is little or no water flow in a large portion of the head.

One of the best things you can do to check out a head is try to force a TIG welding wire through the passages.
If you find blockage, you might be able to punch through it with a hard rod (like a mold ejector pin) as a chisel.
 

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Hello there. Does anyone have any solid data concerning the benefits of using a 4-port water bypass on a small block chevy manifold? Does it help equalize cylinder temperature? Release steam pockets? Drag race or circle track use? What is your experience?
Yes it is an improvement. I'm surprised that in 2021 equal cooling of each individual chamber is still ignored by so many.

You want every cylinder doing the same thing. Same air flow, same compression, same fuel, same timing, ergo....the same threshold of detonation for each cylinder. Cylinder cooling is a very big part of that.

The engines that make longer runs are more affected by it, such as circle track and mile events. When I got into this racing gig full time over 40 years ago it was already figured out. Engine builders were running 6 exits on a Small Block Chevy. The four corners had exits, which was made easy with the manifolds already made to accept lines from the back to the water neck, then we added two more in the center to let water exit on the intake side in the center of the head, to cool the siamesed exhaust port portion of the head. On some engines we also ran fresh water from the water pump to the exhaust side of the heads in the center to help cool the siamesed exhaust port section some more. When that part of the head ran too hot the aluminum would anneal and it was very easy to blow a head gasket there.

Later on guys were even drilling small water ports through the deck to let water flow through the thin section of the deck. Yates heads had this IIRC.

Steam lines that allow air out of the top of the water jacket are good. Water boils off the back side of the chamber, just like dripping water on a hot skillet. There are3 ways to get around it. One is to raise the water jacket pressure a lot which raises the boiling temperature of the water. The NASCAR guys have done this for decades. Most drag guys won't do this. Or you can refrigerate the engine like Comp and Pro Stock does now. Or you can run steam lines if you're up for the work. Steam lines on a Buick headed Comp engine were worth 10 hp on even a short dyno pull.

The very best cooling system I have ever witnessed was reverse cooled, where you have a log manifold feeding fresh water onto the back side of each chamber, and have 4 exits on the block.

Mirror polishing the chambers reduces flow of heat into the water jacket too. Again, there is some work involved.

I read RW Tech's response to you on ST. He's a good friend of mine. And if he talks to you he is trying to help you. He's correct in what he said about water needing to come in on the exhaust side of the head.... then flow across towards the intake side, then exit. You can google images of NASCAR heads and can see heads that have a water exit for each cylinder on the intake side. There was a separate water manifold that bolted on before the intake manifold was installed.

The LS and LT chevy are horrible for cooling. Luckily Cometic will make a head gasket with the water ports anywhere you want them so it can be corrected. That and 4 corner exits will turn a track car that goes into limp mode into a car that runs a full session. It will turn a power adder car that melts number 7 and 8 piston into one that makes a full weekend at a Mile event.

The thing to keep in mind is...you need solid water on the backside of the chamber. If not, and there is not good water contact with the chamber things go into thermal runaway. The chamber walls superheat, and the engine detonates and blows.

What Jon said above about water jackets restrictions is spot on. Look at the water jackets. I have to port water jackets on some heads. There is an LS7 head on the market that has a bad reputation for overheating. It's a simple fix. The water passages that go around the top front head bolt hole are less than head the area of a factory head. But after porting, and installing a custom head gasket with improved passages, and water exits on the back of the heads....life is good.

Keep looking under every stone.
 

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Hello there. Does anyone have any solid data concerning the benefits of using a 4-port water bypass on a small block chevy manifold? Does it help equalize cylinder temperature? Release steam pockets? Drag race or circle track use? What is your experience?

For example, here is my 434 with an Edelbrock 2892 SVII with the rear ports plumbed to under the thermostat...

View attachment 302903
This modification helps even out the temps from the rear cylinders to the front.
Often the sbc will have a larger bore but shorter stroke on the front two cylinders.
This progresses as you work towards the back of the block, farther back you go
the smaller the bore gets and the longer the stroke.

Nascar engines of old suffered from this too. Common SBF trick before the FR9.

This water bypass helps even out the temps thus helping the aft cylinders.

Let the haters hate.

R.I.P. Robert Yates
 

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SB2.2 cooling mods - Don Terrill’s Speed-Talk maybe Chris will chime in since he's BTDT 15 years ago.

https://www.stewartcomponents.com/index.php?route=information/information&information_id=13 no pitchers but text. I don't know if there will be a redirect due to google thinking stewartcomponents is a compromised site.

More stuff. SB2 cooling help. - Don Terrill’s Speed-Talk

Joisey boy can search all over the net for pitchers and post them on this scrapbook thread. It doesn't take much digging to get info from other sources. Still no data though except for more laps between head gasket replacement. If you google this, one can find all the modified SBC coolant routings you desire. sb2.2 coolant routing pictures - Google Search

Valley Plate Assembly - SB2.2 - KarlKustoms.com

Page 170 shows "twice pipes" Chevrolet Performance - Full Performance Parts Catalog 2015 Pages 151-200 - Flip PDF Download | FlipHTML5

SB2.2 Heads Warp's BTDT too. :)
 

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Discussion Starter · #92 · (Edited)
‘Joisey boy’ enjoys his scrapbook. In the case of this topic, SBC is referring to the classic Gen 1 SBC with 23 degree heads, not SB2 or SB2.2. But as long as you’ve brought it up, that valley plate assembly on page 170 has cast in integral passages to equalize coolant flow from the front and the rear of the cylinder heads. Basically the same principle as the external lines on the manifold.
 

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86 Camaro, 8.8 rear, 700r4, 383 in the works
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Wow much information here and on ST, this seems to be an interesting area still with some gray. I too am interested in this modification, I'm building a 383 street driven engine with an intake tapped in the rear corners. I would like to do this bypass honestly mostly because I am a plumber by trade and like the way anodized aluminum and stainless braided hoses look. I also would like to plumb water from the water pump to the the area on the head between the exhaust valves. I feel that adding additional water to the heads in this critical area and removing the water at the 4 corners of the intake will aid in potential trapped air and gain some sort of cooling aid. Like anything this seems like a good idea to me but could not produce any results and be a waste of time and money, this could also lead to negative results... only one way to find out!
 
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