exhaust port divider ??

my way

Well-known member
CI tech sounded neutral on using the port divider and didn't sell one with their headers. What's the experience here?
The CI alloy head is divided, but then the ports are larger too. What do they do down south and across the pond?
My Way
 
Yes there is some benefit to using the port divider for a little added performance that the separated ports will give. That is if you are willing to take the time to carefully grind it to fit. Many people also tack weld it so it stays in place (a very good idea to do), otherwise as the engine warms up and expands if it's not fitted very tightly it will loosen up and rattle. Good luck :nod:
 
thanks Bubba- ya found out about the grind deal. About every feature has to be adjusted. and maybe a little over adjusted here and there.
Went back to grinding after posting the question. Do have nickel rod for cast iron so It will get done.
As far as expansion - the devider looks like cast too and with poorer contact to the water cooled head, so maybe it will expand more than the head??
My Way
 
If you plan to use headers i would recommend the center divider. Reason being those center cylinders will get benefit from the headers.
If you have a stock engine with a stock cast iron exhaust manifold i would not install the divider.
 
I ran with and without.

Honestly, I didn't notice a difference. Its one of those, if I'm there, I'd put it in. Otherwise, it's not worth the effort to do it on its own.

Regards,
 
my way":1ow5d9x1 said:
thanks Bubba- ya found out about the grind deal. About every feature has to be adjusted. and maybe a little over adjusted here and there.
Went back to grinding after posting the question. Do have nickel rod for cast iron so It will get done.
As far as expansion - the devider looks like cast too and with poorer contact to the water cooled head, so maybe it will expand more than the head??
My Way

That's a good question My Way, I think it could depend on a number different things. Like how close is the port dividers cast iron material that they used to make it and it's density in comparison to the head casting also how tight it's fitted. Heat removal can happen by transfer if it's touching or radiant by air. My best educated guess though is that it won't expand more then the head does and likely less. Good luck :nod:
 
If you leave a enough material that it doesn't retreat behind the gasket surface, perhaps stand out ever so slightly, you will get an interference fit. That will keep it from moving once the header is clamped down nice and tight.
 
Welding should have been done before head went to machine shop, and welding on cast that's been heated very high many times like the edges of the exhaust port causes problems at least in my experience, and also in this case. Any rate I got it done except for a final effort to get a surface that will hold a gasket?? Should have tried for the clamping fit. this will not be a daily driver, so a little rattle might not be noticed for the limited life of this engine.
Hope this is helpful for any one considering this. Thanks All
My Way
 
I had a commercial welder put mine in. He ground little triangle voids on the three outside corners and only put a blob of weld right there. He said the rest could work as it got hot, but he was still skeptical about welding cast. Anyway, I never have had any problems. At the very least the gasket held it in place.
 
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