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Halvernaz

Removing the carburetor water cooling lines

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Have a question about removing the carburetor water cooling lines from my 72 240.
I’m planning on plugging the holes in the intake manifolds, my question is about the rest of the circuit. Can I just block the lines where they come out of the block or do I still need to connect the lines together that go around the outside of the block.

Thanks

 

 

240Z Carb Cooling System.jpg

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It is best to run a line from the thermostat housing back to the pump inlet so that the coolant can circulate before the thermostat opens. This prevents hot spots and also prevents the pump from cavitating.

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I'm going back to the original SU's from Webber's and though it was a good time to remove the carb lines.  The original thermostat also no longer works.

I live in San Diego and only drive the car in nice weather so really don't need the heat.

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When I did my rebuild, I opted to keep the carb coolant lines, it was for the reasons  that 240260280 posted above, and some other research over from zCar.com . Some people say that they can run them with no issues, I'd rather just have the coolant moving around.

If you are going to replace the thermostat, go OEM, aftermarket have accuracy and precision issues. 

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14 hours ago, Halvernaz said:

I'm going back to the original SU's from Webber's and though it was a good time to remove the carb lines.  The original thermostat also no longer works.

I live in San Diego and only drive the car in nice weather so really don't need the heat.

I only mention it because there are some applications where the coolant is used to heat a spot at the bottom of the manifold to mitigate any fuel pooling from throttle changes.  It doesn't matter what the ambient conditions are.  Maybe just carbs with accelerator pumps?  It's been 35 years since I've wrenched on a Z so I've forgotten most of the details.  I haven't dug into my cooling system yet to see if this is the case with a Z. Edit:  I just looked at the cartoon at the top of the page and it looks like this is the case, there seems to be heating spots in the manifold.  Anybody know for sure?

Edited by BDJeff

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I have mine plugged, never thought about running a line from the T stat housing to the pump inlet.  That would be easy to do now that I think about it, just go around the front of the head like the 280s.  I can't tell any difference in the way mine runs since I did that, drove it a couple of years with the flow now over a year without.  I finally got the flow going back through the heater core after replacing the hoses and the control valve.  I never run mine hard until the TEMP gauge gets set at normal after reading where somebody on here had theirs dead headed and romped on it cold and blew one of the core plugs out.  Can't have that. 

I did mine at the circles and also the intakes. 

dec4th.png

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You can delete it if you want to...just keep in mind there is zoro benefit. common sense says it will become more cold blooded.

I'm in vegas and are tuned relativity lean due to elevation, once warmed up its perfect, yet its still relatively cold blooded. drivability greatly improves after 5 minutes of driving (or so).

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I think I've been talked into keeping the water lines going through the carburetors. I have the intake off and there isn't any flow going between the two halves of the intake. It looks like the tube that connects both halves is plugged. Is there a way to clean/unplug that center tube. Do I need to remove it, can it be removed without damaging it. 

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Normal, run a rod thru it and knock out the blockage, finish it off by spaying some carb cleaner/ compressed air.

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The purpose of the water circulation  lines in the intake manifold is for heating - not cooling. When the carbs are at idle, there is a large pressure drop for the air entering the intake manifold. The large pressure drop means a large temperature drop. As the manifold is cooled, fuel droplets tend to wet out against them. This pools fuel in the manifold rather than making it into the cylinders.

This is akin to your glass of iced tea wetting the outside of the glass while sitting on your patio table.

 

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