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Discussion Starter · #1 ·
I was at a car show all weekend and I kept seeing these cars with SBC's with the heater cores disconnected and the fittings in the manifold/waterpump plugged. Is there any pro's/con's to doing this? My car is being built as a 90% track car 10% street car. Is it worth it to just leave it connected like it currently is?
 

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Sometimes with no core with a standard rotation pump you may experience thermostat opening issues if you don't drill a couple small holes in the thermostat housing.
 

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84TA406 said:
I was at a car show all weekend and I kept seeing these cars with SBC's with the heater cores disconnected and the fittings in the manifold/waterpump plugged. Is there any pro's/con's to doing this? My car is being built as a 90% track car 10% street car. Is it worth it to just leave it connected like it currently is?
Run a thermostat, retractors require you mess around till you find the right size that will eventually bring the engine up to temp. The race guys use them to avoid any potential DNF kind of problems from a 2 dollar part, that's all. 160 is kind of cold, engine wear goes up with excessively low or high temps. On the low side the oil never gets hot enough to vaporize the water that gets into it which then forms nasty corrosion products with internal engine parts and with the chemistry in the oil. ZDDP often thought to be associated with boundary cam to lifter lubrication is also performing the same function in oil as zinc plates on a ships hull. Water wet oil uses up ZDDP at a really fast rate starving the cam for boundary lubrication. The other problem with a cold-cool engine is the need to run rich mixtures to keep it going, the extra fuel washes upper cylinder lube off vastly increasing piston, ring, and bore wear not to mention dilutes the oil lowering its viscosity. Running without a thermostat or with a restrictor greatly increases the time it takes the engine to get to operating temps. Faster warm-up reduces the need for excess fuel, vaporizes water out of the oil, most of which is a combustion product not from the atmosphere, and allows the engine to establish its proper running clearances between parts. Excessively hot wipes out the viscosity and cooks the oil, wipes out clearances, and increases octane requirements; so you don't want that either. Running the engine temp somewhere between 190 and 210 provides the best solution, to do that you need a thermostat that opens between 180 and 200 degrees.

The SBC has an internal bypass so removing the heater circuit usually isn't a problem. The bypass is intended to keep a small amount of coolant circulating to prevent the formation of hot spots inside the heads till the thermostat opens and allows complete circulation.

Bogie
 

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I think the big motivation for plugging them is convenience. Many climates don't need heat, so when something fails about the heater system (leaking heater core, broken cable, busted hose, fan broken) its easy to just plug it and not worry about it.

Many engines have internal (or external) bypasses to let water circulate in the block prior to thermostat opening, but some don't. Some rely on the heater core as their bypass.
 

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Discussion Starter · #9 ·
My whole heater system is fine less the blower motor not being hooked up yet since its a new A/C delete box. I was just curious since I saw a lot of older cars with just the end sticking out of the firewall. Wasnt sure if it was laziness or gave some kind of performance advantage etc. Wouldnt keeping the heater systems allow an engine to stay cooler? I know when the heat goes on the engine temps should cool.
 

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84TA406 said:
My whole heater system is fine less the blower motor not being hooked up yet since its a new A/C delete box. I was just curious since I saw a lot of older cars with just the end sticking out of the firewall. Wasnt sure if it was laziness or gave some kind of performance advantage etc. Wouldnt keeping the heater systems allow an engine to stay cooler? I know when the heat goes on the engine temps should cool.
An old drag racing "trick" is to run the heater wide open on the return trip to start the cool-down.

Most of the time, there is no real good reason to not use the heater, other than one less thing that can go wrong- heater hose leaking/blowing off, heater core leaking, that kind of thing.

If it's a DD, I would use the heater- if for nothing else, as a defroster to defog the windshield on those mornings that it's needed. But it's still nice to have some toasty, warm air coming from the vents when it's 30 degrees outside.

Track only (or mainly)? Who cares- delete it. ;)
 
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