Water Pump Bypass hole on block
Race Director
Joined: May 2000
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Re: Water Pump Bypass hole on block (GRX)
When the engine is cold and the thermostat closed if there is no bypass the pump impeller will cavitate and their will be no flow. You need flow to promote even warm up of the engine.
SHP/FI engines also have an external bypass - the small hose between the manifold and top of the pump casting, and the heater circuit also acts as a bypass.
The bypass also helps avoid thermal shock when the thermostat begins to open by mixing coolant coming out of the block with the cold slug than comes in from the radiator.
You want the bypass.
Duke
[Modified by SWCDuke, 6:19 AM 8/14/2003]
SHP/FI engines also have an external bypass - the small hose between the manifold and top of the pump casting, and the heater circuit also acts as a bypass.
The bypass also helps avoid thermal shock when the thermostat begins to open by mixing coolant coming out of the block with the cold slug than comes in from the radiator.
You want the bypass.
Duke
[Modified by SWCDuke, 6:19 AM 8/14/2003]
Thread Starter
Le Mans Master
Joined: Jul 2001
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From: Silicon Valley Kalifornia
Re: Water Pump Bypass hole on block (SWCDuke)
My bow-tie block has no hole for the bypass. Will drilling about four .20" holes in the thermostat create the same effect?
Race Director
Joined: May 2000
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Re: Water Pump Bypass hole on block (GRX)
If you have a heater, it functions as a bypass circuit. Otherwise you could run a line from the heater circuit outlet on the manifold to the heater circuit inlet on the water pump. I wouldn't drill the thermostat. Because water will be going through the radiator it will be slow to warm up. You want the engine to warm up as quickly as possible.
Duke
Duke
