Heater core hose quick disconnect upgrade

[evilunclegrimace]

That's called cavitation, and you really don't want it. The restriction would actually aid cavitation.

The pump moves the coolant faster than the restriction allows it to flow, causing a pressure drop which allows the coolant to boil, i.e. change state to a gas, at the inlet of the pump. Coolant flow stops until the flow through the restriction catches up and pressure restores at the pump, which cannot occur until the pump slows back down.

Cavitation causes spikes in coolant temperature and possibly exhaust seat cracks. It also causes pitting and wear in the water pump inlet.

The restriction at the intake gasket does not cause cavitation because there is more than one flow path in the cooling system AND the system is under pressure

 

[Schurkey]

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This is what you are saying happens in a TBI engine? This is the way the coolant flow was on older pre TBI engines and even then it flowed from the rear to the front. The main differences for a TBI engine are that the heater core is fed from the rear of the engine where the coolant is hottest at operating temp and that the heater core return is feed directly to the radiator.

Well, sort of. The TBI heater core supply more-or-less begins near the thermostat area. The intake manifold has a coolant passage from the thermostat area to the right rear of the manifold. Then the famous restricted quick-coupler--the thing that began this whole long thread--supplies the heater core through the matching quick-coupled heater hose. Yes, the heater return can go directly to the water pump inlet, or to the radiator. My vehicles have it going to the rad. I don't know about Camaros or Caprices or whatever.

The restriction has NOTHING to do with system pressure, The pressure is equal through out the system.

No.

There's two "pressures" acting on the coolant. There's static pressure--from the radiator cap. THAT pressure, which would be equal thorughout the system, is in fact modified by WATER PUMP PRESSURE, which is dynamic. Any pump you can think of works by lowering pressure on the inlet side, and raising pressure on the outlet side. If there was no pressure difference, there'd be no coolant flow. If the pump is moving coolant--there's a pressure difference.

A centrifugal pump (within the limits of it's capacity) becomes dramatically more-efficient as the RPM increases. Double the speed, (rpm) you get much more than double the pumping action.

On the outlet of the pump, you've got static (rad cap) pressure PLUS dynamic (water pump) pressure, added together.

On the inlet to the pump, you've got static pressure MINUS water pump pressure.

At the heater supply outlet fitting, there'd be static pressure plus some amount of dynamic pressure. Not 100% of dynamic pressure due to some restriction in the block as the coolant has to flow around cylinder barrels and up through coolant openings in the block, head gasket, cylinder head, etc. Even so, at high rpm, you've got way more than 16 psi at the heater supply fitting on the intake manifold.

I could see it surging during higher rpm periods, near the pump, but it would likely be momentary as it would equalize.

Dynamic pressure--increased pressure due to the pump on the pump side of any restriction in the flow path--and there's heaps and piles of flow restrictions of varying amounts.

That's called cavitation, and you really don't want it. The restriction would actually aid cavitation.

There is such a thing as cavitation. What I'm talking about is not a result or cause of cavitation.

The restriction at the intake gasket does not cause cavitation because there is more than one flow path in the cooling system AND the system is under pressure

Even a pressurized system can cavitate under the right conditions. Even a "non-pressurized" system is still under atmospheric pressure.

 

[evilunclegrimace]

http://asecertificationtraining.com/water-pumps-in-automotive-engine-coolant-systems/

Read this!

 

[Schurkey]

"The water pump is a centrifugal pump that can move a large volume of coolant without increasing the pressure of the coolant."

First part true. Second part, not so true.

 

[Erik the Awful]

The restriction at the intake gasket does not cause cavitation because there is more than one flow path in the cooling system AND the system is under pressure

Coolant is pressurized to raise the boiling point. If the water pump pushes the coolant out faster than it can return, the pressure drops at the inlet to the water pump and the coolant boils, cavitating the pump. It was a common problem on first-gen RX-7s if you regularly spun them over 6,000 rpm. The solution was installing a reduced-diameter crank pulley to slow the water pump down. If you were spinning to 9,000 rpm there was a larger water pump pulley you could also install, but it wasn't recommended for street driving.

It's true the centrifugal water pump is not a positive displacement pump, but that doesn't mean the pressure of the coolant isn't higher at the pump outlet than it is at the inlet. If the pump weren't creating pressure, how would coolant even flow through the system?

 

[Donald Mitchell]

You are overthinking a simple long proven system. The only reason I can see for the restriction is that the heater core actually doesn't need a lot of flow to do its job of transferring heat to the cabin. I have never seen one on earlier cars but cars with ac did have a heater control valve, and a 1969 Z28 camaro with a high revving 302 did not. On another note, If you don't use the factory replacement for that hose how do you get it to curve enough without collapse. I want to do this but as yet I haven't figured it out. I used a heat gun with little result.

 

[El Tigre]

AN-10 socketless hose/fittings...

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