Meziere water pump
 

Hey everybody,

I have a Stock location new Meziere Electric water pump and wondered if it would be helpful to unblock the factory bypass in order to reduce cavitation or trapped air?

Thanks, Craig

I personally never saw a reason to block the Factory By-Pass hole from the intake cross-over to the Timing Cover, unless you were doing some unique water flow scheme.

Tom V.

You know Tom I trust your advice implicitly. Just to share – I just talked to the tech line at Meziere and the gentleman said that if I was running a thermostat it would promote a signal to the thermostat and possibly vent some air. Without running a thermostat – he said it wouldn't make any difference.
Thanks guys and take care, Craig

The tech at Meziere is correct.
I should have added in my post that if you are not running a thermostat, or a thermostat with a couple of holes in the flat part of the piece, or a "orifice ring" then it makes no difference. The idea is to remove trapped air in the timing cover behind the water pump.
If you pump trapped air from the timing cover/water pump into the block/heads then the cooling is reduced. This is the race section so not a big deal either way for cooling efficiency. Some with race intakes and special cooling plug the timing cover to cross-over passage routinely.

Tom V.

I had the bypass blocked in my previous set up with a SBC electric water pump, however, I had to reconnect it with a braided hose to get the trapped air out of the timing cover area.

We all do agree that the movement of coolant through the bypass is from the cross over to the water pump? In a stock situation it creates flow under the thermostat and allows it to respond much quicker on cold startup. If the bypass is blocked the coolant is basically stagnant under the thermostat. If there is no thermostat there really is no reason to have the bypass working - especially since every CC of coolant routed back to the low pressure area in the water pump is coolant that doesn't make the trip through the radiator. A bypass allows some hot coolant to go right back into the pump and through the engine, and the larger the bypass hole the more coolant that cycles through the engine without going through the radiator on that pass.

The trapped air in the pump area is interesting, but I would think that with the agitation of the impeller that air would mix with the coolant and be purged in short order.

I run a 160 deg thermostat with a 1/8" hole drilled in the flat part which takes care of any trapped air in the system along with crossover by pass working. Never had a problem.
New engine is getting the same thing. Have extra piston to wall clearance because of a filled block and I want it to get up to temp as soon as possible.
Trying out KREs new crossover made to go with their High Ports.

Water temp cost horsepower, why do you want it up to temp as soon as possible?

The info is right there in my post.
Extra clearance piston to wall so I want it to warm up as soon as possible. Filled block.
IMO the less time the piston is slapping around the better.
The engine will not run any hotter because it gets up to temp sooner than it would if I have no thermostat and a disc with quarter sized hole in its place.

I try to go to the lanes at 100° and stage at 120° or less if possible. A thermostat and quickly warming engine just seems odd to me in a race engine.

There is a difference between getting up to operating temperature sooner and maintaining temperature.
They are not the same thing. Why in the world would I want the pistons slapping against the cylinder walls any longer than I have too ?
Once that thermostat is open there is zero difference between that and a disc that would be in its place.
As it is right now I can hot lap the car with iron heads. Done it many times racing 2 classes at the same time. Have taken home a 1st and 2nd before but have not yet taken home two 1st place trophies the same day.
Never have had a cooling issue, why should I change ? If I have troubles then I will do something different .

Sorry wasn't saying it was wrong just not what im use to. Not one of our race cars has a thermostat in them. If it works don't change it!

Good enough.

Not sure what I am going to do about the water pump. I have a new aluminum pump. A new Morroso electric belt drive. And a CSI electric pump, used. It could use a new motor. I guess Summit sells them.
Think I will start out with standard/stock belt and fan. Then go from there.

Trapped Air and Coolant Circulation
 

Good Evening Everyone,

If trapped Air is of concern after blocking the Thermostat Bypass Port in the Timing Cover then install a Bleed Screw in the Top of the Timing Cover at the 12:00 position. Simply crack the Bleeder Screw open while filling the Cooling System and your problem is solved.

In a Racing Engine a Thermostat Bypass is of no use whatsoever. Any Coolant flowing through the Thermostat Bypass Port is effectively bypassing the Radiator and causing the Engine to run hotter than normal.

In an Engine utilizing a Thermostat and a High Flowing Mechanical/Belt Driven Water Pump, a real concern is Thermostat Head Pressure. In other Terms what I'm talking about is the Pumping Pressure created on the underside of the Thermostat by the Mechanical Water Pump. If the Thermostat Bypass is blocked, the Head Pressure can become excessive enough that at elevated Engine RPMs, the Thermostat won't open against that Head Pressure and the Engine will begin to run extremely Hot, that is until the Engine RPM Levels return to a lower Level.

A way around this is to drill Bleed Holes (As Tom has mentioned) in the Thermostat and allow some of the Coolant to flow to the Radiator. This effectively reduces the Thermostat Head Pressure without bypassing the Radiator.

While testing various Orifice Sizes to the Heater Core Inlet and through the Thermostat Bypass Port for a Performance Street Engine that utilized a Moto-Rad High Flow Thermostat and Flowkooler Mechanical Water Pump, I actually witnessed the Thermostat getting rammed (turned inside out) up into the Thermostat Housing at around 5000 RPM. It did not have any Bypass Holes drilled into it at that time.

Some food for thought is all.....

Take Care,
Laurence Snyder