Cooling system restrictor with hi volume pump
 

What size restrictor is used when changing to a high volume cooling pump like a mezarie?I ve got a 3/4 hole in place of the thermostat now,and it seems like the water runs through there pretty fast,and the engine is heating up faster.How small shoud i go?

Re: Cooling system restrictor with hi volume pump
 

Most of time I use thermostat w/center taken out,if it's heating up you may need bigger hole than you have now.
You may have to trial and era it a little till you get where you want.
Mike Taylor 3601

Re: Cooling system restrictor with hi volume pump
 

Small block Fords like a 5/8" for a start

Re: Cooling system restrictor with hi volume pump
 

that is what i have in there now is a 3/4 hole.Im thinking i need a smaller hole like5/8.If you take off the cap and watch the water in the radiator ,it is really pouring out of the tubes,where it just barely flowed out of them with the old heater style motor pump before.

Re: Cooling system restrictor with hi volume pump
 

When I switched from an old low volume Moroso pump to a Meziere 50 gpm pump ,I found reducing the restrictor from 3/4" to 1/2" was what the system wanted....Take a look at the actual area of an open thermostat, it isn't very much!
You definatly want to make sure the coolant stays in the radiator long enough.
Also a hi volume pump need an equally good cooling fan to go with it .
A good shroud and a fan with at least 1500cfm is worth a lot of cooling.

Re: Cooling system restrictor with hi volume pump
 

Lyn,

What works for me on a 13+ comp. 383 sbc was to use a high flow 160 deg. thermostat with 2 or 3 small 1/8" holes drilled in the outside ring. The holes get the air out and allow for a nice "full" radiator. With more small holes or if the holes are too large like 7/32" or 1/4", the car takes too long to warm up in cool weather which is what happened if I tried to use essentially a washer with a hole in it. I also use a high flow aluminum radiator, a Meziere 35 gpm water pump and a 3,300 CFM Flex-a-lite fan which includes a shroud which is sealed to the radiator all the way around the shroud. The car basically runs what the thermostat is rated at even in hot weather. This allows me to go to the line with the SAME temp. each time. With back to back runs in 85-90 deg. air I might see 180 deg. water temp. This works for me, and eliminated trying to get the hole size "just right" with air temperatures all over the map.

Re: Cooling system restrictor with hi volume pump
 

Re: Cooling system restrictor with hi volume pump
 

If the radiator or what is rejecting the heat does not have time to transfer the heat, more water flow will not help. Slowing the flow down will allow the radiator time to pickup and reject the heat. If the radiator is not efficient due to corrosion or the tubes contaminated not allowing heat transfer that will need addressed. Water flow is only as good as the heat rejection mediums ability to remove the heat. Overflowing the heat rejection medium will do just the opposite, the heat will be retained and the temperature will increase instead.

Sean

Re: Cooling system restrictor with hi volume pump
 

Here's something I've found that takes some of the guess work out of finding the right restrictor opening -

http://www.doveengineparts.com/adjus...estrictor.html

It's made by Dove Engineering in Ohio who specialize in FE Ford motor parts. Probably overkill on my set-up with the water-pump belt driven, but I hope to upgrade soon.

Re: Cooling system restrictor with hi volume pump
 

Lyn, correction....


I just went out and took ours apart. At the water pump (elect) it has a threaded adapter from CSI to stock hose restricted to 7/8 and at the lower hose connection we have a 1.200 restrictor. Been in there for 5 years!

Re: Cooling system restrictor with hi volume pump
 

From Stewert racing web site.
http://www.stewartcomponents.com/tec...ech_Tips_3.htm

Tech Tip #3 - Thermostats & Restrictors

Thermostats & Restrictors
We strongly recommend NEVER</B> using a restrictor: they decrease coolant flow and ultimately inhibit cooling.

For applications requiring a thermostat to keep the engine at operating temperature, we recommend using a Stewart/Robertshaw high flow thermostat. This thermostat does not restrict flow when open. The Stewart/ Robertshaw thermostat enhances the performance of the cooling system, using any style of water pump. However, the Stewart Stage 1 high-flow water pump may require this thermostat to operate properly, and Stewart Stage 2, 3, and 4 water pumps simply will NOT operate with a regular thermostat because these pumps have no internal bypasses.

Stewart further modifies its thermostat by machining three 3/16" bypass holes directly in the poppet valve, which allows some coolant to bypass the thermostat even when closed. This modification does result in the engine taking slightly longer to reach operating temperature in cold weather, but it allows the thermostat to function properly when using a high flow water pump at high engine RPM.http://www.stewartcomponents.com/tec...rmostat125.jpg

A common misconception is that if coolant flows too quickly through the system, that it will not have time to cool properly. However the cooling system is a closed loop, so if you are keeping the coolant in the radiator longer to allow it to cool, you are also allowing it to stay in the engine longer, which increases coolant temperatures. Coolant in the engine will actually boil away from critical heat areas within the cooling system if not forced through the cooling system at a sufficiently high velocity. This situation is a common cause of so-called "hot spots", which can lead to failures.</SPAN>

Years ago, cars used low pressure radiator caps with upright-style radiators. At high RPM, the water pump pressure would overcome the radiator cap's rating and force coolant out, resulting in an overheated engine. Many enthusiasts mistakenly believed that these situations were caused because the coolant was flowing through the radiator so quickly, that it did not have time to cool. Using restrictors or slowing water pump speed prevented the coolant from being forced out, and allowed the engine to run cooler. However, cars built in the past thirty years have used cross flow radiators that position the radiator cap on the low pressure (suction) side of the system. This type of system does not subject the radiator cap to pressure from the water pump, so it benefits from maximizing coolant flow, not restricting it.

Re: Cooling system restrictor with hi volume pump
 

Put a 5/8 hole restrictor in place of the thermo.Cools fine now.