Cooling system restrictor with hi volume pump

[Lyn Smith]

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?

[Mike Taylor 3601]

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

[BlueOval Ralph]

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

[Lyn Smith]

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.

[Tom Goldman]

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.

[Gary Wiegand]

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.

[1legjerry]

If your engine is heating up you should take the restricted out, most drag racing application don’t need it. If you over heat you want more flow. If you are running to cool then you should add the restrictor. Also make sure all the air is out of the system could be a problem on Mopar engine as they are harder to get air out of. If you continue to have issues call Meziere’s, and ask for Greg or Jerry.

[Sean Marconette]

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

[Lew Silverman]

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.

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!