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Restricting the bypass on the water pump

B

bk95td

6.5 nut job/addict
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Since I am putting a new HO water pump in my 94 k3500srw I'm thinking about restricting the bypass that comes from the coolant crossover just below the thermostat. I remember something in a thread here that Bill Heath does this to the latest style pumps with the spin on fan clutch.
Has anyone tried this?
The idea behind it is to force more coolant through the radiator once the thermostat opens. I have modified the hose nipple that goes on the water pump restricting it to 3/8". I'd like to hear from anyone that has tried this or seen what size opening that heath went with. I made the restrictor out of a 1/2" pipe plug. The id of the hose nipple was the right size to just tap threads into with a 1/2" pipe thread tap.IMG_1383_7.JPGIMG_1382_6.jpg
What do you think? :???::agreed::nonod::rolleyes5: or:WTF:
 
I know it wouldn't be HO but would this work on a stock early 90's pump? The 93 I got has a new pump and extra flow through the radiator would be nice even if its not high output flow.
 
If you are running the original single thermostat crossover, there is no need for this. Bill does this for the dual thermostat crossovers because they don't have the blocking thermostat like the old singles do.
 
Barry

I went with the 2000 year model HO, balanced flow WP with the Heath low temp clutch and spin on fan. I also went with Heath's bypass restrictor. It's about 1/4" or maybe 5/16th's diameter opening. I really haven't had a chance to tow with it in warm weather yet. I towed during hunting season (early Oct) and did fine, but the temps here in Oregon then were max in the mid forties to low fifties.

Coming home from hunting I pushed it over Santiam Pass with never going over 210*. The toughest part is about a 2000 ft elevation climb in somewhere around 5 miles. I was able to keep up with traffic flow which was about 45 MPH due to trucks.

I do have a dual therm crossover in my 94. It origionally had the single therm. With the single will you need the restrictor? My single stat crossover thermostat had a restrictor built into it just like oilburner described. It blocks the bypass until the coolant warms up enough to open the thermostat.

Don
 
there is a really long thread discussing wp and someone posted the dia of Bill's. I'll see if I can find it.
 
Thanks AK. That cleared it up. I guess I made a restricter for a duel stat system. I have 3 of those.
 
buddy said:
I'll give you $20 for it :)

Does Heath sell them standalone if you call? Maybe Leroy or Patrick would have them made for sale ala carte
Click to expand...

If you are asking about the restrictor for the water pump, yes. That's how I got mine. I did order his fan clutch at the same time though. I was asking his guy about the balanced flow WP and ended up saying I'd get it locally. He was fine with that. That was my only time to deal with them,but from that experience I have nothing but praise for how they work with the customer.

Don
 
I don't know but I wonder if the bypass was sized so big to help to make sure the water in the heads are flowing fast at all times and mixing thoroughly? And I wonder if you restrict the bypass you might should put a "weep" hole in one or both of the thermostats?

The whole system is a closed loop so to increase flow in the heads you have to reduce the pressure at the exit of the heads (where the stats are). The bypass allows the water to recirculate fast when the stats are closed or modulating. I think this helps insure there are no local hot spots in one or both heads. Probably not a problem if things are good and healthy but its probably a conservative strategy in case rear cylinders are heating up fast or a injector is uneven on a back cyclinder. Say if a guy lives at the bottom of a hill and just cranks up and tears off going up the hill pulling his trailer without letting the truck warm up????

A cool trick mod would be a secondary stat that blocks off this bypass route 10 -15 degrees??? over stat opening.
 
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