Water circulation
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
Water circulation
If you look that small hose connecting water pump and intake manifold:
http://www.crateenginedepot.com/stor...78-P11C54.aspx
An here it is not intended to be there:
http://www.worldcastings.com/prods_pages/108052.htm
Does somebody know the logic here? Should I just plug the water pump outlet and be happy and no problems will arise?
http://www.crateenginedepot.com/stor...78-P11C54.aspx
An here it is not intended to be there:
http://www.worldcastings.com/prods_pages/108052.htm
Does somebody know the logic here? Should I just plug the water pump outlet and be happy and no problems will arise?
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
If you look that small hose connecting water pump and intake manifold:
http://www.crateenginedepot.com/stor...78-P11C54.aspx
An here it is not intended to be there:
http://www.worldcastings.com/prods_pages/108052.htm
Does somebody know the logic here? Should I just plug the water pump outlet and be happy and no problems will arise?
http://www.crateenginedepot.com/stor...78-P11C54.aspx
An here it is not intended to be there:
http://www.worldcastings.com/prods_pages/108052.htm
Does somebody know the logic here? Should I just plug the water pump outlet and be happy and no problems will arise?
Unless you know for sure...I would run a bypass of some sort. Don't want to mess with the cooling system if you don't understand why something is there.
Tech Contributor
Joined: Aug 1999
Posts: 14,385
Likes: 6,413
From: At my Bar drinking and wrenching in Lafayette Colorado
1986 and newer big blocks used a bypass hose. The one engine in your referenced picture is a late-model big block with the hose. The other engine is patterned after the early big block design and does not use the hose. When using an aftermarket intake manifold with the late-model blocks/water pumps, you have to use Edelbrock part number #8028 waterneck adapter to retain the hose feature.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
1986 and newer big blocks used a bypass hose. The one engine in your referenced picture is a late-model big block with the hose. The other engine is patterned after the early big block design and does not use the hose. When using an aftermarket intake manifold with the late-model blocks/water pumps, you have to use Edelbrock part number #8028 waterneck adapter to retain the hose feature.
So if I buy that engine:
http://www.worldcastings.com/prods_pages/108052.htm
I do not need to use a hose between water pump and the manifold - I just block the outlet from the water pump!?
How come in my old 1968 396 with a GM iron short water pump and GM L-88 intake manifold there is also a hose connecting manifold and the pump
That does not fit what you said about early big block design? Or did I misunderstand that part?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
When I was just a bit younger my elders had a '65 Impala 396/325 that had the bypass hose, and a very long stream of others I've seen have also had it, including my '69. It allows water to circulate thru the water pump and block before the t'stat opens to the radiator..
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
Now I see. The water comes back from the engine into water pump via that small hose - so it bypasses the radiator before termostat opens!?
So if you have a small drilled hole in your termostat or have a hi-flow type termostat that also has a small bend (allowing small amount of water to go through the termostat before the engine has warmed up) you do not basically need that hose in any application.
Maybe it only prevents hot spots to happen before termostat opens in applications with normal totally closing termostats. And also via circulation the warming water a bit, ensures that the termostat really gets average warmth of water and opens as soon as needed - if no circulation at all the water staying still close to termostat does not warm up that fast at all and at the back of the engine the not moving water is really hot already...
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Safety Car
Joined: Aug 2000
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From: San Antonio TX
The purpose of the bypass is twofold: 1)Allows a faster and more even warmup when the t-stat is closed by circulating the water throughout the block. So the path is into the water manifold, into the pump, and back into the block; 2)gives you a narrow buffer in the event of t-stat failure. Instead of the engine going thermo-nuclear immediately, the engine temp will rise gradually and give you an opportunity to get off the road. This is because the water temp is rising evenly instead of immediately boiling in the heads.
Drilling holes in the t-stat, as you can see, does not do the same thing as a bypass. By doing it that way, you will ensure a slower and less even warmup by introducing cold radiator water into the engine. On warm up, you don't want the water to enter the radiator. You want the engine to come up to temperature, then regulate that temp with the radiator. Besides, it would be very difficult to get the same flow volume through a drilled t-stat that you get through the bypass.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Okay...all that being said, will an engine, say a small block, run okay with no bypass?
I have a 400, with '89 heads, reverse flow water pump, and an LT1 manifold.
The water pump does not have a bypass or heater hos nipple. Just the ports that bolt to the block.
How will this affect cooling, and do I need to plumb anything special?
I have a 400, with '89 heads, reverse flow water pump, and an LT1 manifold.
The water pump does not have a bypass or heater hos nipple. Just the ports that bolt to the block.
How will this affect cooling, and do I need to plumb anything special?
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Okay...all that being said, will an engine, say a small block, run okay with no bypass?
I have a 400, with '89 heads, reverse flow water pump, and an LT1 manifold.
The water pump does not have a bypass or heater hos nipple. Just the ports that bolt to the block.
How will this affect cooling, and do I need to plumb anything special?
I have a 400, with '89 heads, reverse flow water pump, and an LT1 manifold.
The water pump does not have a bypass or heater hos nipple. Just the ports that bolt to the block.
How will this affect cooling, and do I need to plumb anything special?
...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...
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...ech_Tips_3.htm
The rest of their website has good info too and some schematics of other flow maps.
As far as the Robert Shaw tstats and bypasses are concerned, they are the only ones I know of, that fail in the open position so as to not create this:
the engine going thermo-nuclear immediately
It may be in your best interest to give Stewart's a call for your specific application.
Hope this helps
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Take a look at the mounting bosses on the SB water pump. Note there are 4 holes on one side and 3 on the other, (counting the water passages. That extra hole is the bypass on a small block.
Le Mans Master
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Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
Race Director
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From: Wellington, FL
St. Jude Donor '11 thru '25
Race Director
Joined: Mar 2006
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From: Florida
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Great paper Jud. Thanks.
My engine is an LT1 manifold on a Gen1 block. Because I'm using the '92 Camaro serp, I had to use a modern reverse rotation pump.
I know the flow will work just fine in the block, and I will get all the reverse flow benefits...but I'm confused about the bypass. I will have to use the remote thermostat housing, with the two heater hoses coming from the back of the intake manifold.
I will drill a few holes in the T-stat if that's the fix.
Thread Starter
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
Great paper Jud. Thanks.
My engine is an LT1 manifold on a Gen1 block. Because I'm using the '92 Camaro serp, I had to use a modern reverse rotation pump.
I know the flow will work just fine in the block, and I will get all the reverse flow benefits...but I'm confused about the bypass. I will have to use the remote thermostat housing, with the two heater hoses coming from the back of the intake manifold.
I will drill a few holes in the T-stat if that's the fix.
My engine is an LT1 manifold on a Gen1 block. Because I'm using the '92 Camaro serp, I had to use a modern reverse rotation pump.
I know the flow will work just fine in the block, and I will get all the reverse flow benefits...but I'm confused about the bypass. I will have to use the remote thermostat housing, with the two heater hoses coming from the back of the intake manifold.
I will drill a few holes in the T-stat if that's the fix.
