SB waterpump, 6 blade impeller vs. 8 blade?
#78881
06/23/08 08:23 PM
06/23/08 08:23 PM
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Joined: Jul 2003
Posts: 6,167
Maryland
GO_Fish
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Maryland
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If I understand correctly, A/C impeller is 8 blade, but 6 blade unit is recommended for non-A/c and HP applications? I read on here that the water pump pulleys are different sizes and that they are spun at different speeds. Is this true? I have been taking steps to cool down my hot running 360. I've got it running cool now when moving, but the temp still jumps quickly at a red light. Nearly to "H" on the stock guage on a long light. Engine then won't idle when its that hot, she's not happy sitting still. Presently running 9:1 comp, stock 318 2 row 22" rad with shroud and 5 blade viscous fan. Iron heads. 9.5" stall converter with deep pan and 2 medium sized trans coolers in series in front of the radiator. (68 B'cuda, non-a/c) My next thoughts are (in order) 1) high flow thermostat, 2)high flow waterpump with disc on the impeller. 3) aftermarket radiator.  EDIT: I just got done reading the MP A engine book. It says use 6 blade pumps for drag racing and/or iron head and 8 blade pumps for aluminum heads and/or oval track racing if enging cooling is marginal or overheating. No mention of street use, but it sounds like an 8 blade is in order? Not that I have a lot of faith in what MP says... 
Last edited by GO_Fish; 06/23/08 08:34 PM.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: GO_Fish]
#78883
06/23/08 09:00 PM
06/23/08 09:00 PM
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Joined: Jun 2007
Posts: 2,432
NorCal
RylisPro
top fuel
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top fuel
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Posts: 2,432
NorCal
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I use an 8 blade pump with my 340 I don't use underdrive performance crank pulley from March. At first I did but was overheating, replaced it with a larger pulley and am cooling fine. The underdrive pulley will slow down the water pump to gain a couple of horsepower also Flow Kooler has a pump with 16 blades http://www.flowkooler.com/pump.php?pid=WP1700&pid0=TS370never tried one, just a heads up 
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: Andrewh]
#78886
06/24/08 06:51 AM
06/24/08 06:51 AM
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Joined: Aug 2004
Posts: 3,333
MARYLAND
69Cuda340S
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Quote:
actually it is the other way around. 8 blade for non-ac. 6 blade for a/c cars.
the a/c pulley is smaller so it spins faster.
That is correct. The 6 blade is for the AC cars because they spin the fan faster to get more air through the radiator so less blades are used to try and prevent cavitation. The 8 blades are for the non AC cars which spin the fan slower. Both have the same shaft offset and can be interchanged. The older water pumps ('69 and earlier) are shorter then the later water pumps.
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: Andrewh]
#78888
06/24/08 10:28 AM
06/24/08 10:28 AM
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Anonymous
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Anonymous
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Most of the AC pulleys were on a big offset to the front and don't line up on car without AC. Here is a pic of an AC pulley I modified to line up with stock non-AC pulleys. It was pretty easy to do, just took the outside of an AC pulley and the inside of the stock pulley and connected them with a piece of 3" exhaust tubing. (the alternater is repositioned too, to clear turbos but has std pulley on it) 
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
#78889
06/24/08 08:48 PM
06/24/08 08:48 PM
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Joined: Jul 2003
Posts: 6,167
Maryland
GO_Fish
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Well I just came back in from doing MP's cooling system "test". Not very scientific, but all it consists of is bringing the engine up to operating temperature with the radiator cap off and watching the coolant flow across the top of the radiator. There was very little flow with the engine at idle, you could see it pick up some, but not greatly when you gave it gas. Then I did my own test for air flow. I took a 8.5"x17" piece of corrigated cardboard, and put it in front of the radiator and trans coolers with the engine idling. The fan sucked the cardboard up tight against the trans coolers and held it there, so I'm definitly getting adequate airflow at idle. I just re-read Sanborn's Oval track cooling tips at Rapid Robert's suggestion ( ), and I think my next move is installing a 8 blade pump with a homemade Flowcooler disc (since they don't sell them any more  ) and a high flow thermostat. If you look at the stock impellers, they are just a piece of flat steel, cookie cuttered, then bent into shape. This makes a cheap but leaky impeller, prone to cavitation. They clearly were more so worried about keeping assembly costs down rather than creating a superior pump. The engineers and bean counters decided what was "good enough" and that's what we get in a stock pump.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: GO_Fish]
#78891
06/25/08 12:02 AM
06/25/08 12:02 AM
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Joined: Apr 2008
Posts: 1,195
Snowing in the north!
Dart 340
moparts member
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moparts member
Joined: Apr 2008
Posts: 1,195
Snowing in the north!
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Quote:
Well I just came back in from doing MP's cooling system "test". Not very scientific, but all it consists of is bringing the engine up to operating temperature with the radiator cap off and watching the coolant flow across the top of the radiator. There was very little flow with the engine at idle, you could see it pick up some, but not greatly when you gave it gas.
Then I did my own test for air flow. I took a 8.5"x17" piece of corrigated cardboard, and put it in front of the radiator and trans coolers with the engine idling. The fan sucked the cardboard up tight against the trans coolers and held it there, so I'm definitly getting adequate airflow at idle.
I just re-read Sanborn's Oval track cooling tips at Rapid Robert's suggestion ( ), and I think my next move is installing a 8 blade pump with a homemade Flowcooler disc (since they don't sell them any more ) and a high flow thermostat.
If you look at the stock impellers, they are just a piece of flat steel, cookie cuttered, then bent into shape. This makes a cheap but leaky impeller, prone to cavitation. They clearly were more so worried about keeping assembly costs down rather than creating a superior pump. The engineers and bean counters decided what was "good enough" and that's what we get in a stock pump.
I bought a Mildon hight flow with a disk that is a nice unit.
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: GO_Fish]
#78892
06/25/08 02:12 AM
06/25/08 02:12 AM
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Anonymous
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Anonymous
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Not to change the subject, but you can only do so much with a 22" radiator.
Glad my 74 360 4 speed Chally came with a 26" radiator.
Ma Mopar alway's thought a 22" radiator was fine for a 318 or 340 in the 70-73 years. NOT !!!!
I run a 3 core 26" radiator, 8 blade impeller water pump, thermostatic fan, iron heads, 4 speed, fan shroud not needed.
No fan shroud, and depending on what thermostat I put in (160 or 180), that is exactly what I measure all day long .....IN THE HOT TEXAS SUN, STOP AND GO.
Who needs a 26" fan shroud ?
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Re: SB waterpump, 6 blade impeller vs. 8 blade?
[Re: 69Cuda340S]
#78894
06/25/08 02:26 PM
06/25/08 02:26 PM
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Joined: Jul 2003
Posts: 6,167
Maryland
GO_Fish
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IIRC, Mancini sells the early version high flow water pumps. They are cast iron though (as are most other early versions). I however have come across 2 aluminum early versions. 1 is on the 360 now and not getting the job done. The other is an aluminum '69 and earlier 8 blade that I got on EGAG last winter. This is the one I will make a disc for and run.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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