somebody please educate me on this

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trudysduster

trudysduster

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I read that a 6 blade water pump is for an a/c car and an 8 blade water pump is for a non a/c car. I just pulled the pump on this non a/c 440 and it has a 6 blade pump on it. The new Milodon high volume pump I bought from Summit is an 8 blade pump. Is this gonna help my water problem or does it even matter.
 
I think it is the other way around.....8 blade for AC...6 for non.....more blades for more cooling
 
bbrroowwnn said:
I think it is the other way around.....8 blade for AC...6 for non.....more blades for more cooling
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Well that is what I would have thought but this is what someone posted on here 10 years ago.

The factory installed 6 blade water pumps on the AC cars with a pulley ratio that would spin the pump/fan faster to get more air flow through the radiator at low speeds. The non-AC cars got the 8 blade pumps and different pulley ratios that would spin the water pump and fan slower then the AC cars. I run the flow kooler water pump with the non-AC pulley set up.

So, I don't know and that is why I am asking because I only want to do this once.
 
Daves69 said:
........
http://www.mymopar.com/downloads/mtsc/280.pdf
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Read this and cannot tell what they are saying. Are they talking about the size of the blades themselves or the number of blades or the total width of the blades. Because the 6 blade pump has a little bigger blade on it and measures 4.25" across and the 8 blade pump has slightly smaller blades and measures only 4" across the blades. So back to my original question, which one do I use. Is the 6 blade that has been in there causing the heating problem that I have been having like it states in the ad. Another thing that puzzles me is that the 8 blade is a high volume pump. Does that mean it pumps more and if it does will it have more pressure.I am also putting a high volume thermostat in here.
 
trudysduster said:
Read this and cannot tell what they are saying. Are they talking about the size of the blades themselves or the number of blades or the total width of the blades. Because the 6 blade pump has a little bigger blade on it and measures 4.25" across and the 8 blade pump has slightly smaller blades and measures only 4" across the blades. So back to my original question, which one do I use. Is the 6 blade that has been in there causing the heating problem that I have been having like it states in the ad. Another thing that puzzles me is that the 8 blade is a high volume pump. Does that mean it pumps more and if it does will it have more pressure.I am also putting a high volume thermostat in here.
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well for what it is worth, I called Summit tech support and they told me that the 8 blade vs. the 6 blade was for more cooling. So, I guess I am going to put this 8 blade on and go from there.
 
I think I'd go with the smaller diameter too. It should take less to drive it. I'm thinking the two extra blades can more than make up for the blade size difference in volume. I don't know what pressure differences can be. I wouldn't expect anything major.
 
old school thought if you move the water too fast through the rad, it does not have time to cool when we races our 340 demon with the 6 blade it over heated put on an 8 blade pump no help, at that time an old guy that had flat head fords told me to drill 1/4 hole in every other blade on the 6 blade pump so we tried it end of problem slowed the water down so it had time to cool in the rad.
 
Daves69 said:
I think I'd go with the smaller diameter too. It should take less to drive it. I'm thinking the two extra blades can more than make up for the blade size difference in volume. I don't know what pressure differences can be. I wouldn't expect anything major.
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well I went with t new 8 blade and we will see. It is back together and waiting for paint to dry. Thanks
 
340demon said:
old school thought if you move the water too fast through the rad, it does not have time to cool when we races our 340 demon with the 6 blade it over heated put on an 8 blade pump no help, at that time an old guy that had flat head fords told me to drill 1/4 hole in every other blade on the 6 blade pump so we tried it end of problem slowed the water down so it had time to cool in the rad.
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I will keep that in mind in case this don't work out. But after I get the fan on it shouldn't be a problem. Thanks
 
do you have the fan shroud on the car if not that is your problem without the shroud the air that comes in hit the hot block and the is deflected back through the corner of the rad.
 
340demon said:
old school thought if you move the water too fast through the rad, it does not have time to cool when we races our 340 demon with the 6 blade it over heated put on an 8 blade pump no help, at that time an old guy that had flat head fords told me to drill 1/4 hole in every other blade on the 6 blade pump so we tried it end of problem slowed the water down so it had time to cool in the rad.
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This may have happened as you say "functionally" but it was for a different reason than "have time to" do something in the radiator. IT MAY have to do with turbulance in the engine block
 
I run that water pump. Some of the best money I've spent.

Make sure your radiator is up to the job. And make sure that your pulleys turn the water pump faster than crank speed.
 
The different pulley diameters between AC and non-AC is the reason, and yes AC cars got a 6-blade pump (at lease some engines, some years). Most other discussion here is correct, except the "water flows too fast" idea. A Robertshaw engineer published how that false idea arose, which I have linked several times.
 
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