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#1341
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Pinion,
What kind of problems have you come across using the later pump with the 64 design radiator? I'm doing a "day two" resto on my 64 GTO and trying to keep stuff period correct and appearance wise as much as possible. I would be using an aftermarket radiator with the in/out on the same side. I have a 68 400. |
#1342
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#1343
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#1344
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Jack P.
Thanks for the info. My 64 GTO used to run hot/overheat with the original 389, water pump, radiator, clutch fan and no shroud. The original engine long gone (before I knew their worth) and was replaced with a with a complete 68 400 WT with the OEM non-clutch fan. I used the original radiator and had no cooling problems. Engine rebuild is a way off but always good to get info from members for future reference. |
#1345
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I had clearanced the water pump impeller, but at the same time, had milled half the blades off the cast impeller to reduce the power consumption at high rpm's. That was something I saw in one of those magazine articles of tips. They said that Wally Booth had reclaimed 25 hp at 6500 rpm in his AMC by doing that and they said that cooling could actually be enhanced by doing it. I didn't seem to have any adverse effects by doing it. I still have the pump on one of my engines, a 455.
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Rich The real democratic American idea is, not that every man shall be on a level with every other man, but that every man shall have liberty to be what God made him, without hindrance. Henry Ward Beecher "The problem with socialism is that you eventually run out of other people's money." Margaret Thatcher |
#1346
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Yep, it was the HO engine with the OEM stainless flex fan and used a spacer between the fan and pulley. It would would run at 195-200 degrees. Back then I didn't know about the divider plate to impeller clearance but that will certainly be checked during the rebuild. I read about modifying the vanes but don't think I'll need that for the cars intended usage. Still have a lot of body work ahead first before I get back to the engine.
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#1347
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I did a little research on pump flow and efficiency. The article stated that cooling could be enhanced because less vanes slowed down the flow. That's not true. The flow at low speeds should be roughly equivalent. At higher speeds, the efficiency of the pump falls off and the discharge head is reduced, that means that maximum flow of the pump is reduced, power required is tied to flow, not pressure, Pressure is tied to the combination of flow resistance (friction) and the radiator pressure cap.
The pump will produce more head than is required and will actually heat the water up due to energy absorption when it can't use all the flow it's speed generates, much like a water brake on a dyno. That would explain the power gain from less vanes. At highway speeds, it would appear that it might actually be true that the pump will cool better because of these reasons and not because of slower flow.
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Rich The real democratic American idea is, not that every man shall be on a level with every other man, but that every man shall have liberty to be what God made him, without hindrance. Henry Ward Beecher "The problem with socialism is that you eventually run out of other people's money." Margaret Thatcher |
#1348
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Fewer vanes?
So it seems like you are saying that fewer vanes on the impeller may actually help the car run cooler. Does this hold true in general or would this only be for specific combos like higher HP...?
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#1349
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It may cool more, but not because, as the articles stated, the water moves more slowly. The vanes serve to throw the water to the periphery where the kinetic energy is converted to pressure in the expanding volute At low speeds, reduction of the number of vanes does not significantly affect the efficiency of the pump. Now, look at the volume of the pump, before and after removing the vanes. You can see that the volume per revolution goes up while the expansion ratio within the impeller will stay the same because the vane is no longer present. It seems that the flow may actually go up because of higher volume. At higher rpm's, the flow will drop off because of less efficiency, but there will still be plenty for the engine because it will always pump to its theoretical shutoff head. In other words, if the shutoff head is equal to 200', it will pump to that corresponding nominal pressure, about 87 psi. Friction in the system is a loss and will reduce the pressure point where the pump reaches shutoff.
The main difference in having less vanes is that there will be more pronounced pressure fluctuations in the discharge. The more vanes, the smoother the discharge. I can't state what the results were with my altered pump because I built the engine and installed it with the altered pump from the very beginning. I had no problems in traffic with it and I remember 190-195 on a blistering hot day. That's the hottest I remember.
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Rich The real democratic American idea is, not that every man shall be on a level with every other man, but that every man shall have liberty to be what God made him, without hindrance. Henry Ward Beecher "The problem with socialism is that you eventually run out of other people's money." Margaret Thatcher |
#1350
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Interesting...do you have any pics of the mods? Do you remove every other vane or do you grind them down a certain amount? Curious to see if any one else has tried this mod on a Pontiac that was running just a bit too warm and if it made a difference. Thanks for the info.
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#1351
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No pics. I just jigged the pump in a milling machine and cut away. Every other vane until they were flush. Instead of 6 I ended up with 3. The impeller was cast and the vanes were full-length
I'd had pump theory while studying engineering, although we hadn't gone very deeply into it, and while I wasn't too sure about slowing the flow and improving cooling, I could see that it might be possible because the extra heat picked up would have more time to be removed in the radiator. The air flow would remain the same so there would be more heat removal. Several people in here have disputed that, I don't know for certain what the final result would be. Bottom line, though, is that coolant flow at low and crusing shouldn't be reduced. The one potential problem I thought I might have was bearing or seal wear, but it never happened. As I still have it, that doesn't seem to be a problem. I probably put 40k miles on it.
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Rich The real democratic American idea is, not that every man shall be on a level with every other man, but that every man shall have liberty to be what God made him, without hindrance. Henry Ward Beecher "The problem with socialism is that you eventually run out of other people's money." Margaret Thatcher |
#1352
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Thanks for the explanation...seems like it might be something worth experimenting with....with no other changes just to see the results
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#1353
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So, long story short, what is the best available water pump at the moment? I see that Online Tube advertises one with a cast impeller. Any others available where the cast impeller is a known?
I think the rebuilt units are hit or miss.
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Greg Reid Palmetto, Georgia |
#1354
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Check that, l found the post l was looking for.
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Greg Reid Palmetto, Georgia |
#1355
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Occasionally will run out of one version or another. 5 different cast impellers were used between the 8 bolt & 11 bolt wps.
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Buzzards gotta eat... same as worms. Last edited by 'ol Pinion head; 11-19-2019 at 12:31 AM. |
#1356
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I meant hit or miss on whether you get a cast impeller. Anyway, l ordered one by Gates and hope for the best. l ordered an 8 bolt made by them last year and it was nice.
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Greg Reid Palmetto, Georgia |
#1357
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ol' Pinion Head: That's fine and dandy but how to get in touch with you? I've PM'd you in the past. No Response.
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#1358
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Feel free & drop me a PM, I've deleted near a dozen messages, have room in PM box, & will PM back.
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Buzzards gotta eat... same as worms. |
#1359
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https://www.ebay.com/itm/NOS-GM-4882...p2047675.l2557 This is the late style abbreviated impeller designed to create less drag & move less coolant. This type impeller works fine on a short deck block & works equally well on std deck height blocks that have been hardblocked to the bottom of the freeze plugs. Needless to say, the parts usage description in the eBay ad is far from correct. On the previous 8 bolt design water pumps, the early ones used a lazy impeller which was designed to move a certain volume of coolant due to the cooling needs of a '64 or '65. Later 8 bolt wps received a much more aggressive design impeller which moved coolant through the system quicker & will move the coolant too quickly to transfer heat into the coolant in an early system. On several instances, have ran across owners of vehicles having cooling problems which had sourced the incorrect cast impeller pump.
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Buzzards gotta eat... same as worms. |
#1360
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What are the two water pump lengths? A body uses the shorter one, right?
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Greg Reid Palmetto, Georgia |
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