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Water Pump Info circa 2019 |
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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A bit of common sense... though, it will kill city driving on a hot day. Though, my feeling is, if your engine is to run above 6000 RPM 90% of the time... then you would be better off with underdriven crank and waterpump pulleys. Problem is they will need to be a home brew custom setup, since nobody makes them for AMC. Though if Edlebrock has both AMC and GM patern on its water pump, and your using an ATI or early harmonic damper with Chevy pulley bolt patern, you could find under drive pulleys to work. Also I would think having power steering shared on the same belt would add side load on the pump to the torque being generated at the RPM extremes. NASCAR and many other motor sports will offset sideloading on the pump bearing by using a separate belt to the power steering pump. Though another benefit is making belt jump minimal with using smaller belts. There is a lot of subtle things to ponder that when added all together can make a big difference. |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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I suppose you could consider the early V8 pulley setups underdrive compared to the later 4-bolt crank pulley stuff.
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1968 AMX 390 w/T5
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Steve_P
AMC Addicted Charter Member Joined: Jun/28/2007 Status: Offline Points: 3806 |
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Modern cars all use aluminum pumps and many turn 7k+ RPM. If the AMC aluminum pumps are failing the problem isn't RPMs and aluminum, it's the design of the pump
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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I dont think anyone said it was the use of aluminum that is faulty. Looking at the overall dimensions, nothing indecates the castings were enlarged enough at the snout end to retain the bearing from being pulled and breaking through. The lack of proper reinforcement on GMB castings, is never going to be as strong as iron. You would need to double the thickness at around the parameter to help with the lack of material from 90° cut for bearing and seal retension. Haven't taken any of these aluminum pumps apart to verify how well chamfered, and thickness at the bearing seat, but assume they did not make it a critical part of manufacturing design. |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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ChillyB
AMC Nut Joined: Nov/14/2018 Location: PA Status: Offline Points: 371 |
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Agree with all of that. Replicating iron parts with aluminum castings skips any design effort and goes ahead with a lot of assumptions. Titanium gun parts are my favorite example of this. A well designed steel part is made out of titanium instead and advertized as an upgrade. For dimensionally equal parts steel is stronger than Ti. Ti advantage is only realized when size of part is increased such that for a comparable weight the larger Ti part is stronger, often with addition of extensive gussetting. A Ti scope mount dimensionally equal to steel is weaker but much lighter. Sometimes that is strong enough. Sometimes not.
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FSJunkie
AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742 |
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GMB new iron pumps routinely only last me about 30,000 miles before the shaft bearing gets loose and begins to wobble. It gets looser until I replace it. Six and V8.
...which is why I buy them from NAPA with a lifetime warranty and keep the receipt. No, I am not over-tightening my belts. I wonder if the shaft seal slowly leaks and contaminates the lubricant in the bearing. I've started using an anti-rust and water pump seal lubricant additive in my coolant so we'll see if that helps. Edited by FSJunkie - May/15/2019 at 3:16am |
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1955 Packard
1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5818 |
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I've been running GMB aluminum pumps at high rpm for years no failures. in circle track and drag. Hundreds of laps
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5818 |
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Another basic aluminum GMB pump at work that I've ran for years with zero issues..
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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My NAPA cast iron lifetime warranty pump started leaking after 5000 miles. Fat lot of good the warranty does me when they don't offer an early style pump anymore.
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1968 AMX 390 w/T5
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
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I wonder what accessories where on the engine that constantly broke the pump nose?
Seems like the two replies with users of the GMB pump, have tested race only motors that may not have power steering or may have a belt setup that does not overly effect torque at the nose of the pump. Since my theory with bearing break out is based on how torque is applied through the belt setup with a base copy of tye iron core using cast aluminum. |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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