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Water Pump Info circa 2019 |
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Hurst390
AMC Addicted Joined: Apr/20/2008 Location: secret Status: Offline Points: 5752 |
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SC/Hurst Rambler
11.62 120 100% Street Legal |
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9081 |
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Thanks! Seems that side loading with accessories is not the issue with bearing breakout. The only other thing would be cooling fan type. Looks like you have chosen proper mechanical fan for your application. As noted in the picture, a 4 blade, which uses less torque for high rpm use. So, in short there is no reason for nose breakage from overall design, if properly installed, and use with a proper fan for engine application. As stated by the reply that brought up breakage, a heavy clutch fan in high performance use shouldnt be used. I dont know of any strip cars using them, if any thing, electic fans are common. Well, it seems like a lot of hot air on theory with why there is pump breakage. Maybe a wee lot of bad castings, who knows? |
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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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Here is a theory based on mostly nothing. The fan will have considerable gyroscope effect that torques it sideways under acceleration and deceleration. Holding a spinning bearing isnt a tough job and the side load on the bearing due to belts and weight of fan seems insufficient to break anything. But that gyro effect can apply side loads that seem disproportionate to the static weight of the loads hanging on it. Now cantilever all of that gyro load out on the end of a shaft with an extension.
Some of you guys are obviously running thise pumps hard and not breaking them. But that's the nature of design reliability. Rarely is the design so bad that it fails most of the time. But a premature failure rate as low as 5% is still pretty awful. And a lot of customers will feel OK about the product because theyre part of the 95%.
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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The race cars are using a light weight fan or electric fans. A street application will use a heavier fan, and in some cases a clutch fan. I suspect those using a light weight fan or electrics fans (no engine fan) don't have an issue, but running something heavy like a clutch fan causes breaking.. as already mentioned. They seem to hold up fine at more normal street rpm though (only occasional short burst to 5000 rpm or so, hardly ever higher). Not really necessary here, but I'll point out that the stock AMC pump (or the MOPAR!) wasn't designed to work at sustained high rpm. Stock pumps are designed to work well in normal driving ranges -- like idle to 3000-3500 rpm. Start getting over 5000 for any length of time and I can understand having issues!!
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Frank Swygert
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9081 |
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Its mostly about the snap of sudden change on rotational forces. The spin of the fan and its mass, along with accessories with pull the nose to the driver side, and torque twist. Plus if one is to romp and stomp roller coaster rpms, they are begging to snap a nose off, when a mechanical fan is too great for the demands of the application. |
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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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SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5428 |
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There are at least 2 guys in the Detroit area that rebuilds original water pumps if anyone is interested. I have been taking a few of my cores with the part numbers in to this fellow. He is very reasonable, ships, and has a one year warranty. I will post up pictures etc. when I get a chance. Dan Bailey 4706 Detroit St Dearborn Hts, MI 48125 313-530-2893 Edited by SC397 - May/16/2019 at 7:31am |
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bigbad69
Supporter of TheAMCForum Joined: Jul/02/2007 Location: Ottawa, Ont. Status: Offline Points: 6614 |
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There are lots of variables. If the bearing and bearing retainer (in this case the pump casting) design is marginal, some will fail, and some won't.
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69 Javelin SST BBO 390 T10
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Red Devil
AMC Addicted Joined: Jul/10/2007 Location: Canada Status: Offline Points: 1743 |
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I have a Flowkooler aluminum pump (GMB with Flowkooler impeller) with a thermostatic clutch 18" fixed fan (heavy compared to a stock flex fan), PS with AGR pump, Delco alternator on my '74 Javelin 401. Sees 6500 rpm on occasion (rev limiter). Been fine for 10 years, but just a summer cruiser so not lots of miles. Different combinations will have different harmonics and different loading. If you're concerned, save up and buy an Edelbrock pump.
Hope this helps, RD.
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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So I ordered the GMB-1040P, which is their aluminum high-performance pump version. Again, here's their lineup: 1) 110-2908: Cast iron
stock replacement pump, long housing, late model design. 2) 110-1040AL: Aluminum housing long late model pump. 3) 110-1040P: High-performance version of 1040AL. They tout the 1040P high-performance version as having a better impeller and better bearings, and compared to the stock replacement version that appears to be true. The shaft on the 1040P is larger than stock at 0.750" diameter, and is turned down to 0.625" for the pump mounting flange, which is really nice as then the bearings are larger. Unfortunately it does prevent us from pressing the flange on further to make a long pump into a short pump. The impeller on the 1040P is a different shape than the stock replacement version, having the same number of vanes, but they are longer. The lower cost 1040AL appears to use the same impeller design, so I expect that the difference between the 1040AL and the high-performance 1040P is the larger shaft/bearings used in the 1040P. Here you can see the larger shaft diameter as it comes out of the pump housing, then back down to 0.625" for the mounting flange. For comparison, here's a NAPA pump, the shaft is 0.625" diameter all the way through.If you consider that the GMB pump flange location is actually 3/8" further out than the stock pump shown (late model vs early pump), you realize that the GMB housing extends out further than the stock unit did, placing the bearing closer to the load. And if you compare the relative diameters of the bearing housing area to the diameter of the fan/pulley flange, it's looks like the GMB casting is a bit larger OD in the bearing area. And it has a bunch of reinforcing ribs as well.
Edited by Greyhounds_AMX - May/21/2019 at 12:44pm |
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1968 AMX 390 w/T5
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Greyhounds_AMX
AMC Addicted Joined: Nov/14/2009 Location: Kansas City Status: Offline Points: 1268 |
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I measured and found that the GMB aluminum pump only has 3/16" of clearance between the back of the fan mounting flange and the shaft seal face.
So even if the lower tier 110-1040AL version has a 0.625" shaft all the way, there's not enough room to push the flange on further and make it line up with an early crank pulley. It would need to be pressed on 5/16" further, and there's only 3/16" available.
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1968 AMX 390 w/T5
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