Thread: 348/409 reverse flow water pump help

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Hey guys, been a long time since I have been on here and hope your all doing g well. I need some advice on a sepentine belt set up on a 348. I built a drive system for it and put a reverse flow impeller on the water pump as suggested, and ran it last night but the pump does not seem like it is pumping. The heater hoses are cold like no water is going through, the radiator and both radiator hoses are hot along with my engine. I ran it twice and the temp will slowly climb until I shut it off. Am I overlooking something or does in notwork to reverse a water pump.

Good to see you back! Here's a picture of the difference in the casting of the pump flow path for a standard CW vs reverse CCW pump rotation direction.

waterpump-castings-and-flow-direction.jpg

Unfortunately swapping the impellers doesn't work. Billet Specialties makes a CCW rotation pump, but they're proud of it - http://paceperformance.com/i-1347631...409-chevy.html

I understand it's different strokes for different folks, but I never understood spending money, time and effort to change something that works. V-belts work.

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Thanks ,I'll have to take it off and check what I can do. Thanks for the nice to see you again tech, I sure feel welcome here by asking a simple question and then getting called an idiot.

53Chevy5, you might look at getting a different pulley for the pump and re-routing your serpentine belt to spin your pump CW. That's how March does theirs, using an up & over the top belt route. A 348/409 pump is expensive anyway, but when it's reverse rotation it becomes just about one of a kind. Gotta think about the future, and what happens when you need a pump and you're in Slippery Rock, or worse. I looked over on Rocky Hinge's site to see what they do, but they only do SBC & BBC, nothing for the 348/409.

Originally Posted by 53 Chevy5

Thanks ,I'll have to take it off and check what I can do. Thanks for the nice to see you again tech, I sure feel welcome here by asking a simple question and then getting called an idiot.

That was not my intention, I was merely making an observation. Sorry you have such a thin skin.

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Hi and welcome back. I'm interest now as I have never heard of reversing the flow of a water pump before so if you don't mind Mr 53Checy5, why would one need to and to what advantage does reversing accomplish ?

Originally Posted by Whiplash23T

Hi and welcome back. I'm interest now as I have never heard of reversing the flow of a water pump before so if you don't mind Mr 53Checy5, why would one need to and to what advantage does reversing accomplish ?

Not to butt in, but it's simply a reversed rotation direction of the pump. "Standard" rotation creates flow tangential to a Clockwise rotation of the impeller (as viewed from the front of the engine), and "Reversed" rotation creates flow tangential to a CCW rotation of the impeller. Flow through the engine and radiator is the same with either pump, and the differences are shown in the pictures in #2 posted above.

Thanks Roger as I thought it had something to do with the flow of the water through the whole system but then, I have just proved beyond doubt that I'm just a dumb bum. LOL. So in layman terms, what does it all mean as I looked up the dictionary to see what tangential means and as I said above, I'm a dumb bum and still can't understand what advantage one accomplishes by changing the flow of the water pump.

Originally Posted by Whiplash23T

Thanks Roger as I thought it had something to do with the flow of the water through the whole system but then, I have just proved beyond doubt that I'm just a dumb bum. LOL. So in layman terms, what does it all mean as I looked up the dictionary to see what tangential means and as I said above, I'm a dumb bum and still can't understand what advantage one accomplishes by changing the flow of the water pump.

Conventional V-belts turn the water pump clockwise. A serpentine belt turns the water pump counter-clockwise. There is no advantage one over the other. Some folks prefer one over the other for whatever reasons, maybe braggin' rights down at the Sonic, I don't know. Personally, I prefer whatever works for cheap. You still have to carry a spare, V-belt or serpentine.

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Originally Posted by techinspector1

Conventional V-belts turn the water pump clockwise. A serpentine belt turns the water pump counter-clockwise. There is no advantage one over the other. Some folks prefer one over the other for whatever reasons, maybe braggin' rights down at the Sonic, I don't know. Personally, I prefer whatever works for cheap. You still have to carry a spare, V-belt or serpentine.

100% correct. When you look at the specs for a water pump they say 1) what engine, and 2) what direction does your water pump rotate. The "reverse flow" terminology came about with the advent of serpentine belts, when it became easier to rotate a pump backwards for belt routing. The terminology has caused all sorts of confusion.

As for "tangential", if you look at the impeller and draw a radial line from the center of the hub to the outside diameter, the flow is at 90 degrees to that line as it rotates, tangent to the circle. If you look at the case casting, the void hugs the impeller, and then starts to expand away forming an increasing volume for the flow. That's what captures the energy of the flowing water, and creates the pump differential pressure.

Welcome Back 53Chevy!

I love the looks of billet and serpentine - my avatar is a SMB in my 63 Nova with March setup. Below is as it was going together - even though it's a serpentine belt, I used standard rotation. How about some pictures of what you're workin' on?

Best,
Glenn

Yeah, I have no problem with the billet & serpentine. I'm running a billet setup from Rocky Hinge, but it's v-belt. The thing is, for a 348/409 they are a unique engine, so going to a reverse rotation pump on that setup is a high dollar decision, and ties you down for future pump needs. I'd try to go CW rotation.

First i'd like to apologize to tech inspector for ripping you earlier, between thing breaking at work, teenagers, lack of sleep, and then this, i was pretty much pissed at that point.
This is what i found, show cars convinced me i needed their reverse impeller and it would work fine so that is what i put in the water pump. Well tonite i took it off an filled it with water and spun it and it didnt pump water in either direction. I took the impeller out and looked at it closer and the fins need to be 3/4 inch longer to match the original. I put the original one back in and it pumps more backwards than the other one did in either direction.I'll run it tomorrow and see if it will work ok, if not, i'll figure something out. As far as why I am using a serpentine set up, this project is on its 12th yr of slowly getting this pickup together. When i was younger, with less kids and more energy I thought this thing had to be different from anything else out there so the belt setup on a 348 with the TBI seemed like a great idea. Now I wish I went with v belts or better yet, should have put the ls1 i had in it. It is different and cool, but I'm getting sick of it and just want to drive it.

here is the best pic i can find of it. bit further now but you get the idea