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Discussion Starter #1
I'm in the process of swapping my old water pump with a brand new Edelbrock 8840.
It's on a 351W, running "outside" the serpentine belt, so I believe Counter Clockwise.

When looking at the impeller, the old one seems CCW, but looking at the Edelbrock 8840, the impeller seems to be CW.
The 8840 is supposed to be CCW, but I have doubts... impeller design seems counter intuitive to me.
It's difficult to see on the 8840, the the blade seems to "catch" the water CW...
 

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FFCobra Fanatic
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See if the bolt pattern of the pulley matches up with the Edelbrock water pump. The CW rotation have a different bolt pattern for the pulley to stop you from just bolting it on. The notes on Summits website for that part number are as follows:

Notes: 5.750 in. hub height. Gaskets included. Fits all 1986-93 5.0L V8s using a serpentine accessory drive belt. Reverse rotation. Not for early model 289-302 V8s. Has heavy-duty 3/4 in. ball/roller bearing. Dimension from block surface to hub: 5-3/4 in. Inlet diameter 1.78 in.

That would lead me to believe you are all set, spin it with the back of the belt and it will turn the correct way. Hope this helps!

Mike
 

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Based on the coolant paths out to the two sides of the block the two pumps are the same. If you google sbf water pumps you will see the difference in the path.

Rick
 

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ALL water pumps flow from the center to the outside, doesn't make any difference which way they turn. If the fins are angled in the same direction then they turn in the same direction. The old pump is counter-clockwise, can't make out the fin angle on the new pump. Now the twist is some performance pumps have fins that aren't angled and can rotate in either direction. But judging by the discharge shape of the ports they are the same.
 

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Both impellers have blades at similar angles. The cast impeller appears to have curved blades,
Both are CCW and should fit the smooth pulley.
 

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Discussion Starter #6
Based on the coolant paths out to the two sides of the block the two pumps are the same. If you google sbf water pumps you will see the difference in the path.

Rick
Thanks Rick, yes the path are definitely the same. Even the back plate has the same 2 round "universal" holes.

ALL water pumps flow from the center to the outside, doesn't make any difference which way they turn. If the fins are angled in the same direction then they turn in the same direction. The old pump is counter-clockwise, can't make out the fin angle on the new pump. Now the twist is some performance pumps have fins that aren't angled and can rotate in either direction. But judging by the discharge shape of the ports they are the same.
Thanks Rich, yes it's difficult to see the fins and even worst trying to get a picture of those :grin2:

See if the bolt pattern of the pulley matches up with the Edelbrock water pump. The CW rotation have a different bolt pattern for the pulley to stop you from just bolting it on. The notes on Summits website for that part number are as follows:

Notes: 5.750 in. hub height. Gaskets included. Fits all 1986-93 5.0L V8s using a serpentine accessory drive belt. Reverse rotation. Not for early model 289-302 V8s. Has heavy-duty 3/4 in. ball/roller bearing. Dimension from block surface to hub: 5-3/4 in. Inlet diameter 1.78 in.

That would lead me to believe you are all set, spin it with the back of the belt and it will turn the correct way. Hope this helps!

Mike
Thanks Mike, I didn't notice the pattern difference between the CW and CCW but yep, it does match

Both impellers have blades at similar angles. The cast impeller appears to have curved blades,
Both are CCW and should fit the smooth pulley.
Thanks Mark, that's those curves which got me suspicious, they seemed to be designed for CW, but I guess it's designed to expel the water out to the inlet ports.

I need now to mount and test, but no rush, have to wait for the snow to melt... :crying2:
 

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FFCobra Craftsman
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What is funny to me is that my 408, built on an 84 351 block, has the style water pump that has the sheet metal back cover.
 

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Discussion Starter #8
What is funny to me is that my 408, built on an 84 351 block, has the style water pump that has the sheet metal back cover.
It’s not on the picture but actually both my old and the new pump also have a sheet metal back cover with the 2 holes matching the coolant ports on the block.
I just had to remove them to expose the impellers.
And also to apply some RTV on both side of each gasket.
 

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Official OLD GUY
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Rotation basics

This chart might help . . .

Remembering that the pump must be looked at from its back side - all references to orientation are from the drivers seat.



"Normal" rotation for SBF's is the image on the right, counter-clockwise. "Reverse rotation" pumps are the ones used on serpentine belt systems.

IF your pump spins in the same direction as your crank, it's "standard" rotation.

HTH

Doc :beerchug:
 

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Discussion Starter #10
Hi Doc,

My water pump is definitely running with a Serpentine belt, and being driven "outside" of the belt loop, the pump is definitely Counter Clock Wise.

Your drawing explains it clearly, I was under the impression that the blade were supposed to "scoop" the water, but I was wrong, it's supposed to "push" it out ;-)
We learn everyday! Thanks!
 
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