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What rpm do sea water pumps need to be spun?

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Old 08-27-2017, 10:06 AM
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4 rib AC pulley? Are you trying to run a motor vehicle serpentine setup? Are you sure bolt pattern on that pulley will attach to this or any raw water pump? The press-on style is much more common and universal.
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Old 08-27-2017, 02:30 PM
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The pump I was looking at has bolt on pulley instead of Mercs press on pulley. Im making a bracket to mount it lined up with factory ac drive pulley on balancer of these engines. If I need the pump to slow down or speed up I can have other pullies made for the waterpump and change them out on the boat easily, instead of a press on.

Thats my current idea, unless someone has a better one?
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Old 08-27-2017, 04:48 PM
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None use a bolt on pulley. If you look at your original listing at ebay you can see that there was a hub which was pressed on and then the pulley bolted to it.
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Old 08-27-2017, 05:14 PM
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the pump speed is not much of an issue. small pumps running slower than crankshaft do the trick. big pumps running faster do the trick. unless you are way out of the ball park, like using an alternator pulley it will work.
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Old 08-27-2017, 07:07 PM
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Like I said in your other thread I built my own 2 stage pump very similar to a Hardin Marine one. At first I ran it at 1:1 and was having some cooling issues so I then ran it a 1.5:1 which worked great up till about 5000rpm(7500rpm pump speed) I couldn't flow enough water to keep the impeller load and I destroyed the impellers quickly.

I went back to a 1:1 pulley and changed some cooling things around and haven't had any problems lately(100+hrs)

I will say this, if you plan on using that style pump with the rear inlet/outlet it get really tight with the motor mounts in the factory AC location.
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Old 08-27-2017, 09:13 PM
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you can not spin impellers to fast as it will cause cooling water to cavitate within the housing / impeller --- hence cooling issues ( reduce volume and air in the cooling water ) .

When Volvo Penta went to the GM LS base engines they had to move the impeller / housing off the crank and relocate the assembly with a belt & pulley set up. The reason was because their GM LS marine version engines spin the engine at 6000 rpms for WOT - this caused cooling issues ( cavitation) because the impeller was spinning too fast.

Volvo used a belt and big pulley to slow the impeller down to prevent cavitation for a jist of info.

pic below

http://www.volvopenta.com/volvopenta...es/V8-430.aspx
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Last edited by BUP; 08-27-2017 at 09:22 PM.
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Old 08-27-2017, 09:18 PM
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Turbo what did you change in your system to allow it to cool at 1:1? How does your pump setup work what exactly does it consist of? I may have to pick one of those pumps apart and shorten the assembly up then, didnt think of that Turbom700

AllDodge didnt notice there is a hub on it, but the end result is a bolt on pulley setup.
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Old 08-27-2017, 09:20 PM
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Quote:
Originally Posted by BUP View Post
you can not spin impellers to fast as it will cause cooling water to cavitation within the housing / impeller --- hence cooling issues ( reduce volume and air in the cooling water ) .

When Volvo Penta went to the GM LS base engines they had to move the impeller / housing off the crank and relocate the assembly with a belt & pulley set up. The reason was because their GM LS marine version engines spin the engine at 6000 rpms for WOT - this caused cooling issues ( cavitation) because the impeller was spinning too fast.

Volvo used a belt and big pulley to slow the impeller down to prevent cavitation for a jist of info.

pic below

http://www.volvopenta.com/volvopenta...es/V8-430.aspx

Ive seen the Volvo setup, looks liek their pulley is about same as balancer diamter (1:1) Thats why I wanted the bolton pulley setup, was pretty sure Id have to go bigger on its pulley or as small as possible on the AC pulley
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Old 08-27-2017, 09:26 PM
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just an FYI as we call them -- the Merc race pumps has a bolt on pulley. I keep them on hand.
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Old 08-28-2017, 09:31 AM
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Quote:
Originally Posted by BUP View Post
just an FYI as we call them -- the Merc race pumps has a bolt on pulley. I keep them on hand.
Have a part number so i cna look up pictures?
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