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Small diameter water pump pulley #2958829
08/29/21 08:46 PM
08/29/21 08:46 PM
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Washington
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hemienvy Offline OP
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hemienvy  Offline OP
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Washington
For big block, p/n 3698907, this is a single groove pulley, about 5-7/8 OD.

The pulley groove sits pretty far forward, it's "2 belt groove widths" farther forward than my 6-7/8 pulley.

Is this about the smallest diameter W/P pulley there is ?

Is there a pulley that is only sits one groove width forward ?
Or maybe a small diameter double groove pulley ?

Re: Small diameter water pump pulley [Re: hemienvy] #2958985
08/30/21 12:01 PM
08/30/21 12:01 PM
Joined: Sep 2003
Posts: 19,239
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
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i have a 76 400 from my wife's newport sitting on the shelf that had a small diameter, single groove water pump pulley.
i took it off for some reason, but i just looked, and can't find it. i know it's out "there somewhere", because when i took it off, i was after some bracketry for the power steering pump. i then stashed it so "i would know where it was" when i needed it in the future, and of course "now i can't find it". mad
i'm also thinking there is a small [just a tick over 5" or a tick under 5"] single groove pulley used on some ac small block applications, but i can't confirm. i'm just remembering something from the past, so that may, or may not, be correct.
hopefully, others can provide a correct answer for you.
anyway, consider this a bump.
beer

Re: Small diameter water pump pulley [Re: hemienvy] #2958987
08/30/21 12:08 PM
08/30/21 12:08 PM
Joined: Jan 2003
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Florida
Locomotion Offline
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Originally Posted by hemienvy
For big block, p/n 3698907, this is a single groove pulley, about 5-7/8 OD.

The pulley groove sits pretty far forward, it's "2 belt groove widths" farther forward than my 6-7/8 pulley.

Is this about the smallest diameter W/P pulley there is ?

Is there a pulley that is only sits one groove width forward ?
Or maybe a small diameter double groove pulley ?



I hope I'm figuring this correctly, but based on another post of yours about 7,000 rpm operation, wouldn't you need a bigger water pump pulley to slow down the water pump? Or use a smaller crank pulley? (But that would slow down the alternator too.)

Re: Small diameter water pump pulley [Re: Locomotion] #2958993
08/30/21 12:16 PM
08/30/21 12:16 PM
Joined: Sep 2003
Posts: 19,239
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
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north of coder
yes, a bigger water pump and alternator pulley diameter will slow those accessories down at high rpm, as well as using a smaller than stock diameter crank pulley with the factory water pump and alternator pulleys.
beer

Re: Small diameter water pump pulley [Re: Locomotion] #2959002
08/30/21 12:34 PM
08/30/21 12:34 PM
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Posts: 900
Washington
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hemienvy Offline OP
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hemienvy  Offline OP
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Washington
Yes for this one motor project I want my cake and eat it too, 7000 RPM capability
with no chance of overheating or alternator undercharging at idle/cruise.

But it would not be prolonged high RPM, no cannonball runs.

Everyone worries about the internal engine components, but I started thinking
about the water pump and alternator RPM too, and the V-belts.

I had a buddy long ago that had a Z-28 302 car, he said he would routinely
take the motor to 8500. Perhaps there is more details to those stories then he let on ?

Re: Small diameter water pump pulley [Re: hemienvy] #2959008
08/30/21 12:45 PM
08/30/21 12:45 PM
Joined: Sep 2003
Posts: 19,239
north of coder
moparx Offline
"Butt Crack Bob"
moparx  Offline
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north of coder
i have seen fabricated belt "retainers" made from [approximately] 1/2" round stock with a flat strap welded to the back that bolted to the water pump/alternator to keep the belt in place at high rpm.
when the belt would rise up out of the groove, the round stock "retainer" would rub on the top side of the belt, keeping it in place. these were placed approximately 1/8"[or a tad closer] above the pulley[s] after the belt was installed and properly tensioned.
beer

Re: Small diameter water pump pulley [Re: moparx] #2959340
08/31/21 09:27 AM
08/31/21 09:27 AM
Joined: Jun 2014
Posts: 1,319
VA
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dragon slayer Offline
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Posts: 1,319
VA
You need to pay attention to your WP impeller. Faster speed if it results in cavitation does not result in better cooling. Plus your clutch fan rotation. Chapter 7 I believe gives you many of the specs including ratios and impeller size. If you go with a normal RB balance you have more pulley selection options then the hemi balancer.

Re: Small diameter water pump pulley [Re: dragon slayer] #2959686
08/31/21 08:41 PM
08/31/21 08:41 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert Offline
Circle Track
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Lincoln Nebraska
In addition I would tack an anticav plate on the vanes


live every 24 hour block of time like it's your last day on earth
Re: Small diameter water pump pulley [Re: RapidRobert] #2960555
09/03/21 09:41 AM
09/03/21 09:41 AM
Joined: Mar 2006
Posts: 1,229
In The Hills
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jughed Offline
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In The Hills
I have a couple of those smaller water pump pulleys. Not sure what they came off of ...they've been in my parts stash forever.
The smallest one is 5 1/16" across, 1" from face to center of belt groove.
The other is 5 3/4" wide, and 15/16" deep.

Originally Posted by moparx
...
i'm also thinking there is a small [just a tick over 5" or a tick under 5"] single groove pulley used on some ac small block applications, but i can't confirm.


maybe the same as the small one in these pics.?.?... but i have no clue on its original application

IMG_20210903_083009981.jpgIMG_20210903_083104334.jpgIMG_20210903_082555930.jpg


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