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Discussion Starter #1
Worth doing ? I remember seeing leading edge of crescent with a slight angle or lead in machined on it , can't remember if it was inside or out side of crescent.
or was I dreaming
 

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Nope, weren't dreaming, i do it to all pumps,,,,, along with other mods......some of my customers have even picked up 200 rpm of stall......
 

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Discussion Starter #4
Thanks for the replies, Do other mods include converter feed to .250, new stator support, new steel gears ?
 

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will a stock pump hold 600hp? with mods

I would say YES,,, i have some in 1000 hp, 700 hp, 800 hp
door cars.and dragters....if they are done right they are as good as any aftermarket.....unless you would for some reason you think you need more volume..........which everyone thinks so...for some reason

hope this helps
 

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Discussion Starter #8
Port matched interesting , have you or do you use cryoed parts ?, As far as 600 hp. I have worked on a few that where running 1200 hp. and on inspection the pumps where stock and I mean stock GM had so many variations in pumps it is hard to believe they lasted as long as they did. I was working on a pump today the converter feed hole was .093 dia.
 

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Does anybody have pics of these mods? I'd love to see what you are refering too. The you tube link goes to some russian video or something like that........must have been hacked.
 

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If the flexplate is true, the converter hub runs straight and the case to block dowel alignment is good , there is NO need to alter the crescent of a powerglide pump with a grinder. If the gear is worn out where is contacts the converter hub and its running into the crescent , don't grind away the crescent , get a new set of pump gears.

For those who consider this a performance "mod" , what advantage does this mod have?


Hutch
 

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Discussion Starter #11
X2 on the vid , I have seen the alum billet pump when things come apart , those pumps will not take to many band or clutch failures before they get scored up badly.
 

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Discussion Starter #12
So Hutch, the lead in will not let it pump more fluid, or create less turbulence at the point where the oil enters gears.
 

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If the flexplate is true, the converter hub runs straight and the case to block dowel alignment is good , there is NO need to alter the crescent of a powerglide pump with a grinder. If the gear is worn out where is contacts the converter hub and its running into the crescent , don't grind away the crescent , get a new set of pump gears.

For those who consider this a performance "mod" , what advantage does this mod have?


Hutch
X100 !


I too would like to know this advantage ?

All the pumps that I recieve in with cresent "mods" usally hit the circular pile because there was/is a problem.

A properly looked after stock pump with minor mods will live under very stout power & abuse.

Hutch - Whats wrong with using a grinder on a pump :rolleyes:


By the way I'm still in the zone ................. lol

Dave
 

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It is possible for the pump gear to contact the cresent end and split the gear in two... seldom are all the related stuff eggzackly correct like the engine dowels, pump bushing, converter hub
 

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X100 !


I too would like to know this advantage ?

All the pumps that I recieve in with cresent "mods" usally hit the circular pile because there was/is a problem.

A properly looked after stock pump with minor mods will live under very stout power & abuse.

Hutch - Whats wrong with using a grinder on a pump :rolleyes:


By the way I'm still in the zone ................. lol

Dave
what minor mods are these you do?? getting ready to put glide back together so any help on pump mods is appreciated
 

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So Hutch, the lead in will not let it pump more fluid, or create less turbulence at the point where the oil enters gears.
Thats a pretty critical point in the pump , changing the clearance at that point will alter the pumps performance at some rpm range for sure but im betting it won't be an increase. The changes I see made to the crescent are removal of material from the suction side , not really a good area to increase clearance on.

I can tell you this for sure. PG pumps (stock) can be out in left field. They are good pumps but the location of the crescent in relationship to the pump bushing bore can be off as much as .020" . With that said , there are good and bad pumps from the get go. When I remachine them I have seen many variations where the pump pocket and/or crescent will not clean up at .030" over nor will it clean or just barely clean at .060" over.

Feel free to test , this is just my opinion.



Hutch
 

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Fortunately I am mentally ill and use new gears in every transmission I build.The slightest contact drives me insane so I just dont use old ones.Modding the crescent is an accepted practice when THERE IS NOISE FROM RUBBING.Not when trying to improve a pumps output.I should have worded my original post differently.I just dont do it.
 

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Fortunately I am mentally ill and use new gears in every transmission I build.The slightest contact drives me insane so I just dont use old ones.Modding the crescent is an accepted practice when THERE IS NOISE FROM RUBBING.Not when trying to improve a pumps output.I should have worded my original post differently.I just dont do it.
YASU CHRISTOS.
AND CAN YOU SELECT ANOTHER SONG TO LISTEN TOO,PLEASE.


BUT ALL THAT RUBBING IS CAST IRON CONTACT ON THE PUMP GEARS/CRESCENT.
METAL TO METAL MMMM NO GOOD.

I AGREE WITH HUTCH AND CHRIS .
YOU SHOULD NOT HAVE TO GRIND / ALTER PUMP CRESCENTS TO CATER FOR BAD PUMP ALIGNMENT PRACTICES.
NEW GEARS ,FACE ALL 3 SURFACES,CANT GO WRONG,WITH A-
PUMP GROUND ALIGNMENT TOOL,-BAND STRAP, DOWELS FOR PUMP HALF'S
AND THEN THEY JUST PUSH INTO CASE( NO SOFT HAMMERS HERE ).

HERES A TIP.YOU MIGHT OR MIGHT NOT BE INTERESTED IN.

NOT LONG BACK P/G PUMP GEARS WERE SHORT SUPPLY TO GET HOLD OF IN AUSTRALIA .
SO WE SLIGHTLY POCKET BORED THE P/G PUMP GEAR CRESCENT FACE GROUND DOWN TH 180 GEARS WHICH ARE STEEL FITTED THEM INTO P/G PUMPS WHICH GAVE A SLIGHTLY THICKER GEAR-DEPTH AND EVER SAVED A FEW P/G PUMPS.

REG.
DAVE
 

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what minor mods are these you do?? getting ready to put glide back together so any help on pump mods is appreciated
*Always make sure the converter feed & return passages are drilled to 1/4"

*Aftermarket stator tube (sonax)

*Stake the tube in with a set screw

Hope this helps

Dave
 
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