I think my shaft is too small
04-10-2005, 10:54 AM
#1
Race Director
Thread Starter
I think my shaft is too small
I've just been reading that the Corvete short style water pump uses a 3/4" shaft (as opposed to the regular chevy short pump that uses a 5/8" shaft).
I noticed my pump kind of grinds when you turn it so I removed it and started taking it apart. I measured the shaft and it's a 5/8" diameter. (engine is 1970 LT1) This means that someone along the way replaced it with the wrong pump. They must have replaced the fan and clutch too.
I've read that with this pump there are alignment problems - does this refer to the alignment of the alternator pully?
Also, if they changed the pump did they have to change out the crank pully?
Finally, if I buy a new Corvette pump (3/4" shaft) do I need new pullies? (I figure I'll have to buy a new fan and clutch too...)
Or should I just go with a new 5/8" pump and leave it be?
What year did the General start the 3/4" shaft pumps?
thanks!
I noticed my pump kind of grinds when you turn it so I removed it and started taking it apart. I measured the shaft and it's a 5/8" diameter. (engine is 1970 LT1) This means that someone along the way replaced it with the wrong pump. They must have replaced the fan and clutch too.
I've read that with this pump there are alignment problems - does this refer to the alignment of the alternator pully?
Also, if they changed the pump did they have to change out the crank pully?
Finally, if I buy a new Corvette pump (3/4" shaft) do I need new pullies? (I figure I'll have to buy a new fan and clutch too...)
Or should I just go with a new 5/8" pump and leave it be?
What year did the General start the 3/4" shaft pumps?
thanks!
04-10-2005, 11:47 AM
#3
I am looking for the rest of the parts,(crank pulley, fan clutch, fan, etc), for my 70. I do have original 71 stuff that someone put on my 70 way back before 1973 when I bought it. If you have the pieces I need ,maybe we can switch if you want the 71 pieces. BTW the larger diameter started in 71. Yea, I have a 3/4 pump too.
As for the alignment, some people have said they're alt belt rubs, and may be attributed to this.
As far as 1970, you should have the 5/8(608#), water pump. also 3888366,(5 blade fan), or 3955182 (7 blade fan for A/C, not LT1), 3937771 or 3916139 clutch, with a 3858533 crank pulley.All are long disco'd except the crank pulley. Still available from the general.
Did I forget anything?
As for the alignment, some people have said they're alt belt rubs, and may be attributed to this.
As far as 1970, you should have the 5/8(608#), water pump. also 3888366,(5 blade fan), or 3955182 (7 blade fan for A/C, not LT1), 3937771 or 3916139 clutch, with a 3858533 crank pulley.All are long disco'd except the crank pulley. Still available from the general.
Did I forget anything?
Last edited by dennis; 04-10-2005 at 12:26 PM.
04-10-2005, 02:29 PM
#6
Senior Member since 1492
Originally Posted by mandm1200
She says the same thing about me too!! 
Just Joking
Just Joking
04-10-2005, 06:51 PM
#9
Le Mans Master
Member Since: Apr 2000
Location: Houston,Tx. USA
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I just successfully installed on my recently acquired 80, 1 from NAPA (short shaft) for $60 dollars with gaskets, and the fan, pulleys all went back fine.
