[BILTIT]

Looking to spin my water pump faster, know what year pulleys would work?

Currently have stock 74' pulleys, looks to be 7.25 crank and 8.0 water.

Ooops, this should be in the heating/cooling tech section.

[Blue '66]

Check with the Goat Farm.Shemp the Bat is a member here.Thats where I got mine $30-$35.

[BILTIT]

Got one off ebay which looks like it will work, 5 5/8'' diameter.

[BILTIT]

http://cgi.ebay.com/ebaymotors/71-72...4506.m20.l1116

This is what i bought. Will update when i get it installed.

[67blackcherry]

Originally Posted by BILTIT

http://cgi.ebay.com/ebaymotors/71-72...4506.m20.l1116

This is what i bought. Will update when i get it installed.

Thanks, I just picked one up as well. Now I can kill two birds with one stone; overdrive the water pump AND get rid of the FoMoCo pulley on my water pump!

[71 T/A]

No you won't. They just e-mailed me that the pulley is just a 6.5 incher - not the 5 5/8" they advertised.

[67blackcherry]

Originally Posted by 71 T/A

No you won't. They just e-mailed me that the pulley is just a 6.5 incher - not the 5 5/8" they advertised.

Same here; back to the drawing board!

[cressy]

The 1971 and up cars that had air had the 6.5" diameter water pump pulley and a 8" diameter crank pulley.

[Pontirag]

smaller driven pulley =slower speed, larger driven pulley=higher speed

Originally Posted by Pontirag

smaller driven pulley =slower speed, larger driven pulley=higher speed

Negative. Just the opposite.

Smaller crank pulley (or larger pump pulley) = slower pump speed

Smaller pump pulley (or larger crank pulley) = faster pump speed

[67blackcherry]

Originally Posted by Pontirag

smaller driven pulley =slower speed, larger driven pulley=higher speed

WRONG!
You don't win the prize, not even a consulation prize or a nice parting gift!

Thanks for playing...

[Region Warrior]

62Lemans is correct.
Just find pulleys from any 71-79 Pontiac V8 with A/C.
All use;
8" crk
6-5/8" wtr pump

[BILTIT]

Mine is in the mail. 6.5'' or whatever it is will be better than my ~8''.

[Pontirag]

I'm checking the math on that. So your saying that a larger pump pulley rotates faster than a smaller one if the crank pulley remains the same size?

Originally Posted by Pontirag

I'm checking the math on that. So your saying that a larger pump pulley rotates faster than a smaller one if the crank pulley remains the same size?

Pulleys are just like gear sets.

Every crank gear has twice as many teeth as the cam gear (and is 2 times larger)!

The factor is two. So the cam turns 2 times for 1 time of the crank - in a 4cycle engine anyway.

[sleepy]

Originally Posted by 62Lemans

Pulleys are just like gear sets.

Every crank gear has twice as many teeth as the cam gear (and is 2 times larger)!

The factor is two. So the cam turns 2 times for 1 time of the crank - in a 4cycle engine anyway.

You must be dyslexic. The cam gear is twice the size of the crank gear. The crank spins twice for every spin of the cam.

Originally Posted by sleepy

You must be dyslexic. The cam gear is twice the size of the crank gear. The crank spins twice for every spin of the cam.

You are exactly right. Big dummy had it backwards.... Duhhh. Sorry bout that.
The crank gear is smaller and the cam gear is bigger. Its been a while since I changed a timing chain or belt (about 40 years).

[Region Warrior]

What?...aaa?...
Now i'm confused.

[71 T/A]

No, the smaller the WP pulley the faster your pump will spin regardless of the present crank pulley size.

[Region Warrior]

Ok, try to visilize the pully speed on a non-A/C system(7" crk and 8" w/p).
Now A/C system(8" crk and 6-5/8" w/p).

Which set would spin the w/p faster.