vettecrazy88

For 75 that has big block w/ power steering and air.

I am looking to put 2 groove pulley on and don't know if its bolt on or press on. Is there a way for me to tell visually which type of pump/pulley it is?

Better yet here's a pic

http://i295.photobucket.com/albums/m...od1/PSpump.jpg

I do not know if P/S pump is stock (would be pump that came with 75 SB)

As you can see the belt routing is currently wrong and I'd like to correct it, i.e. power steering drives alternator from second pulley groove.

I need to determine what pulley to get.

Any advice appreciated.

69Vett

the picture is a late model press on fit.
the Early models had a nut that screws on.
you will need a late model press on pullry for that pump.
69VETT

vettecrazy88

Thanks 69Vette!!

73, Dark Blue 454

My 73 with original BB, has the two groove cast iron pulley, and is pressed on and has a nut for safety. There's also a groove for the key on the pulley shaft.

If you have a press-fit pulley, you'll need a pulley puller to remove it.

FWIW.

Jim Shea

I am not the pulley man but this observation may be of help. In 1975 two things happened. General Motors went to the interference fit pulleys on all engines. The driveshafts on all of the GM pumps starting in 1975 were changed. All pulleys had to be redesigned to work with the new pumps starting that year. The other was the elimination of the big block in the Corvette. So any two groove pulleys for big block Vettes would all have been designed to work with the old style, male threaded driveshaft, with the nut and woodruff key. (Pump driveshafts and pulleys before 1975 do not interchange with any driveshafts and pulleys starting in 1975.)

That new driveshafts were completely smooth with a female spline and a 3/8-16 female thread in the end of the shafts. You might have to switch the pump back to the old style rather than the interference fit type in order to end up with a big block pulley.

Otherwise, maybe there are truck pulleys (1975 model year and later) that may work.

It is also probable that you could take the pump in the picture and just swap the driveshaft from an older pump in order to make it accept the old style big block pulley.

It is also true that the new style interference fit pulleys require special tools to remove and also install the pulleys on the driveshaft. Do not even think about removing the pulley without borrowing, renting, or purchasing the special tools.

Jim

69Vett

Jim is correct, in the fact if you want the old style cast double pulley you will need an old style pump,
yours is the newer late model (1975)type.
I had to change pump styles because of that.

They do make a stamped steel late double pulley,
( http://www.midwayautosupply.com/pc-5...s-300-121.aspx )

but you may run into pulley alignment issues.
I just spent 3 weeks sorting out pulleys and belts for my BB 69.
good luck... 69Vett

vettecrazy88

Thanks all!

Can I work the pulley exchange in place or is it much easier just to remove the pump and work it outside the engine bay?

69Vett

you can remove the pulley in place.
Make sure you use the correct removal tool,
and the correct installation tool.
leave the pump in place.
69VETT

69Vett

Use a Yard-stick to check pulley and Belt alignments,
just lay the yardstick across the pulley face or in the belt groove.

69VETT

Clue

Is special tools needed to remove the PS pump pulley on a 1974 BB?

vettecrazy88

Thanks for all the help!!!

Do I need to press the pulley all the way on or do I have a little lattitude (1/4") to help with belt alignment?

Jim Shea

The service literature says to press the pulley flush to the pump driveshaft. However, you do have a slight amount of leeway as to how far you press on the pulley. You probably can't press the pulley past the end because the pulley hub will begin rubbing on the pump housing.

Jim

TimAT

YES! I can't think on ANY GM car or truck that you can get the P/S pulley off and on without the tools. (there probably are a couple, but not on a C-3)

vettecrazy88

Thanks again!!

Much appreciated.

jnb5101

you will also need the bb alternator pulley, the type that has the groove in the position of where a second groove would be in a two groove pulley.

vettecrazy88

anybody got a pic of the pullet jnb5101 is referring to?
Thanks JNB

Steve's74

Well, I hate to disagree, but Jim Shea already stated otherwise. And the OEM pulley on my big block is a slip fit held on with the nut on the end of the pump shaft, verifying his statement. I can't speak from memory on pumps earlier than my '74, but I tend to think Jim is correct. I don't need any special tools to change the pulley on my '74.

If the OP picks up a pump at Autozone or equivalent to fit a '74 (or earlier?), and picks up the correct pulley (used, good luck) from Zip or other vendor, it shouldn't require special tools to assemble. It should also fit into OEM brackets for '70 thru '74 big blocks and the pulley alignment should be fine. As noted by jnb5101, an alternator pulley with the equivalent of a second outer groove is necessary as well. The OEM alt pulley has one groove spaced out and no inner groove, and the alt belt runs from the outer P/S pump pulley groove to that outer groove on the alternator. I found a good used two groove pulley at a local alternator rebuild shop that works just as well. I'm not NCRS driven.

By the way, if the OP has A/C as well and wants to make it functional, the OEM belt arrangement included an idler pulley to apply additional tension and some offsetting thrust on the water pump belt. Add in an additional $250 to by the pulley and mounting hardware as well. Aren't big blocks fun?

Steve

Steve's74

Oh, and here is a shot of the alternator pulley and drive belt installed for Vettecrazy88:



and



and




Steve