pulleys

[sendo]

changing pulleys to add a/c to my car and ran into a problem with the new crankshaft pulley hitting the fan pulley. cant find a 3 groove pulley that is the same size as the original 2 groove. is there one or is there a different size fan pulley?

 

[Rob Peters]

That's a pretty big difference.  Good luck in your search.  Maybe some one in the club can help you out

rob

[cny first gen 71]

Summit has some listed but mostly aluminum.

[jft69z]

I checked my stock lower pulleys from the 72 402. I have 2 of them kicking around here, (one I got from a dealer when I built an older Monte, different part numbers, but same pulley dimensions). Both are the same 7 11/16" as you have. The water pump pulley that was on the car originally is 6 3/16" diameter and has a GM part # 3995631AO.  At least on my car, those are the stock pulleys used on a BB A/C engine. What diameter is your WP pulley?

The WP pulley listed above seems to fit both small & big blocks.

[1970mcss]

What size engine are you working on??

[sendo]

will have to take it off and measure it

 

 

 

[sendo]

454

[1970mcss]

Parts book doesn't show size but it looks like it fits all the way up to 1975

 

70 Chevelle w /A ir Cond. (454),
70 Pass. w/C.A.C., A.T. (454),
70 Pass. w/Acc. Air Cond. (454),
71-72 All w /A ir Cond. (454),
73-75 All (454) ............................................. 3 9 3 7 7 8 7  1 12.90 PULLEY (3 groove) (Note 1)
NO TE 1 N o t u s e d o n m o d e ls h a v in g A c c . A i r Cond. a n d 2 .5 6 o r 2 .7 3 a x le ra tio .

[sendo]

2 hours ago, jft69z said:

I checked my stock lower pulleys from the 72 402. I have 2 of them kicking around here, (one I got from a dealer when I built an older Monte, different part numbers, but same pulley dimensions). Both are the same 7 11/16" as you have. The water pump pulley that was on the car originally is 6 3/16" diameter and has a GM part # 3995631AO.  At least on my car, those are the stock pulleys used on a BB A/C engine. What diameter is your WP pulley?

The WP pulley listed above seems to fit both small & big blocks.

don't have time to take it off till next week, but just measuring from the top of the wp shaft its bigger then 6 3/16.

so that may be the problem

[jft69z]

2 hours ago, 1970mcss said:

Parts book doesn't show size but it looks like it fits all the way up to 1975

3 9 3 7 7 8 7        1 12.90 PULLEY (3 groove) (Note 1)
 

That's the part number I have for the original lower 3 groove on my '72, except with an "AC" suffix.

The superseded part number for the same sized 3 groove lower that I also have is 14025185BN

Can you make out a part number on that pulley Rosendo?

[DragCat]

Just throwing this out there, got this info from the parts place website. Crank 3937787 approx 7 5/8 and wp 3995631 approx 6 1/4. Those are listed for a 1970 BB

[sendo]

this is what I have, guess there is a difference with having a/c 

https://www.ebay.com/i/254181594636?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=254181594636&targetid=858513787104&device=c&mktype=pla&googleloc=9032210&poi=&campaignid=6470636538&mkgroupid=81597521470&rlsatarget=aud-622524041038:pla-858513787104&abcId=1140476&merchantid=7978624&gclid=Cj0KCQiAvJXxBRCeARIsAMSkApoWBY9JJGIc36j_GtE_Ai8SWMxlDnIGOMsQKrlGKbTBkhg2wFOeTQ4aAiM2EALw_wcB

https://www.heartbeatcitycamaro.com/store/product/20884/1969-Camaro-Chevelle-Nova-SB-%26-BB-Water-Pump-Pulley-GM%23-3932402/

[jft69z]

Well that's good, mystery solved. Now maybe get one of those 3995631AO  pulleys listed for an A/C car from ebay & you're good to go. There's at least a dozen to choose from, all in the same general price range.