Swaping to single groove crank pulley, could this make the car run hot?

[greenpigs]

  I switched to manual steering and now have a two groove crank pulley that I would like to change to the correct 1 groove. The 440 source sells one that has the slot in it so it will bolt up to my 72 440. BUT from what Mancini says the smaller Dia acts like an underdrive & slows the WP and alternator down. This is a factory REPO piece so it should be fine but it has me confused. If I go with the 1 groove that is 6 1/2 Dia will it cause charging issues or the motor to run warmer? The 2 groove is something like 8 inch Dia.,,,,,whichever it is noticeably larger.
   Do I need a different size water pump pulley to keep the ratios correct? Also if it is OK to do the switch do I need a spacer to keep the pulleys aligned?

[firefighter3931]

Keep the crank pulley the same size as stock or you will have cooling/charging problems. Underdrive pullies work fine on drag cars but have no business on a street driven ride. 


Ron

[greenpigs]

OK Ron I understand to stay away from the race pulleys, point taken.

   But this is just the factory one groove pulley. I have one purchased from Ebay as well but the re pop from 440 source sounds better & is the same size & pre slotted.

  I guess my question really is the aftermarket is 5 inch and the stock 1 groove is 6 1/2 and the 2 groove on it now is 7 1/2 both overall diameter. Would dropping an inch be enough to cause a problem? The car runs fine now as far as running hot. Plus I plan on swapping to an aluminum WP housing and HV pump this spring.

Not trying to be bull headed I'm just a little confused how the stock pulley could be a bad move.

THANKS!

[elacruze]

The 6-1/2" pulley will drive your water pump and alternator at 87% speed compared to the 7-1/2" pulley.
Whether that affects your cooling and charging depends on whether you have any to spare or not.
Alternator and water pump style come into play. So does your gear ratio, driving style and driving environment.
Driving on the freeway, it won't matter. Idling in rush hour, it could.

[firefighter3931]

The 6-1/2" pulley will drive your water pump and alternator at 87% speed compared to the 7-1/2" pulley.
Whether that affects your cooling and charging depends on whether you have any to spare or not.
Alternator and water pump style come into play. So does your gear ratio, driving style and driving environment.
Driving on the freeway, it won't matter. Idling in rush hour, it could.

Exactly.....i would keep the same size you're currently using....you know it works good.   

Put it this way ; if it were my car and i couldn't find the correct diameter single groove pulley, i'd keep the dual groove on there. Function trumps appearance 

Overheating and discharged batteries are a PITA....been there, done that ! 

[firefighter3931]

Ok, went and did a little research. The factory 2 groove pulley has 2 different dimensions....the waterpump/alt groove is 6.5in and the PS froove is 7.5in so when you measured yours you probably measured the front diameter which is the larger PS groove.

So a single lower pulley with 6.5in will give you what you currently have. 

The problems for me occured with the race pully which was smaller than the stocker (5in i think) but it's been awhile. 


Ron

[greenpigs]

 

You would think since I measure things for a living I would have picked up on that.

[firefighter3931]

You would think since I measure things for a living I would have picked up on that.

No worries, i had to research it myself to be sure....the little light bulb went on when i looked at an old pic of my 440 while it was on the stand and the grooves in that pulley looked staggered.

Bouchillion sells reproduction pullies with dimensional info so i checked on their website to confirm what i thought i was seeing.

Happens to all of us 

Below is a pic from the Bouchillon website showing the 2 different sizes 



Ron

[elacruze]

My original '68 dual groove PS pulley has two grooves the same size. Could it have to do with which pump came with it?
I'll try to remember to measure them tomorrow.