Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: Are there any "small" OEM BB crank pullies? [Re: BradH] #2722365
12/07/19 05:26 PM
12/07/19 05:26 PM
Joined: Jan 2003
Posts: 26,483
Oregon
A
AndyF Offline
Too Many Posts
AndyF  Offline
Too Many Posts
A

Joined: Jan 2003
Posts: 26,483
Oregon
Here is a March dual groove pulley. This one is about 5 inches in diameter. I'm underdriving the water pump a little bit but over driving the alternator. The PS pump will also be underdriven.

DSC_4040 (Large).JPG
Re: Are there any "small" OEM BB crank pullies? [Re: AndyF] #2722378
12/07/19 05:49 PM
12/07/19 05:49 PM
Joined: Jan 2007
Posts: 6,545
flint michigan
mopar dave Offline
master
mopar dave  Offline
master

Joined: Jan 2007
Posts: 6,545
flint michigan
Is my water pump seriously over driven with 4.5 wp and 5.5 crank pulleys or just right for street/strip? Do you think its eating up an excessive amount of power?

Re: Are there any "small" OEM BB crank pullies? [Re: BSB67] #2722516
12/08/19 11:29 AM
12/08/19 11:29 AM
Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
B
BradH Offline OP
I almost got away with it!
BradH  Offline OP
I almost got away with it!
B

Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
Originally Posted by BSB67
Originally Posted by BradH


Not sure what diameter the Moroso is, only that it says a 30% reduction in pulley speed, IIRC. My brain hasn't shifted into calculator mode to reverse-engineer the diameter.
.


Reduction will be directly proportional to diameter.

Diameter? 70% of 6.25 is only about 4.3... unless the standard factory pulley is actually 7+".

Last edited by BradH; 12/08/19 02:04 PM.
Re: Are there any "small" OEM BB crank pullies? [Re: AndyF] #2722518
12/08/19 11:34 AM
12/08/19 11:34 AM
Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
B
BradH Offline OP
I almost got away with it!
BradH  Offline OP
I almost got away with it!
B

Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
Originally Posted by AndyF
At 3500 rpm cruise you could use a smaller pulley without any trouble. My guess is that the factory designed the water pump to be really effective in the 2000 to 2500 rpm range so you are probably overdriving your pump a little right now. A smaller crank pulley might improve cooling on your setup.

I was thinking pretty much the same standard RPM range; 30% slower than 3500 is 2450...

Re: Are there any "small" OEM BB crank pullies? [Re: BradH] #2722534
12/08/19 12:00 PM
12/08/19 12:00 PM
Joined: May 2011
Posts: 566
Rochester, Wa
HOTMOPR Offline
mopar
HOTMOPR  Offline
mopar

Joined: May 2011
Posts: 566
Rochester, Wa


67 Barracuda, 470" B, Glide, MS3 Pro, Precision, Ptc, QA1, Calvert, Smith racecraft, Afco, Dana 60. 275 radials
Re: Are there any "small" OEM BB crank pullies? [Re: HOTMOPR] #2722560
12/08/19 01:39 PM
12/08/19 01:39 PM
Joined: Jan 2003
Posts: 26,483
Oregon
A
AndyF Offline
Too Many Posts
AndyF  Offline
Too Many Posts
A

Joined: Jan 2003
Posts: 26,483
Oregon
Originally Posted by HOTMOPR


That is the Doty pulley.

Re: Are there any "small" OEM BB crank pullies? [Re: BradH] #2722565
12/08/19 02:06 PM
12/08/19 02:06 PM
Joined: Feb 2005
Posts: 3,986
Prospect, PA
BSB67 Offline
master
BSB67  Offline
master

Joined: Feb 2005
Posts: 3,986
Prospect, PA
Originally Posted by BradH
Originally Posted by BSB67
Originally Posted by BradH


Not sure what diameter the Moroso is, only that it says a 30% reduction in pulley speed, IIRC. My brain hasn't shifted into calculator mode to reverse-engineer the diameter.
.


Reduction will be directly proportional to diameter.

Circumference, not diameter. 70% of 6.25 is only about 4.3...


And 70% of circumference still results in 4.3" diameter. Pulley speed, circumference and diameter are all proportional.

So either Moroso made an error, or their pulley is 4.3, or they started with a different pulley diameter for the claimed 70%. FWIW, the crank pulleys I have here range from 6.5 to 7.25.

Re: Are there any "small" OEM BB crank pullies? [Re: BSB67] #2722570
12/08/19 02:33 PM
12/08/19 02:33 PM
Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
B
BradH Offline OP
I almost got away with it!
BradH  Offline OP
I almost got away with it!
B

Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
I must have been editing my original comment at the same time you were posting your response above. I think we're actually on the same page now.

Re: Are there any "small" OEM BB crank pullies? [Re: BradH] #2722586
12/08/19 04:18 PM
12/08/19 04:18 PM
Joined: Feb 2005
Posts: 3,986
Prospect, PA
BSB67 Offline
master
BSB67  Offline
master

Joined: Feb 2005
Posts: 3,986
Prospect, PA
I kinda figured that you probably knew. I know that I've raced to real stuff back in.

Re: Are there any "small" OEM BB crank pullies? [Re: AndyF] #2722589
12/08/19 04:35 PM
12/08/19 04:35 PM
Joined: Sep 2003
Posts: 273
montana
BANDIT Offline
enthusiast
BANDIT  Offline
enthusiast

Joined: Sep 2003
Posts: 273
montana
Years ago, MP used to sell March pulley sets. When they quit, they were selling them off cheap. I picked up a few different sets with that smaller lower pulley and have used it on a couple of street cars. They are quality pieces.


64 Dodge Coronet 440. In progress
1998. Dodge Avenger. 8.50@162. 4900 DA
250” Neil and Parks Slip Joint. 7.36@183.
4600 DA
Re: Are there any "small" OEM BB crank pullies? [Re: BANDIT] #2722730
12/09/19 10:51 AM
12/09/19 10:51 AM
Joined: Jan 2003
Posts: 11,587
Marion, South Carolina [><]
an8sec70cuda Offline
I Live Here
an8sec70cuda  Offline
I Live Here

Joined: Jan 2003
Posts: 11,587
Marion, South Carolina [><]
I used to run the small Moroso crank pulley w/ a belt driven water pump setup on my 14:1 Indy headed 440. That was years ago in my cuda, ran 10.40s, but ran great on the street. No cooling issues whatsoever, just went through a lot of C12, lol.


CHIP
'70 hemicuda street car...8.91 at 150.5 mph w/ 4.10s, 8.97 at 152.5 mph w/ 3.54s so far
'69 road runner 440 w/ Indy SRs
'69 road runner 440-6, 4 speed...Dad's ride
'71 Demon 340 resto project
'06 GMC 2500HD LBZ Duramax...toy hauler
'16 Grand Caravan SXT...baby hauler
Re: Are there any "small" OEM BB crank pullies? [Re: an8sec70cuda] #2722899
12/10/19 09:04 AM
12/10/19 09:04 AM
Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
B
BradH Offline OP
I almost got away with it!
BradH  Offline OP
I almost got away with it!
B

Joined: Jan 2003
Posts: 15,326
Val-haul-ass... eventually
Not sure from where at the moment, but I do expect to get a smaller diameter pulley to try out.

Page 2 of 2 1 2

Advertisement
Sponsored Link
Moparts Newest Topics
Gain 13-Plus-Rear Wheel Horsepower With Hughes Engines
by Rustymuscle. 01/23/20 01:48 AM
O/T three phase motor amperage question
by Hemi_Joel. 01/23/20 01:28 AM
brake line clip & retainer locations
by buzz440. 01/23/20 12:27 AM
69 Roadrunner Interior Panel Fitment Issue
by BigDaddy440. 01/22/20 10:12 PM
Moparts Recent Posts
Gain 13-Plus-Rear Wheel Horsepower With Hughes Engines
by Rustymuscle. 01/23/20 01:48 AM
O/T three phase motor amperage question
by Hemi_Joel. 01/23/20 01:28 AM
Aluminum 8 3/4 center section P4876445
by Doc Fiberglass. 01/23/20 01:10 AM
Wow, '18 WB Hellcat with 101k miles
by Doc Fiberglass. 01/23/20 01:04 AM




Powered by UBB.threads™ PHP Forum Software 7.7.1