Need help with pulley setup
June 10th, 2011, 10:58 AM
#1
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Join Date: Jul 2006
Posts: 7
Need help with pulley setup
I'm currently running a 1974 SBO 350 in an 84 Cutlass and no matter what I have tried, the belts squeal really badly at start up and at WOT. I’ve tried different belts and different belt tensions but have had little luck.
The motor came with the following pulley setup:
2 groove crank pulley, 3 groove water pump pulley (2 small diameter pulleys behind 1 large diameter pulley, and a 1 groove P/S pulley. One belt is running from the crank, to the water pump, and then to the P/S pump and then back to the crank. The second belt only runs from the water pump to the alternator. The car does not have AC or a smog pump.
The brackets look like they came from a 307 setup for a G-body with AC (Alternator on driver side).
I am considering running a 3 groove water pump, 3 groove crank, and a 2 grove p/s pump setup but I have heard that Oldsmobiles came with a variety of different pulley setups.
I would like to keep the 307 style aluminum alternator bracket that I’m running but I don’t know what 3 groove pulleys would be compatible with it.
Any suggestions?
The motor came with the following pulley setup:
2 groove crank pulley, 3 groove water pump pulley (2 small diameter pulleys behind 1 large diameter pulley, and a 1 groove P/S pulley. One belt is running from the crank, to the water pump, and then to the P/S pump and then back to the crank. The second belt only runs from the water pump to the alternator. The car does not have AC or a smog pump.
The brackets look like they came from a 307 setup for a G-body with AC (Alternator on driver side).
I am considering running a 3 groove water pump, 3 groove crank, and a 2 grove p/s pump setup but I have heard that Oldsmobiles came with a variety of different pulley setups.
I would like to keep the 307 style aluminum alternator bracket that I’m running but I don’t know what 3 groove pulleys would be compatible with it.
Any suggestions?
June 10th, 2011, 12:00 PM
#2
Sounds like what I had on my 68 350 in my Delta
Is the squeaking belt in question wrapped around the front pulley and around the front pulley on the PS pump?
If so the belt is the wrong size and it trying to be turned at a different speed than the other belts
Is the squeaking belt in question wrapped around the front pulley and around the front pulley on the PS pump?
If so the belt is the wrong size and it trying to be turned at a different speed than the other belts
June 10th, 2011, 12:03 PM
#3
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,361
Use ALL the 307 brackets and water pump as a matched set. Be sure the pulley isn't glazed. Be sure you have the two spacers correctly located between the PS pump bracket and the block. Be sure to properly adjust the tension in the PS pump belt by loosening all three fasteners (two between the pulley and the front of the pump, one at the bottom rear of the pump), then prying between the tab on the front bracket and the nose of the pump (behind the pulley) while tightening the fasteners. I continue to be amazed by this problem, as I've never experienced it on my 307s, EVEN without the A/C belt in place.
July 16th, 2011, 09:42 AM
#4
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Thread Starter
Join Date: Jul 2006
Posts: 7
Thanks for the advice Joe.
Update:
So I went to a salvage yard and picked up a bracket/pulley setup out of a 1986 Custom Cruiser with a 307. I cleaned and installed everything from that car to my car (nuts, bolts, spacers, etc) setup the exact way it was in the junk car. The pulleys did not appear to be glazed.
I started it up and everything was going great. Then I turned on the headlights, small chirp from the pulleys. Then I turned on the vent fan and the belts started screaming. I gave it a little gas and they squealed even louder. I turned the accessories off and it stopped squealing but now they squeal when I blip the throttle and it's very annoying. The belts are about as tight as I can get them (barely any deflection when pressed on).
I'm using NAPA belts, but I don't think they would be the issue.
Any other suggestions?
Update:
So I went to a salvage yard and picked up a bracket/pulley setup out of a 1986 Custom Cruiser with a 307. I cleaned and installed everything from that car to my car (nuts, bolts, spacers, etc) setup the exact way it was in the junk car. The pulleys did not appear to be glazed.
I started it up and everything was going great. Then I turned on the headlights, small chirp from the pulleys. Then I turned on the vent fan and the belts started screaming. I gave it a little gas and they squealed even louder. I turned the accessories off and it stopped squealing but now they squeal when I blip the throttle and it's very annoying. The belts are about as tight as I can get them (barely any deflection when pressed on).
I'm using NAPA belts, but I don't think they would be the issue.
Any other suggestions?
July 16th, 2011, 10:45 AM
#5
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
1 problem, is a water pump pulley with 2 different diameter circles on it.
The other problem is the press on pulley power steering pump.
The easiest way to go is a NON ac setup. 2 groove crank 2 groove water, 2 groove ps pump, 2 belts around everything. They will turn together instead of fighting each other.
Keep in mind this is a dirt track car pictured, and an alternator must be added in to the equation.
The other problem is the press on pulley power steering pump.
The easiest way to go is a NON ac setup. 2 groove crank 2 groove water, 2 groove ps pump, 2 belts around everything. They will turn together instead of fighting each other.
Keep in mind this is a dirt track car pictured, and an alternator must be added in to the equation.
July 16th, 2011, 10:55 AM
#6
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
This is a problem, because the water pump isn't the boss of anything except pumping water.
The crank pulley is the boss of all the accessories.
When piggybacking something, it can't keep up fast enough with the instant torque that the crank puts out.
The crank pulley is the boss of all the accessories.
When piggybacking something, it can't keep up fast enough with the instant torque that the crank puts out.
July 16th, 2011, 02:33 PM
#7
Old(s) Fart
Join Date: Mar 2007
Location: Northern VA
Posts: 47,361
Sorry, but I have exactly this belt setup on my 84. Given ALL the problems everyone seems to have with the PS pump belt on these motors, I specifically ran mine with the A/C belt off. Guess what? With the PS belt properly tensioned, there is NO squealing.
How have you tensioned the PS pump belt? Pulling on the pump by hand? That will never work. First, be sure ALL three fasteners are loose (two bolts behind the pulley and the nut on the bottom rear of the pump). Now locate the tensioning tab on the front bracket, next to (and inboard of) the nose of the pump, behind the pulley. Use a large screwdriver or pry bar between the pulley and pump nose to properly tension the belt while tightening the fasteners. This might take two people.
How have you tensioned the PS pump belt? Pulling on the pump by hand? That will never work. First, be sure ALL three fasteners are loose (two bolts behind the pulley and the nut on the bottom rear of the pump). Now locate the tensioning tab on the front bracket, next to (and inboard of) the nose of the pump, behind the pulley. Use a large screwdriver or pry bar between the pulley and pump nose to properly tension the belt while tightening the fasteners. This might take two people.
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