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  underdrive pulleys=trouble?

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Author Topic:   underdrive pulleys=trouble?

Posts: 16
From: CO
Registered: Jul 2000

posted 05-28-2002 08:18 PM     Click Here to See the Profile for CannedHeat   Click Here to Email CannedHeat     Edit/Delete Message   Reply w/Quote
Hey guys,
I was wondering if any of you had problems with underdrive pulleys and what you did to fix it. My problem is at idle; when I come to a stop at a light, the car quits running or barely runs. I usually have the electric fan running in traffic and turned off at cruising speed. The problem gets worse when I turn on the headlights, radio, etc. I am curious if my stock 55 amp alternator just can't put out the amperage at idle with the underdrive pulley's. I was thinking about getting a powermaster 140 amp alternator but I am unsure if this will cure the problem. I really don't want to loose those underdrive pulley's! The car ran fine with a mallory dual point distributor but when I switched to a mallory unilight unit, the problem reared its ugly head. Any opinions or suggestions?

1968 coupe
12.5:1 domed pistions
Ported and polished heads 1.94 1.60 valves
.500 Solid lifter cam
Performer RPM intake
Mallory unilight distributor with promaster coil

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70 Pony

Posts: 1814
From: Glenmoore, PA, USA
Registered: Jan 2000

posted 05-28-2002 08:41 PM     Click Here to See the Profile for 70 Pony   Click Here to Email 70 Pony     Edit/Delete Message   Reply w/Quote
Wll Canned Heat, the longer you're here the more you'll realize I'm no take all this with a grain of salt...BUT...
I've heard similar complaints from others who have tried U/D pulleys, and the fix does seem to be an alternator with a lot more amps.
Personally, I'll take reliability, over a few extra ponies.....then there's always an electric fuel pump etc....
Just my 2 cents...worth one cent.

Resto Mod '70 Sport Roof
Arrest Me Red
'02 GT, Torch Red
"If I knew I would have lived this long, I would have taken better care of myself !"

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Posts: 48
From: Tuttle Okla
Registered: Mar 2002

posted 06-19-2002 01:54 PM     Click Here to See the Profile for Mustang66   Click Here to Email Mustang66     Edit/Delete Message   Reply w/Quote
You might bump your idle up.I had to do it with my U\D pullys? My 2 cents

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Posts: 392
From: penna
Registered: May 2002

posted 06-19-2002 08:45 PM     Click Here to See the Profile for fastford34   Click Here to Email fastford34     Edit/Delete Message   Reply w/Quote
a lot of rodders have this problem with u/d pulley set ups. i believe your problem is the alternator now that the u/d pulleys are on and the load demand is to much for the 55 amp alternator. the powermaster high output alternator is the way to go,get the one thats high idle and high output. the powermaster people are great to work with if you have trouble. have all your info ready and they will recommend which alternator for your car. good luck, let us know how you make out.

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