pulleys
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Joined: Feb 2003
Posts: 38
From: tennesee
pulleys
what do you do to install the underdrive pulleys from summit on my car ive posted this onnce and didnt get much of a response,and the guy who replied said somthing about them being bolted toghether some body help me in this department?and is there anytype of improvement from these pulleys?
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Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
There are two different types of underdrive pulleys.
One type is an integrated pulley and damper. To install that type, you take the old pulley/damper off the hub, and put the new underdrive pulley/damper on the hub, and you are done.
The second type is an underdrive pulley ONLY. To install that type, you remove the old pulley/damper from the hub. Then you sandwich the underdrive pulley between the stock pulley/damper and the hub, and put the three bolts back in and tighten the new underdrive pulley between the old pulley/damper and the hub.
First determine which kind you bought... the integrated pulley/damper will be almost identical to the stock piece, heavy, with a rubber ring between the inner hub and the outer grooved pulley. The "pulley only" is going to be much lighter than the stock pulley/damper.
As far as removing the stock pulley/damper from the hub, in theory you remove the 3 bolts (do NOT remove the single bolt in the center that holds the hub to the crankshaft), and the pulley/damper will pull right off. Unfortunately, after a couple years, the old piece rusts like crazy, and sometimes takes a few taps of a hammer, a little gentle prying, or even a 3-jaw puller to get it off the rusty hub.
When you go to put the pieces back together, you should notice that the three bolts are not evenly spaced, and the pieces will only fit correctly in one position.
Whatever you do, if you have the "pulley only" that needs to be sandwiched between the damper and the hub, do NOT leave the damper off. It will cause an early fatigue failure of your crankshaft.
There is not much to be gained with an underdrive pulley. The dyno test at Keith WS6.COM PULLEY DYNO shows a peak HP gain of 0.7HP.... yes that would be 7/10's of one whole HP. The average gain is a little bette though.
One type is an integrated pulley and damper. To install that type, you take the old pulley/damper off the hub, and put the new underdrive pulley/damper on the hub, and you are done.
The second type is an underdrive pulley ONLY. To install that type, you remove the old pulley/damper from the hub. Then you sandwich the underdrive pulley between the stock pulley/damper and the hub, and put the three bolts back in and tighten the new underdrive pulley between the old pulley/damper and the hub.
First determine which kind you bought... the integrated pulley/damper will be almost identical to the stock piece, heavy, with a rubber ring between the inner hub and the outer grooved pulley. The "pulley only" is going to be much lighter than the stock pulley/damper.
As far as removing the stock pulley/damper from the hub, in theory you remove the 3 bolts (do NOT remove the single bolt in the center that holds the hub to the crankshaft), and the pulley/damper will pull right off. Unfortunately, after a couple years, the old piece rusts like crazy, and sometimes takes a few taps of a hammer, a little gentle prying, or even a 3-jaw puller to get it off the rusty hub.
When you go to put the pieces back together, you should notice that the three bolts are not evenly spaced, and the pieces will only fit correctly in one position.
Whatever you do, if you have the "pulley only" that needs to be sandwiched between the damper and the hub, do NOT leave the damper off. It will cause an early fatigue failure of your crankshaft.
There is not much to be gained with an underdrive pulley. The dyno test at Keith WS6.COM PULLEY DYNO shows a peak HP gain of 0.7HP.... yes that would be 7/10's of one whole HP. The average gain is a little bette though.
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