16 April 2011

Reflections

I did a little un-scientific testing to see if there is a difference w tightening the main pulley bolt in one stage or in 3 stages as proscribed by ARP.
I tightened the bolt to spec, 100Nm + 90deg. I then loosened it and noted the force it took to loosen.
Then with a different bolt, I did the following:
- 100Nm >loosen
-100Nm + 45deg >loosen
-100Nm + 90deg >loosen and observe force

there was definately a difference between the 1 stage and 3 stage force it took to loosen the bolt. While this is un-scientific and I have no empirical evidence, I am certain that it took more effort to loosen the latter method.

What I will do the next time: 
-Start with a new bolt (actually I did this last time, this is just a reminder)
-apply a liberal amount of Loctite high strength
-torque using the 3 stage method
-my final rotation value will be more than 90deg...maybe 135deg or so..that is TBD right now while I look into it a little more.

The main pulley sees much higher loads with the blower than the factory intended, and short of installing a load assist (keyway) I think more torque is the ticket (to a point)

Incedentally, when I fixed my timing I saw boost levels drop. How much i cant be sure as I also went from a 3.0 pully to a 2.8, bit w the 3" the car made ~12psi and w the corrected cam timing and 2.8 pulley i saw 11psi! Talk about breathing better.... 

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