Another ASP Pulley DIY Thread
I busted the torx head for the one on the S/C belt loop and had to replace the whole belt tightener assembly ($60). Upon doing so, I found something very informative and wanted to share:
Pry out the plastic cap on the tightener pulley using a flat-head screwdriver; this exposes a 15mm bolt. Use this bolt, instead of the torx head at the end, to loosen the pulley. A standard 15mm long socket will do. I also used a pipe extension and the far right air filter box bracket to hold the "loosened" pulley stationary so that it was a lot easier to put on the belt! See the attached pic for details.
The worst that could happen on using the 15mm bolt is you might loose the bolt by applying too much force. This is not a problem at all, just retighten it and try again, much better than deforming the super ductile torx head!
Last edited by 20FHK02; Oct 23, 2002 at 02:17 PM.
I used fine sand paper to smooth out the steel ring surface, applied grease as instructed, and even used torque wrench to get it to about 100 ft-lb (I know Lee suggests 85 but that sounds kinda low).
Dang!
Guess my car really hates the pulley...
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Did you really torque it to 220 ft-lb? I think this is the spec for the steel stock pulley, but the strength for the aluminum ASP pulley is a lot lower than steel.
When I put back the stock pulley last time I also only torqued it to 100 ft-lb or so and it did not leak. Anyway, an under torqued pulley might fall off later, but 100 ft-lb is a pretty strong force to create a tight contact already, so I don't think the torque strength is the cause of the leakage.
mctwin2kman:
The think only leaks when it is under load. If you leave the engine running at idle it will not leak. And when I put back the stock pulley it did not leak.
Yeah, yeah...why doesn't it leak with the stock pulley? I don't know but, mechanical seals sometimes have a funny way of interacting with different seal surfaces. They "get used" to the mating surface then leak when that surface is changed.
I would also suspect that the seal surface of the new pulley is too rough (you said you sanded it). It should be polished to 32 microinches or better.
I'd replace the seal and see what happens. It's the only thing other than the pulley that would cause a leak.
Yeah, yeah...why doesn't it leak with the stock pulley? I don't know but, mechanical seals sometimes have a funny way of interacting with different seal surfaces. They "get used" to the mating surface then leak when that surface is changed.
I would also suspect that the seal surface of the new pulley is too rough (you said you sanded it). It should be polished to 32 microinches or better.
When I take off the pulley again I'll also take off the seal (if doable) to check for damage.
If everything fails, I will give up and conclude that my car really hates aftermarket pulley.
220ftlbs will cause an aluminum pulley to deform! This is possibly flaring out the part of the pulley that is against the oil seal. take off the pulley and inspect it for cracks caused by over torquing it then put it back on with half that torque.
I should talk to my guy at Kleemann and see what they recommend.
Why do you have to remove the pulley to re-torque the bolt?
Mark
The typical elastic modulus for steel at room temperature is about 30E6 psi, and 10E6 psi for aluminum. This indicates that the stiffness for steel is roughly 3 times higher than aluminum.
So if 220 ft-lb is the safe zone torque for the steel pulley, it should be 220/3 = 73 ft-lb for the aluminum ASP pulley, since the same bolt and washers are used providing same bolt parameters.
The elastice modulus is lower at higher temperatures when the engine is hot, so over torquing the ASP pulley is very dangerous in the long run.
So Lee's suggestion of 85 ft-lb is already on the high end. I think the machinest should know what he is doing so I trust his recommendation.
Last edited by 20FHK02; Oct 25, 2002 at 01:13 PM.
OKay, I went back to my textbook and here is what I found:
The typical elastic modulus for steel at room temperature is about 30E6 psi, and 10E6 psi for aluminum. This indicates that the stiffness for steel is roughly 3 times higher than aluminum.
So if 220 ft-lb is the safe zone torque for the steel pulley, it should be 220/3 = 73 ft-lb for the aluminum ASP pulley, since the same bolt and washers are used providing same bolt parameters.
The elastice modulus is lower at higher temperatures when the engine is hot, so over torquing the ASP pulley is very dangerous in the long run.
So Lee's suggestion of 85 ft-lb is already on the high end. I think the machinest should know what he is doing so I trust his recommendation.


