VR-4

[Duke]

Where do you set the rotational torq at, for the vr-4 kit. It is supposed to be 44 inch lbs?

[suede57ford]

That sounds right from what I remember. I looked through my notes and could not find it. The larger impeller needs a tighter setting.

You can tell if they are set too loose as, when they do slip internally, the boost drops off really fast once it slips.

I set the VR57 to SN conversions I build to 55 inch lbs. They use all SN internals and a VR4 beville washer and they seem to last very well on my street motors. The VR57 is direct oil from the engine, so it has the engine oil flowing through it to keep the heat down, and that could be why I can run high pressures with them. I tried 33 inch lbs on a VR57 and it would slip internally at high rpms. Once again a converted VR57 '57 Ford Supercharger is a little different animal so maybe case reinforcement differences necesitate the VR57 using a higher torque than a standard SN.

[Duke]

Where do you set the rotational torque at?

[suede57ford]

The check the rotational torque you will need an inch lbs torque wrench. It needs to be the style that has the needle(like a old schol torque wrench) and not a cliker style.

Mount the blower in a vise or in some way it will not move when you turn the input shaft with the torque wrench. I have two long 5/16 bolts that I screw in the back of the blower case on a VR57 and then clamp the shafts of the bolts in a vise.

Put the torque wrench on the bolt that holds the front pulley on and then rotate the wrench around in a circle, turning the blower input shaft, and watch the needle to see what torque number of resistance the needle is at while you are turning the wrench and input shaft at a steadly speed.

I used to have someone watch the needle while i focus on turning smothly. But now I painted a dot on my torque wrench where the needle needs to point while rotating.

To increase the tension add another shim behind the beville washer. Doesn't take much of a shim .005-.010 to change the torque.

I do the initial set-up without the front cover gasket and add a shim the thickness of the compressed gasket. I check with the seals in place as it doesn't seem to make much difference, and then when I hit the final number I'm done.