Shimming impellor...

[Nutzy19]

I have a used Impellor shaft and races coming from Craig. How do I check the clearances for the impellor , what are they ( I have shims ) ? and what is the turning torque ( filled or empty) of the pulley after assembly ? Thanks !!

[Nutzy19]

N E 1 ????

[pavement pounde]

I don't know the exact clearence for the impeller, I always check if it does not touch the case on both sides, and use less or more shims.
The turning torque is between 35-45 inch/pound for the SN series and between 45 -55 inch/pound for the VR4, filled with oil.
You can use the search button for quick answers.

[speedytang]

I always set my impeller at .010 from the inlet.

[Nutzy19]

I always set my impeller at .010 from the inlet.

speedy how do you check that???? I have feeler guages..

[speedytang]

First thing is take the back impeller cover and color it with a marker to verify your not hitting the case when you rotate by hand. With the cover on, bend your feeler gauge and wedge it between the impeller and case to verify shim depth.

[Nutzy19]

went together nicely , impellor is .015 away from case and roughly .010 from the scroll cover. HOWEVER..... turning torque was low ...like 20 ft lbs at best. It only makes 3 lbs of boost and even that falls off around 4500 rpm . HELP !!

[Nutzy19]

I meant in lbs..... do I need shims for my sn89, I put the factory stack back in and maybe its not enough. Who's got shims?

[speedytang]

You need shims then you will need to adjust the impeller depth again.

[Nutzy19]

so I add shims to the inner race to increase the ball tension and then add shims to the impeller to get the clearance to the scroll cover back right ?

[speedytang]

Correct, Check it then check it again. Just make sure on the case bolts you torque them the same pressure because that will also cause the ball drive pressure to vary if you don't. Keep the bolts at the same in/lbs each time so that everything is equal each time you check the rotation.