Installation and Operation Manual
SA-07-11-87, Rev A
46
January 2019
Shim Calculation
Based on the measured clearance for the front and the back side of the impeller, the goal is to shim both
the impeller and cover to obtain a NOMINAL clearance of .060” with a tolerance of +/-.010” on both the
front and the back side of the impeller. To achieve this, it is recommended to follow the steps below:
Shim Calculation
1. Add the Front Clearance and the Back Clearance of the impeller to calculate the Total Clearance
(TC)
2. For the
Back Clearance (BC)
, the cover is shimmed. NOTE: The cover can only be shimmed by
a
maximum
of .015”
a. If TC - .120” is GREATER than .015”, SHIM = .015”
b. If TC - .120” is LESS than 0 (negative value), then SHIM = 0.0”
c. If TC - .120” is GREATER than 0.0” AND LESS than or equal to .015”, then SHIM = TC -
.120”
3. For the
Front Clearance (FC)
, the impeller is shimmed from the shaft.
a. If the FC is LESS than OR Equal to .060”, then SHIM = 0.0”
b. If the FC is GREATER than .060”, SHIM = FC - .060”
Example 1
Existing Clearance
Back = .05”, Front = .065”, TC = .115”
Logic
Back
TC - .120” is LESS than 0.0” (For Example: .115 - .120 = -.005).
SHIM = 0.0”
Front
FC is GREATER than .060”.
SHIM = .065 - .060 = .005”
New Clearance
Back = .055, Front = .06”, TC = .115”
Example 2
Existing Clearance
Back = .07”, Front = .065”, TC = .135”
Logic
Back
TC - .120” is GREATER than 0.0” AND LESS than or equal to .015”.
SHIM = .135 - .120 = .015”
Front
FC is GREATER than .060”.
SHIM = .065 - .060 = .005”
New Clearance
Back = .06, Front = .06”, TC = .120”
Sundyne can provide an Excel Spreadsheet to facilitate the calculations. Contact your Sundyne
Representative.
