Precision Measurement Supply - Fixtures, Tooling And Measuring Devices For Professional Engine Builders

Indicator Adaptor Operating Instructions

The PMS Indicator Adaptor consists of three basic pieces:

 “A”  ARBOR ADAPTOR:  This is the piece that the indicator attaches to – it is placed over the moveable arbor above the top pad on the tester.

“B”  BASE ADAPTOR:  This part bolts on top of the existing lower spring pad of the tester with a 5/16” socket head cap screw which is provided with the adaptor. NOTE:  Do Not Remove the RIMAC Base Pad

“C”  2” STANDARD:  This is the round bar – used to calibrate the indicator at exactly two inches spring height.


  1. Remove socket head cap screw and top pad from the tester arbor, slide part “A” (Arbor Adaptor) over arbor with the “arm” pointing left (opposite side of existing scale) and Ό” set screw in part “A” facing front of tester.
  2. Remove 5/16” socket head cap screw from base pad of tester.
  3. Place part “B” (Base Adaptor) over existing base pad and secure with longer cap screw which is provided with adaptor.  Note:  Arm on part “A” and “B” should be on the same side of tester (left).
  4. Attach dial indicator to arm of part “A” with Ό” cap screw (provided with adaptor).

Calibrating Adaptor:

  1. Place part “C” (2” Standard) on tester in the same manner you would a valve spring.
  2. Compress adaptor to about 20 pounds.
  3. Lock part “A” to arbor with Ό” set screw and “zero” indicator.
  4. The adaptor is now set at exactly 2 inches spring height.  Note:  Indicator Pre-load:  It is always a good idea to pre-load a dial indicator .010 - .020.  That is why the needle points to the left of zero with no load on the indicator.  Please understand that pre-load does not affect your reading -- you are measuring from ZERO where you calibrated the tool.

How to Use the Adaptor:  

EXAMPLE #1: Assume you want to check a spring at an installed height of 1.750.

  1. Set up and calibrate the adaptor as described.
  2. Place spring on tester and compress it until the indicator travels .250” from zero (this would be two and one-half revolutions).  Your spring is now at exactly 1.750”.   [ 2.00” - .250” = 1.750” ]
EXAMPLE #2:  Suppose you want to check open pressure at 1.500”.
  1. Compress until indicator travels .500” (five revolutions) and read the pressure.  [2.00” - .500” =1.500”]  

Note: If springs are to be tested over 2” installed height, simply make a longer standard of a known length for calibrating – or call PMS and we’ll send you whatever you need.  Also, your RIMAC scale on the right side of the tester will be off by .375” because of the 3/8” base adaptor.


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