ACL FLEXIGAUGE/ PLASTIGAUGE AG-1 .001”-.003” (0.025mm-0.076mm) MEASUREMENT

Flexigauge is a precision manufactured plastic strip
It is available in four sizes and is used to check clearance of main and connecting rod bearings, and is suitable for Automotive,
Marine, and Industrial applications.

Flexigauge strips are 12” inches long (309.8mm) and are packed in individual envelopes, which are marked in appropriate graduation one side in thousandths of an inch and the other side in millimetres. Ten strips in their envelopes are packed in their appropriate colour coded carton.
Directions for use, which are printed on the outside of each carton for easy reference, are as follows :
1. Remove the bearing cap, wipe the journal and bearing shell clear of all oil
2. Place a piece of Flexigauge across the bearing at the crown (see fig 1)
3. Install the bearing cap and using a torque wrench tighten the bolts to the correct tension.
DO NOT ROTATE THE SHAFT OR BEARINGS.
4. Remove the Bearing cap. The Flexigauge will be adhering either to the bearing or shaft.
5. Compare the width of the flattened Flexigauge with the graduation of the envelope. The figure within the graduations
indicates the clearance in thousands of an inch or millimetres, depending on which side of the envelope is used. (fig 2)
6. Taper is indicated when Flexigauge is wider at one end than the other, the amount of taper being the difference between
the readings. The widest part of the flexigauge represents the area of least clearance. “Barrelling” of the shaft happens
when the Flexigauge is wider in the centre of the bearing.
P r e c a u t i o n
When checking main bearings, with the CAP supporting the crankshaft, the weight of the crankshaft and
flywheel must be taken off the the bearing caps to avoid inaccurate results. This can be done, for example, by
‘jacking’ on the crankshaft balance weight.
Main and connecting rod bearing clearances should be checked on the area of least journal wear. Main
bearing checks should be made with the adjacent crankpin situated about 30 degrees after bottom dead
centre.