ACL Flexigauge Plastic Gauge for Engine Bearings

ACL Flexigauge plastic gauge for accurate radial clearance measurement of engine bearings. Essential engine building tool to validate rod, main and cam bearing clearances against manufacturer specifications before final assembly.

Common technical specifications

• Manufacturer: ACL (Australia)
• Product name: Flexigauge
• Type: Calibrated plastic gauge wire
• Application: Radial clearance measurement in engine bearings
• Use: dry, without oil, on clean surfaces

Available part numbers

• Green - Range 0.025 to 0.076 mm: for very tight clearance measurements (0.001" - 0.003")
• Red - Range 0.051 to 0.152 mm: for medium clearance measurements (0.002" - 0.006")
• Blue - Range 0.102 to 0.229 mm: for looser clearance measurements (0.004" - 0.009")
• Yellow - Range 0.203 to 0.406 mm: for very loose clearance measurements (0.008" - 0.016")

How it works

Plastic gauge is a calibrated plastic wire that crushes precisely under applied pressure. Placed between the bearing and journal before torquing the cap to manufacturer specification, it flattens under the load. After disassembly, the width of the flattened wire (measured against the printed scale supplied with the product) gives the exact radial clearance of the bearing. This is the worldwide standard method used by professional engine builders.

Colour selection

The colour choice depends on the expected clearance range for the application:

• Green (0.025 - 0.076 mm): ideal for checking tight clearances typical of built motorsport engines, race, drag. Maximum precision on small clearances.
• Red (0.051 - 0.152 mm): the versatile choice for most performance and automotive engine building applications. Covers typical OEM clearances in general use.
• Blue (0.102 - 0.229 mm): for looser clearances, certain specific applications or large-displacement engines.
• Yellow (0.203 - 0.406 mm): reserved for very loose clearances, mainly encountered on diesel, industrial or worn engines.

Generally, an experienced builder keeps at least Green and Red colours in the workshop to cover the most common performance building cases.

Application

Use in engine workshop for:

• Rod bearing radial clearance measurement
• Main bearing (crankshaft) radial clearance measurement
• Camshaft bearing radial clearance measurement (where applicable)
• Verification after journal grinding
• Conformity check before final assembly

Important: plastic gauge is used dry, on clean and unoiled surfaces. Torque the cap to exact manufacturer specification following the prescribed sequence, then disassemble without rotating the crankshaft. Compare the flattened wire width to the scale printed on the packaging.