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How to use plastigage


Whiplash
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PLASTIGAGE was designed as a final check of total vertical oil clearance during reassembly. It was not meant as a replacement for properly measuring crankshaft journals, housing bores or bearing dimensions before engine reassembly with accurate mics and gauges.

 

To properly use PLASTIGAGE during reassembly, readings should be taken on the bearing cap half shell while the weight of the crankshaft or piston and rod assembly is supported by the other half shell.

 

Place a small amount of oil on the crankshaft journal only where the PLASTIGAGE will be placed and wipe any excess oil off with a clean rag. This will result in a more accurate reading by preventing the PLASTIGAGE from sticking to the journal.

 

Place a strand of PLASTIGAGE across the length of the journal parallel to the crankshaft.

 

Set the cap in place and tighten bolts to the proper OEM torque specification. NOTE: if the crankshaft is moved at this point it will smear the PLASTIGAGE, resulting in inaccurate readings.

 

Carefully remove the cap and measure the crushed PLASTIGAGE using the graduations printed on the package. Measure the crush along the entire length of the PLASTIGAGE, noting the highs and lows for proper clearance.

 

After you have made your measurements, carefully remove the crushed PLASTIGAGE from the components without scratching the bearing or the journal.

 

PLASTIGAGE is available in four different sizes to check total vertical oil clearance on connecting rod and main bearings. Each package has a measuring scale printed in inches and millimeters. Strips are color coded for easy size identification and are soluble in oil.

 

MPG1 .001â€â€”.003†(.025 —.075mm) Green

MPR1 .002â€â€”.006†(.050 —.15mm) Red

MPB1 .004â€â€”.009†(.10 —.23mm) Blue

MPY1 .009â€â€”.020†(.23 —.50mm) Yellow

Edited by Whiplash
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