Vernier (Dial) Caliper
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Useful because it can read inside and outside measurements.
Use only as a
“rough” guide.
Add the reading on the blade to the reading on the dial.

Micrometer
 The most used measuring instrument in engine service and repair
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Each revolution of the thimble moves the spindle .025”.
The thimble is graduated into 25 equally spaced lines so ….
Each line represents
.001”

Crankshaft Measurement
 Measure for out-of-round
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Measure the journal in at least six different positions across the diameter at 60 degree increments. This should be done at the same horizontal position.
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Subtract the highest from the lowest to factor outof-round.

Crankshaft Measurement
 Crankshaft taper – measure the journal at two different horizontal positions across the journal and subtract to factor taper.

Telescopic Gauge
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Used in conjunction with a micrometer to determine the inside diameter of a hole.
The gauge is inserted until contact is present and then locked.
A micrometer is then used for measurement.
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Use only if necessitated.

Small (split)-ball Gauge
 Similar to a telescopic gauge in that it is used in conjunction with a micrometer to determine the inside diameter of a hole.

Small (split)-ball Gauge
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The gauge is inserted until contact is present and then locked.
A micrometer is then used for measurement.
Used for small bores.
 example: valve guide

Split-ball Probe
 More accurate than a split ball gauge
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Often used for larger bores

Feeler Gauge
 An accurately manufactured strip of metal used to factor the gap or clearance between two components.
 Used for:
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Piston ring gap
Piston ring side clearance
Connecting rod side clearance
Warpage

Straightedge
 A precision ground metal used to check to flatness of a component. Used for:
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Cylinder heads
Block deck

 Measures variations from zero. 14-21
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Used to check
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Runout
Crankshaft endplay
 Valve guide wear
Dial Indicator

Dial Bore Gauge
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The most accurate way to measure bore diameter, taper or outof-round.
Gauge must be “set-up” and zeroed before usage.
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Used for:
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Cylinders
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Main bores
Connecting rod bores
Bearing bores