How accurate is Plastigauge?

Tech Tip: Be sure to always use the inch side of the Plastigage package. Most good micrometers will measure down to 0.0001 inch (one ten-thousandths of an inch), which is plenty accurate.

What can be measured precisely using Plastigage?

Plastigauge is a measuring tool used for measuring plain bearing clearances, such as in engines. Other uses include marine drive shaft bearings, turbine housing bearings, pump and pressure system bearings, shaft end-float, flatness and clearance in pipe-flanges and cylinder heads.

Why is it important to remove the Plastigage?

Remove the engine sump cover to reveal the big-end and its retaining set-screws. Ideally you should remove the PLASTIGAUGE stripe with a clean oily cloth or industrial de-greasing solvent, but users may be assured that any PLASTIGAUGE left behind is oil soluble and cannot harm the engine in any way.

How do you check Plastigage bearing clearance?

Tear off a piece of plastigage. Open the paper to remove the plastigage, and place the plastigage across the surface of crankshaft. Position the plastigage in the center of the journal surface. Install the bearing cap and torque the bolts to specification.

What color is Plastigage?

It comes in three diameters and colors. It is color coded by size — green Plastigage measures the range . 001 – . 003”, red measures .

How is the Plastigauge positioned on the journal bearing?

Position the plastigage in the center of the journal surface. Install the bearing cap and torque the bolts to specification. You will see the crushed plastigage on the journal. Using the paper that came with the plastigage, use the scale on the side of the wrapper to measure the crushed plastigage.

What is the typical connecting rod bearing clearance?

The Rule of Thumb The factory specs include 2.450-inch main bearing journals and 2.100-inch rod journals, which means the target bearing clearance should be about 0.0024-inch (0.0025 is the common spec) on main bearings and 0.0021-inch on the rod bearings.

Do you use oil with Plastigage?

A modern engine is a little better off, as the insert is a little harder then babbitt, but you can still improve the Plastigages use, by using oil. To remove the used Plastigage from Shaft, and Bearings, Lacquer Thinner, will take care of it fast.

What’s the difference between red and green Plastigage?

It is color coded by size — green Plastigage measures the range . 001 – . 003”, red measures . In each case the measurements in the top 1/3 of the range are suspect and should be be verified by using the next size larger if possible.

What is red Plastigage used for?

Plastigage (also called Plastigauge or Plastic Gauge) is a measuring tool for measuring plain bearing clearances, especially in engines. Plastigage is also used to measure clearances on marine drive-shaft bearings, turbine housing bearings, shaft end-float, pipe flange clearances and pup and pressure system bearings.