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> So, do you know what the hell the "Plasti-gauge" is? I was flipping
> through the Bently last night looking for critical dimensions when I saw
> the reference to it. How do you use it to measure bearing clearance?
>Thought I'd CC the list on this one...
>Plastigauge is this plastic "string" you buy. It is very precision made
>string, and comes in a number of "calibrations".
>It's used to measure bearing clearances, a very useful thing to know on
>a nice freshly-blueprinted engine! (also useful on old worn engine to see
>just how worn it is).
>To use, you snip off a small piece (1/4 to 1/2 inch typical) and care-
>fully lay in on the bearing surface(s) -- cam, crank, etc. -- and then
>assemble the engine *DRY* (no oil, grease, "assembly pre lube", or any
>of that stuff!), torqueing down everything to spec. You then take it
>all apart again (e.g., pop the bearing caps) and look and see how much
>the plastigauge string has been squashed (they give you this little
>chart -- piece of paper with assorted "widths" lines), which in turn
>tells you exactly how much clearance you have. I don't remember how
>many sizes/etc, it comes in, but the resolution is easily .001 inch,
>i.e., much smaller than "allowable variations" in bearing clearances.
>The stuff costs a few bucks for enough to do a veritable fleet of en-
>gines . . .
>PlastiGauge and HeliCoils, perfect Xmas present for all those gearheads
>on your shopping list!
Both are life- and $$$$- savers!
Stephen A. Marinello, Ph.D.
Newpark Resources, Inc.
P.O. Box 6411 - Metairie, LA 70009