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Plastigauge use

Started by Jens, August 31, 2010, 06:54:50 PM

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Jens

I am about to use plastigauge for the first time but know very little about it short of "squish it and see how wide it gets"
Let's say you wanted to make sure clearances on the journals of your listeroids were correct ...... How would you place the plastigauge prior to torquing down the big end cap. Do you use a strip across the width of the journal or do you lay it in line with the rotation ? Do you use a single strip of plastigauge or do you use multiple strips in multiple locations ? The obvious way would be to put a single string of plastigauge into the center of the big end cap, torque it to operating torque (anybody know what the torquewould be on a 20/2), remove it and measure. Anybody know the torque spec on the central bearing carrier of the 20/2 ? Are the clearances similar on the center carrier and the connecting rod big ends (torque on the center carrier will be a LOT less although I do not know yet exactly what it will be).






mobile_bob

use a single strip running perpendicular to rotation, basically across the width of the brg
torque to spec (whatever that is) and the remove and check the width of the now smashed plastigage.

kinda like checking piston squish but with something soft enough to not damage the brg white metal.

as for torques?

hellifiknow

:)

bob g

Crofter



One strip at a time as the total clearance must all be forced to one point by the resistance of the plastigage. Wrapping it bracelet style would give confusing readings. Take an impression at 6 o'clock and separately also near 8 and 4 oclock to make sure you are not tight (er) side to side than top to bottom. I have no torque specs in my manual but I know I have seen them posted.


[/quote]
Frank


10-1 Jkson / ST-5

veggie

Jens,

Lay the plastigauge in-line with the crank shaft. Like the attached picture.
Place the strip 90 degrees from the con rod cap joints.
Tighten the cap nuts to spec.
DO NOT rotate the crank at all.

Undo the nuts, remove the cap, and measure the squash against the guide on the package.

Good luck,
Veggie

Apogee

Jens,

Why not email the manufacturer and ask?

They will know the correct specs with certainty...

Steve

JohnF

Jens;

Don't know that torque setting, I 'seem" to remember that it is in the 45=60 lb range.  On mine I used to torque them down until I could get the cotter pin through - then I stopped using cotter pins.......
John F
www.woodnstuff.ca
Listers, Changfas, Redstones, AG's and anything else diesel I can get my hands on!