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bdonally bdonally is offline
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Join Date: Dec 2001
Location: Off grid in Eastern ONtario
Posts: 201
Originally Posted by Trakrat View Post
The tough part is going out and buying the correct tool.
If you have your parts at a machine shop then an option is to have them do the measurements.

regarding Plastigage, the issue is less about reading the amount of squish but rather

a)holding rods steady while the bolts are torqued. It is really hard to avoid moving the rod and therefore likely affecting the squish of the plastigage

b)inaccuracy measuring all the main bearings at once. There is some tolerance on the alignments of the bearing bores, so the crank will sit on the two highest points and lift the other journals off the bearings, resulting in the plastigage being more compressed on those journals, giving a falsely tight reading. I noticed this and wound up testing it by doing two bearings at a time, with results closer to the measurements. Total P{ITA, thought, as the cases must be assembled/disassembled a lot.

Plastigage seems more accurate on the IM bearings, where there are only two on the shaft.
Clevite's plastigage instructions for doing an engine with individual main caps refers to not installing all the bearings but rather only two at a time to make sure it is accurate.
Bob D.
'84 Carrera - MAF, Wong chip, RSR flywheel, ER bushings and other bits, CTR fiberglass F/R bumpers, 7/9 Fuchs, 22/27 TB, 22/21 SB, bunch of other little stuff
'69 Lotus 7 Series 3; '74 Fiat X1/9
'14 X5 diesel
Old 09-05-2018, 02:03 PM
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