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Rod Bearing Clearance Question...
Thread Starter
Teching In
Joined: Apr 2019
Posts: 3
Likes: 0
Rod Bearing Clearance Question... I'm building a 5.7 iron block LS (5.3 punched out to 5.7), and I'm checking my rod bearing vs crank journal clearances. I wanted to see what you guys thought of the results before I start installing the rods to make sure the clearances aren't too tight.
.00185
.00205
.00200
.00205
.00185
.00195
.00200
.00195
The main crank journal clearances were .002 +.0004/-.0000
Based on those numbers, I'm going to be running 5W20 oil through it.
I just wanted to make sure the clearances were't too tight as this is my first LS motor build (going in my 68 Camaro). Really taking my time with it to make sure I don't miss anything.
.00185
.00205
.00200
.00205
.00185
.00195
.00200
.00195
The main crank journal clearances were .002 +.0004/-.0000
Based on those numbers, I'm going to be running 5W20 oil through it.
I just wanted to make sure the clearances were't too tight as this is my first LS motor build (going in my 68 Camaro). Really taking my time with it to make sure I don't miss anything.
TECH Addict
Joined: Oct 2016
Posts: 2,513
Likes: 480
From: PDX-OR-USA
Something to consider,, Plastiguage is measuring the displaced gap,, the rod and crank need oil pressure to center the crank in the rod bore.
Hydraulic pressure is pretty magical, so for high power tight tolerance I'd go with a GOOD micrometer and bore gauge and measure several places each to check fore oval journals and rod bores.
(This is why my question above..
)
Hydraulic pressure is pretty magical, so for high power tight tolerance I'd go with a GOOD micrometer and bore gauge and measure several places each to check fore oval journals and rod bores.
(This is why my question above..
) Well with that being said I think it's a little tight for an iron block build. Curios to know just how you measured the rod bores. Did you measure without the bearings installed to get the bore minus the bearing thickness or did you measure with the bearings installed on the rods after torqued? You may want to look at a different set of bearings.
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