Dave,
This is from Foley Engines : "Lets take rod bolts next.. People ask us
why we stress the importance of using new connecting rod nuts and bolts.
They note that we put new con rod fasteners into all of our Foley Engine
overhaul parts kits. (Dr. Diesel fought hard for this here at Foley
Engines. These fasteners aren't cheap!) Simply put, your old rod bolts and
nuts have stretched over millions of engine cycles. You can even prove that
by measuring rod bolt length with a micrometer or a specialty gauge that is
fitted with a dial indicator. Both BHJ Products (510 797 6780) and Goodson
Shop Supplies, Goodson Part Number RBG-1, (800 533 8010) have rod bolt
stretch gauges. The maximum stretch from the relaxed length to the length
of the bolt when installed and torqued to value should be no more than
.006< Rather than even measure your old bolts you can replace them easily
with new ones. When an old rod bolt fatigues and stretches, bad things can
happen. The rod no longer is at a consistent height with the other rods,
the bolt is not at peak strength, the big end is no longer round, and soon
the the engine will throw the rod creating a window in your block. (Wall
St. types in pink shirts and people who never took automotive shop class
sometimes think TRW stands for Thompson, Ramo and Woolridge, the automotive
parts conglomerate that was created out of Thompson Wire. Now you know what
TRW really means)."
FWIW, that is one professional's opinion.
Chuck Lattimer
'66 TR4A IRS
'46 Dodge PU WD-20
Brownsville, TX
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