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Author Topic: How to polish the connecting rod journal?  (Read 13225 times)

mobile_bob

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Re: How to polish the connecting rod journal?
« Reply #15 on: September 22, 2007, 04:32:37 AM »
another point worth mention

first a question :)

"why do we torque?"  (specifically the rod bolts)

the reason we torque is to get the big end bore back to perfectly round.

when the big end is machined its bolts are first torqued to spec,, then machined and honed to size.

if we do not torque to the same spec's we cannot have a perfectly round bore in the big end... now

the question become's

what is the proper torque?  and

how can we be assured it was torqued properly before the big end was machined?

we can hope they did it properly, or we can assume they did?
or we can check it by removeing the rod, torque its bolts to spec
and check the bore for round,, if it is perfectly round and not egg shaped all is well.

same goes for main brgs, cylinder heads etc.
that is why they torque main bolts in an engine before they align bore and hone
and why they use torque plates when the bore engine cylinders.

it assures that the affected area's remain perfectly aligned and round.

also the lube they use on the threads will have a dramatic impact on how much torque is used
i have no idea what the indians use to lube the bolts before torque and machining or if they lube at all.

also a bolt must stretch to maintain its torque, some bolts are designed to stretch a particular limit and are one time use
other are designed to stretch less and are reuseable.

i have no idea what the indians use, but if in doubt replaceing  them seems prudent to me.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

rcavictim

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Re: How to polish the connecting rod journal?
« Reply #16 on: September 22, 2007, 05:34:32 AM »
You explained some good points Bob!
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