> Date: Mon, 17 Jun 2002 09:05:28 -0400
> From: Wayne Osborne <wayne@chevytrucks.org>
> Subject: Re: [oletrucks] GM V8 Engine questions
>
> Isn't rod knocking a sign of a turned bearing on the crank, of course on
> the connecting rod? --wayne
>
>
> At 12:18 PM 6/14/02 -0700, BORDER,RYAN (HP-FtCollins,ex1) wrote:
-snip-
> >
> >What is the typical cause of "rod knock", and what is the usual repair
> >entail?
Rod bearings will knock when they get too much clearance, usually from
wear caused by lack of oil (or just too many miles). When the bearing
and crank journal get too hot, then the bearing might spin in the rod;
the bearing material "welds" to the crankshaft material, and the
bearing's locating tangs cannot hold it in place. Usually the next
thing that happens is that one of the rod nuts comes off due to the bolt
getting too hot and relaxing; then the rod big end comes off the crank,
which we call "throwing a rod".
But as Ryan discovered, the engine that he was buying that had "rod
knock" actually had a damaged piston! It's not easy to tell just
exactly what's making the noise without taking the engine apart.
Jim F
59s in AZ
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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