let me add one thing, this is all true of our old trucks, but many newer
vehicles Do have balance weight built into the harmonic damper (and the
flywheel). I only add this in case someone trys to use a late model
damper. I belive that all the small block chevys EXCEPT the 400 are OK,
but I doubt any V-6s are.
--
John Dorsey
Wauchula, FL
'49 Chevy Panel http://www.strato.net/~jrdorsey/truck.htm
'52 GMC Firetruck http://www.strato.net/~jrdorsey/fire/fire.htm
'51 Chevy suburban http://www.strato.net/~jrdorsey/burb/
Jack Halton wrote:
>
> Deve et al,
>
> The term "Harmonic Balancer" is something of a misnomer, as it doesn't
> really "balance" anything. It is referred to in the GMC manuals as a
> "crankshaft damper" which reflects it's true purpose, which is to dampen
> torsional vibration from the crankshaft, inherent in any inline engine. The
> bigger the "damper", the more rubber it contains, and the better it can do
> it's job. The 235 has a longer stroke than the 216, so it needs more
> damping. In theory at least, it's likely that by using a 216 pulley, the
> damping effect will be reduced, perhaps causing the damper and pulley, as
> well as the flywheel on the other end, to eventually loosen and come off.
>
> This happened to me with a stock 228 GMC engine, not from swapping
> parts, but just due to normal wear and deterioration of the damper/pulley
> assembly. It was not a pretty result, taking the fan and radiator out when
> it happened.
>
> All of the above is mainly a concern at higher (>3000 RPM) engine
> speeds. So it may be that you can get away with the smaller damper/pulley if
> you don't push things too hard. Drilling the snout of the crank for a
> retainer bolt would eliminate the problem, but you may be reluctant to do
> this...at least be aware of the onset of a light "knocking" noise that seems
> to come from the water pump area. It can often be traced back to a loose
> damper/pulley.
>
> Jack Halton
> 51 GMC 1/2 ton
> Winter Park FL
> ----- Original Message -----
> From: "Deve Krehbiel" <dkrehbiel@kscable.com>
> To: "OleTrucks" <oletrucks@autox.team.net>
> Sent: Thursday, October 05, 2000 10:17 AM
> Subject: Re: [oletrucks] Disquised 235's
>
> > My concern with adding a 216 Harmonic Balancer to a 235 is the "Balancer"
> > part. The 235's HB is larger and has more centrifugal weight around the
> > outer edge than a 216's. Is there any reason to be concerned about that?
> > Would doing that result in an unbalanced engine and cause premature engine
> > wear?
> >
> > On the hand crank issue, keep in mind that after 1950, they stopped
> putting
> > the hole in the grille and grille pan to recieve the crank.
> >
> > Deve Krehbiel
> > Hesston, Kansas
> > 1950 3100 * 1949 3600 * 1948 4400
> > www.speedprint.com/Deves50/index.html
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