[Spridgets] Harmonic balancer bolt, to loctite or not to loctite?

[bjshov8 at tx.rr.com]

I have pulled off and put on very many harmonic balancers, mostly on American
pushrod engines.  I have never had a problem with them nor heard of a problem.
We put the balancer on, torque the bolt to its spec, and that's the end of
it.

I have also owned a few foreign DOHC engines (for a V6 or V8 engine this means
4 camshafts).  I have heard of problems with these engines and had this
problem with one that I owned.  A pushrod engine has one camshaft with a
relatively short chain but an engine with 4 OHC's has a lot of cams to move
and long belts or chains.  My engine as it got a lot of miles on it started
running poorly.  It just had much less power then when it was newer.  I tried
a lot of things and never found a solution.  Then another person on the
internet posted a story about their engine.  It made sense to me so I checked
mine and sure enough it had the same problem.  All of these engines have cam
drive gears on the crankshaft, these gears slip onto the crankshaft snout and
are held in place by a woodruff key, and clamped into position by the harmonic
balancer being bolted on.  The woodruff key plus friction transfers rotational
force to the gear and rotates the cam(s).  If there is any slack in the system
then the gear can vibrate back and forth and eventually wear the key and
keyway and allow the gear to move back and forth.  It was easy to check my
engine- I rotated the crankshaft slightly and observed that the cams didn't
move.  My cams, and thus ignition timing as well, were retarded about 20
degrees or so.  I Put in a new key and cam gear and the engine ran fine after
that.  I don't know why I had never seen this type of thing before, but I
theorized that the long cam drive belt might have introduced some kind of
harmonics into the system that caused the cam gear to want to rock back and
forth.

So I think you should torque the balancer bolt to specs, but I'm not sure that
loctite is required.


---- derf <derf247 at gmail.com> wrote:
> Having recently gone through a LocTite seminar I would say LocTite is
> good stuff.  Use the blue and you should be fine.
> Of course, many have done it without and I don't think there are any
> problems with that, either.
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