> From Fred Katz
> The other clue for replacement, is wear between the gear teeth, forming
> circular notches. That's what my old gears looked like. Another clue is
> finding the lower chain guide broken, with pieces in the oil pan (I also
> found that!)
Yep!
Also with the chain off, and held horizontally, I can tell the difference
in the amount of chain wear by how far it 'droops'. When compared next
to a new chain you'll realize the amount of wear to the links.
Usually by the time I get into the timing chain's, I just replace EVERYTHING.
On my '67 2000. The upper guide had a little notch from wear. Odd, as the
chains were replaced by the previous owner. Then it dawned on me that all
he replaced during a rebuild was the chains and tensioner, not the gears
nor guides.
One other trick, thanks to Bruce Schluderman, is to replace the two 6 mm
hex head bolts with counter sink screws for a flush installation. Usually
I like installing allen key bolts, as the chain (with age) can brush up
against the bolt head. Flush screw allows for a cleaner installation, but
does require machining the guide AND BLOCK with a 82 degree counter sink.
Amount of metal removed on the block is only 0.020" at the entry of the hole,
so it is something I only recommend doing prior with a bare block.
> I've got a couple of questions for you. Tonight I installed the new timing
> chains on my rebuild. The lower chain tensioner assembly doesn't bolt onto
> the block in one fixed position. There's a little bit of play before
> getting torqued down. Does it make any difference where it gets torqued
> down? I more or less held it against the bolts away from the timing chain,
> before torqueing it down. Also couldn't find the torque value, so I guessed
> it's 5 ft-lbs. One more question - what direction does the rubber head of
> the tensioner point to? The picture in the manual is hard to make out, but
> it looks like the rounded end points to the left towards the jackshaft,
> while the almost straight narrow end points towards the crankshaft. Did I
> get it right?
Fred - I usually push the tensioner body TOWARDS the chain, enough to remove
any slack in the chain. Not forcing it, but just a light push. Then tighten
down the bolts. Always a good place to clean all the oil out, and use locktite
242 on the threads.
My lower tensioner is the same as you describe. Personally the rounded edge
should be towards the "incoming chain" which means pointed down towards
the crank!
I am still down right baffled by that lower chain guide. I think mentioned
asking a mechanical engineering friend to make a computer model of the chains
and jackshaft and camshaft. The lower chain guide can ONLY function as a
step of high rpms being let off, and the chain 'back slapping' that guide.
Odd thing is with time, and VERY WORN OUT chains, it will break that lower
guide off. Basically it serves no purpose other than to fail with worn out
chains! Odd. No never got the full model made, but maybe I'll get LEARN
how to use the full engineering package of Matlab & MatrixX someday to play
with this some more. Dynamic model is pretty interesting with a camshaft.
Fun thing with my job, as I get paid to go off an think about these things. ;-)
Cheers,
Tom Walter '67 2000
Austin, TX '68 2000
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