71 GTV camchatter

[Simon Favre <simon@domain.elided>]

Here's my "old timer's" list of ways to check an upper timing chain.

1) If you're in there to adjust the valves, then you should also check
the chain. The simplest way to check it is to drape one end of the chain
over a cam sprocket and pull on the middle of that part of the chain
that's draped over the sprocket. You're trying to pull the chain away
from the sprocket in spite of the fact that it is engaged with the
sprocket. If the chain pulls away from the sprocket about half a chain 
roller diameter, replace the chain. I believe there's actually a spec 
for this. If you have a new chain handy, try the same test. If you can 
still pull the chain away from the sprocket, then it's the sprocket 
that's worn. A new chain on a new sprocket will barely lift at all.

2) Lay the old chain out on a clean surface next to a new one. Pull both
chains out to their max length. Measure the difference. There is a spec
for the amount of stretch, but I don't have this handy. If the old chain
is noticeably longer, replace it.

3) For the truly posessed, try pushing the links together while it's on
the flat surface. Don't let them bunch up. Measure the difference between
compressed and extended. A significant difference indicates a worn chain.

All of these basically measure slop in the chain, which can cause noise.
The first measures chain to sprocket clearance, combined with chain slop.
The last two just measure chain slop. Any measurement of chain stretch can
be divided by the number of rollers to get a measure of how much wear
there is on each joint in the chain.

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