I haven't seen a reply to this, so here's mine ...
> But, there is approx. 1/2 inch or better play in the chain
If that's from one extreme to the other, it's probably not too bad. You
can't actually judge chain wear very well this way, normal manufacturing
tolerances mean there will be some variation even with a new chain and gears
(and there is a certain amount of slop designed in to accommodate the worst
case variation). That's why there is a tensioner instead of a fixed
adjustment.
> (can't find any specs on normal tension and measurement
Method I was taught was to remove the chain and hold it up horizontal at one
edge. If it droops noticeably, it's worn and should be replaced along with
the gears. The gears wear to match the chain, so they should be replaced in
sets. (Otherwise, the new chain will rapidly wear to match the worn gears.)
> Last year when I had
> the 6 on the road I was having some problems maintaining exact timing but
> hadn't really isolated the problem.
Unlikely to be a worn timing chain, unless your tensioner has failed. A
worn chain will let the cam timing go late, reducing performance at high
rpm, but the engine will still run consistently. Ultimately the chain will
jump a tooth, which will make the engine run really bad (but still
consistently if at all).
> I'm inclined to just go ahead and replace the gears and chain
> since chain is
> minimal cost and engine is already out. Any reason to not do
> this?
I don't know if this applies to TR6 components, but there have certainly
been some bad TRactor motor components on the market. This includes timing
gears that are not cut properly, preventing (in some cases) correct timing
of the cam.
Randall
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