During the past several months I've been trying to get the valves on my '74
TR-6 set properly and have not been having much success -- I always end up
with more valve noise than I'd like. In an effort to try new (and hopefully
better) methods I bought a Clik-Adjust tool and gave it a shot. Here's
my assessment of the tool.
The first challenge in using a Clik-Adjust was finding one. I knew it was
made by Gunson, but I didn't know where to buy one here in the states. A
letter to Gunson (Gunson Limited, Pudding Mill Lane, London E15 2PJ, England)
brought a surprisingly fast response from Samplex, a state-side distributor of
Gunson's entire product line. If you are interested, you can reach Samplex at
Samplex, Inc.
30 Parkview Drive
Succasunna, NJ 07876
201-584-9370
Their price for a Clik-Adjust is $25.25 plus $2.95 shipping and handling. You
must pay by check or COD as they do not accept credit cards. After a couple
weeks I had the tool in hand and was ready to go.
The Clik-Adjust tool is about what you'd expect. It is an approximately 6"
lever arm connected to a 1/2" drive, with an integral screw driver piercing
the drive. The screwdriver clicks as you rotate it either direction, and the
top of the screwdriver has a ratchet that snaps at a (more or less) fixed
torque. The lever arm, drive, and screwdriver bit are metal while the handle
of the screwdriver is plastic.
You adjust the valves with the following process:
1) Use the lever arm to back off the lock nut,
2) Tighten the adjustment screw until the top of the screwdriver "snaps",
3) Back the adjustment screw off one "click" of the screwdriver for each
one thousandth inch of clearance (e.g., 10 clicks for 0.010"), and
4) Set the lock nut with the lever arm.
Nothing to it.
Unfortunately, I see (and experienced) two major problems with the tool. The
first has to do with step '2'. The intent is to tighten the adjustment screw
until there is zero clearance, and the assumption is that this is achieved at
the torque required to "snap" the top of the screwdriver. In practice the
"snap" torque varies according to the downward pressure exerted on the
screwdriver and in some cases the valve spring is partially compressed before
the screwdriver "snaps". Either the zero clearance torque changes from valve
to valve, or the "snap" torque varies according to technique, but in either
case the zero clearance point is not found consistently.
The second problem is less critical and has to do with the "click" aspect of
the tool. The designers of the tool assume a thread pitch on the adjustment
screw of 1mm per revolution and accordingly divided one revolution into enough
"clicks" so that each one equates to 0.001" (I'll let someone else do the
math). This appears to be a valid assumption for a TR-6, but even still I
have some suspicions. When the adjustment screw is being "clicked" back
from zero clearance it is not under any load, essentially floating in the
threads of the rocker arm. When the lock nut is seated it places an upward
load on the adjustment screw and pulls it away from the pushrod (per however
much slop there may be in the threads). I don't know if this amounts to much,
but it still concerns me.
The net result of all this is that I wasn't impressed with the tool. I set
the valves with the Clik-Adjust and then checked them with a feeler gauge and
found the results to be quite inconsistent. The biggest problem was
establishing the zero clearance point -- the screwdriver seemed to "snap" at
a different place every time. It may be that a "pro" could get better
results, but I certainly didn't find it to be a big help.
I call it $28 poorly spent. If anyone is interested in a slightly used
Clik-Adjust I can offer you a fairly good deal -- how about $20 plus S&H?
Ron
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Ronald C. Hood U S WEST Advanced Technologies
hood@uswest.com Boulder, Colorado
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