At 04:57 PM 5/22/2001 +0000, Jack W. Drews wrote:
>Henry Frye wrote:
>
>Thanks for the kind comments.
>
>Thought you might be interested in some findings after an afternoon of
>studying
>transmission tops. Since your trans doesn't pop out of third, this is just
>arcane and unrequested knowledge at this time -- but eventually you may
>need it
>because this popping out of gear afflitcs almost every TR sooner or later.
>
>A basic cause is worn tophat bushing on the main shaft, allowing too much
>endplay in the third / fourth gear. Assuming that is all okay, there is
>another
>way to fix it.
>
>That way is to make the detent on the shift rod stronger. This is most easily
>done by putting another little spring inside the 3 - 4 detent spring. The
>problem here is that most TR4's have so little tension on their original
>spring
>that even with the extra spring there is too little pressure. The TR6 used a
>heavier detent spring (now wonder why that was?) when they were made, but now
>only one spring is specified in the Moss catalog for both TR6 and TR4, and it
>is weaker than the weakest of the other two. The TR6 spring is made of .065n
>wire and the TR4 spring is made of .055 wire.
>
>There is also a spec in the TR4 and TR6 books on how many pounds it should
>take
>to disengage -- it's higher for the TR6 -- you can measure it with a cheap
>fish
>scale.
>
>Howsomever, I am postulating that there is yet another refinement to this fix.
>I find that the disengagement of reverse is significantly higher. So, although
>I haven't tried it yet, it seems that if one replicated the reverse rod notch
>into the 3/4 rod, and used a reverse detent plunger, spring, and spacer, that
>3/4 should also take lots more to pull it out of gear. I'm going to try this
>when I get time.
That makes lots of sense. It's been a while since I went through my stash
of top cover bits, but I seem to remember the reverse notch is bigger. If
you need some levers to play with, I can probably supply a few.
During my 1070 mile drive home, I had lots of time to think. Long drives
are usually good times for me to think about things...
Jack, the more I thought about the RPM's your tach was reading compared to
mine, the more I convinced myself of this thought:
When accelerating down the straight to Canada Corner in your car, I was
hitting the upwards of 6500 before the brake markers. On my car, my tach
reads maybe 5700 at that point. This can mean a few things, but the
important one for you is this...
If your tach is reading about 500 or more higher than the engine, and Ken
Gillanders says the stock gauges always read higher with time, this means
you are short shifting. I felt that the engine at 6000 was pulling very
strong, as if there was LOTS of room left before the cam started falling
off. On the main straight, (not downhill) I was getting above 6000, and
again it felt like the engine was just getting into the real power. If you
are short shifting, you are losing lots of potential.
If my tach is wrong, well, the fact I have not blown my engine yet is amazing!
First thought of many to follow. The brain is tired, the back is tired from
unloading the rig.
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