Yeah, I didn't go into the details. But since a few people have asked,
here's the longer version of double-clutching:
1. Put the clutch in and shift into neutral.
2. Let the clutch out and blip the throttle.
3. Put the clutch in before the revs drop.
4. Shift to the lower gear and let the clutch out.
What this does is, it uses the engine to accelerate the tranny components up
to a higher speed (when you blip the throttle). Then the synchro has less
work to do to match the speeds of the components.
It feels really awkward at first but once you get it, you can throw a
downshift from 5th all the way to 2nd coming into a very tight turn and make
it completely smooth with no graunching. It's really great.
Another advantage besides saving the synchros is that it doesn't unbalance
the car as much as just shifting down and dumping the clutch. When you do
that, the sudden application of engine compression braking can easily
transfer more weight to the front end right when you're trying to get the
car balanced for a turn.
It used to be a "basic" move that all racers knew, but then they started
building custom race gearboxes where you don't even have to use the clutch
except to start. Takes all the fun out of it.
Gordon Glasgow
Renton, WA
-----Original Message-----
From: Patrick P. Castronovo [mailto:slick1@mohaveaz.com]
Sent: Saturday, February 17, 2001 9:07 PM
To: Gordon Glasgow; Craig Odell; datsun-roadsters@autox.team.net
Subject: Re: Can't find it grind it
Gordon, you did'nt mention rev-ving the engine to catch up to the rev's of
the transmission on the downshifts. Pat
-----Original Message-----
From: Gordon Glasgow <glasgow@serv.net>
To: Craig Odell <CDADDYO@prodigy.net>; datsun-roadsters@autox.team.net
<datsun-roadsters@autox.team.net>
Date: Saturday, February 17, 2001 7:03 PM
Subject: RE: Can't find it grind it
>2nd gear synchro is always the first to go out, because it gets the most
use
>in traffic. And shifting down into a gear is harder on the synchro than
>shifting up because it has to accelerate the countershaft, input shaft and
>clutch disk up to the speed that they will be going in the lower gear.
>
>Switching to something like Redline MTL can make it better provided you
>don't wind up with leaks. A better solution (short of rebuilding the tranny
>and replacing 2nd gear synchro) is to learn to double-clutch on the
>downshifts. Takes a bit of practice to get it, but it eventually becomes
>second nature. I automatically double-clutch all my downshifts to either
2nd
>or 1st no matter what I'm driving - except the Maxima automatic. ;-)
>
>Gordon Glasgow
>Renton, WA
>
>-----Original Message-----
>From: owner-datsun-roadsters@autox.team.net
>[mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of Craig Odell
>Sent: Friday, February 16, 2001 5:15 PM
>To: datsun-roadsters@autox.team.net
>Subject: Can't find it grind it
>
>
>Hey Roadster folks -
>I've been having difficulty down shifting from 3rd gear into 2nd gear.
>It will grind every time unless I am going extremely slow (slow enough to
>actually be in first).
>I replaced the 5th gear last summer with "The Tillinger 5th Gear" (Monster
>truck voice here too).
>But I don't recall if I had the problem before the gear swap as it was a
new
>car to me.
>Could this be a problem with gear oil?
>Or do I need to consider a total rebuild?
>The tranny seemed very clean at the time of gear swap.
>TIA
>
>Craig Odell
>68 2000
|