Gear Grinding at the Track.
06-01-2002, 07:24 AM
#11
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Like krazik, grinds were of the 2-3 and 3-2 variety. The cadence I have developed over the decades of shifting is clutch to floor, then start the shift level moving, though with this car, that obviously is not enough to prevent grind, and maybe too easy to overlap the sequence.
The grind seems to be at the later part of the shift motion; what this means about the grinding cause I am not sure. Any thoughts?
The grind seems to be at the later part of the shift motion; what this means about the grinding cause I am not sure. Any thoughts?
06-01-2002, 07:50 AM
#12
Registered User
FWIW
There is a metal ring that presses on the syncro cones to get them to work, there are only 6 small teeth that press on the ring. The ring needs to deform slightly to let the gear engage. When hot, the ring will flex easier than when cold, letting the the syncro collar try to engage before the syncro cones have time to work.
The problem is the balance between stiff shifting/no grind and easy shifting/maybe a grind. Very sensitive to tolerance.
I would take the stiffer shifting any day over a grind.
BTW This is also why Woodwork says to slow down your shifting.
There is a metal ring that presses on the syncro cones to get them to work, there are only 6 small teeth that press on the ring. The ring needs to deform slightly to let the gear engage. When hot, the ring will flex easier than when cold, letting the the syncro collar try to engage before the syncro cones have time to work.
The problem is the balance between stiff shifting/no grind and easy shifting/maybe a grind. Very sensitive to tolerance.
I would take the stiffer shifting any day over a grind.
BTW This is also why Woodwork says to slow down your shifting.
06-01-2002, 08:14 AM
#13
[QUOTE]Originally posted by cmnsnse
[B]FWIW
There is a metal ring that presses on the syncro cones to get them to work, there are only 6 small teeth that press on the ring. The ring needs to deform slightly to let the gear engage. When hot, the ring will flex easier than when cold, letting the the syncro collar try to engage before the syncro cones have time to work.
[B]FWIW
There is a metal ring that presses on the syncro cones to get them to work, there are only 6 small teeth that press on the ring. The ring needs to deform slightly to let the gear engage. When hot, the ring will flex easier than when cold, letting the the syncro collar try to engage before the syncro cones have time to work.
06-01-2002, 09:19 AM
#14
Administrator
FWIW,
I attributed most of the grinding to driver error. I am out there, running timed. Running for fastest lap time, so I am of course trying brake, downshift and go as quickly as possible. I found I ground a mainly in turns 3, 4, 5a, 7 and sometimes in 9 but less (all second gear turns). (see map below)
Turn 3 with my 275 hooisers I was toping out 3rd (~100mph) gear with a hard brake, heal-toe/revmatch in to 2nd then go. I would find that when I was being forcefully trying to get the car into second as quickly as possible I would grind more. When I waited just a bit longer to downshift in my braking I started to grind a lot less.
(Spring Mtn is 2.2 miles)
Defender: This isn't the 1-2 grind issue as we only use 1st gear for the first 100 feet out of the pits. But the 1->2 & 3->2, do share the second gear syncro.
I attributed most of the grinding to driver error. I am out there, running timed. Running for fastest lap time, so I am of course trying brake, downshift and go as quickly as possible. I found I ground a mainly in turns 3, 4, 5a, 7 and sometimes in 9 but less (all second gear turns). (see map below)
Turn 3 with my 275 hooisers I was toping out 3rd (~100mph) gear with a hard brake, heal-toe/revmatch in to 2nd then go. I would find that when I was being forcefully trying to get the car into second as quickly as possible I would grind more. When I waited just a bit longer to downshift in my braking I started to grind a lot less.
(Spring Mtn is 2.2 miles)
Defender: This isn't the 1-2 grind issue as we only use 1st gear for the first 100 feet out of the pits. But the 1->2 & 3->2, do share the second gear syncro.
06-02-2002, 03:24 PM
#16
Registered User
The black arrow is where the sleeve teeth are pressing on the spring, and the blue points to the actual teeth that engage.
This one is the best I can get of the teeth ramps that do the pressing . . . The actual 1-2 synchro sleeve.
This one is the best I can get of the teeth ramps that do the pressing . . . The actual 1-2 synchro sleeve.
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