Can syncros wear out!?
12-04-2002, 10:29 AM
#12
Here is the link about the new TSB (https://www.s2ki.com/forums/showthread.php?...&threadid=92711) for difficult 5th gear selection.
12-05-2002, 09:31 AM
#13
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Synchros do wear out, that's part of their job and why they they are made out of copper (I assume BeCu or phos-bronze).
Through normal driving I think they are intended to have an infinite life (a few hundred thousand miles). Most street-driven (lightly driven) cars have no problems. When you get into hard or racing conditions where engine/driveline speeds are high, all the forces multiply and the timing of clutch operation becomes critical.
Honda is renowned for making "strong" gearboxes that are delicate. Most Honda gearboxes can withstand very high power levels (as opposed to a box like from Subaru), but if you are sloppy on the clutch or hamfisted when shifting... goodby tranny.
I have some examples at home of mutilated Honda gears/synchros (H22 Prelude) and can post if anyone is interested. It's all pretty moot, since few people here will take apart their tranny and compare them.
And whoever said it is right- replacement is expensive. It requires a complete teardown of the tranny. It also gets more expensive the more you wait- since as the synchros wear, the gear teeth and block rings end up wearing as well. Which means more metal in the tranny, which means the magnet fills up, which means the oil ports can get clogged...
Through normal driving I think they are intended to have an infinite life (a few hundred thousand miles). Most street-driven (lightly driven) cars have no problems. When you get into hard or racing conditions where engine/driveline speeds are high, all the forces multiply and the timing of clutch operation becomes critical.
Honda is renowned for making "strong" gearboxes that are delicate. Most Honda gearboxes can withstand very high power levels (as opposed to a box like from Subaru), but if you are sloppy on the clutch or hamfisted when shifting... goodby tranny.
I have some examples at home of mutilated Honda gears/synchros (H22 Prelude) and can post if anyone is interested. It's all pretty moot, since few people here will take apart their tranny and compare them.
And whoever said it is right- replacement is expensive. It requires a complete teardown of the tranny. It also gets more expensive the more you wait- since as the synchros wear, the gear teeth and block rings end up wearing as well. Which means more metal in the tranny, which means the magnet fills up, which means the oil ports can get clogged...
12-05-2002, 09:40 AM
#14
Originally posted by marcucci
And whoever said it is right- replacement is expensive. It requires a complete teardown of the tranny. It also gets more expensive the more you wait- since as the synchros wear, the gear teeth and block rings end up wearing as well. Which means more metal in the tranny, which means the magnet fills up, which means the oil ports can get clogged...
And whoever said it is right- replacement is expensive. It requires a complete teardown of the tranny. It also gets more expensive the more you wait- since as the synchros wear, the gear teeth and block rings end up wearing as well. Which means more metal in the tranny, which means the magnet fills up, which means the oil ports can get clogged...
12-06-2002, 12:46 PM
#15
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Synchros can wear out with time, no doubt accelerated by imprecise shifting. I had problems with a weak synchro on my 1964 SAAB, which had a 4 speed column shift [to go with the 3 cylinder, 2 stroke engine, no doubt - but that's a whole other story]. Starting at about 50,000 miles, I would get a noticeable scraping/crunching noise on a 4-3 downshift. Not all bad; at least I learned how to double clutch that downshift. Got rid of the car at about 67,000 and never did replace the synchro.
12-07-2002, 04:45 AM
#16
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To replace a synchro, you replace the whole gear set, and thats why is gets expensive.
I think I was quoted $280.00 for a 2nd gear set.
The magnet in our tranny is just in front of that big 14mm service plug. The synchro's dont grind or flake unless there is something really wrong. They are rather malleable.
HEY I got photo's of a toasted S2000 tranny if you all want to see how bad a synchro can get, heh.
Sorry about the poor quality, I didnt have a good digital camera back then.
Ont the very bottom row are needle bearings, the next row up is first gear set, then second gear. The brass colored rings are the synchros and rings to their left are the intermediate cones. Notice the first gear intermediate cone looks a little thicker than 2nd.
Thats all synchro shaved and piled up in there. Top row is the color difference of severe over heating.
I think I was quoted $280.00 for a 2nd gear set.
The magnet in our tranny is just in front of that big 14mm service plug. The synchro's dont grind or flake unless there is something really wrong. They are rather malleable.
HEY I got photo's of a toasted S2000 tranny if you all want to see how bad a synchro can get, heh.
Sorry about the poor quality, I didnt have a good digital camera back then.
Ont the very bottom row are needle bearings, the next row up is first gear set, then second gear. The brass colored rings are the synchros and rings to their left are the intermediate cones. Notice the first gear intermediate cone looks a little thicker than 2nd.
Thats all synchro shaved and piled up in there. Top row is the color difference of severe over heating.
12-07-2002, 11:02 AM
#17
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Not to hijcak the thread but this query has really got me thinking.
When I accelerate (say merging on the freeway), I frequently run the car pretty hard through first and second. At that point I'm usually with traffic or just slower than traffic. I normall then shift to third and then slowly shift to 5th or 6th (depending on traffic conditions).
I've always assumed that this wasn't bad for the car but you guys have me re-thinking this.
As I hope to keep this S a very long time what is the best way for me to handle this?
Should I shift up through each consecutive gear? Or am I stressing over nothing.
Your thoughts/opinions are very much apprecaited.
When I accelerate (say merging on the freeway), I frequently run the car pretty hard through first and second. At that point I'm usually with traffic or just slower than traffic. I normall then shift to third and then slowly shift to 5th or 6th (depending on traffic conditions).
I've always assumed that this wasn't bad for the car but you guys have me re-thinking this.
As I hope to keep this S a very long time what is the best way for me to handle this?
Should I shift up through each consecutive gear? Or am I stressing over nothing.
Your thoughts/opinions are very much apprecaited.
12-07-2002, 12:06 PM
#19
I think that as long as you wait a couple seconds between 3rd and 5th (or 6th) to allow the tranny internals to slow down, I think you are fine. I used to take 3rd gear up to redline, then stick it straight into 5th without a pause. This gave the 5th gear synchronizer a much larger internal shaft speed differential to negotiate. It eventually cracked.
12-07-2002, 02:47 PM
#20
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[QUOTE]Originally posted by gernby
[B]I think that as long as you wait a couple seconds between 3rd and 5th (or 6th) to allow the tranny internals to slow down, I think you are fine.
[B]I think that as long as you wait a couple seconds between 3rd and 5th (or 6th) to allow the tranny internals to slow down, I think you are fine.