Synchro is dying Could this be related to Z3 short shifter?

Lowen · #1 (**permalink**) 03-30-2002, 11:00 AM

cleanazzE30 posted something about this in another thread but what is the concensus on this? do the makeshift shortshifters really kill synchros? do i have to get a better shortshifter to prevent this or is the problem in the nature of the shortshifter itself?

dave92ic · #2 (**permalink**) 03-30-2002, 11:38 AM

I don't see how a short shifter would cause the syncros to wear out faster, unless it was binding in some way where it was continually putting pressure on the selector rod while it was in gear. I think it would be pretty obvious if this was the case.

I know people will often rest their hand (and subsequently apply some force) on the shift lever while they are driving, which will cause the forks to wear out faster. I am not sure if you could affect the syncros without really pushing hard though. Having a short shifter will lessen the effect of resting your hand on the shifter, since you essentially have less leverage.

Dave

CleanAzzE30z · #3 (**permalink**) 03-30-2002, 09:39 PM

wears the synchros because it is forces it into gear much quicker than its supposed to be. The shift is supposed to be (leave gear go into neautral, and then go into the next gear), with the synchros, its just jams it into gear and puts more stress on the synchros. If you know what the synchros serve as, in the tranny, its easy to see how they would be put into more stress by shortenting the throw of the shift.

#4 (**permalink**) 03-30-2002, 09:58 PM

just stop using the syncros, and double clutch all the time

ROB89M3 · #5 (**permalink**) 03-30-2002, 10:26 PM

hmmm,this is an interesting thread.(I also have a short shifter)

I had a problem with 3rd gear not going in.It also was grinding sometimesin third gear.
I changed the tranny fluid and problem was solved.

I now have a problem getting it into gear when the car is cold,sometimes.What could this be?

Also,at around 4000rpm's,there is a buzzing noise in my shifter. This is really annoying. I heard it could possibly be a bushing..

Lowen · #6 (**permalink**) 03-30-2002, 10:44 PM

i have the same buzzing..is this the flex disc? what else could it be?

dave92ic · #7 (**permalink**) 03-30-2002, 10:48 PM

Quote:

Originally posted by CleanAzzE30z
wears the synchros because it is forces it into gear much quicker than its supposed to be. The shift is supposed to be (leave gear go into neautral, and then go into the next gear), with the synchros, its just jams it into gear and puts more stress on the synchros. If you know what the synchros serve as, in the tranny, its easy to see how they would be put into more stress by shortenting the throw of the shift.

Yes, I know what syncros are. In the manual transmission I worked on a long time ago (I think it was a fiat), the syncros were brass tapered rings with sharp grooves cut into the surface. These are pressed into a polished, tapered steel sleeve, causing the "synchronization" of the speed of the gears. I assume the syncros work in a similar manner in the BMW transmissions.

With a short shifter, the shift is still "leave gear go into neutral, and then go into the next gear" I don't shift gears faster with my short shifter, I just have less movement.

If I were racing I could see how the short-throw shifter would cause "quicker" shifts. However, when racing I would also expect my syncros (as well as most other engine/drivetrain components) to wear out quicker.

Dave

ben325is · #8 (**permalink**) 03-31-2002, 01:13 PM

Quote:

Originally posted by Lowen
i have the same buzzing..is this the flex disc? what else could it be?

Grassroots motorsports did a big writeup about shifter buzz during their 'project m3'. here is the link GMS M3
Hope this helps.

Well, I guess this doesn't help very much. I would try to contact Grassroots too ask what their final 'formula' of parts was.

Bahnstorminge30 · #9 (**permalink**) 03-31-2002, 02:59 PM

Ben did you ever get that 2nd gear syncro fixed? Hows the front end did you find a new IS spoiler to snap on there? If not I might have foundone pretty cheap but its used let me know Ben.
Peace
Pete

ben325is · #10 (**permalink**) 03-31-2002, 06:54 PM

Pete- Spoiler is still broke-ass, and so is the tranny. The synchro doesn't seem to be getting worse so I'm going to leave it till I either transplant or can find a dogleg one...and the money to pay for it with. Send me a PM or an IM about the chin spoiler.