Ausmini
It is currently Fri Aug 08, 2025 10:58 am

All times are UTC + 10 hours




Post new topic Reply to topic  [ 11 posts ] 
Author Message
PostPosted: Thu Nov 27, 2008 7:50 am 
Offline
848cc
848cc
User avatar

Joined: Sat Oct 25, 2008 1:06 pm
Posts: 155
Location: Adelaide
Hi all,

I looked at a car last night and when the car goes from 3rd to second and you are going to fast it doesent want to change back and makes a weird noise.

Is this something to be very concerned about?
Synchro problem? :shock:


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 7:58 am 
Offline
1360cc
1360cc
User avatar

Joined: Tue Jun 01, 2004 3:41 pm
Posts: 6858
Location: Special Tuning Sydney
Well you shouldn't really be trying to get into second while doing high RPM in third... Yes it could be about the synchros as it is trying to spin up 2nd to match the speed of your engine but it's not designed to do this at super high speed or with any sort of racecar efficiency. Say if you are over 3000rpm or more on third, changing into second, you'd be doing well over 4500rpm which is far too quick to shift back into without dammage/wear on the synchros...

Safest alternative if you must do it is to double clutch. Have a search about that and start practicing...

_________________
Lillee - 1969 Morris Mini K


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 8:05 am 
Offline
848cc
848cc
User avatar

Joined: Sat Oct 25, 2008 1:06 pm
Posts: 155
Location: Adelaide
woops :oops:
meant changing between those two gears too quickly as in you need to take your time getting the gear accross the 2nd from 3rd
what would need to be done about it?
how much etc?
thanks :)


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 8:57 am 
Offline
Yay For Hay!
User avatar

Joined: Wed Sep 08, 2004 9:27 pm
Posts: 15912
Location: Wodonga - Vic/NSW border
yeah, worn out 2rd gear synchro - it's a gearbox rebuild job, so save up, and learn to double clutch until you have around $1500(*)

briefly...

clutch in
out of 3rd gear
clutch out
blip throttle
clutch in
in to 2nd gear
clutch out

it sounds cumbersome, but it becomes natural quite quickly. Try youtube, someone will have put up videos of people doing it

(*) before someone jumps up and down and says a gearbox rebuild costs less than $1500, I've said that figure as a rough high-ish estimate based on
- he can't do it himself, so needs someone to pull the motor, split it, do the box & reassemble
- the other parts required are unknown
- cos I f*cking said so

_________________
did I tell you that I won a trophy?


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 9:12 am 
Offline
ET 13.457 seconds , OH YEAH !!!!
User avatar

Joined: Sun Sep 19, 2004 8:35 am
Posts: 7826
Location: Somewhere Around Sydney
simon k wrote:
- cos I f*cking said so[/size]


word.

_________________
Image
Starlet Conversion:
http://www.ausmini.com/forums/viewtopic.php?t=15484


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 10:21 am 
Offline
1275cc
1275cc
User avatar

Joined: Thu Mar 18, 2004 1:33 pm
Posts: 2213
Location: Darling Downs QLD
simon k wrote:

before someone jumps up and down and says a gearbox rebuild costs less than $1500, I've said that figure as a rough high-ish estimate based on
- he can't do it himself, so needs someone to pull the motor, split it, do the box & reassemble
- the other parts required are unknown
- cos I f*cking said so


My gearbox rebuild (with diff and Hardy spicers) came in at over $2500.00 (Bloody cooper s tax, parts cost more than the labour!) and that involved no stripping off the block!

So the costs can be quite high. My box still worked, slight crunch on changes if you weren't sympathetic, but it worked. Take it apart and it was completely shot! go figure :wink:

_________________
68 Deluxe.... it's shiny..... I like shiny!!


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 10:22 am 
Offline
1360cc
1360cc
User avatar

Joined: Tue Jun 01, 2004 3:41 pm
Posts: 6858
Location: Special Tuning Sydney
is it a problem with getting into second full stop or just when coming from 3rd to second?

If you have problems going from 1st to second as well then it is definately a synchro issue, it is totally busted, start saving. If it's only happenning from 3rd to 2nd then see my earlier post. ie. You shouldn't really be doing this too often! my gearbox is brand new with brand new synchros and it's still difficult to do this at high speed without double clutching. Doing it with worn synchros is definately going to be harder... It's not designed for this sort of shifting.

Bringing your engine from low RPM to higher RPM via gears is a general NO NO... it flexes cranks, introcude gearbox stresses bla bla. Just take off in 3rd or double clutch.

Either way it sounds like the synchro is on it's way out

_________________
Lillee - 1969 Morris Mini K


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 11:40 am 
Offline
848cc
848cc
User avatar

Joined: Sat Oct 25, 2008 1:06 pm
Posts: 155
Location: Adelaide
Lillee wrote:
is it a problem with getting into second full stop or just when coming from 3rd to second?



It's only when you go from 3rd to 2nd fast you can avoid it just going real slow between the gears?
this is starting to sound expensive :? lol


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 11:43 am 
Offline
998cc
998cc
User avatar

Joined: Wed Feb 13, 2008 2:25 pm
Posts: 687
Location: Sydney
Yea when your going to fast in 3rd gear it makes a sort of grinding noise when downshifting into 2nd gear, mine does it aswell some times. If you slow down to a certain speed or rpm then it wont do it anymore, unless ofcourse it does it no matter what speed your going :?

_________________
Image


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 11:49 am 
Offline
848cc
848cc
User avatar

Joined: Sat Oct 25, 2008 1:06 pm
Posts: 155
Location: Adelaide
fast is in shifting the gear down into second not as in RPM :D
am i confusing you yet?


Top
 Profile  
 
 Post subject:
PostPosted: Thu Nov 27, 2008 11:55 am 
Offline
ginger ninja
ginger ninja
User avatar

Joined: Thu May 15, 2008 3:50 pm
Posts: 5806
Location: Hiding from mini maxx's moggie army somewhere in Brisbane northside
stevos wrote:
fast is in shifting the gear down into second not as in RPM :D
am i confusing you yet?

Yes (but i'm a redhead so that's not hard :oops: )

_________________
sports850 wrote:
guess he never learnt that important lesson, don't piss off a redhead


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 posts ] 

All times are UTC + 10 hours


Who is online

Users browsing this forum: No registered users and 88 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  

© 2016 Ausmini. All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.