
Whats a crash box???
#1
_lcnewby_
Posted 21 June 2006 - 06:41 PM
Have seen and older car advbertise with a 3 speed crash box. What IS a crash box????
#2
_dave720gtr_
Posted 21 June 2006 - 06:46 PM
hence the name crash box
#3
Posted 21 June 2006 - 06:57 PM
#4
Posted 21 June 2006 - 07:12 PM
"Crash boxes" don't have sycnro on any gears. The driver has to learn how to do the old "double shuffle". If you don't know what that means then I guess it doesn't matter.
Bazza
#5
_lx5008_
Posted 21 June 2006 - 09:07 PM
#6
_finer70_
Posted 21 June 2006 - 09:19 PM
As said perviously they have no synchros on any gear. They are also spur gears not helical. That is straight cut.
Changing gears requires, as said before, a double shuffle.
Changing up gears. Depress clutch, move to neutral release clutch, pause (the period depending on whether the gear oil is hot or cold, short if cold longer if hot), depress clutch and select higher gear, release clutch. You just have to have rhythm.
Changing down. Depress clutch, move to neutral, rev motor to speed needed for lower gear, depress clutch and select lower gear , release clutch.
Now when you get realy good you can do all of this without touching the clutch. That takes real skill and daring as if you stuff it you could very well stuff the box.
So in the old days learning to drive involved a lot more understanding of the mechanical function of the vehicle. Then when these basics were learnt in a paddock you ventured onto the road to learn how to frighten the hell out of passengers and pedestrians alike.
Up until syncros were designed all boxes were driven in this fashon. Even with syncros today the double shuffle should be used when needing a fast down shift whilst maintaining engine revs to ensure effective engine control at all times to the driving wheels.
In fact simply because I can I most often use the double shuffle changing down in the LC GTR with OPEL box as it reduces load on the synchros and clutch and gives maximum engine control over speed and lessens load on brakes.
Edited by finer70, 21 June 2006 - 09:21 PM.
#7
_lx5008_
Posted 21 June 2006 - 09:24 PM
#8
_finer70_
Posted 21 June 2006 - 09:43 PM
I believe I answered the question.
An early Holden and most other boxes of the same period had a three speed box with one crash gear, that being first. Those boxes were not generally refered to as a crach box.
#9
Posted 21 June 2006 - 09:48 PM
Early Holden boxes aren't true "crash boxes" they just don't have syncro on 1st. You don't have to stop to go back to 1st - you just have to know how to 'double de-clutch" aka "double shuffle".
Sorry to be pedantic, but if we are discussing the subject, we should get it right.
Bazza
#10
Posted 21 June 2006 - 10:23 PM
My first EH had one and it was absolutely impossible to get back to first while in motion without grinding the crap out of it. My pop tried to tell me I was doing it wrong so i let him try...nice try, fail...and he could drive crash boxes...so could I..just not that one.
#11
_Hotrodder_
Posted 21 June 2006 - 11:19 PM
Technically the Holden 3 speed is not a true crash box, those as described in the really early stuff are true crash boxes, the name has been carried over into those with only no synchro in 1st gear under false pretenses.I would disagree they were not/are not called crash boxes..for as long as i have had anything to do them they have been the crash 3 speed or crash box.
My dads restored 35 chev sedan was a true crash box, as is my unrestored 27 chev tourer. They take a fair bit of learning how to drive, if you think the holden boxes are difficult try going back another 30 years.
#12
Posted 22 June 2006 - 12:09 AM
Technically as this is a Holden forum one would have to assume the question was related to Holden boxes. Which relates to the Holden 3spd, no synchro on first, array of Holden boxes. Thats the way I read the Q. And me being an older fart can relate to what he means.Technically the Holden 3 speed is not a true crash box, those as described in the really early stuff are true crash boxes, the name has been carried over into those with only no synchro in 1st gear under false pretenses.I would disagree they were not/are not called crash boxes..for as long as i have had anything to do them they have been the crash 3 speed or crash box.
My dads restored 35 chev sedan was a true crash box, as is my unrestored 27 chev tourer. They take a fair bit of learning how to drive, if you think the holden boxes are difficult try going back another 30 years.
Edited by rodomo, 22 June 2006 - 12:11 AM.
#13
Posted 22 June 2006 - 12:14 AM
would love to see pics of your chevs....one of these days my great grandfathers 1930 chev will pass to me...its in need of rescue badly..would love to see what yours looks like...maybe a pic or 2 in the projects section?
#14
_finer70_
Posted 22 June 2006 - 07:03 AM
Just for those who think they can drive a crash box using the double clutch method even on first gear and any other, the proof is in the pudding.
If you can great. But to say any box that has any synchros is a crash box is just a nonsense.
There is no doubt over the years as full crash boxes disappeared the term was used to describe the first gear crash box when all synchro boxes cam in to being.
So no one is wrong just some more correct than others.
#15
_devilsadvocate_
Posted 22 June 2006 - 08:47 AM
The original post didnt refer to holdens, just 3 speeds. I suppose there is no official dictionary definition of a "crash box", but I understand it to be no synchro on any of the forward gears and/or the combination of straight cut forward gears. When cars first started getting synchros on a couple of the gears, I would have anticipated there would have been a lot of hype about "get rid of that old car with the crash box and get our new easy to drive quiet synchro model even if 1st remained without synchro. Have driven a few crash box heavy vehicles(synchros gone).....not a load of fun in traffic.
I suppose all cars have trouble selecting reverse on the move, does that make them all crash boxes?
Edited by devilsadvocate, 22 June 2006 - 08:50 AM.
#16
Posted 22 June 2006 - 10:34 AM
#17
Posted 22 June 2006 - 02:40 PM
Bit off topic, but -
When Synchros started to be used most cars got em on 2,3+.
Those built for dirt (Landrover type ve-hicles) got em on 1st and R for rocking out of stubborn patches.
Grant..
#18
Posted 22 June 2006 - 04:43 PM
Some of the fancy Euro-exotica, Maseratis, Lamborghinis etc also have synchro in reverse.
I think had the original question been 'What is meant by a Holden crash box ?', I think some of the responses may have been a little different.
Dr Terry
#19
_lcnewby_
Posted 22 June 2006 - 06:32 PM

#20
_TORANR AMORE_
Posted 22 June 2006 - 06:36 PM
A crash box is a Mitsubishi Lancer.....What IS a crash box????

Edited by TORANR AMORE, 22 June 2006 - 06:37 PM.
#21
_devilsadvocate_
Posted 22 June 2006 - 07:48 PM
back to hairsplitting again......but to continue arguments on the ridiculous and to also answer Makka's own question which he has answered himself? if the reverse ratio is different to any of the other forward ratios then no one could argue that its not a 5 speed, so the m20 no, as first and reverse are the same ratio, but mc6 would be a 5 speed.does that make all m20's and m21's 5 speeds because they have reverse, I dont think so Devils
thanks for that info Dr Terry on the synchro in reverse, I was thinking about that, have often been annoyed about having to completely stop the car to get reverse, but gather its handy for stunt driving?
Edited by devilsadvocate, 22 June 2006 - 08:01 PM.
#22
Posted 22 June 2006 - 10:55 PM

#23
_rorym_
Posted 22 June 2006 - 11:02 PM
SHIT!!
R
#24
Posted 23 June 2006 - 12:32 AM
Edited by rodomo, 23 June 2006 - 12:40 AM.
#25
Posted 23 June 2006 - 12:39 AM

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