cracking gearboxes

[pulsarboby]

ive got a damaged gearbox coming in next week (no 3rd or 5th) i will remove the casing from it, and mount rear casing on a press and apply pressure to the inner casing to see how many nm it can withstand without my gizmo fitted, before it cracks! then il do another test with one fitted and see what the readings are before it eventually breaks!
thats the only way i can think of testing the thing to see if it works!
but im very confident that the results will be good.

has anyone else got another casing i can break from a damaged box???
i dont want to break a good gearbox casing just to test it.

 

[antgtir]

Is the damage to the box as a result of a sudden impact rather than a gradual increase in force?

You may not be able to replicate the impact without using the box in normal conditions?

Would still be interesting to see though.

Ant.

 

[pulsarboby]

yes your correct ant, it would appear to me that the rear end case cracks, due to a sudden take up of the input shaft, which in turn puts immense pressure on the end cover and causes it to split.

its more of a jolt in pressure rather than gradually applied pressure. but the test im thinking of should still be a good and fair compromise to simulate the conditions which it will be under!
ie, the pressure will be applied then taken off, then repeated time and time again with more pressure constantly added, untill the casing finally gives up the ghost and splits!

then will do the same test with my cunning little invention, and see how many more nm it can take before that also breaks, my guess is a lot more8)

its the only way that i can think of to replicate the mechanics of the gearbox, i will also use on the press an input shaft bearings etc so it is an exact copy of a gearbox minus the gears.

if the final results are good, then i will get these gizmos into production, my car will be a good test for them, and i will give one away for free to someone who is prepared to fit one to there car, who is using it for mainly drag events and who is running big horses.

if both cars can last a year without gearbox case failiure then i think we can say a 100% that it deffo works.
but the tests to be carried out will be a very good indication on that anyway!

 

[stevepudney]

yes your correct ant, it would appear to me that the rear end case cracks, due to a sudden take up of the input shaft, which in turn puts immense pressure on the end cover and causes it to split.

its more of a jolt in pressure rather than gradually applied pressure. but the test im thinking of should still be a good and fair compromise to simulate the conditions which it will be under!
ie, the pressure will be applied then taken off, then repeated time and time again with more pressure constantly added, untill the casing finally gives up the ghost and splits!

then will do the same test with my cunning little invention, and see how many more nm it can take before that also breaks, my guess is a lot more8)

its the only way that i can think of to replicate the mechanics of the gearbox, i will also use on the press an input shaft bearings etc so it is an exact copy of a gearbox minus the gears.

if the final results are good, then i will get these gizmos into production, my car will be a good test for them, and i will give one away for free to someone who is prepared to fit one to there car, who is using it for mainly drag events and who is running big horses.

if both cars can last a year without gearbox case failiure then i think we can say a 100% that it deffo works.
but the tests to be carried out will be a very good indication on that anyway!

Fair play to you Bob if you have come up with a good idea that works, however you do it, as long as it works

Just bear in mind that the next weak point in the chain is also in the gearbox. I think others have had the case break on the inside (inside the bell housing) where the shaft is trying to escape from the other end (I think).



Steve

 

[ashills]

yep even with si's big brace it transfered stress to opposite end so some work is needed there like the fwd boys do in usa on the sentras etc or get rid of 5th gear and use a strap link to stop the shafts moving apart

 

[AZ STE]

So I guess we are talking a bracket that acts like the master Brake cylinder anti flex bracket ? that acts on the outer of the casing ? if so? casing will still crack slightly on the flex of the external bracket then no Oil. Only a refab of the end casing thickness and a bracket would solve this.The casing web looks quite thin I think.Also depends on the quality of alloy Nissan actually used on the gearbox casing .Ive found massive differences in grain structure between Honda alloy and everthing else. Interesting
PS if you attach your bracket to the casing bolts their threads become the weak point?

 

[pulsarboby]

nope still not on the lines of my idea lol
but in all fairness it will not stop the casing cracking at the bell housing end! but other than a complete new casing or reinforcement at that end too, theres little i can do about that.

ive got a box stripped down at the moment and it does seem that this input shaft is causing the cracking to take place, by the immense amount of torque thats applied to it under launching, couple this with the turning forces of the shaft and the poor moulding of the case which leads to bye bye end cover then bye bye gearset.

i wont know whether this works or not untill ive carried out some tests.
but its hard to replicate the torque and turning forces, i will only be able to test the thing for strengh to see if i have made it stronger or if theres no benefit from what i have done.

 

[creedy]

well good luck and i hope it works out... just dont forget to tell us the details

 

[MarkTurbo]

well good luck and i hope it works out... just dont forget to tell us the details

I might start doing some crack testing of my own on gearbox casings ;-) Infact ive got the box off a certain blue R that i might take a hammer too tomorrow :lol: :lol: :lol:

 

[creedy]

I might start doing some crack testing of my own on gearbox casings ;-) Infact ive got the box off a certain blue R that i might take a hammer too tomorrow :lol: :lol: :lol:

lol dont you dare!

 

[pulsarboby]

I might start doing some crack testing of my own on gearbox casings ;-) Infact ive got the box off a certain blue R that i might take a hammer too tomorrow :lol: :lol: :lol:

dont break it:shock: send it to me and let me smash the living daylights out of it:lol:



ive had a lucky day today, just managed to aquire another complete fooked gearbox, from a guy i just sold a gearbox to, so now have the 2 casings which i needed to test n smash. cheers to creedy no only joking mate:lol:

so will get testing under way as soon as my gizmo is made, which is proving to be a bit of a booger to make, but il get there shortly!

 

[MORF114]

your not gonna cover the box in acetel or some kind of poly resin acting as a second probably stronger skin on box ?

 

[Dooie Pop Pop]

yep even with si's big brace it transfered stress to opposite end so some work is needed there like the fwd boys do in usa on the sentras etc or get rid of 5th gear and use a strap link to stop the shafts moving apart

if your drag racing or on a track you dont use fifth anyway do you? sounds like a good remedy for dedicated 'off roaders'

 

[creedy]

cheers to creedy no only joking mate:lol:

so will get testing under way as soon as my gizmo is made, which is proving to be a bit of a booger to make, but il get there shortly!

:lol: i think i would cry if you did...

are you thinking of filling up the webbing on the endplate with sumstore of resin or metal?

 

[JIMMYBACK]

its this a complete stupid brain wave ive just.or is it anything along the lines of the same idea used in japanese buildings? if this sounds crazy id explain a little..... japan is used to having a few crazy earth quakes so they have developed a fantastic gizmo thats installed in the roof to absorb the inital temor/shock thus keeping the building in one piece...or am i jibbering on:lol: :lol: ;-) just a thought thou

 

[Fast Guy]

I don't think we'd have much room in the box to fit a tuned mass damper.

http://www.didierbeck.com/2005/09/pictures-taipei-101.php

We could put it in a trailer behind the car, but at 660ton, it might require a couple of Gtirs to tow it.:lol:

 

[pulsarboby]

all will be revealed once ive carried out some tests, to see if my cunning plan works, or is a failiure.
at the moment, its all just an idea being put into practice with no test results at all to back it up with, and thats why im not saying anything as i will only be mocked and laughed at.
once i know that it has a very good chance of working, and its fitted to my box i will tell you all what it is and how it will work.
then you can all pull it to pieces if you wish too or pm me and il make you one.

lets just say there are special materials involved, as my plan has now moved on from the original one, after carefull thought and studying the box.
like kieron i am now on the mark 3 version:lol:

im also now trying to figure out how i can run a box off the car and apply huge amounts of torque to it to simulate it being launched!
very difficult to do as you have all the drive elements to take into consideration.
the only way i can think of to do this is by fitting the driveshafts and to clamp them somehow so they hardly turn (simulating loading of wheels to tarmac)
but what would i use to drive the shaft other than an engine running on a bench?

any ideas anyone???

 

[Fast Guy]

Only way to do it accurately would be to fit it to the car and try to kill it. As that's what you're trying to do, you have nothing to lose (bar a few hours labour). It will be abit safer than trying to rig something up on the bench.

Or we could call myth busters and tell them the box can't be made unbreakable and see if they can bust the myth

 

[pulsarboby]

lol:shock: it will be fitted to my quaiffe, so there is a lot to lose:doh:
was just thinking of a way to run another box without fitting it to a car, and somehow try to simulate the load conditions to test it. but may just have to stick to using a press to pressure test it before it breaks.

 

[creedy]

use a lathe...? you would have to make somthing up the hold the box down and a long input shalf.

you can get alot of power threw the box, but depending on which lathe you use you mite not be able to start it up fast enough to simulate a launch.