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9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Wed Oct 05, 2011 2:09 pm
by faero
I was going to wait until i got it all together but I'll just go with the step by step post method so any trouble can be caught on the fly. Aim is to consolidate it all at the end into a useful document...

In this case the build is for a 9k box with quaife LSD but the build is identical for 9-3 and GM900 internally. Photos with the iPhone so apols for the quality but they give you the message.

The groundwork was done here: This includes parts, prices etc etc.
REFERENCE: http://www.uksaabs.co.uk/UKS/viewtopic.php?f=32&t=74303

The Quaife was done here - Mark D's thread with some bits on the end from me.
QUAIFE http://www.uksaabs.co.uk/UKS/viewtopic.php?f=2&t=81411&hilit=quaife

IMPROVEMENTS / REFRESHES

This is an area that could go on forever so it was a case of cherry picking the cost effective ones and we'll see how it works out.

1) START WITH A DECENT BOX
! This is hard these days but if you have one that's at least not been in a tuned car there is hope. You can also drive a 2litre injection like an idiot and wreck the box. This is the gamble but take your time to find the donor(s).

2) PLAN YOUR RATIOS: Final Drive choice: 3.61, 3.82, 4.05, 4.45. 3rd gear: 1.12 or 1.18. 5th gear : 0.7 or 0.66.
From that lot you can really play about. The smaller the number, the taller the gear. For my plan I'm going with 4.45 + 1.12 3rd, and 0.66 5th. One theory says that "the shorter the FINAL drive, the less relative stress there is on the internal gears"

3) FRESHEN UP: I'm doing the entire bearing set including needles - All Timken (non-Saab source). See Knowledgebase thread above.
New syncros: 2nd, 3rd, 4th, 5th. I got them cheap so suggest this would not be cost effective normally.
New Circlips: 3rd, 4th, 5th on input shaft.

4) MODIFY:

GEAR TOUGHENING: 2nd, 3rd, 4th pairs are all Shot Peened and Cryo Treated. This means the input shaft is done as 2nd gear input is part of the shaft itself. The first batch were also superfinished (posh!) but the entire sets were trashed by the courier in spectacular fashion. Not as expensive as you'd think. This idea will not work if the gears already have big internal cracks but once again , that's the gamble.

INPUT SHAFT:
Mod shaft to run the later 3rd gear circlip and syncro hub. £20 at local machine shop. Hubs from any 9-3 or very late 9ks/GM900s. See Reference link above.

OUTPUT SHAFT SUPPORT: Dowel location mod. This was Nick T's one after seeing movement around the bolt but has been tweaked and made easier for those without a milling machine by Mark D. This would make it the 'Degiorgio Dowell' ...
See below

OUTPUT SHAFT BEARING SHELL LOCATION: The pinion bearing shell can spin once loaded up - it works loose in the casing and creates a groove in the back of the bearing support plate. This will be loctited into position. Thanks to Mark D for spotting and Nick T for confirming fix for this one.
See below

THE BUILD

STEP 1 : CLEAN THE CASING
I washed mine down in petrol and then jet washed it for about 20mins until it looked a bit shinier.

STEP 2: The DOWELL MOD:
The standard design has a lot of slop so the casing can twist a little under heavy load. We don't want this.
Required:
Dowell from balance chain mech. Tap to M8 thread internal.
Sharp 9mm drill bit + big pillar drill if you have it.
Grinder with 1mm slice disc.

Check that the bearing support plate is not damaged from previous exploits with loose bearing shells. (i.e. the underside of the round part of the plate is smooth with no ridge from wear)

Clear the hole in the plate to 9mm. Just enough for friction fit of the dowel
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Take the casing and get it really flat - line up the 9mm drill and take the hole down to approx 5mm max from the surface.

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Ditch the original torx bolt and use a Cam cover bolt. Cut it to about 5mm longer than the original bolt. This makes up for some of the lost thread caused by the Dowell.



Carefully sit the dowell into a position where the top of the dowell is just below the top of the bearing plate. We want to make sure the head of the bolt still clamps on the plate. Take account that the dowell will not go right to the top of the bolt.
Run the dowell as far up the bolt as you can and test fit. Check the 3 chamfered bolt holes around the bearing all line up ok too.

The Dowell will be just under 10mm long. 5mm in the casing and 4.5mm in the bearing plate.

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So - you now have zero slop in the main box strengthening plate.... in theory!


STEP 3 FITTING THE DIFF BEARINGS:


This is the first step to preparing the diff. I don't have many special tools so will use heat/cool method where-ever I can to help me along.

1) Chill the diff in the freezer. I did it overnight. It can be disguised as a small chicken if this is deemed unacceptable by the freezers owner...

2) Heat the bearings in a tin to about 120C - No higher as apparently damage can be caused.
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As you can see I use a Kelly Bronze Turkey thermometer for something much more useful...
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3) You will find that the aluminium intermediate driveshaft cover is a perfect match for the bearing centre - In this case it's for backup as it really is not needed.

4) Lift out the bearings with pliers and using gloves, drop them onto the diff. Literally - they will FALL into position.
Quick tap if you must:

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5) All done! A relaxing start to this job tbh. The will undoubtedly be trouble ahead!

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NEXT EXCITING INSTALLMENT WILL FIT THE CROWNWHEEL TO THE DIFF

Re: 9k 9-3 GM900 Gearbox Build - Faero Style!

Posted: Wed Oct 05, 2011 10:38 pm
by faero
So - ditching the iphone as the pics are rubbish in lower light...

STEP 4 Fitting the Diff


I have the 1996 onwards diff without the offset crownwheel. This is the same as the GM900 of the same year and all 9-3 and 9-5.
You can see there is a chamfer on the inner edge of the crown wheel. This must go against the flange on the diff - Don't get it the wrong way round. You'll also see traces of the bolt heads on the other side to give you extra clues.

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Clean up the diff flange and crownwheel and for ease, warm the crown and chill the diff. Excessive but it just drops on with zero effort if you are not in a hurry.

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After adding a little touch of threadlock (not required but no harm)- I used a socket driver to speed things up.
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Evenly torque up all the torx E bolts to 90 NM
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Drop in the outer shell into a clean housing. This is usually really easy and needs no special tools.
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Check the LSD actually works - I used an old drive hub and you can turn it by hand - it's stiff but nice to see it all spinning smoothly.
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Oil up the lower bearing - just used Saab syth gearbox oil here.
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Drop the diff in - Note that the 4.45 crown is pretty big so you can't get it in with the pinion bearing plate in place.
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Check the speedo drive fits in happily
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PROBLEM! Spinning the diff, I feel a rumble and manage to convince myself it was the heads of the torx bolts. This would not be good as that would mean the diff was lower for some reason. Then I recalled some words on casing tweaks for the LSD and found that the LSD body where the helical gears stick out were rubbing on the casting. The casings can be pretty rough so I can see that some will be worse than others in this area.

Note: All the marks above the blue are saab clean up marks from factory as far as I can work out.

This is shown in blue crayon and was fixed in 2mins with a drill and grinding tip. I need to take it all for a good clean out again now though :(

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Re: 9k 9-3 GM900 Gearbox Build - Faero Style!

Posted: Wed Oct 05, 2011 11:40 pm
by mrd2525
Small amount of loctite on the threads?

Re: 9k 9-3 GM900 Gearbox Build - Faero Style!

Posted: Thu Oct 06, 2011 9:50 am
by faero
Good spot - I did put some on. Thread updated! Cheers.

Re: 9k 9-3 GM900 Gearbox Build - Faero Style!

Posted: Mon Oct 10, 2011 11:58 am
by faero
Havent done much - was away at the weekend but here are some pics of the progress:

DIFF BACK IN
Ground back casing a little more for full clearance, then took everything off again and jet washed it down to get rid of any crud.
I also put the diff in the little parts washer just to make sure the bottom bearing didnt have any bits caught in it:

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GEARS ARE HERE!!!

Finally my treated gears arrived - And they are undamaged this time. This lot are all duplex shot peened and cryo treated.

A tip from Mark was to ensure the oil-way in the input shaft was clear. In my case it was OK but I'm giving it an extra clean as you can see where the cleaner jet is spraying against the hole.

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STEP 5 - BUILDING THE INPUT SHAFT

The input shaft can be built up seperately to the rest of the box and doesnt have to be done right now but I thought I'd have a go.

First on is the bearing at the clutch side. Shaft was chilled and bearing heated to 120C and it was still a tight fit needing a few taps with an intermeditate drive shaft which is a perfect fit.

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Next up is the new Roller bearing for 3rd gear. This just drops on and was lightly oiled.

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Now drop on 3rd gear

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Then fit the syncro ring with 3 leaf springs, and then the syncro hub. In this case I am using the hub from a 9-3 which has the recess for the circlip washer: More detail on the leaf springs when 4th goes on. The hub was pretty tight so it got heated in the oven for 20mins and tapped lightly into place.

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Next : put the 3 little coil springs with pins into the holes in the side of the hub and put the sycro sleeve over the hub.
It's critical you line up the sleeve to the hub - there are 3 pairs of larger sleeve teeth that line up with hub grooves. The larger sleeve teeth do not go in the 'gap' where the spring plungers sit. If you do that the hub will appear to move OK but only partially engages the gear(!).

Look at the teeth where the yellow mark is - that's the part to be lined up. (Assume Saab use this to help later fiascos from happening)

Once the sleeve is on, carefully push the plunger springs back with a small flat bladed screwdriver and push in the rollers.
Here it is all done: You can see the circlip support washer in the centre too.
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Dilemma: I happed to pick up a new sleeve cheap and using it. It's on the right and you can see it's machined out more on one side. I can't see any impact of this on my box design so going with it as shown unless I see something later.

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Now fit the famous 3rd/4th gear circlip. It goes in with the chamfered edge facing up the way - you'll find that new circlips are vastly springier than the old ones you take off but this one is pretty nice to do.
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Fit the 4th gear roller bearing and oil lightly
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Now sit the 4th gear sycro on: You can see I'm using the late style sintered ring as yet to be tested! 3rd and 4th syncros are identical

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Here are the cheeky little leaf springs- 3 of these wrap round each of the 3rd and 4th syncros.

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I found it easier to put 2 springs in place then twist the other side up to get the 3rd one in. If I had 6 fingers I could probably do them all together but no such luck.

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Next up on input shaft : Top bearing and the nasty litte circlip...

Re: 9k 93 95 NG900 Box Build - Faero Style! Onto Input Shaft

Posted: Wed Oct 12, 2011 11:17 pm
by faero
INPUT SHAFT - FINISHING OFF

First off the top bearing : This was rather tight even with the chilled / heated method and in retrospect I should have used a soft brass drift but it didnt need 'too' much force to get it on.

Here's the bearing in situ. (with snap ring already on)
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There's a clearance measurement between the bottom of the bearing and the top of 4th gear. It should be between 0.1 and 0.4mm. In my case it was 0.22mm so about right and I know the bearing is seated down as it's quite hard to tell for sure.

Checking Clearance with feelers:
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Same goes for the gap between 2nd and 3rd: 0.1mm to 0.4mm. In my case it was 0.15mm so all good.
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Now put on the top circlip on. It's a tight little booga! I used a tip from Mark D which is to spread it while holding in a vice and the head of an M8 bolt in the gap gives 'just' enough clearance to get it on.

Once it's over the end I just used an old bearing to press it down and it makes a nice 'snap' as it goes in.
INPUT SHAFT IS FINITO

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ONTO OUTPUT SHAFT

BUILD UP The 1st, Reverse, 2nd 'pack'

Here is 1st gear on the bench with the double syncro in the order it goes on. Make sure you align the 3 inward tabs with the slots in the gear. And you'll find the 2 brass syncro rings interlock too.

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Here you can see 1st gear with syncro's attached and I'm dropping on the Reverse gear which also acts as the 'syncro sleeve' I didnt take the 3 little tabs and locating spring ring out - I only cleaned it up but you can see them in the pic.

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Now I fitted my nice shiny new 2nd gear syncro set. These are nice and sharp so hopefully mean a good 2nd gear change at least.... who knows!

Once the 'stack' is built up, you can drop in the bearing/bush. Where 3rd and 4th have roller bearings, 1st/2nd uses an oiled plain bearing which I assume is due to the higher loading. It's supplied by an oil way in the output shaft and can go in any way up. (Bearing not shown in the pics, but it just drops inside 2nd gear.

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Now I used 2 small sockets as spacers and dropped the 1st, Rev, 2nd gears onto the output shaft, followed by 3rd and the spacer/crush sleeve.

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BUILD UP REVERSE IDLER:
There are a few bits to this so I'll not list them all out - The key here was to slip a tie wrap through all of the reverse idler as you remove it - then it's easy to take off.
Give each part a close inspection - the syncro is tiny and can be mashed up.... mine was Ok.

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FIT THE REVERSE IDLER AND INPUT SHAFT


This is the fun bit!

With the Reverse idler built up on the pin, angle it and then stand it up in position against the output shaft.
Then angle in the entire input shaft and remove the spacers beneath 1st gear taking care to always support 1st gear so it doesnt fall down on it's own. As you drop the gears on the output shaft down, wriggle the input into position.

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FIT THE MAIN SELECTOR SET

I had 3 selector sets and choose from and the one that seemed to have the least wear on the brass tabs that sit in the syncro rings. Quite hard to measure as they are tapered on the ends so went with visual.

To fit I found this works:

1) Set to 2nd gear (bottom ring is pulled up and 3rd/4th ring is central).
2) Set the Selectors to 1st gear. (the big fork is dropped low, the other 3 pins are sitting in a 'neutral )
3) Wriggle the selectors in - they will sit high and this makes it easy to swing it in.
4) Now push the lower syncro ring into true 1st gear to match the selectors. This will pull the selectors into position.

Much easier to show than type!!

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Fit the reverse gear selector and fork : I had a 9-3 selector one and a 9k one. The 9k one is the bottom one and you can see the lever point is centralised. The later 9-3 one has an offset which changes the lever point and looks like it will make it a touch less effort to get into reverse.
I just played safe and fitted the 9k one as I wasnt bothered about reverse.


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The fork goes onto the pin which just drops in. Make sure you get the fork the right way up! It fits both ways...

FIT THE SELECTOR ROD

Loctite all the bolts: 3 for selector block and 1 for the selector Rod, then torque them all to 22Nm

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CHECK THE GEARS WORK!!!

Run through all the gears except fifth. ( I think you 'can' do fifth now but I was nervous about loosing detent balls when the fork isnt on...)

ALIGN the Reverse gear support shaft.

On later 9k's this is bolted in from the bellhousing but can spin round. It needs an exact angle to pick up the side bolt from the casing too.
So -with the bellhousing bolt loose, test fit the casing and teese the pin to the correct angle. Fit the side bolt.

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Now go underneath and torque up the bolt

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Remove the side bolt to release the casing again until you are ready !

Re: 9k 93 95 NG900 Box Build - Faero Style! Looking like a b

Posted: Thu Oct 13, 2011 8:41 am
by Bitter and Twisted
I spotted a wine glass :geek: in the workshop at the same time as you using a torque wrench :argh: .....is this good practice? :park:

Re: 9k 93 95 NG900 Box Build - Faero Style! Looking like a b

Posted: Thu Oct 13, 2011 10:35 am
by faero
ah - the glass is empty! 1 Glass works well to reduce panic moments. 2 glasses sees a drop in build quality..... Normally it's a coffee cup though.

Not far off getting the bearing preloads done now! That's the really tricky/skilled part.

Re: 9k 93 95 NG900 Box Build - Faero Style! Looking like a b

Posted: Sun Oct 16, 2011 9:19 am
by faero
A little more done last night.....

BEARING SHELLS INTO THE HOUSING

Input shaft bearing:
This tapped in with a bit of wood quite happily. Once you start shimming for preload you want to gradually draw it in with the bearing plater so don't put it in too far now - leave a good few mm proud at the top.

Output shaft side: I popped this one in the freezer for a bit and then whacked it in... run this all the way to it's own end stop (you can see the flange on the top)



SHIM UP (Input Shaft)

Find some shims!! Saab make: 1.0mm, 0.30mm, 0.15mm and 0.10mm Luckily have had plenty after taking a few boxes apart

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Make a 1.5mm shim pack
then bolt on the top plate. This is a starting point for the shims.

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FIT THE END CASING

Last chance to check inside the box for any random bits you've left in there.... Clean up the flanges then put on Loctite 518 gasket all the way round.
Then bolt up the whole lot - bolts to 24Nm. And tap in the big steel locating dowels.

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FIT THE OUTPUT SHAFT BEARING RACE AND 5TH GEAR - LIGHTLY


RACE
Saab do a special tool for this part but it's expensive so I wound down the bearing using bits of old bearing. The hard part is stopping the shafts from spinning so I welded a bar onto an old 5th gear syncro hub to hold it whilst cranking the bearing down. DO NOT take it too far.... just until the rollers are about to touch the bearing shell.

5th Gear:
This is the gear from a 9-3 so the longer ratio. It's tight, so I heated it in oil and it just dropped down.

Now, I wound the gear/bearing down a bit at a time, checking the end float each time by pulling the gear up. All you are trying to do here is get the gears below to behave while you work on the input shaft. - I took it to the point where I could still lift it up a touch with my hand.

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SETTING INPUT SHAFT PRELOAD

Now it gets fun... Set the little dial gauge up on the bracket - the ebay cheepy magnet bracket has an M8 end that fits nicely. The gauge has a tiny travel so takes a bit to settle in.

Next I used a bit of old idle valve hose and 2 jubilee clips to attach the drill to the top of the input shaft.
Make sure the bearings are oiled up too then start spinning with the drill - not too fast.

With the drill pressing down (just under it's own weight is enough) - then zero the dial. With it still spinning, pull up and see what it reads.

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In my case this was 0.60mm
Target: 0.09 to 0.15mm so I am miles out.

Right - I don't want to want to overcook it so I dropped the shims from 1.5mm down to 1.10mm.

TRY AGAIN:
Shims at 1.10mm : This time it was 0.14mm end play. This 'should' be fine but I want this box to be nice and tight and would like to try and get to the lower end of the spec.

TRY AGAIN
Shims to 1.05mm : This time it was 0.07mm end float. Too tight! Well is it? The old style Saab manual lets you run down to 0.05mm where the later is 0.09mm. I'll mull this over!!

Re: 9k 93 95 NG900 Box Build -Faero Style! Bearing preload

Posted: Sun Oct 16, 2011 9:56 am
by nutcase
Finally got around to reading this - interesting to see the innards of a more normal gearbox! Biggest practical difference I see is the use of needle bearings for the various gears rather than on the 99/900 boxes that use bushings. And is that a synchro on reverse? Biggest bit missing from the 99/900 boxes!

Re: 9k 93 95 NG900 Box Build -Faero Style! Bearing preload

Posted: Mon Oct 17, 2011 10:10 am
by faero
yeah - in this box 1st,Rev.& 2nd gets bushings but 3rd, 4th, 5th get needle bearings. I assume the busing can take more loading and are cheaper but let precise? Not sure what other factors are involved.
And yes - there is a little 'mini-me' syncro on the reverse pack I have in my hand in one of the pics.

Re: 9k 93 95 NG900 Box Build -Faero Style! Bearing preload

Posted: Tue Oct 18, 2011 10:04 am
by mrd2525
I did mean to slot my pics inbetween Phils commentary but missed the slots. I'll add ones that I think might assist...as they say a pictures worth a thousands words! :wink:

Making the dowel (fitted bolt)

Use dowel from the camshain guide

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To maintain roundness whilst tapping 8mm thread hold in a drill chuck..

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Test fitting to bearing support plate..

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Marking off dowel to ensure correct size...drill hole out 9mm as per Phils instructions above...then place plate over hole, push dowel into the hole and press down until it bottoms out. Then mark dowel with ink and scribe mark to you know the correct length required...

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Using a test hole drilled in some aluminium plate, push dowel in until scribed line shows thru...cut dowel squarely with blade of cutting disc....

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Place theaded dowel onto bolt and screw into place to check the bolt doesn't bottom out on the dowel before the bolt head comes into contact with the bearing plate. The pic showns the bolt in position and I used the plate as a 'big feeler' gauge ensuring it wouldn't slid under the bolt head by about 1mm when the bolt was tightened .

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This was my tip to Phil dealing with refitting of circlip....

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Re: 9k 93 95 NG900 Box Build -Faero Style! Bearing preload

Posted: Tue Oct 18, 2011 11:27 am
by faero
Thanks mark!


Input shaft end play - take 2 !

After some messing and a little hiccup I went back and got the end play of input shaft to 0.08mm which I am happy with.
In the video below I am spinning the shaft with the drill attached. When you see the needle move, I am pulling the drill upwards to show end play. Video a bit crud as I'm holding the phone in the other hand...

http://img.photobucket.com/albums/v200/ ... G_0775.mp4


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Re: 9k 93 95 NG900 Box Build -Faero Style! Bearing preload

Posted: Thu Oct 20, 2011 11:10 am
by faero
FIT 5TH GEAR ON INPUT SHAFT

1) Fit the roller bearing (oiled) into the 5th gear.
2) Pop this onto the input shaft
3) Take the syncro ring (I managed to find a new one so will be interested to see if it's nice to use)
4) Pop on the steel ring and then push in the 3 leaf springs behind the ring.
5) Slot the syncro into the Syncro Hub.
6) Put a lump of wood under the input shaft
7) Tie wrap the syncro ring to the hub - or whatever way you can hold it together without the saab tool.
8) Tap the hub on.... some are not too bad. Others are really tight and need a good bashing! (like mine)


SET THE OUTPUT SHAFT END FLOAT to 0.06mm

1) Set the dial gauge up on the shaft as shown in the pic. - You need room to get the socket on if you don't want to move the gauge each time.

2) Put the box into 1st gear and then fit and drop down the 5th gear selector sleeve. This locks the box in 1st and 5th and means you can torque up the nut on the output shaft.

3) With a big flat scewdriver blade, life the 5th gear upwards and then let it drop back. It will hopefully be much more than 0.06mm!

4) Torque up the output shaft nut (eg 1/4 turn) and measure again. To do this I also needed to screw the whole gearbox down onto the bench.

This is only the lifting and dropping end play to get things in the right ball park - and is a lot less than the 'spinning' end float. I found that 0.06mm lifting / dropping with screw driver is actually about 0.24mm once spinning up - so don't get too worried about it being bang on here.

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SET THE DIFF BEARING PRELOAD

Here you use a 'dummy' bearing (loose fit) shell to calculate the shim thickness. You then replace it with the 'real' shell which you can't get back out once it's in!

1) Make the dummy shell: I used the same timken bearing as the main bearings so it would be an exact match. This is a £20 luxury for a bearing but I wanted it pretty accurate. I then ground the outer edge to it easy dropped in and out of the casting - I pulled it back out with a magnet.

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2) Fit the drive shaft casting:
I cleaned up the casting mating faces to remove any aluminium 'crud'. For this you also need to remove the rubber o-ring. Drop in 2mm of shims to get you started.
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3) FIT 10kg Weight and Spin Up!

I used Argos' finest dumbell weights here - First time they have been put to any use .....

I then spun the output shaft using the trusty rubber joiner, whilst holding the weights on with a big screwdriver. Spin at LEAST 20 times to settle the bearings.
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4) ADJUST THE SHIMS to get 0.3mm gap

This is a bit of a fiddle as the casting is not perfect - you need to move the feeler gauge round and make a judgement. I found I would adjust the shims so the gap was too small, then build up again and make sure the >0.3mm was then too tight. Pretty soon you get the feel for it but I reckon there were about 5 or 6 changes of shim. Make sure there is no grit or crud on the shims as this wrecks the measures.

5) FINAL FIT OF DIFF BEARING - Preload down to 0.15mm
Once you are happy (you'll never be happy but you know you are as good as it will get).

1) Remove the dummy bearing shell and shims.
2) Fit the O-ring to the drive shaft casting
3) Tap in the final bearing shell - Usually not to tight. I tapped very carefully at the end - just to the point where the the rollers are starting to get gripped. Put it too far and the next step gets a bit messed up.
4) Put on the spring plunger to the drive shaft. In the pic below, the standard one is in my hand and the Abbott one for the use in the LSD is fitted. As the Quaife doesnt have a central pin to push against, the pin needs to be long enough to push against the other output shaft. Note that the pin is spring loaded and the idea is to prevent the driveshaft cups pushing inwards and rubbing on the castings.

5) Fit the Casting/cup and very carefully wind the bolts to 0.15mm feeler gauge gap. THis is no more than hand tight on the screwdriver shaft - If you overcook it, take the cup off and tap the whole diff upwards from underneath to release the preload again.

Normal and LSD spring pins:
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Measuring the 0.15mm temporary preload
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MEASURE INPUT SHAFT ROTATING TORQUE:

This uses a 'Torqometer' and the aim is to get between 0.1 and 0.3 Nm. When you turn the input shaft, the output shaft stays still. It's worth checking the bearings are oiled and give it a good fast spin to make sure the syncros don't snatch whilst measuring after.
I had forgotten to oil the 1st/2nd gear bushing so probably had more drag.

Steadily turn the Torqometer and read the dial- Give it a good few goes. I ended up with 0.27Nm


THE FUN PART: OUTPUT SHAFT PRELOAD AND CRUSH SLEEVE:

Aim: Work out the spinning end float, then remove all endfloat AND crush the sleeve 0.08mm.

1) Set the gauge on the output shaft. I used the 5th gear as there is a nice little groove in the end and it was a stable reading.
Measure end float: In my case it was 0.22mm - pulling drill up and letting it fall.

2) We need to remove 0.22mm end float AND add 0.08mm to the crush: = 0.3mm.
I made a graduated socket - The thread moves 1mm for every revolution so it's easy enough to do. I used an old clutch release bearing welded to a socket

3) Lock the box in 1st and 5th, then turn the nut through 0.3mm on the markings. It's getting really tight so you need a long bar. If in ANY doubt, don't go too far!


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4) Check the spinning Torque in Neutral. In this case, when you spin - it turns both output shaft, input shaft and the diff.
The output shaft range is 0.5 to 1.0Nm. So the maximum total is 1.0Nm + 0.27Nm of input shaft = 1.27Nm.
My first test only got 0.7Nm total so well under.

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5) If it's too low, turn the box up again, set to 1st and 5th to lock and give it another 0.05mm of preload turn. In the end I think I added about 0.13mm extra preload to get it about right....

6) Now that you are slightly happier again - Torque up the driveshaft castings to 24Nm.
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FINAL VALUES:

Input Shaft: 0.27Nm
Total : 1.23Nm
Output Shaft: 1.23 - 0.27Nm = 0.96Nm. This is just on the tight side of the limits which was the plan for this box.

As an extra check I ran the output shaft torque AFTER fully preloading the diff. This was 1.85Nm. I guess this will vary a bit with choice of final drive - in my case it's the shortest gearing so easiest to turn the diff.

Next I fitted the 5th Gear circlip (new).
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Just left to fit the 5th gear selector, end casing and check all the torques and we are done....

Re: 9k 93 95 NG900 Box Build -Faero Style! Almost there!!

Posted: Fri Oct 21, 2011 9:20 am
by faero
FITTING 5TH GEAR SELECTOR AND END COVER

I had several selector forks and went for the one that looked least worn - Measuring with the verniers suggests that there is sod all wear on any of these so not much of a concern.

1) Do a test fit of the syncro sleeve - it will fit in 2 positions, but one of them will not allow it to drop down and select the gear. Note the position.
2) With the box in neutral, Put the syncro sleeve into the syncro fork and make sure the little pin is 'started' in the hole in the syncro sleeve.
3) Carefully push the selector fork down
4) Once in position, tap the pin into position.

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5) STAKE the Output Shaft Nut in 3 places to make sure it's going nowhere!
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6) Clean up the end cover and make sure the oil flow tube is all nice and clear:

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7) Fit a gasket - I had bought a new one as the first box I took apart ripped the gasket - of course the other boxes I stripped all had nice gaskets so I reckon you shouldnt need to buy this pricey item.

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CHECK TORQUES AND FIT SPEEDO DRIVE

I went round the casing and any exposed bolts again checking they were torqued up. Almost everything is 24Nm.

One exception is the bolt that holds the reverse gear pin inside the bell housing - That is 28Nm
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I should have probably fitted the speedo drive a lot earlier (it was test fitted but never screwed down). Check the teeth on it are in top condition with no flat tops or chunks missing. Press fit the drive (it's got an O-ring) then fit the little support tab as shown. Note that the big nut around the speedo drive has nothing to do with holding it into the box...


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CONCLUSION
1) Now tidy up your tools.... Each time you can't find something you will assume it's lost inside the gearbox.
2) Open a beer

Thanks go to Mark D, Nick T, Norman L, Stuart A for all the information and putting up with my endless questions on this...

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THE END

Re: 9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Fri Oct 21, 2011 9:37 am
by Mike9000Aero
Phil stared to glaze on the pre-load bits but I am sure that with a couple of reads....one job I have never attempted is a gearbox unless you count a Royal Enfield 250cc many years ago.
Very interesting and helpful.
Mike

Re: 9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Fri Oct 21, 2011 9:47 am
by Trackside
Isn't there a bushing that goes in here or is it different on the LSD? Only saying as the bushing on my box has worn and the inner driver slops around a bit. I bought the bushing to replace it but it's a pig to get in and out.
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Re: 9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Fri Oct 21, 2011 10:00 am
by faero
One of the few differences between 9k and 9-3. In the 9-3 the output shaft casting has a socket/hole in it and the drive shaft is pushed right into the diff. (i.e. pull the driveshaft on a 9-3 and all the oil comes out..) As it pushes through the hole, there's a bush/seal to keep the oil in and i assume, support the shaft. - is that what you mean? If you need a sample casting to 'pre-prepare' - let me know as I have one that's no use to me.

(On the 9k the casting has the cup and stub axle as part of it so the box is always sealed.)

Re: 9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Fri Oct 21, 2011 10:03 am
by Mike9000Aero
(i.e. pull the driveshaft on a 9-3 and all the oil comes out..)

Been there and done that accidentally on my GM 900 - pushed it back quick. :roll:
Mike

Re: 9k 93 95 NG900 Box Build -Faero Style! Finished....

Posted: Fri Oct 21, 2011 10:17 am
by Trackside
faero wrote:One of the few differences between 9k and 9-3. In the 9-3 the output shaft casting has a socket/hole in it and the drive shaft is pushed right into the diff. (i.e. pull the driveshaft on a 9-3 and all the oil comes out..) As it pushes through the hole, there's a bush/seal to keep the oil in and i assume, support the shaft. - is that what you mean? If you need a sample casting to 'pre-prepare' - let me know as I have one that's no use to me.

(On the 9k the casting has the cup and stub axle as part of it so the box is always sealed.)

That explains it perfectly!