• Please only use these forums for blogs, they are not a discussion forum

PollyMobiles Rebuild

Stani1029

Club Member
Ask for a complete replacement, apple do it with there products within the 1yr warranty no matter how little the fault. (Yes i know apple have unlimited money) but same rules should apply
 
indeed.
not sure all the lsd faults are fixed if their tech can't even find the cause. I'm hoping the replacement preload ring is of a modern batch that might be better quality.

if this one also fails again soon, then this LSD won't turn out to be reliable. Can't see myself having to rebuild the LSD every few months/per year.
worse case last resort would prob be to tell em to replace the weak preload ring with additional clutches.
What do you do as a customer if you've been sold a product that's not reliable or fit for purpose? other than getting it rebuilt every year under warranty or selling it at a loss?
You ask for your money back and buy another :) its getting a bit daft in my opinion
 
OP
OP
pollyp

pollyp

Club Member
Ask for a complete replacement, apple do it with there products within the 1yr warranty no matter how little the fault. (Yes i know apple have unlimited money) but same rules should apply
I'll need to assess the small print.
12mth guarantee from invoice is prob invalid now but lifetime warranty still applies and their T&C seem to mention something bout either repair or replace defective goods.
 
OP
OP
pollyp

pollyp

Club Member
You ask for your money back and buy another :) its getting a bit daft in my opinion
am I allowed a refund even after 2yrs? although it has also been rebuilt after each yr so yea abit inconvenient.
what other options are out there that won't break the bank?
although my income (tiny funding to help start new business) at the mo is not even minimum wage! so no chance of any upgrade/changes for the next few months :(
 

frank

Club Member
i would just run the diff semi open personally paul (low preload) that way you will have some "limited slip" but a lot less stress on that diaphram
 
OP
OP
pollyp

pollyp

Club Member
here's the rebuilt LSD for the 2nd time

DSC08074.JPG


but hold on, that wasn't like that before

DSC08077.JPG


gArgh someone at gripper needs a good bollucking cos it's obviously been dropped and dinged a section of the 1mm thick bearing cage :mad:
further thinking, maybe it could've been dropped badly during parcel transit? wasn't labelled Fragile

I can't straighten it up with pliers but don't think its a major issue and it'll still roll but certainly won't help cos the once straight edges of the cage now bends in slightly at the edge of the roller bearings and could wear it out abnormally?, especially since I push it on track. that'll bug me

DSC08078.JPG


before servicing, lets check the preload torque. insert the spare driveshafts, secure one end on a breaker bar and my electronic torque wrench on the other.
slowly increase torque till it slips and the wrench shows the peak torque the preload provides is 55Nm (in future I can lift one wheel and use the wrench to monitor the preload torque monthly against this reference and spot if it fails again)

DSC08079.JPG


to undo the cover, I insert the cogs and engage multiple gears to bind/lock/hold the diff before loosening the bolts in a diagonal progressive manner to prevent warping the parts

DSC08087.JPG
DSC08088.JPG
DSC08089.JPG


the new preload ring

DSC08090.JPG


the previous rebuilt ring on page 51 had a heavily copper coated appearance, while this new one looks abit darker so maybe a new batch?

DSC08092.JPG
DSC08093.JPG


old preload ring was 2.6mm thick with a conical offset of 1.2mm
this new one is a slightly thicker 2.66mm and a conical offset of 1.04mm

DSC08096.JPG


now lets measure the plates and see whats been replaced or swapped (before -> after rebuild)

Outer Plate 1 (1.89 - 1.90) same

DSC08098.JPG
DSC08099.JPG


Inner Plate 1 (1.74 - 1.73) same

DSC08100.JPG
DSC08101.JPG


Outer Plate 2 (1.10 - 1.54) swapped outer plate 4 to outer plate 2

DSC08102.JPG
DSC08103.JPG


Inner Plate 2 (1.54 - 1.53) same

DSC08104.JPG
DSC08105.JPG


Outer Plate 3 (0.95 - 0.94) same

DSC08106.JPG
DSC08107.JPG


Inner Plate 3 (1.53 - 1.53) same

DSC08108.JPG
DSC08109.JPG


Outer Plate 4 (1.55 - 1.34) new plate

DSC08110.JPG
DSC08111.JPG


Inner Plate 4 (1.55 - 1.53) same

DSC08112.JPG
DSC08113.JPG


previously the total plate thickness was approx 11.85mm with a 2.6mm thick preload ring and 1.2mm offset = total 15.65mm free length

tdays rebuilt diff has a total thickness of approx 12.04mm with a 2.66mm thick preload ring and 1.04mm offset = 15.74mm free length

given the distance between the planet driver surface and the LSD cover remains the same, the new preload ring seems to be squeezed tighter.

planet driver

DSC08114.JPG


before reassembly, always good practice to tap & clean all threads.
gripper technician clearly hasn't, even though the bolts been 'blue' thread locked upon arrival, cos here you can see the remains of the old 'red' thread lock on the thread tapper :rolleyes:
(yes r-reg I sense you'll be commenting bout the Matrix-like 'red/blue pill' theme :p)

DSC08116.JPG



this is why I tend to disassemble and reassemble stuff I've received/purchased, even if it's new, cos in most cases it's never built/assembled carefully to my level of quality attention to detail.

prob a mild form of mechanical ocd/perfectionism? but tis just piece of mind to know that I've triple checked the things been built correctly so it'll function efficiently and reliably (learned since old days of weekly overhauling my bicycles). if ya want stuff done proper, you do it yourself eh

now a long video of reassembling the LSD


rechecked the preload and it remains 55Nm.
 
Last edited:
OP
OP
pollyp

pollyp

Club Member
Can they not just send you a new bearing Paul?
I doubt they supply bearings for the micra diff.

johns reply was


Bearing damage is one of the reasons we suggest never shipping heavy
parts with the bearing on the end.
However there is also a good possibility of damage when removing the bearings,
This type of compression of the tin cage is not critical part.
We would carry out the checks you suggest and even carefully straighten the cage.
few pointers.
  • tis abit inconvenient to pull out the bearings to prevent damaging the bearing each time I need the lsd rebuilt
  • I dont have a puller. but even if I do or get someone to do it, it'll prob damage the bearing anyway!
  • so really, each time i get the diff sent off to be rebuilt, if it gets dinged it'll need a new bearing? = more time & money.
only suggestion would be to shield the bearings against any outside impact with a solid cap taped to the diff body before transit.

just spun the bearing on the gearbox casing and it runs fine n smooth so the dinged cage isn't causing an issue yet. I'll just try straighten her abit n get on with it. can't be bothered wasting unnecessary time n money letting a shop replace the bearing when it seems to work as it should.
 
OP
OP
pollyp

pollyp

Club Member
the rubber boot on the selector rod is abit torn which isn't good for keeping muck out so I'm gonna have to swap over the one on the spare gearbox

DSC08118.JPG


split pins out and removed spare gearbox selector rod

DSC08119.JPG


I think someone on the forum or on ciscos was asking bout this selector rod oil seal so here's some pics
ah this thread:
http://micra.org.uk/threads/gear-selector-shaft-oil-seal.23245/

DSC08120.JPG
DSC08121.JPG


swapped the boots, reinstalled the rod and wtf the boots too big for the lip? did i fit it the wrong way?
rod removed again, and huh, oh ffs the spare gearbox selector rubber boot has a bigger hole than this gearbox :/

DSC08123.JPG


here's the bigger end on the spare gearbox, which I later found was removable

DSC08124.JPG
DSC08125.JPG


the current gearbox has a smaller but metal lipped seal

DSC08126.JPG


without damaging it with a screwdriver, I hold the ends with needle pliers and just pry it off and off it comes

DSC08127.JPG
DSC08128.JPG


both fit the same hole so can be swapped

DSC08130.JPG
DSC08131.JPG
DSC08132.JPG
DSC08133.JPG


now lets try to straighten the diff bearing cage. don't have such a tool for the task so lets make one

DSC08134.JPG


abit of refinement led to this

DSC08135.JPG


slip it in the gap and bend it up progressively along the lip like a tin opener

DSC08136.JPG


this is as best as I'll get, better than nothing suppose

DSC08137.JPG


the slot edges in the cage still slightly curved but it'll be fine. tisn't critical and still spins freely with no issues so meh

DSC08138.JPG


all cleaned n assembled

DSC08139.JPG


next is prep the bay, steam wash all the oil stains off, repaint crossmember and fit the gearbox
 
Last edited:

Stani1029

Club Member
Paul what split pins did you remove? I was going to take the one out at the linkage end, ive just ordered a new one of those seals
 
OP
OP
pollyp

pollyp

Club Member
Paul what split pins did you remove? I was going to take the one out at the linkage end, ive just ordered a new one of those seals
that's a point.

if the new/replacement boot is exactly the same and has the same hole size, then yeah you could just punch out the dual split pins that hold the external gear linkage arm bracket bit to the selector rod, slide the bracket off, replace boot, refit the arm bracket. so you don't have to take the whole gearbox apart.

but if the boot has a different size hole like what I just discovered last night, then you have to disassemble the gearbox, punch out the split pins holding the rod to the casted selector finger, slide the whole selector rod out, swap over the selector rod oil seal, replace the boot and reassemble.
 

Stani1029

Club Member
My gearbox is in pieces anyway so ill just do it whatever way seems best. I really hope i have the correct boot, he took my registration but sometimes that means nothing!
 
OP
OP
pollyp

pollyp

Club Member
steam cleaner was next to useless, just milks up the oil stains. wipe it best I can.

fly & clutch on

DSC08140.JPG


gearbox mounted

DSC08141.JPG
 
Last edited:
OP
OP
pollyp

pollyp

Club Member
I meant the boot thats currently on the gearbox, its a new oil seal ive ordered so i hope i have the correct boot to match whichever seal i get :p
ah its an oil seal u ordered. when u receive the new seal, test fit it against the boot. if wrong send it back for another type.

just looking through nissan4u and seems that from Nov 94 they changed the oil seal & boot from the original larger lipped, larger holed, all rubber oil seal to the smaller holed, metal covered oil seal
 

Stani1029

Club Member
Yes we'll I believe I have the wrong seal, it's the one on the left in your picture above....I will double check it first before I go back to nissan and complain that they didn't offer a choice
 
OP
OP
pollyp

pollyp

Club Member
freezing tday

drive shafts on

DSC08142.JPG


the brake discs are in a sorry state rusting over the snowy/wet month

DSC08143.JPG
DSC08144.JPG
DSC08145.JPG
DSC08146.JPG


few mins of wire brushing the thick rust coating off

DSC08147.JPG


back to bare metal. slight bit of tiny rust pitting but few thou miles will wear that smooth again

DSC08148.JPG
DSC08149.JPG


DSC08150.JPG

DSC08151.JPG


calipers on

DSC08152.JPG


taking a break cos its so cold and slightly murky headache.
then continue with the pads and the rest of the bay
 
Last edited:
OP
OP
pollyp

pollyp

Club Member
pads sanded clean n flat n fitted

the oil galleries will be bone dry so lets prelube it by injecting oil via the turbo oil feed line

DSC08153.JPG


the down pipe metal gasket starting to crack, tis minor but will need replacing soon

DSC08154.JPG


with the wheels on I can check the LSD static preload behavior.

one wheel is held static on the floor while the other is raised and my torque wrench measures the torque in both directions.

DSC08156.JPG


LH (clutch & ramp) side measures
50Nm deceleration & 60Nm acceleration

RH (floating ashtray) side measures
50Nm deceleration & 80Nm acceleration

The planet driver ramp relies on the torque difference between the LSD body and the pinion gears to generate additional clamping force against the clutch plates. more torque difference = more clamping force

Also once the plates begin to slip, it goes from a high static friction to a lower dynamic friction so the torque value drops.

The LH of the diff has a lower Acceleration static preload torque than the RH cos the LH side-gear is engaged to the clutch-pack, which means it moves/slips the clutch plates & reaches peak torque earlier before the pinion ramp gets to generate extra clamping force.
It also moves against a floating RH side gear & ashtray driver (zero deg ramp), which means it doesn't generate as much 'ramp' force as the other side.

Now the RH of the diff in comparison is just floating and independent to the clutch pack, it mainly just acts on the planet ramp.

When I turn the RH wheel, the LH side gear & clutch pack is initially held static by the preload ring while the RH side gear is free to turn and push the pinion pin against the ramp angle of the planet driver.
This ramp action increases the clamping force on top of the preload, which further increases the static friction of the plates.

When the RH torque exceeds what the static friction of the plates can hold (from the preload & addition clamp force from the ramps), the plates begin to slip and reach peak torque.
 
Last edited:
OP
OP
pollyp

pollyp

Club Member
oh ffs bollucks it's still friggin broke :mad:


hard to start, still semi-misfiring, very rich mixture, very poor idling and smoking but coolant doesn't blow so HG fine.
once again unplugging the spark and injectors would lower the rpm except for cyl3.

drive round the block, big ploom of oily mist when leaving the t-junction, light acceleration and cruising, poor turbo response, wirebrushed front discs obviously wasn't working well and felt like stone, but the lsd preload certainly came back judging by the very heavy steering.

not a good day at all :(

compression test says:
11.6 / 11.7 / 3.5! / 11.6bar dry
12.4 / 12.2 / 4.3 / 12.0bar wet
+0.8 / +0.5 / +0.8 / +0.4 difference

since the valves are lapped and sealing and the HG not blowing and piston tops intact, I'm guessing broken ring land frank?

so situation is
  • car's still broken and gonna be off road for some time,
  • so gonna need to SORN and cancel insurance to reduce running cost,
  • this stock engine is not worth fixing anymore,
  • already have another broken engine in garage taking space,
  • not worth time & non-existant money buying another stock engine to clutter the garage,
so really my last and only option is plan B, finish rebuilding the forged piston engine, fit it and bed it in properly.
just need to obtain a piston ring grinder to set the end gaps (can only source on US ebay £58)

but also I need to know if I should:
  • pre-stress the open block with a torque plate before measuring,
  • if you position the gaps pointing at the same orientation on the bore or orientated as they would on the piston
reason is cos when i position the ring gap at a different angle, I got a different reading as though the bores were oval?

with this much issue, I can't say for sure if I'll be ready for PPC
 
OP
OP
pollyp

pollyp

Club Member
aye, sounds like a ring problem eh paul :( i have spare pistons etc you,re welcome to mate :)
ah thats a bumma indeed.
I've got a spare engine in garage for bits n bobs, twas the old stock engine that came with the turbo kit I won off ebay, except it now has the incorrectly over-bored block that was originally from the forged engine I brought off noddie (does that make sense?)
so basically on that engine everything except for the block is fine as spares and can technically swap over the cyl3 pistons but it doesn't guarantee it'll work or if the bores are ok and with the amount of effort required on my setup to swap the pistons, I may as well focus my limited resources towards the forged engine now.

have been waiting for a time when this stock engine finally dies before considering the forged engine and this seems to be the sign

I just took her out one last time in the country roads at night (so I don't gas everyone in daylight with smoke) to bed the front discs in. she still develops 10psi but at a higher threshold due to the lack of energy from the misfire and after afew hard caning, i think the smoking has reduced alot but still sounds like a subaru and really struggles to idle on 3cyl.
oh and during slow speed turning, I can feel and hear the LSD clicking. so that's working, for now.
 
OP
OP
pollyp

pollyp

Club Member
correct me if wrong, when I SORN her, can I cancel the insurance till I fit the new engine? or do I still need fire & theft cover?
 

Enuo

Glorified Electrician
It's not a legal requirement, but I knew a guy with an interceptor he was rebuilding. Declared sorn, no insurance, the garage next door caught fire and his car was ruined. He had no insurance and was not covered by his contents cover for some reason. If you love it, insure it.
 
OP
OP
pollyp

pollyp

Club Member
my workm8 also mentioned yeah i'll prob need it cos one of his m8 had his sorned car in garage nicked and the rozzas fined him for havin no insurance?

think I'll maybe try reducing cover down to fire & theft only
 
OP
OP
pollyp

pollyp

Club Member
rang sky bout if I need insurance during SORN, nope.
ok how much to cancel?

I paid £572 to renew on 19th mar, so used £10 worth upto now.
says if I cancel, I'd only get £368 back after all the admin/cancel fees etc:eek:
and once she's back on road I'd then need to get a new quote to resume cover.

bugga that, just gonna leave it running onwards.
 
OP
OP
pollyp

pollyp

Club Member
was gonna order a piston ring grinder from US ebay but with the UK customs, import tax etc, could cost more.

so thinking of getting this one from UK ebay for £68

$T2eC16JHJF0E9nmFQguLBQ11l,7e1w~~60_12.JPG

http://www.ebay.co.uk/itm/Motorcycl...54?pt=UK_Motorcycle_Parts&hash=item43b71aace2

unless someone has a ring grinder I can borrow?

or shall I get a shop to gap it for me for that much cos I'll prob only use a ring grinder once?
don't trust my local machinist teesside motor factors tbh. stuff either wasn't machined to exact spec or some stuff weren't done at all.

and with such an important 'last chance' engine, I personally prefer to suck up the investment cost and do it properly myself
 
OP
OP
pollyp

pollyp

Club Member
finally got some interest from huggy444 in the 13" nissan alloy wheels i had on sale for um 3yrs

time to grab em off the dusty shelf

DSC08157.JPG


hair nets did their job keeping em pristine

DSC08158.JPG
DSC08159.JPG


they were stored fully deflated so took long few mins of back breaking hand pumping to get em each up to 2.2bars :/

found the old set of nuts

DSC08160.JPG


and taped em in the wheels

DSC08161.JPG

DSC08162.JPG


cover in cardboard & bin bag next
 
Last edited:

Seb_

Give me some frogs.
Site Supporter
I'm glad that at last they are sold, good condition stock alloys for a very descent price + extra money for Paul !
 
Unlucky with that engine, forged one should be good though, means youre finally gonna get on it! As always from the read up the rest of the car looks mint too, nice work polly!

Also can i ask a question as frank said you may know... do the pre-coilpack facelifts (1999 in this case) have an electronic or mechanical speedo? I'm meant to be getting a gearbox from one and hope it will fit my 95 model...
 
Also can i ask a question as frank said you may know... do the pre-coilpack facelifts (1999 in this case) have an electronic or mechanical speedo? I'm meant to be getting a gearbox from one and hope it will fit my 95 model...
Mines a 1999 precoilpack facelift bud & its an electronic speedo



P.S Paul i hope the forge build goes alright first time for you :)
 
OP
OP
pollyp

pollyp

Club Member
Unlucky with that engine, forged one should be good though, means youre finally gonna get on it! As always from the read up the rest of the car looks mint too, nice work polly!

Also can i ask a question as frank said you may know... do the pre-coilpack facelifts (1999 in this case) have an electronic or mechanical speedo? I'm meant to be getting a gearbox from one and hope it will fit my 95 model...
cheers joe. though I feel it's gonna be a slow progress due to work.
gotta obtain a finer set of feel gauges, then make a dremel ring grinder, clear the spare bedroom to work on the forged engine and the long process of fine tuning the rings, rebuild the engine, rip the old engine out, swap bits, fix bits, reinstall engine n bits, yada yada yada

even though PPC is awhile, with priority on work than car, i'm not certain it'll be ready & bedded in let alone setup for track :/

on nissan4u it seems the k11 switched over to electronic speedo round Feb 98
 
Lotta work then, hope there's no more hiccups! I'm gonna try finally doing a high comp build soon myself.
Shame about that with the speedo, box I was getting has only done 25k
 
OP
OP
pollyp

pollyp

Club Member
the electronic speedo body and the bore is slightly smaller than the mechanical.

if both elec/mech speedo 1.3L gearboxes have similar bits inside (which mine did when I won the turbo kit), then u can convert an electronic speedo box into a mechanical speedo box by:
  • just swapping the bellhousing or
  • get the hole enlarged by machinist to fit the mechanical speedo.
 
Tempting to still go for it then... Need one as the main bearing on mine is rattling horribly and sounds like a bag of nails out of gear, and on the move whines a lot.
 
Top