Screwed my clutch?

[zedevan]

not so much a question as a statement, changing gears this morning on my way to work it failed to engage (never had a problem or even a sign of slipping) as soon as i realised i stopped accelerating and then it clunked back in so started again, only to notice it slip when it got more than 3500rpm through it.

 

the clutch is now about twice as easy to push down on as before, and doesn't do so smoothly, and makes the rear end of the car shudder quite badly when engaging. i pulled over, checked fluid, can't see anything obviously wrong, so i caught the bus so i dont do more damange for now, although i assume its screwed and even if only part of it needs replacing i assume its the main part so may as well do all of it?

 

any ideas or tips on whats wrong/how to change it/any manuals i should purchase?

 

the only thing thats annoying me is that i was hoping this clutch would last me till i had a different engine and gearbox...which could be coming up quite soon, and if i'd blown the engine it would be happening now, so i'm tossing up whether to do it now, but a clutch isn't that expensive so kindof a stupid reason ? as if i did start playing with the engine etc, realistically it woudlnt b back on the road till the end of the year, i have another car to drive but i'd prefer to keep driving the zed as it is, knowing that eventually the clutch just wont engage at all, but there's nothing i can brake that doesn't already need replacing? yeah?

[zedevan]

well a new clutch is only $130 so looks like thats the way to go for now, just they say there are two different types used on zed's and there's no way to tell until you get it out, is this true? just would be nice if i knew what sort it was so i can get it now and then in over the weekend, instead of just taking it out on the weekend and getting the clutch on monday

 

thanks for any help in advance!

[luke_mcmahon85]

From the Datsun Z Garage:

 

Measure the width of your flywheel's shiny clutch contact surface.

 

If it's 225mm wide then you have a coupe version which uses a 550lb pressure-plate.

If it's 240mm wide then you have a 2+2/turbo version with a 780lb plate and a wider disc.

Both flywheels are the same at weight at 23 lbs, and the diameter is the same (only the contact area is wider). But a turbo pressure plate and disc clutch are definitely heavier than coupe version by a few pounds. So how much performance is actually lost with a heavier assembly? A good one to argue at Z meetings...

 

I haven't tried any of the competition clutches, but truthfully the only time you really need a stronger one is if your engine torque is causing the clutch to slip. I agree it sounds neat to say your car has a "competition clutch", but it doesn't make the car faster. I autocross and dragrace my Z, and my stock clutch works fine (really) after 2 years (Zoom brand). A buddy has a Centerforce 2 which feel very solid, but rumor has it the Centerforce One is a stock clutch with only extra weights hanging on the pressure plate fingers.

 

LIGHTER FLYWHEEL

Used for decades to reduce drag on the engine and to make it spin up faster. It won't make the engine develop any more horsepower internally, but can cut down on parasitic drag. Better for track racing than dragracing, as on smaller engines the rotational inertia that helps the car off the line is reduced. This loss of inertia can make the engine rev down quickly between shifts. Some people consider them undriveable on the street, because the engine can stall easily, especially when cold. On motorcycles, having a too-light flywheel can make it stall between shifts(!) So keep this tradeoff in mind if you want one for your car.

 

CONVERSION NOTES

 

There are 2 versions of flywheels on all '75-83 motors: coupe and 2+2/turbo. 23 lbs each.

Coupe and 2+2 clutches aren't interchangeable because the pressureplate dowel holes won't match the flywheel dowels.

You can use a Z 5-speed on any year Z block, and any year L28 clutch can be used, but the throwout bearing "collar" must match the style of the flywheel (coupe or 2+2). In other words, if you have a 2+2 flywheel, you need to change the throwout collar to a 2+2 version when using a coupe trans. And vice-versa.

Auto trans engines have a 1/4" metal spacer between the driveplate and crankshaft, remove this when adding a flywheel.

A pilot bushing needs to be installed in the crankshaft if using an auto trans engine (they didn't get one).

Unless you need the accessories, don't use a big 3-row harmonic balancer in front, get rid of it. Compared to a 280Z 2-row it weighs about 5lbs more. I've read that taking 10lbs off a 10" rear flywheel is the equivalent of taking 207lb off the front of the car. So I believe removing 5lbs from the front of the crankshaft is desirable. Also, I've been told the 3-rows like to break up over 6,000rpm.

All L28 balancers have identical TDC timing marks and are interchangeable.

 

 

 

I think i need a new clutch kit as well, let me know how yours goes

[gav240z]

Hey Evan, have you checked the clutch fork? The thing that sits out of the gearbox and is what engadges the clutch (throwout bearing) when you press the clutch pedal?

 

I know of someone with a Z who had this snap on them I guess the metal can fatigue over time.

 

If your clutch all of a sudden fails I would be looking at one of these items.

 

Clutch Fork

Throw Out Bearing

Slave Cylinder

Rear Main Seal - If your clutch is slipping it could be from oil out of the back of the engine. The rear main seal can often leak. It should be replaced when putting in a new clutch also.

 

A clutch itself is probably not too expensive, but as quoted above you need to do several other things at the same time such as remachine a flywheel. Also my pressure plate was stuffed (the plate with all the teeth on it).

[zedevan]

thanks for the info. i havn't looked at it at all yet as i was on my way to work, and already ended up being late as had to catch a bus which takes longer lol. i'll have a good look around tonight probably.

 

the clutch still disengages completely as far as i can tell (as otherwise it would cruch when changing gears yeah?)

 

as quoted above you need to do several other things at the same time such as remachine a flywheel. Also my pressure plate was stuffed (the plate with all the teeth on it)

 

hmmm i dont read that anywhere? the pressure plate comes in a clutch kit yeah? thats the (trade?) price for the kit, remaching the flywheel sounds like one of those while your at it type jobs, or am i going to notice a difference if i do this?

 

good to see to you back gav, i had money and some shocks to give back to you the other night, so next time

[zedevan]

just got a quote for getting the work done by the mechanic i use, $140 for clutch, $40 for machining of the flywheel, and $200 in labour assuming its 4 hours of it.

 

i'd like to give it a shot myself but comes down to time i guess, although i have another car i can use, just dont really want to spend nearly $500 on a problem that wasn't there when i woke up this morning lol. but yeah he said that there might just be something cheap wrong so best to have a look first.

 

the clutch had never slipped on me before this :oops: mayb its $300 labour, can't remember, as i htink he said the total would be 480, or mayb he said 380 so with tax 4 something, should call again...

[tattoo_ink]

i agree with gav, the first thing id do would be check the throwout forkand pivot for damage before dropping your wallet into it !

[zedevan]

yeah, was just getting the prices of stuff so i know, and its all i can do while sitting at work, as my cars not hear to go walk out and tinker with thought peak hour traffic probably wasn't the best thing to put it through

 

with the pivot damaged though woudlnt it have trouble disengaging not engaging?

 

people at work have given me a couple of things to check and i'm sure my dad will be of some help, a couple of the guys said it could be the oil thing but my thought is that woudlnt it change the feel of the clutch pedal?

 

spending $500 on getting the clutch replaced seems stupid right now, would prefer to unregister it, which is a pain as just paid rego yesterday, and pay someone to put a gearbox in the gt4 as thats one job i know i dont want to try to tackle for sure! although even in peak hour driving the zed is atleast twice as fun as my dads crappy old corolla, so i'm sure the gt4 woudlnt compare either

[JP240z]

i agree with gav,

i have clutch problems in my car, most of them are due to the clutch system meaning to allow for a worn clutch plate. I think problems with the throw out bearing would be very noisy. But that clutch fork can be problematic. Best bet is to investigate further there i think.

[zedevan]

what do you mean by investigate? is there an inspection plate i can remove? just looked at the manual thing i have and its not very helpful, although i'm giong to go poke around now, but probably better to have info first lol

 

the clutch fluid is now above the max mark, no idea where it used to be, does this help with diagnosing the prob? i just drove it home from where it was (3-5km) and besides some vibrations you woudln't know anything was wrong, although i was driving it as nicely as possible and trying not to change gears

 

thanks everyone

[tattoo_ink]

get someone to push the clutch in while you have a look at the slave cylinder on the side of the bellhousing (which should move approx 30mm+) when they depress the pedal. if it does that then your hydralics shouldnt be the problem, next take note of the throwout fork see if it seems to flex at all . try take the rubber boot off and look in the hole where it goes in and you mite be able to see the pivot as well (im not sure as im not knowledged on the datsun gearbox,correct me if im wrong fellas) while your friend is still on and off the clutch, have a bo-peep around in there, you never know what youl find . if everything is looking like it doing as its told, im affraid its time to get the box out sorry to say. good luck mate! -chris.

[zedevan]

have it up nice and high on jack stands now but all i can see is that there is no cover over what the manual i have refers to as the withdrawal lever, and i assume gav refered to as the clutch fork? not sure if there is ment to b one, although there looks to be the remains of one there

 

if the clutch needs to b redone and i can't do it i'm leaning towards the idea of getting the gt4 back on the road while i can sort out plans for my car a lotus 7 is still on my mind back there somewhere, but i dont really want to b run over! lol

 

sorry i kinda of use this to think through my options, any input is welcome

 

thanks chris, read that after writing this, thats what i was planning on doing, just wondering if there were any better ideas lol, but good to know what it should be doing so thanks! ohwell time to wait till there's light

[JP240z]

that rubber is a dust cover that prevents dirt and stuff flying into the gearbox. mine was split and it had filled up the gearbox with dirt, replaced it today. If that clutch rod has snapped as gav said,it wont push the cltc fork as far and wont engage/disengage? the clutch to the normal extent. My clutch problems were fixed tonight by fabricating an adjustable clutch rod, as the 260s had, to adjust for slight clutch plate wear.

Hope my little knowlege comes of use.

[zedevan]

thanks for ur knowledge where do you get the dust cover from as mine is rooted.

 

if that clutch rod has snapped the clutch wont disengage. pulled the gearbox out this afternoon and the pressure plate looks stuffed so hopefully a new one of them fixes the problem, and the clutch bit that wears is pretty worn, the slots in it are only just visable, so was nearly time for another clutch anyway i guess

 

i called gio today re: engine conversion and they said they wouldnt b able to cover me at all :s so obviously talked to the wrong person lol. will call again another time and approach it differently, and hopefully talk to the lady i talked to the first time!

[JP240z]

im pretty sure the old lady got my dust cover from essendon nissan.

[zedevan]

thanks for the tip, i'll have to chase one down from a nissan sometime. i'm not going to have a chance to put it back in over the next couple of weekends as am going to be away, so hopefully i get inspired to do it one or two nights this week

[JP240z]

all you have to do is disconect the clutch rod through 4 bolts to put the dust seal on the clutch fork. 5 minutes tops.

[zedevan]

...i was meaning to install the new clutch and put the gearbox back in lol

 

but thanks for the tip of how to install the dust cover, no idea when i'm going to get time to get one from a nissan, hopefully the blackburn one has one and i can convince my mum to stop in there

 

would you happen to have the part number for it?

 

thanks -evan

[tattoo_ink]

hey mate, you should be able to put the dust cover in after youve got the gearbox back in anyway, so dont worry about it till youre cars back on the road, just dont go rallying till its in there :lol: ! maybe even put some duct tape over the hole till you do get one so nuthing gets in to your new clutch. chris.

[zedevan]

thanks chris, i'd figured as much, it will prob crack within a month like my new rack boot covers that were a pain to put on, dam oil everywhere lol, ohwell

 

the main prob is i can't b bothered getting so dirty for only a couple of hours and then it will get dark and i dont have enough lighting, so will prob just wait till i'm back from holidays, giving public transport a shot, so off to the bus now :s well tram then bus, or tram train bus, so many options hehe

[zedevan]

my dad was able to get a clutch for me today, and comparing the old clutch to the new about half the pressure plate spring things had gone, well weren't springing back out to their orginal position

 

whats the point of having the fly wheel machined? to make sure its balanced? my dad says its about as worth while as having disc rotors machined...but then...

[tattoo_ink]

hey mate, something i shoulda probably mentioned earlier.....you should chuck a new throwout bearing in it as well while your at it, as there would be nothing worse than getting all the work done and driving it for a few weeks then hear the bearing start to squeel its head off at the traffic lights! then you gota pull it all out again, just the sake of 20 or so bux !

 

as for the machining of the flywheel.....its the same sort of story, as itl have grooves & maybe fine cracks from"wear & tear" which makes a uneven "mating"(for the lack of a better word. lol !) suface for your new clutch plate, so that will shorten the life span a fair amount just bedding it in, and im sure you dont want to go through this lil mission to soon.

 

ohh now that im thinking in advance .......you might be able to get whichever machine shop you goto to press the throwout bearing on as well mate, and if you know anybody with a alignment tool to suit the datsun, or a front shaft out a gearbox, this will help heaps to ! good luck mate, keep us posted on how you go -chris.

[zedevan]

yeah that makes sense as to why get the flywheel machined, as its not like brake pads which are pretty cheap and easy to replace so it doesn't really matter that your wasting some of it to bed it in.

 

i dont think i know anyone with an alignment tool

 

i'm not going to get a chance to work on it tonight or tomorrow ofcourse, so the update might be awhile off lol, thanks for your help!

[Rod F]

Hey Evan, i've got an input shaft I used on mine last year for the same thing. Let me know if you need it (or a hand, i'm eastern suburbs as well)

[Zeddophile]

there is another trick for an aligning tool - a bit of broom handle with some electrical tape to bring it up to size. Works very well, although using a dead input shaft is much quicker!

 

Just curious, why would the throwout bearing need to be pressed on? when I put my 280 gearbox in, the throwout bearing was a complete assembly that just slides on, no pressing required? The brass spigot bush can be a pain to put in, but thats in the back of the crankshaft, and isn't too hard to fit with a soft faced hammer....