Car jerking forward = clutch going out?

[Matej]

Tonight I burned my clutch a few times, and about ten minutes later, on my way home, the car started jerking forward while driving.

It feels as if the clutch grabs randomly, I'm guessing there are bald spots on it. I would be giving it gas and barely moving for a few seconds, and suddenly the car would start out forward for a little while, then lose power again. This cycle kept repeating until I made it home, luckily. I even got pulled over, but the officer saw I had my hazard signals on and was nice about it.

Can anyone confirm if this indeed means the clutch is going out? Or if this is a symptom of something else entirely, please let me know. I just want to be sure, before I waste my money on a clutch and find out that's not the problem.

Speaking of clutches, what would Zilvia recommend? It's just an N/A KA, so I don't need anything crazy, but I would like a clutch that's known to usually last a long time, since I really really dislike replacing the clutch, not fond of it at all, haha.

Thank you for any help!

[slider2828]

Yup that is it... F...ed up clutch.... It could be you have hot spots on your flywheel too as well causign the issue...

Exedy Stage 2 3-puck street clutch..... The 3 puck race clutch is thinner but grabs harder but lasts 2/3 less than the street clutch....

Stage 2 is awesome, smooth and light and grabs.

Might wanna look for a flywheel while you are at it.... Go fidanza, or resurface if you can the OEM...

www.nopionline.com or nopi's store... they usually have good deals.

[Matej]

Ok thank you, just wanted to be sure. Would +rep you for sure. :)

And yes, I plan to use this as an excuse to also buy an aluminum flywheel, if money allows.

[drifterken]

damm sounds like u fu*ked that Sh*t up... lol..

[Matej]

Bringing this thread back.

So far, out of the things I have had to do to my car, I have despised a clutch swap the most. That is why I have been so unenthusiastic about doing another one. However, after almost three months of procrastination, I have finally decided to get started on this.

Well, upon taking the clutch out, this is what I see.

http://www.matejblahut.com/blog/2009/05/clutch02a.jpg

That looks like it still has plenty of life left, correct?
My first time, the clutch was shattered to pieces with all the material on the bottom of the bellhousing. This one is in better shape than the used one I was about to replace it with.

Could these things; or should I say the lack of them; be the cause?

http://www.matejblahut.com/blog/2009/05/clutchbrackets01.jpg

They are the brackets that connect the bottom of the transmission to the motor.
I took them off last year when I had to swap the oil pan. I left them off for awesome weight reduction, knowing it might not be a good idea, but I live on the edge.

Well, after hitting enough things with the bellhousing, I am guessing the bottom of the transmission got slightly pushed back, as I did notice a gap between the bottom of the bellhousing and the motor, even prior to my car being rendered undrivable.

Does that sound reasonable, could it be the cause?
Have I seriously not driven my car for three months and just did pretty much all the work of a clutch swap only because of this?

Haha, oh geez.

[Bigsyke]

It didnt sound like a clutch issue in the 1st place, If anything inputshaft or a bearing. was the jerking foward like a fast pulse? the bottom gussets are pretty important IMO, it could put undue stress on the input shaft of the bellhousing warps.... thats if its true you had a gap on the lower part of the bellhousing.

[S14DB]

Lets see the PP and flywheel face. The PP looks glazed in the picture but hard to tell.

[slider2828]

Yes the PP looks glazed, groozed and burnt.... but better pictue please.

[Matej]

It didnt sound like a clutch issue in the 1st place, If anything inputshaft or a bearing. was the jerking foward like a fast pulse?
If it was an input shaft or a bearing, wouldn't the jerking be quick and at regular intervals? Just curious, I do not know much about troubleshooting the drivetrain/motor.
This felt random. For a little while the car would pull normally, and then it would suddenly feel as if the clutch was slipping badly, and the process would repeat.

I'm just hoping the motor isn't about to go out. Sadly I can't rule that out at probably almost 150K miles.

What are the symptoms of a glazed flywheel?
I will take a better picture of it.

[Matej]

Here is a closeup picture of the pressure plate that was on the car. Is it bad?

http://www.matejblahut.com/blog/2009/05/pressureplate02a.jpg

I also have this pressure laying around. Is it any better/usable?

http://www.matejblahut.com/blog/2009/05/pressureplate03a.jpg

[GSXRJJordan]

Any uneven black marks are signs of overheating... sounds like a clutch issue to me, but your bellhousing problem is kinda serious also.

[slider2828]

Both PP's are done for.... I think you can get em resurfaced, but in general the molecular structure of it is already done for.

[Matej]

So the pressure plate could cause the clutch to feel like it is is slipping, even when in gear?

How does this happen? I have never heard of a pressure plate going bad before the clutch. Hopefully I can prevent it from happening again.

[slider2828]

If you have too much power or torque, the pressure plate is the thing that clamps down the clutch plate to the flywheel. If it can't hold the power that the engine is outputting, the clutch plate will spin and cause hot spots on BOTH the PP and the flywheel. Either way when it doesn't clamp down correctly, either alignment of the clutch plate or insufficient pressure from the plate, it will spin and cause hot spots.

You will need to also take a picture of the flywheel, as I think that thing is scorched as well. This phenomenon also happens to brake rotors as they can get overheated and surface glazing can occur and bite performance is reduced.

[slider2828]

O when you burn your clutch, basically that smell is the burning of the friction material to the plate. Its common knowledge and I have heard of this before. During install, was the PP new and was the flywheel resurfaced, if so was glazing checked during the clutch job. Crappy job = crappy clutch

[MrChow]

So the pressure plate could cause the clutch to feel like it is is slipping, even when in gear?

How does this happen? I have never heard of a pressure plate going bad before the clutch. Hopefully I can prevent it from happening again.
I haven't seen a PP like that for a while.

My PP is going bad... Not like that. It's just getting tired of living because it's still the stock clutch with 185k on it =o But my doesn't slip when it's in gear. I just have a rough time on hill and shifting at low rpms. I have to drop the clutch in sometimes to get it going. But my clutch doesn't slip...

I have a ACT clutch in my bedroom when my clutch goes. If ever does... :hahano:

[xs240]

can someone explain this jerking issue and what bearing and what input shaft are we speaking of... i seem to be having this sort of issue.. when starting from parking lot... if ig ive little gas car goes back and forth jerking... solid engine and tranny mounts... but its anoying as hell...

[slider2828]

I think they are referring to if the tranny is not bolt in correctly, the input shaft of the tranny will try to pull apart from the motor

[GSXRJJordan]

can someone explain this jerking issue and what bearing and what input shaft are we speaking of... i seem to be having this sort of issue.. when starting from parking lot... if ig ive little gas car goes back and forth jerking... solid engine and tranny mounts... but its anoying as hell...

That's different from what they're talking about... You're describing 'drivetrain lash', which is common at low rpm, as the engine spins the drivetrain, and the drivetrain fights back - because you have solid mounts, that lash goes right to the car. The 'discomfort' you feel is the reason solid mounts suck... Live and learn.

I agree that matej needs to resurface. Why not get a new clutch that'll hold up to that abuse? Full-face organic disc is for homos and lames.

[Matej]

It's an n/a KA haha.

I also have an opportunity to buy this Fidanza aluminum flywheel for 140$. Apparently it only has a couple miles on it, but those couple miles were put on during 10 dyno pulls.

Not sure if it's a good deal or not.

http://i181.photobucket.com/albums/x222/smracing1/fly003.jpg

[landins13]

looks fine to me, your original pp and flywheel looked fried, and it seams the issue you were having is very similar to clutch chatter yours was just 10 times worse

[slider2828]

Lol.... Fidanza buy it, and change the face of it which you can get from fidanza.....

[Matej]

Thanks, if it is still for sale I will buy it.

I want to reduce as much rotating mass as possible. In my opinion this also has a lot to do with the fact that I have an n/a KA with heavy wheels and a welded diff. Whenever I pulled into/out of the driveway at full lock I would have to rev really high to even move. I am also going to run more negative camber in the rear for less grip, haha.

[xs240]

^That is retarded

[nrmskate]

So. Your trying to say yours does this?

YouTube - KA24E 240sx Jerking (http://www.youtube.com/watch?v=X3ELh4GyK2E)

[slider2828]

^^ That just straight looks like a crappy driver hahaha.....

[xs240]

So. Your trying to say yours does this?

YouTube - KA24E 240sx Jerking (http://www.youtube.com/watch?v=X3ELh4GyK2E)

yeaaaaa ive had that problem!

So it's MAF? Mine would stay high idle too..., sometimes this would happen... even if im gentle with throttle... even at high revs on highway it jerks in rpms a few hundred rpms back and forth if i press the pedal or let go gently

[thatdrifterguy]

to the OP. did your car make a loud winding noise too whenever it jerked forward cuz thats what mines doing too and i couldnt find anyone with a similar problem.

[ruudbwoy]

it really sounds like it was the brackets you took off. was your engine revving while it slowed down? did it the rpm spike or drop? if your pp wasnt makin full contact ur rpm would spike. i was going to say i had a problem with my throtle position sensor that made my car car lose power and go like there was no problem kinda like that. but clutch pics and mounts not being on most likely caused it.