Driving with a heavy duty clutch
Discussion
I'd not call myself an advanced driver(then what am I doing with a heavy duty clutch? .. but let that go) and yet there seems no more appropriate place to ask this question.\
First, background:
I've had an organic, heavy duty clutch installed for a couple of months and today, in a traffic jam, to my dismay discovered the revs rising while the speed remained the same. I suspect that even this kind of clutch is not supposed to withstand the kind of driving I subjected the car to, however, even with my enthusiastic driving I tried to keep it smooth and heelntoe'd/doubleclutched religiously. So, I wonder if there is another possibility, that the fundamentals of my technique are flawed, for I am very much an amateur driver.
From the start I had trouble getting a proper feel for the clutch, it was the first heavy duty one I had used. It had an unusually late bite (now a lazy nibble..) and would grip with a jerk or smoothly in different situations seemingly without a logical progression from one to the other. At high RPMs it was an epiphany for me, never having used its like, but I could still never figure out if I were best to keep it smooth (worrying about too much slip), or to simply dump it. (worrying about the driveshaft)
My question then, is where did it all go wrong? (the time spent travelling at a 90degree angle, says the conscience, but the heart hopes there are ways to extend the life of the next clutch without cutting out all the fun)
Any suggestions are welcome, whether on the technical side or my technique.
First, background:
I've had an organic, heavy duty clutch installed for a couple of months and today, in a traffic jam, to my dismay discovered the revs rising while the speed remained the same. I suspect that even this kind of clutch is not supposed to withstand the kind of driving I subjected the car to, however, even with my enthusiastic driving I tried to keep it smooth and heelntoe'd/doubleclutched religiously. So, I wonder if there is another possibility, that the fundamentals of my technique are flawed, for I am very much an amateur driver.
From the start I had trouble getting a proper feel for the clutch, it was the first heavy duty one I had used. It had an unusually late bite (now a lazy nibble..) and would grip with a jerk or smoothly in different situations seemingly without a logical progression from one to the other. At high RPMs it was an epiphany for me, never having used its like, but I could still never figure out if I were best to keep it smooth (worrying about too much slip), or to simply dump it. (worrying about the driveshaft)
My question then, is where did it all go wrong? (the time spent travelling at a 90degree angle, says the conscience, but the heart hopes there are ways to extend the life of the next clutch without cutting out all the fun)
Any suggestions are welcome, whether on the technical side or my technique.
Edited by MM2200 on Thursday 14th August 14:51
What was heavy duty about it?
Some heavy duty clutches are just a stiffer backing plate on a standard friction plate - so they will transmit more torque but have the same energy absorption and wear charactistics. Others have a completely different design of friction plate with paddles instead of a circular plate - these offer more grip (higher torque) but much worse heat dissipation and wear characteristics.
Some heavy duty clutches are just a stiffer backing plate on a standard friction plate - so they will transmit more torque but have the same energy absorption and wear charactistics. Others have a completely different design of friction plate with paddles instead of a circular plate - these offer more grip (higher torque) but much worse heat dissipation and wear characteristics.
I assume from that there's nothing fundamentally wrong with the clutch assembly and it's suitable for street use. Biting right at the top implies that the clutch slave cylinder may not be positioned correctly for the clutch. If so, it might mean that the clutch is not being *fully* engaged (some load is remaining on the clutch release mechanism) which could allow the clutch to fret under load and wear out relatively quickly. It's also possible that with the biting point this high it's over straining the spring fingers which might bend or break them.
GreenV8S said:
I assume from that there's nothing fundamentally wrong with the clutch assembly and it's suitable for street use. Biting right at the top implies that the clutch slave cylinder may not be positioned correctly for the clutch. If so, it might mean that the clutch is not being *fully* engaged (some load is remaining on the clutch release mechanism) which could allow the clutch to fret under load and wear out relatively quickly. It's also possible that with the biting point this high it's over straining the spring fingers which might bend or break them.
I don't like the sounds of either..The bite is quite late, but not right at the very top, there is probably about 1/4th to 1/5th of the pedal travel remaining after it kicks in. Is there any other symptom I can identify which would evidence such an incorrect installation?
The previous clutch I had, which was a normal one and very very light, bit right near the floor. When I had that one replaced, the bite was about where this current clutch began. I can't say what the original clutch was like, for when I bought the car the clutch it had had almost expired. (it bit right at the top too, but really was badly worn)
When this clutch goes, what type of clutch would you recommend as replacement? I don't mind a rough ride, so long as I know there is not damage being done to the car. My main concern is durability. I may drive a bit crazily, but I don't take it to the track, it is purely a road vehicle.
RobCrezz said:
I have a higher rated organic clutch on my car, and it seems better than most clutches I have ever used. Not very heavy on the pedal and quite nice feel. Sorry cant be more help!
This sounds a similar type to mine. Mine certainly is better, the difference at high RPMs is where it is most noticable, but it was quite a lot heavier than what I was used to. Whereabouts does yours bite?
Kozy said:
What is an organic clutch? I have one one my car but never actually understood what it meant. Was it grown in a pesticide free field?
I'm not very knowledgable on the subject either, so this is the sum of what I do know: I'm given to understand that the organic material lining the clutch plate is a highly variable compromise between the normal clutch lining in everyday cars and the solid metal (or carbon or whatever else they use) of racing clutches. The organic is supposed to fall in somewhere between, depending on the specific use of the car.
edit: although it occurs to me I probably missed your point; the material itself I think is not hugely different from 'normal' clutches, except that its particular strain is tougher, or the way it is layered on is tougher.
Edited by MM2200 on Saturday 16th August 01:30
I had a clutch fitted to a car from these guys http://www.exedy.com.au/default.aspx
This is the heavy duty, organic clutch and was reccomended by other owners of the same car as me. The friction material itself was better than a standard clutch but the big difference was in the fingers of the pressure plate which provided extra clamping force. To be honest it felt a little heavier than a standard clutch but there was definately no 'On / Off' feeling about it and the pedal action / bite point did not change.
Even though the clutch is designed for road use I changed my driving to adapt to it...so in taffic I would wait for the cars in font to move off a good distance so I could fully engage drive and not be constantly using the clutch and jumping up and down on the pedal.
Dont forget that you should look at you clutch as a disposable saftey device that potects you engine and tansmission from harsh loads geneated by grip fom the tyres.....I would rather my clutch slip than stripping a gear or snapping a CV joint on a full bore start.
For a road car I would be looking to avoid anything like this:
They do not take well to slipping and have such a harsh take up that they are very hard to drive normally, you have to build the revs and just pop the clutch and lurch off down the road. They transmit all the load straight in to your transmission with no 'give' so a hard start is pretty cruel.
Ceramic and brass ones are even harsher and often wear the flywheel out quicker than the friction material.
This is the heavy duty, organic clutch and was reccomended by other owners of the same car as me. The friction material itself was better than a standard clutch but the big difference was in the fingers of the pressure plate which provided extra clamping force. To be honest it felt a little heavier than a standard clutch but there was definately no 'On / Off' feeling about it and the pedal action / bite point did not change.
Even though the clutch is designed for road use I changed my driving to adapt to it...so in taffic I would wait for the cars in font to move off a good distance so I could fully engage drive and not be constantly using the clutch and jumping up and down on the pedal.
Dont forget that you should look at you clutch as a disposable saftey device that potects you engine and tansmission from harsh loads geneated by grip fom the tyres.....I would rather my clutch slip than stripping a gear or snapping a CV joint on a full bore start.
For a road car I would be looking to avoid anything like this:
They do not take well to slipping and have such a harsh take up that they are very hard to drive normally, you have to build the revs and just pop the clutch and lurch off down the road. They transmit all the load straight in to your transmission with no 'give' so a hard start is pretty cruel.
Ceramic and brass ones are even harsher and often wear the flywheel out quicker than the friction material.
Edited by deviant on Saturday 16th August 02:09
I don't know specifically what an organic clutch is, but on reading the OP, I wondered if he had the latter of those two pictures. Some of the full on racing clutches aren't designed for slip.... The wheels do all that stuff, your only control is revs, and the clutch is on/off.
Are you sure you havn't just worn out the flywheel and/or clutch plate?
Are you sure you havn't just worn out the flywheel and/or clutch plate?
Edited by dilbert on Saturday 16th August 02:38
Deviant, I think the exact model is this kit:
I have adapted similiarly to driving in traffic, waiting for cars to move further away etc. Can you tell me how it feels for you shifting at higher speeds in higher gears? Can you get a perfectly smooth shift without slip?
The point about the clutch as a safety device is indeed my other main concern, I don't want to break anything by dumping it. I was considering a ceramic clutch for I read that they last a LOT longer, however it is just this issue of breaking bits that dissuades me.
Dilbert, I am gradually coming around to the idea that it simply isn't designed to handle the kind of crazy driving I get up to.
But here is a point that irritates me; I say crazy, but to me, its not crazy. Thats the label it gets when others have observed me or passengered in my car. (part of my passenger door has just been broken in one persons attempt to find something to hold on to :/) I feel very safe driving the way I do, primarily because I think very carefully about the potential success and failure of the what/when/where of what I do before I do it and concentrate on the details of the situation while I'm in it. Of more concern to me is mechanical failure, like a tyre blowout on the freeway, something I must simply come to terms with as possible, else I would be afraid to drive at all.
The result is that I see that I drive differently from most others on the road around me (and that does not mean breaking the law) and seem to put much more strain on the car. I guess I may be naive, but it disappoints me that the car does not hold up so well as I expect and hence I wonder if my driving technique is flawed, as opposed to merely excessively energetic and that I can change it to extend component life.
I have adapted similiarly to driving in traffic, waiting for cars to move further away etc. Can you tell me how it feels for you shifting at higher speeds in higher gears? Can you get a perfectly smooth shift without slip?
The point about the clutch as a safety device is indeed my other main concern, I don't want to break anything by dumping it. I was considering a ceramic clutch for I read that they last a LOT longer, however it is just this issue of breaking bits that dissuades me.
Dilbert, I am gradually coming around to the idea that it simply isn't designed to handle the kind of crazy driving I get up to.
But here is a point that irritates me; I say crazy, but to me, its not crazy. Thats the label it gets when others have observed me or passengered in my car. (part of my passenger door has just been broken in one persons attempt to find something to hold on to :/) I feel very safe driving the way I do, primarily because I think very carefully about the potential success and failure of the what/when/where of what I do before I do it and concentrate on the details of the situation while I'm in it. Of more concern to me is mechanical failure, like a tyre blowout on the freeway, something I must simply come to terms with as possible, else I would be afraid to drive at all.
The result is that I see that I drive differently from most others on the road around me (and that does not mean breaking the law) and seem to put much more strain on the car. I guess I may be naive, but it disappoints me that the car does not hold up so well as I expect and hence I wonder if my driving technique is flawed, as opposed to merely excessively energetic and that I can change it to extend component life.
Edited by MM2200 on Saturday 16th August 04:47
That definately looks to be an organic, heavy duty clutch.
The Exedy one I had lapped up all the abuse I could throw at it without slip though it did stink a few times
My application was a Mk1 MR2 with approx 200BHP and I have seen the same clutch used in applications up to 280BHP. Bear in mind a mid-engined car generates some massive grip on a hard start which was another reason I wanted the clutch to be a disposable link and not my CV joints!!
I think my exact technique in traffic was to build the revs to around 1800 - 2000RPM and be fairly agressive with the clutch...not 'popping' it per se but letting it out in one, quick move holding the revs constant until I was rolling. My car had lumpy cams and quite a peaky power delivery hence using higher revs to pull off otherwise it would bog down and chuck a s
t fit with me
Under normal driving conditions when I was not hurrying the gearchange I guess I just used it the same...change gear and come off the clutch fairly quickly aiming to not slip it.
When I was getting up it I tended to just dip the clutch going up the gears and on the way down I would heel and toe but again be aggressive coming off of the clutch.
Its very hard trying to really describe a driving technique, behind the wheel you just do it subconciously but as soon as you think about doing it you mess it up
I guess in all my driving I aimed NOT to slip it.
If your clutch is fairly new it might be worth checking out the other mechanics of the car....the crank seal may be leaking, a gearbox leak on to the friction material. When was the clutch fluid last bled (if its hydraulic) or the cable adjusted? It may be that with a heavy duty clutch and ageing seals in the master cylinder or slave cylinder a seal is weeping.
The Exedy one I had lapped up all the abuse I could throw at it without slip though it did stink a few times
My application was a Mk1 MR2 with approx 200BHP and I have seen the same clutch used in applications up to 280BHP. Bear in mind a mid-engined car generates some massive grip on a hard start which was another reason I wanted the clutch to be a disposable link and not my CV joints!!
I think my exact technique in traffic was to build the revs to around 1800 - 2000RPM and be fairly agressive with the clutch...not 'popping' it per se but letting it out in one, quick move holding the revs constant until I was rolling. My car had lumpy cams and quite a peaky power delivery hence using higher revs to pull off otherwise it would bog down and chuck a s
t fit with me Under normal driving conditions when I was not hurrying the gearchange I guess I just used it the same...change gear and come off the clutch fairly quickly aiming to not slip it.
When I was getting up it I tended to just dip the clutch going up the gears and on the way down I would heel and toe but again be aggressive coming off of the clutch.
Its very hard trying to really describe a driving technique, behind the wheel you just do it subconciously but as soon as you think about doing it you mess it up
I guess in all my driving I aimed NOT to slip it.
If your clutch is fairly new it might be worth checking out the other mechanics of the car....the crank seal may be leaking, a gearbox leak on to the friction material. When was the clutch fluid last bled (if its hydraulic) or the cable adjusted? It may be that with a heavy duty clutch and ageing seals in the master cylinder or slave cylinder a seal is weeping.
MM2200 said:
Deviant, I think the exact model is this kit:
I have adapted similiarly to driving in traffic, waiting for cars to move further away etc. Can you tell me how it feels for you shifting at higher speeds in higher gears? Can you get a perfectly smooth shift without slip?
The point about the clutch as a safety device is indeed my other main concern, I don't want to break anything by dumping it. I was considering a ceramic clutch for I read that they last a LOT longer, however it is just this issue of breaking bits that dissuades me.
Dilbert, I am gradually coming around to the idea that it simply isn't designed to handle the kind of crazy driving I get up to.
But here is a point that irritates me; I say crazy, but to me, its not crazy. Thats the label it gets when others have observed me or passengered in my car. (part of my passenger door has just been broken in one persons attempt to find something to hold on to :/) I feel very safe driving the way I do, primarily because I think very carefully about the potential success and failure of the what/when/where of what I do before I do it and concentrate on the details of the situation while I'm in it. Of more concern to me is mechanical failure, like a tyre blowout on the freeway, something I must simply come to terms with as possible, else I would be afraid to drive at all.
The result is that I see that I drive differently from most others on the road around me (and that does not mean breaking the law) and seem to put much more strain on the car. I guess I may be naive, but it disappoints me that the car does not hold up so well as I expect and hence I wonder if my driving technique is flawed, as opposed to merely excessively energetic and that I can change it to extend component life.
I have adapted similiarly to driving in traffic, waiting for cars to move further away etc. Can you tell me how it feels for you shifting at higher speeds in higher gears? Can you get a perfectly smooth shift without slip?
The point about the clutch as a safety device is indeed my other main concern, I don't want to break anything by dumping it. I was considering a ceramic clutch for I read that they last a LOT longer, however it is just this issue of breaking bits that dissuades me.
Dilbert, I am gradually coming around to the idea that it simply isn't designed to handle the kind of crazy driving I get up to.
But here is a point that irritates me; I say crazy, but to me, its not crazy. Thats the label it gets when others have observed me or passengered in my car. (part of my passenger door has just been broken in one persons attempt to find something to hold on to :/) I feel very safe driving the way I do, primarily because I think very carefully about the potential success and failure of the what/when/where of what I do before I do it and concentrate on the details of the situation while I'm in it. Of more concern to me is mechanical failure, like a tyre blowout on the freeway, something I must simply come to terms with as possible, else I would be afraid to drive at all.
The result is that I see that I drive differently from most others on the road around me (and that does not mean breaking the law) and seem to put much more strain on the car. I guess I may be naive, but it disappoints me that the car does not hold up so well as I expect and hence I wonder if my driving technique is flawed, as opposed to merely excessively energetic and that I can change it to extend component life.
Edited by MM2200 on Saturday 16th August 04:47
Are you sure they didn't break the door trying to get out! 
deviant said:
That definately looks to be an organic, heavy duty clutch.
The Exedy one I had lapped up all the abuse I could throw at it without slip though it did stink a few times
My application was a Mk1 MR2 with approx 200BHP and I have seen the same clutch used in applications up to 280BHP. Bear in mind a mid-engined car generates some massive grip on a hard start which was another reason I wanted the clutch to be a disposable link and not my CV joints!!
I think my exact technique in traffic was to build the revs to around 1800 - 2000RPM and be fairly agressive with the clutch...not 'popping' it per se but letting it out in one, quick move holding the revs constant until I was rolling. My car had lumpy cams and quite a peaky power delivery hence using higher revs to pull off otherwise it would bog down and chuck a st fit with me
Under normal driving conditions when I was not hurrying the gearchange I guess I just used it the same...change gear and come off the clutch fairly quickly aiming to not slip it.
When I was getting up it I tended to just dip the clutch going up the gears and on the way down I would heel and toe but again be aggressive coming off of the clutch.
Its very hard trying to really describe a driving technique, behind the wheel you just do it subconciously but as soon as you think about doing it you mess it up
I guess in all my driving I aimed NOT to slip it.
If your clutch is fairly new it might be worth checking out the other mechanics of the car....the crank seal may be leaking, a gearbox leak on to the friction material. When was the clutch fluid last bled (if its hydraulic) or the cable adjusted? It may be that with a heavy duty clutch and ageing seals in the master cylinder or slave cylinder a seal is weeping.
Sigh.. It seems likely then that I probably was too harsh on it too soon and glazed it over. I'll ask my mechanics to check for leaks or any other problems nonetheless.The Exedy one I had lapped up all the abuse I could throw at it without slip though it did stink a few times
My application was a Mk1 MR2 with approx 200BHP and I have seen the same clutch used in applications up to 280BHP. Bear in mind a mid-engined car generates some massive grip on a hard start which was another reason I wanted the clutch to be a disposable link and not my CV joints!!
I think my exact technique in traffic was to build the revs to around 1800 - 2000RPM and be fairly agressive with the clutch...not 'popping' it per se but letting it out in one, quick move holding the revs constant until I was rolling. My car had lumpy cams and quite a peaky power delivery hence using higher revs to pull off otherwise it would bog down and chuck a s
t fit with me Under normal driving conditions when I was not hurrying the gearchange I guess I just used it the same...change gear and come off the clutch fairly quickly aiming to not slip it.
When I was getting up it I tended to just dip the clutch going up the gears and on the way down I would heel and toe but again be aggressive coming off of the clutch.
Its very hard trying to really describe a driving technique, behind the wheel you just do it subconciously but as soon as you think about doing it you mess it up
I guess in all my driving I aimed NOT to slip it.
If your clutch is fairly new it might be worth checking out the other mechanics of the car....the crank seal may be leaking, a gearbox leak on to the friction material. When was the clutch fluid last bled (if its hydraulic) or the cable adjusted? It may be that with a heavy duty clutch and ageing seals in the master cylinder or slave cylinder a seal is weeping.
From what you're saying about your technique, I can't see much wrong with mine, ah well. I appreciate your input, I'll take it in soon and find out for sure which was the problem.
Thanks again all.
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