Clutch wear

[Nicky]

We are running a hydraulic clutch which was self designed and a pneumatic shifter setup(with ignition kill). This is the second set of clutch pack that we've worn out in a week's time of testing. Also our engine's heating up fast and a lot. There's a lot of white smoke from the breathers. If you guys have had any similar problems or have info on this, do help us out.

here's the picture to the worn clutch plate
htt ps: / / www . facebook. com/photo.ph p?fbid=10150157557948671&set=a.10150089424108671.270777.683708670&type=1&theater

Regards,
Nicky
Engine & DaQ
Ashwa Racing

[Nicky]

We are running a hydraulic clutch which was self designed and a pneumatic shifter setup(with ignition kill). This is the second set of clutch pack that we've worn out in a week's time of testing. Also our engine's heating up fast and a lot. There's a lot of white smoke from the breathers. If you guys have had any similar problems or have info on this, do help us out.

here's the picture to the worn clutch plate
htt ps: / / www . facebook. com/photo.ph p?fbid=10150157557948671&set=a.10150089424108671.270777.683708670&type=1&theater

Regards,
Nicky
Engine & DaQ
Ashwa Racing

[vikram.]

not able to see the photo..error,if engine heating fast means clutch not engaging engine running on no load condition,slip. u told clutch is self designed may be problem with that ..what all you designed ?..elaborate the problem

[Paul Achard]

Yeah, I don't know how your self-designed clutch operates, but if you don't have enough pressure on your clutch plates they could be slipping excessively. This might be related to your engine overheating since it must be revved higher to compensate for the clutch slippage, although the overheating problem might be unrelated...

[Wesley]

You may have too much pressure on your shift linkage from your slave cylinder. If you don't let the lever relax all the way, you won't get full pressure on your clutch. This problem makes itself worse, because as your clutch heats up, it slips more and more easily.

It could also be as Plooba said, and your clutch springs aren't heavy enough to hold your torque load. If you have stiffer springs for your clutch pack, install them. Just go in increments until you get the proper clamping force and can still disengage it.

I saw this one time when we had our hand clutch cable too tight. Heavy white smoke came from the breathers after a few accel runs, indicating we were overheating the oil, and the engine ran hot. I'm assuming this is a wet clutch pack with shared engine oil, if it's overheating the engine.

[Nicky]

We've designed a slave cylinder to actuate the clutch arm on our CBR600F4i. We checked on whether the arm is relaxed all the way and it is.

We changed the entire set of clutch plates and when we ran the car last night again, we had a bit white smoke coming out only when we dropped the clutch hard for accel runs. I've increased our ignition cut levels for our shifter to avoid any more wear. Although the car is drivable, the drivers complain that the engine doesn't seem to be as powerful as it was with the old clutch plates. Would installing stiffer springs ease the problem?

Also our idling is around 4500rpm. Would that cause the clutch to wear to such an extent while slowly easing off on the clutch?

Here's the link to the pictures:
Pictures (https://www.facebook.com/album.php?fbid=10150089424108671&id=683708670&aid=270777&l=582f4e7c9e )

Regards,
Nicky
Engine & DaQ
Ashwa Racing

[Boffin]

Do you have any data logging in order to see how much slipping is occurring (RPM Vs Wheel speed)

[manifold]

4500 rpm ,wow

[Nicky]

@Boffin: we use the Motec i2 pro for our datalogging. I've uploaded a screen shot of the instance when we drop the clutch to the time when the wheels started rotating. There's over 170ms of slip in the clutch not to mention the slip on the wheels. The speed sensor is on the sprocket. Let me know if you'd want me to mail the data log file to you.

Here's the picture of the data log I uploaded.
https://www.facebook.com/album...=245260&l=68952437b0 (https://www.facebook.com/album.php?fbid=459756278670&id=683708670&aid=245260&l=68952437b0)

@Manifold: yeah about that now. As an engine guy I'd love a low purring sound of 1300 but our drivers complain while our engine slumps between 2500-3800 and hence we avoid that region entirely.

Regards,
Nicky
Engine & DaQ
Ashwa Racing

[Boffin]

If you could email me the data file that would be great.

[AndrewUofL]

Louisville ran a f4I up until this year when we switched to a RR motor. We had a problem with idle a couple times where the idle would sit around 4500 instead of out 2000 target. The engine heats up very quick.

You could try changing the springs. It may help. I would check and recheck that your clutch is fully re-engaging because this will cause slippage and the symptoms you describe. Also, Make sure that the clutch is re-engaging as soon at you let off the clutch. If your slave cylinder is relaxing slowly, it may be fully re-engaging but allowing enough slip before it does so which may be causing your problems.

I would guess your engine oil temps are heating up a lot because of the high RPM's on idle and then it wouldn't take much clutch slippage to burn the oil.

[AndrewUofL]

Forgot to mention this but what kind of oil are you running. The wet clutches are kinda picky. I know I have heard of people burning out these clutches because of the wrong oil selection. When I first joined formula I had asked about getting some oil from the local parts store and I was told that we had put used "normal" motor oil instead of oil designed for the wet clutches and the car was almost undrivable due to clutch slippage.

[vikram.]

4500 is way too much for any motor,reduce it to 1500 2000 then try, btw which oil?..and as you told you designed the clutch then the springs also must be calculated of how much axial force is required..

[Xeilos]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by vikram.:
4500 is way too much for any motor,reduce it to 1500 2000 then try, </div></BLOCKQUOTE>

I will argue that 4500 is not way too much for any engine. I will provide a counter example of TU Graz from the 2010 competition. By calibrated ear, I guessed it to be 4000 or so, but someone from TU Graz can correct me if I am way out.

Our idle (last year) was stable at around 2300-2400 RPM and it seemed fine.

Vikram, I would suggest you do a complete re-check of ALL of your base assumptions. What principle decides that your idle needs to be 1000-1500? I issue a challenge on this one.

[AndrewUofL]

At 4500 RPM, you are creating more energy that needs to be dissipated as sound and heat. If you have a cooling system that can handle that then it is okay. With most systems (including the stock system on the motorcycle) 4500 is too much. If you design your car and size you cooling system accordingly, 4500 RPM idle is doable. I would bet that in this case that the idle is one of the main issues causing overheating.

[vikram.]

why you always go for a comparison of a fellow fsae team there are many more things in automobile world to see,what i am suggesting over here is ideal idle speed that suits best for any engine, first of all why to increse idle speed. a heavily tuned motor ideal idling speed is also 1500 to 2000 rpm not more than that(depending upon tuners requirement),what are you achieving with increase in your idle speed,useless heat production useless wear and tear, for 2 stroke tuned setup i might think once of keeping it at 2000 2200 because of thin power band limit, so that i can reach the power band quickly(that too depending on application)..i wont say you can't do that keep it 6000 but why.?

[Nicky]

@andrew: we're thinking of changing the u-cup seals to allow better motion on the slave cylinder. Also adding a higher preload on it.

Yup the engine oil's heating real fast. We last used castrol 4T 15w40. Might shift to ows or Mobil 1. Do teams run oil coolers for the F4i?

@vikram: i reiterate, we use the stock clutch but with a hydraulic actuator(which we designed)

@xelios: exactly my point, but T U Graz would have their own reasons to have such high idling. We're avoiding the lower rpms cause of problems with our exhaust tuning.

@Ben(Boffin): thanks for the feedback. Will keep you posted with the results. Thanks a ton again.

[vikram.]

@nicky problem with our exhaust tuning??
please elaborate..

[AndrewUofL]

@Nicky, The F4I had a stock oil cooler (that round block between the oil filter and block). I dont know much about it because I have never worked with one and we have never found the need to modify it.

I did a little research on this last night and found some people were having problems with the clutches failing on a brand new bike in about 2000 miles with light riding. They say that the clutch came adjusted wrong from the factory and was slipping. I have never worked with the motorcycle clutch but it doesn't seem like the adjustment doesnt have to be off by much at all to cause this. Just something to keep in mind.

I would doubt that the clutch slippage would be caused by the oil you have. We have used cheap (still motorcycle oil) and have had minimal problems in the past. We get a discount on the GN4 oil from the local honda shop so that is what we have been using reciently.

[Boffin]

To elaborate for some people, Nicky emailed me data from one of the problem sessions.
The clutch doesn't look like it is slipping excessively (RPM/speed), but there is a lot of slip down low (&gt;20) kph due to the 4500 idle.

But what we have been able to figure out is that they are not running any oil cooler. I've suggested this is the first thing to try to stop the problem.

[AndrewUofL]

Just curious but what is your definition of Excessive slip?

[Nicky]

@Andrew: We're using the stock oil cooler. When you mentioned oil cooler I was looking up on separate radiators for oil.
I've uploaded a picture of the slip Boffin was referring to. Its at the same link below.

@Boffin: I've uploaded the results from the recent dyno run. Have a look at the dip yourself.

Here's the link: http://www.facebook.com/media/...3708670&l=68952437b0 (http://www.facebook.com/media/set/fbx/?set=a.459756278670.245260.683708670&l=68952437b0)


Also, I was just curious to know if teams change clutch packs during the event. Say one for accel, autocross and skid pad, while another for endurance??

[vikram.]

see still you not getting the theme,at initial idling being high and your clutch being normal not able to catch up so slips and ya one more thing check the clutch basket and fix whatever is required...and you did'nt told me your low idling exhaust tuning problem..??

[Mbirt]

I'm with Vikram. No exhaust scavenging trough or antinode could cause enough "reversion" (gosh I hate that word...) to make a car not idle below 4500 rpm.

When I've had idles that liked to hang in the 3500-4000rpm range, richening the fuel map in my intended idle region, taking out some spark timing in that same region, and further richening the area slightly higher load and lower RPM (left and above) than the intended idle zone seemed to help.

[Boffin]

What's your lambda like through that range?

Are you tuning for a flat lambda or good power?

You can take timing off the peaks before and after the dip to flatten out torque so it's not noticeable any more.

[Nicky]

The idle doesnt stick at that rpm. We set it there to avoid the dip in torque and power that happens below 4000rpm. Our lambda reads .85 while heavy acceleration and .93 when cruising in that region. We tried getting the curve flat but couldnt do much. We tried tuning it for torque.

@vikram: we re-torqued the bolts on the clutch springs. Made no difference.

[vikram.]

its wont make,u told your motor wont idle at low rpm.
what do you think? u have motor in front of you,what assumptions can you make out of that?
you told exhaust problem?what are you talking about?elaborate the problem may be i can help.
there must be some problem that engine not idling properly..
(don't tell me you are using high lift cams and you had you port job,that condition i might think engine not idling low)

[AndrewUofL]

I was just talking to an old roommate and he has a 05 CBR 600rr about this problem. He confirmed what I had originally though and that is that the idle is too high which is causing excessive slipping. Also, the high idle is likely what is causing the high engine temps (which if high enough may be heating the oil/just not allowing the cooler to work).

Just curious but have you tried replacing the springs in the basket? My friend rebuilt his clutch receiently and said that the springs must be replaced when rebuilding the clutch and that your rebuild kit should have them in it. If you havent replaced the springs that could be your problem.

Something else I just though of. When you add oil, have you been checking the oil level with the engine running? The oil level should drop when you start the engine and then should be between the lines on the sight window. If the level is low you may be running the clutch too dry which would wear it our very quick.

Also, are you checking oil temps? I really dont know what they should be on these motors but if you have very high oil temps that is enough to degrade the oil, it may cause the clutch to burn out. Ive never experienced this but if nothing else works this could be something else to look into.

Sorry if I'm asking seemingly dumb questions but in my experience, problems like this usually ends up being something very simple. Ive spent countless hours trying to solve a simple problem because I overthought it.

Andrew

[Nicky]

We kind of figured out the reasons as to why we messed our clutch up... The following were the reasons:
1. High idles mixed with half clutching while turning at very low speeds.
Solution: get a proper track to test. We have just one straight where we keep testing for accel and turning around has to be slow else the car hits the pavement. We're prolly gonna reduce the idle for now, but at the event it's still 4k or atleast the engine guys find out why the engines slumping between 3-4k rpm.

2. The slave cylinder actuator not relaxing as fast.
Solution:replacing the u-cup seals to O-rings.

3. Ignition kills were quite less during shifting. Thereby loading the clutch and gearbox a lot. Thankfully we didn't screw our dogs in the last couple of runs.

4. Using a new(just run in) clutch pack for the event.

@Vikram: I never said that our engine doesn't idle at low rpms. I said earlier that we're avoiding that region cause of our power curves. I know that you're an exhaust guy. I really couldn't gather much feedback from my team to post here, but their working on some lengths and wave harmonic something...
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by vikram.:
...u have motor in front of you,what assumptions can you make out of that? </div></BLOCKQUOTE>
Am not quite sure by what kind of assumptions you do when you have an engine in front of you...

@Andrew: we did not replace the springs when we changed the plates, but did later. Ever since the breathers spewed smoke we've been monitoring the oil temperature and levels. The coolant temperature hit 113deg, we hadn't logged our oil temperature, it was 115deg when we stopped to retrieve data. Synthetic oil is said to degrade and break down at over 130deg, but guess localized heating in the clutch took care of that. The engine's been running smoother. I've also backed off on the ignition timing over the entire range for now as we're testing more for handling and setting the suspension up.

Thanks a lot guys. Got quite something to keep in mind.

[vikram.]

i can make full assumptions of what actually happening inside ,you were having a problem of clutch slipping that can be rectified if you had assumed checked and rectified,that's what it is all about..you dont have a sure shot answer always. its an engine mate

[vikram.]

[QUOTE]Originally posted by Nicky:
I said earlier that we're avoiding that region cause of our power curves


power curves???
elaborate