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Old 25th August 2010, 16:32   #16
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@bblost: Clutch contamination in old vehicles which are used off tarmac especially under water, harmonic imbalances especially in slightly high revving older motors with asbestos based clutch plates, pressure plate clamping force deterioration etc etc etc so many factors mate, dont know where to start and where it will end!!! The same clutch can last 1km or 1lac km, now that is something I have literally experienced first hand hence my deliberation mate....
Could you throw some more light on harmonic imbalances in clutch assemblies? A direct co-relation with pedal effort and pedal travel will be really useful. Are you considering constant pressure or constant wear in your calculations?

Spike
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Old 25th August 2010, 16:37   #17
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Guys - getting very OT here. One question - "Can/should we half clutch any point of time". Answer - "A Big NO" -- All other posts can get into a seperate thread for 'All about a Clutch'.
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Old 25th August 2010, 17:05   #18
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Did I ever say we are using 1955's clutch today? The technology has definitely gotten better but that wouldnt compensate for grave driver error right or mechanical failures due to worn out+tolerance altering abuses right? If you dont believe so, give me your jeep, I will bust your clutch in 15mins flat, wana take a bet?
That's why we believe in maintenance and as much as possible, replacing the worn out parts. And if you are talking about wear and tear in offroad situations, trust me these jeeps were designed keeping that in mind. Right from world war days. That's what i have understood from knwoledgable people in jeep fraternity.

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I am speaking about a PERFORMANCE clutch. Performance clutches have tolerances set way beyond street and mild off the road. Simply, they can take atleast 25 and max of 200%+ additional load.
Ok but as far as availability for our offroad vehicles (esp ol WW machines) are concerned, they are not available. So what's the point here? Of raving about technology, tolerance etc of these performance plates.

Dude i have seen enough of those in my times, but unfortunately it doesn't make sense in this 4x4 discussion. The moment you put them into a jeep with bad tolerance or add lil bit of water, they will go bust. Now you wanna take a bet, then i have one for you. Without even moving the vehicle from your parking lot, ill fry those plates off your trophy winning car, 2 launches and some liquids supplements inside the peep hole lol.

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Dont patronize me dude. NO clutch can take abuse without any inherent deterioration, your definition/degree of abuse might vary from mine. Its not about a Jeep or peep in this case. God, Im running out of words, give me better vocabulary . I cant believe you smashing the dead horse open even after reading BD sirs last post, which is sooo conclusive!!!
Now why would i patronize you?

Point that we were discussing is:

- Offroading we need to avoid half clutch, atleast be open to the idea that we need to re-learn and it aint difficult for humans, as far as i know.

- 4x4 M&M clutch plates are quite durable. They work well in difficult conditions, with a good amount of tolerance for abuse.

- Performance plates on the other hand are for specific usage, where they can take great amount of power. They need perfect setting and tolerance from the other end, otherwise they will perform like a tractor.

BD was very clear in his message, the plates are tough and will last long. As long as you use them properly. The last bit you are trying to play around with, saying it will not last with clutch slip.

This is a relative statement, so understand that they might not last the whole 3.5 Lakh km life, that they are designed for BUT its anybody's guess to figure out, it might still last longer than a weaker clutch designed for a gypsy.

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I wouldnt have tried so hard if I hadnt cared. Lets be open, civil, scientific and mature, enlightment is just around the corner.
But I would have replied even if it was hard, coz i would like to understand the truth and not some half baked research. This is not the first time, last time i saw you debating in similar fashion (with your internet info), IIRC with Tejas. Once in a while its good entertainment, but trying to drill irrelevant info to prove your case might not be taken in the right spirits. That's all, nothing personal here.

I know jeep's or peep's are ancient technology, i would still hop on a gypsy if i had to attend another AKC BUT comm'on dont say that they are flimsy or cant take abuse. They can and definitely will take more compared to other modern products out there, atleast thats one thing they are good at.

PS: you have got good research skills, excellent language skills and a pretty ok engineering mind set. Please use it in a more neutral fashion and it will benefit you and the whole community of 4x4's. This is my personal observation as a member of this community, if i have offended you in anyway, i would like to make it clear that was not the intention. But then you were also very pushy with your view points.

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Originally Posted by svsantosh View Post
Guys - getting very OT here. One question - "Can/should we half clutch any point of time". Answer - "A Big NO" -- All other posts can get into a seperate thread for 'All about a Clutch'.
As far as my understanding is, unless the situation is so grave that you cant keep the engine turning without clutch, DO NOT use half clutch. If you are stuck, its better to get help, towed out instead of using half clutch for that extra oomph.

Last edited by Eddy : 25th August 2010 at 21:29. Reason: Deleting off topic content
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Old 25th August 2010, 17:25   #19
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Could you throw some more light on harmonic imbalances in clutch assemblies? A direct co-relation with pedal effort and pedal travel will be really useful. Are you considering constant pressure or constant wear in your calculations?

Spike
I guess I am forced to take this thread completely OT now, hehe but excellent topic for discussion. Takes me back to 2006, when we were rebuilding a car at the tuner shop where I used to get my car tuned. I guess this incident was just before some mumbai event if Im not wrong. Well, we folks took the clutch, diaphragm type pressure plate, fly wheel, pistons, connecting rods, crank etc to a machining shop. The idea was to reduce as much weight as much as possible and balance it to as high a decimal as possible.
Note: we did not have access to high tech equipments or worksman but that didnt deter us in our quest to scavenge power by reducing weight of internal components, imbalances and frictional losses (if possible).

We had a lot of theories in our head, you might laugh but we were exploring power gains by reducing frictional losses due to over lubrication hence wanted to reduce surface area of wet components. HAHA! I know it sound crazy but yes we had that in mind, we learnt early why race cars used crank scrapers blah blah!!!

Now, after hours of machining, making chucks to fit the components tightly etc etc we realised that as the weight on components reduced the chatter was getting more violent. We knew our worksmen werent too equipped to explain that the balancing was getting more and more difficult. The ongoing changes in mandrels was getting more and more difficult and time consuming.

Never the less, we tried going as far as the cheap machines allowed is in terms of balancing. We were happy by the look and feel of newer lighter glazing components. Soon we returned to the work shop and started putting it all together and completed it. We were excited about the first crank, the crank happened, the car started and we immediately knew we had messed something big time. Basically, the whole car was shuddering. Inputs at the ECU looked fine- Ignition timing, AFR, Fueling etc. A spin on the road and the matters got worser our performance clutch started smelling even without gunning the car. The vibrations were getting intenser by the moment, we decided to bring back the car to the tuner shop and assess the situation. We abandoned the day to come back early next morning. We opened the whole assembly, saw the flywheel was mildly bent, the clutch had uneven wear, the whole deal was in mess. Here we started to research..............and learnt so many things I cant even explain!!!

Coming back to your preload and post load chatter, you must be aware harmonic imbalance when subjected to varying loads, the decomposition is exponential coz one leads to another and another gets transfered to next in contact component. Well, when in full load, say when the clutch is engaged the chatter values and different from when it is not. The question is does it matter when the objective is to realiaze how its affecting clutch plate deterioration resulting in underclamping/slipping? Yes it does. Coz the harmonic imbalance at each seperable component will multiply and take incorrect movements (plus bouncing shock waves)......end result is clutch plate bouncing off the flywheel and not all 4 pistons are in harmony= vibrations, deterioration of components.

We did not have the aid of using high tech equipments to check imbalances but knew that the only way to get the car rolling is by relooking at all that we had done. We struck sheer luck, one of our customers manufactured parts for the aviation industry. We rang his bell, took to his factory, got all the parts rebalanced to some 0.00x decimals, came back, fitted everything together again and we had a ultra smooth, super fast car whose clutch never gave haath till it underwent premature replacement for another event.

Man Ive been sitting in the office doing only this all day long, I will be back only after Im done with very imp work. Hope the above adds some value to our OT discussion. Mods, pardon me for the long story...couldnt help explaining. Please delete the post if found unworthy of its existence.
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Old 25th August 2010, 17:41   #20
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Originally Posted by The Wolf View Post
Please delete the post if found unworthy of its existence.
Post is good, coz it explains the basic idea behind harmonic balance thingy. Where we will brick wall is at the implementation, since i don't think we have access to any such facilities for our jeeps.

Question to BD/Spike: Will this harmonics thingy affect that much in our old world vehicle's? Unless its way out of tolerance levels?
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Old 25th August 2010, 20:06   #21
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Hey guys [w.r.t post #144 & 145].

Balancing the parts leave a BIG question unanswered - Do you do dynamic balancing? What RPM do you decide as the base RPM for balancing and what is the range?

Sorry for OT! Maybe this can be a separate thread.

One generally balances the rotating parts for a certain RPM to achieve lesser loads on the running parts!

In other words, A Chuck is Balanced in a Lathe for a desired RPM to ensure the spindle bearings have a longer, better life, in comparison to a unbalanced chuck!

This in turn would affect the Spindle Drives and Motor bearings too, if it is a CNC machine!
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Old 25th August 2010, 21:12   #22
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Originally Posted by The Wolf View Post
I guess I am forced to take this thread completely OT now, hehe but excellent topic for discussion. Takes me back to 2006___
Your views on Harmonic imbalance as referred here is a bit misleading. Imbalance due to rotating parts is due to masses rotating in one or more than one plane, these are centrifugal forces which need to be balanced and hence referred as Dynamic balancing. Balancing of a crank in a slider crank mechanism is the simplest automotive example. Although, there are primary and secondary forces, it is the primary force which creates more havoc in terms of vibration excitation.

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Originally Posted by The Wolf View Post
Now, after hours of machining, making chucks to fit the components tightly etc etc we realised that as the weight on components reduced the chatter was getting more violent. We knew our worksmen werent too equipped to explain that the balancing was getting more and more difficult. The ongoing changes in mandrels was getting more and more difficult and time consuming.
No matter how much you machine, achieve the tightest of surface roughness values,surface finish, if the rotating mass is not "true" you will still have those vibrations.
Why did you make chucks? Rotating circular objects can be easily clamped through a 3 jaw magnetic chuck :-)


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Originally Posted by The Wolf View Post
Coming back to your preload and post load chatter, you must be aware harmonic imbalance when subjected to varying loads, the decomposition is exponential coz one leads to another and another gets transfered to next in contact component.Coz the harmonic imbalance at each seperable component will multiply and take incorrect movements (plus bouncing shock waves)......end result is clutch plate bouncing off the flywheel and not all 4 pistons are in harmony= vibrations, deterioration of components.
Mate, the clamping load of a clutch changes according to its condition (constant wear or constant pressure). I presume, you are not aware of these characteristics that go in while designing a clutch. With a change in clamping load your freeplay and pedal effort changes thereby affecting pedal feel->pedal behavior->gear shift characteristics. The pedal travel and pedal effort is manipulated such that it lies within ergonomic limits. Why should harmonic imbalance resulting in a clutch assembly follow a forced excitation?

Your analogy of a clutch (harmonic imbalance) to a set of four out of sync pistons is incorrect, the imbalance of pistons is due to rotating as well as translatory forces whereas for clutches it is only rotational imbalance. Until today, I had never heard about generation of shock waves in clutch assemblies, good topic for a dissertation :-P.

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Originally Posted by The Wolf View Post
We struck sheer luck, one of our customers manufactured parts for the aviation industry. We rang his bell, took to his factory, got all the parts rebalanced to some 0.00x decimals, came back, fitted everything together again and we had a ultra smooth, super fast car whose clutch never gave haath till it underwent premature replacement for another event.
Yes, this is possible as most aircraft applications are very high RPMs unlike automotive application, wherein the slightest of imbalance could lead to catastrophic results. Some turbine blades spin at several lakh RPMs.


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Originally Posted by Jaggu View Post
Question to BD/Spike: Will this harmonics thingy affect that much in our old world vehicle's? Unless its way out of tolerance levels?
NO, Jaggu bhai, if the tolerances are way beyond limits there will be marginal vibrations, but not such vehement vibrations.

Spike

Mods- Please move to appropriate section if required.

Last edited by SPIKE ARRESTOR : 25th August 2010 at 21:25. Reason: add info
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Old 25th August 2010, 23:37   #23
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Hey Spike, thank you for the specific definitions put to my experience straight out of dissertations and explicit details, guess you do this for a living...atleast you sound like you do. Well, in the below case my knowledge was purely experience based than professor/thesis based purely to quench my inquisitiveness and curiosity to understand mechanicals better and practically come out with quicker, more reliable cars. Definitely not to impress on lookers!!!

Well, as I come from electronics back ground and run a training organization,lol, my detailing is only as explicit as my eye-in-the-machine shop allows me and how much is required to get my car going as well as it can, but one point clear, I understand the points you made pretty well and wouldnt disallow myself in letting you know that a few bits below is pure academic and may not be to relative to the original discussion. I appreciate your deliberation and from academic stand point Id like to understand what you mean by "Although, there are primary and secondary forces, it is the primary force which creates more havoc in terms of vibration excitation." Do you mean the centrifugal imbalance due to material inconsistency or is there anything about resonance here? Primary and secondary is taught in the college not in work shops so further clarity would be better appreciated.

Also your sentence "Your analogy of a clutch (harmonic imbalance) to a set of four out of sync pistons is incorrect", well, Id like to understand if I have ever said these two things are same????? I just said that the imbalance within both these was the outcome of the machine shop execution, that something we felt but didnt understand when we started the car.

Well lastly, if you havent heard of the shock waves created due to sudden clamp, release or any sudden start stop of several moving objects at one time, well why dont you give me a call and lets get to the roots of resonance shock wave theory, there may be a thing or two unknowns we could share, in all honesty. I am not going to pop a "uncontrollable laughter" smiley in reply just coz Id like to discuss this and I dont wana make you feel Im condemning your below posts. Also I feel a serious lack of specific terms to explain my understanding as what I learnt is not out of college books and what I learnt out of college books is not something I remember today even if that should revolve around PCBs, processors, EMg fields or tuning forks...haha!!!

Mods: how about creating a seperate thread to discuss this from here?

p.s: I dont think I can login for the next 3-4days cos of a quick travel tomorrow and then the chikmagalur OTR. Put in your comments, I will reply back on monday. You can call me though

Last edited by khan_sultan : 26th August 2010 at 10:20. Reason: Edited to remove personal references. Please keep it clean -- LAST WARNING.
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Old 26th August 2010, 01:11   #24
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Wow so much to learn from you spikee, just had a quick browse from phone for now. But let's keep it online for the benefit of the community or please make a recording of the conversation and post
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Old 26th August 2010, 02:23   #25
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Originally Posted by SPIKE ARRESTOR View Post
Could you throw some more light on harmonic imbalances in clutch assemblies? A direct co-relation with pedal effort and pedal travel will be really useful. Are you considering constant pressure or constant wear in your calculations?

Spike
Read the ol' machine design book.. did you ??
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Old 26th August 2010, 09:22   #26
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Read the ol' machine design book.. did you ??
Does he have a choice in the matter? Considering he works for Mahindra R&D....

BTW, the topic has become too technical for me. I don't remember Fast Fourier Transforms anymore, never got to use it after college. There goes my chance of understanding this harmonic imbalance business.

Last edited by Samurai : 26th August 2010 at 10:01.
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Old 26th August 2010, 10:12   #27
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Default Flywheel

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, saw the flywheel was mildly bent, the clutch had uneven wear, the whole deal was in mess. Here we started to research..............and learnt so many things I cant even explain!!!
Hi Wolf,

I think you messed up balancing the Flywheel, hence so much trouble.

Regards,

Arka
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Old 26th August 2010, 11:30   #28
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Hi Wolf,

I think you messed up balancing the Flywheel, hence so much trouble.

Regards,

Arka

probably machined only on one side.
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Old 26th August 2010, 12:01   #29
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Post Lets have a healthy discussion

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Hey Spike, thank you for the specific definitions put to my experience straight out of dissertations and explicit details, guess you do this for a living...atleast you sound like you do. Well, in the below case my knowledge was purely experience based than professor/thesis based purely to quench my inquisitiveness and curiosity to understand mechanicals better and practically come out with quicker, more reliable cars. Definitely not to impress on lookers!!!

Hi, my intention of asking you about harmonic imbalance was to ascertain how you reached the conclusion, it had nothing to malign or question your credentials. My earlier posts were straight out of mind and not google, wikipedia stuff as interpreted by you. I am not a professor, nor have I done thesis on the subject. Moreover, I have no intentions on seeking "on lookers", forum members who have met or interacted with me know who I am . It seems you pay a lot of attention to these stuffs.

I appreciate your deliberation and from academic stand point Id like to understand what you mean by "Although, there are primary and secondary forces, it is the primary force which creates more havoc in terms of vibration excitation." Do you mean the centrifugal imbalance due to material inconsistency or is there anything about resonance here? Primary and secondary is taught in the college not in work shops so further clarity would be better appreciated.

I meant centrifugal imbalance in rotating systems as clutch was being discussed here. I can explain about these imbalancing forces in depth provided you have a genuine interest, if banter or leg pulling is intended, I will stay away. Yes, I agree primary and secondary are not taught in workshops but the basis for every experiment is a theory which must be first understood, and then further explored. At-least, this is what my teachers taught. A high rise building with a weak foundation is useless.

A workshop operator may be very skilled but seldom does he know the reason for providing a 118 degree cone in a drill bit, lets not get into this discussion here. :-)

Also your sentence "Your analogy of a clutch (harmonic imbalance) to a set of four out of sync pistons is incorrect", well, Id like to understand if I have ever said these two things are same????? I just said that the imbalance within both these was the outcome of the machine shop execution, that something we felt but didnt understand when we started the car.

Well, I said the comparison isn't correct. What machine shop execution are you talking of here? Is it flywheel run-out (facing)?

Well lastly, if you havent heard of the shock waves created due to sudden clamp, release or any sudden start stop of several moving objects at one time, well why dont you give me a call and lets get to the roots of resonance shock wave theory, there may be a thing or two unknowns we could share, in all honesty. I am not going to pop a "uncontrollable laughter" smiley in reply just coz Id like to discuss this and I dont wana make you feel Im condemning your below posts.

This is something I would really like to listen from you. I had heard of shock waves in jet streams (very high mach speeds) never heard of shock waves in clutch assemblies.
My reply is in bold above ^^
@The wolf, my posts reflect what I am. Luckily, I get to practice things what I learned during my college days. I am here to learn (as well as share)those extra things which my academics could/would never offer, this is the single reason I'm in T-BHP, definitely not to impress on lookers.

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Wow so much to learn from you spikee, just had a quick browse from phone for now. But let's keep it online for the benefit of the community or please make a recording of the conversation and post
Will post more about clutches if there is a genuine interest.

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Read the ol' machine design book.. did you ??
Yeah, I did, during my college days. Please read books from Timoshenko & Young, Thomas Shigley you will also learn a thing or too, very good books.

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Does he have a choice in the matter? Considering he works for Mahindra R&D....
Now you have my pants down LOL!

Spike

Last edited by Rehaan : 3rd September 2010 at 12:10. Reason: 108 >> 118
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Old 26th August 2010, 12:22   #30
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Default Types of Pressure Plate/Cover Assy.

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Will post more about clutches if there is a genuine interest.Spike
Hi Spike,

Please can you tell us more about the Type of Cover Assy's used in M&M Vehicles.

I know of Two types the Diaphragm & Finger Type (Dana/Petrol CJ3B) vs Borg & Beck /MM540/FC Van).

Which is more suited for heavy duty usage (off-road/Towing).

Regards,

Arka

PS - Wolf & Iron Wolf both own MM540's are are different beasts!!!!

Last edited by ex670c : 26th August 2010 at 12:24.
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