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Discussion Starter · #1 ·
Hello all - I am new here. :) This is my first post to DIYElectriccar as a member. I led a EV conversion project in the country of Kosovo, and so far we are 95% complete with the project. The vehicle runs great, but we have things to finish. We have a problem with some motor/transmission noise that we think is increasing over time, and this is what has brought me to this forum. I need some help diagnosing if this is an OK noise, or small problem, or MAJOR problem.

I have two recordings to share with folks in the forum. One recording is of the WarP-9 being throttled up in neutral, and the other recording is of the car being driven up to 35 mph in second gear. You will hear a clacking/clicking type noise.

We would love to get opinions and hear back from people. HOW BAD DO YOU THINK THIS NOISE IS? I do not think we immediately need to pull the motor assembly to see if we have major problems, but we may need to soon.

Audio 1 -
https://www.dropbox.com/s/i4kh06yyi9cfe92/WarP 9 and trans throttled in neutral.m4a?dl=0

Audio 2 -
https://www.dropbox.com/s/6ndvqt9gr1xv9tc/Warp 9 accelerating to 35 mph.m4a?dl=0
 

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If you have photos of how the motor and transmission are put together, that would be helpful also. Does your assembly have a coupling between the motor and transmission? Clutch? Adapter plate(s)? Type of vehicle? It's manufacturer and model? Type of transmission?
 

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Discussion Starter · #5 ·
If you have photos of how the motor and transmission are put together, that would be helpful also. Does your assembly have a coupling between the motor and transmission? Clutch? Adapter plate(s)? Type of vehicle? It's manufacturer and model? Type of transmission?
I will attach some photos electro wrks. We have an interference fit coupler, an adapter plate AND motor ring, flywheel, clutch plate, etc.
The vehicle is a Renault Twingo (2004 but never driven). The manual transmission however, is used.
 

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Discussion Starter · #6 · (Edited)
What controller? Is there a rev limiter? Tach? "Throttled up" to what RPM?

major

PS. I couldn't listen to the links. Have to join some club.
We have a 600 amp ZEVA controller, and we are actually installing our tachometer this week. I can answer questions about RPM's and associated noise when we get better info.

I think the club/service file, which is Dropbox, should be open-able without an account.
Thanks
 

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We have a 300 amp ZEVA controller, and we are actually installing our tachometer this week. I can answer questions about RPM's and associated noise when we get better info.

I think the club/service file, which is Dropbox, should be open-able without an account.
Thanks
No luck with audio file. Without rev limiter it would not surprise me that the throttle up in neutral over sped !motor causing distortion to commutator and/or armature. Can you get a dial indicator on the comm surface and check roundness?

major
 

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Discussion Starter · #8 ·
No luck with audio file.

major
Thank you for your feedback major - for the Dropbox audio files I believe you should be able to close the 'sign up' window and simply download the small audio file without an account. I hope that helps.

...Without rev limiter it would not surprise me that the throttle up in neutral over sped !motor causing distortion to commutator and/or armature. Can you get a dial indicator on the comm surface and check roundness?

major
The sound is the same at low-ish RPM under load traveling down the road. We tested the flywheel with a machinist dial indicator after our original mounting to the coupler and it seemed quite well mounted.

One guess that I have is that something in our clutch assembly is damaged. IT IS IMPORTANT FOR ME TO SHARE in this thread THAT THE LOUD CLANKING/CLICKING NOISE NOTICEABLY DECREASES WHEN THE CLUTCH IS PARTIALLY DEPRESSED. :confused::confused::confused:(damaged clutch disc possibly?)
 

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That's a great photo of the components used to adapt the motor to the transmission... but it doesn't show the release or "throwout" bearing - the part which pushes on the inner "fingers" of the pressure plate assembly to pull the pressure plate away from the clutch disk and flywheel.

  • When the clutch is disengaged (pedal pushed) the release bearing carries the force from the (non-rotating) clutch fork to the (rotating) pressure plate fingers, so if the bearing is bad it can make noise.
  • When the clutch is engaged (pedal released) the bearing is just idling - not under any force - but if it is a sloppy fit perhaps it is rattling and that's the noise? You don't want it dragging, but it shouldn't be rattling around making noise.
Since the transmission is used, and the release bearing is mounted around the transmission input shaft, the release bearing may be the old used one. Maybe it just needs to be replaced; that would involve removing the motor, but with any luck (depending on the adapter design) you can leave the pressure plate, clutch disk, flywheel, shaft adapter, and both parts of the adapter all attached to the motor; that's how it works when you separate an engine from the transmission for access to the release bearing, or as the first step in replacing the clutch.

The audio recordings are quite clear, but I still can't tell from them. Perhaps if you made a recording with the motor running at a constant speed in neutral as you press and release the clutch pedal, it might make any clutch-related sounds more apparent?
 

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Unfortunately, any damage may have already been done and you will have to take things apart to diagnose the problem. This may include the transmission. Have you aligned the motor and transmission properly? Are you sure the weight of the motor is not hanging off the input shaft and deflecting it?
 

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Is the "interference fit" coupler made of aluminum, which is heated and pressed onto the motor shaft?

Does the steel flywheel bolt directly to this coupler? (eight bolts around center)

If so then you have two problems.

1. The coupler is not stiff enough to carry the weight of the flywheel and pressure plate, and hold them concentric to adequate tolerance.

2. You are relying on the thrust-carrying load capacity of the radial ball bearings (6207 drive-end bearing?) of the warp motor to carry the reaction force for the pressure plate throw-out bearing. Typically the axial load capacity is not very much for a radial bearing and it will be easily damaged and fail.

It may run for awhile if you don't use the clutch. Either start in higher gear, or clutchless-shift while at speed.
 

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Discussion Starter · #12 ·
That's a great photo of the components used to adapt the motor to the transmission... but it doesn't show the release or "throwout" bearing...
Here is a picture of our throwout bearing attached. This was a new throwout bearing that came with the new sport clutch that we installed.


The audio recordings are quite clear, but I still can't tell from them. Perhaps if you made a recording with the motor running at a constant speed in neutral as you press and release the clutch pedal, it might make any clutch-related sounds more apparent?
The recordings make the rattling/clicking noise sound louder than in real life, but what the recording cannot convey is the shaking/vibration of the transmission. The shaking is minor and does not seem to be 100% correlated to the rattle/clicking noise because the noise starts at low RPM.

We will need to check flywheel alignment with a dial indicator.

That is a great idea brian about recording at constant speed in neutral while pressing and releasing clutch. We will see how much of a difference that makes. ;)

(I will also comment on electro wrks asking about supporting the back end of the motor - and we do indeed have a back-end support bracket.)
 

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Discussion Starter · #13 ·
Unfortunately, any damage may have already been done and you will have to take things apart to diagnose the problem. This may include the transmission. Have you aligned the motor and transmission properly? Are you sure the weight of the motor is not hanging off the input shaft and deflecting it?
Thank you for the good questions.

You may very well be right electro wrks - we may need to pull the motor assembly to see if something is breaking apart.

We aligned the motor quite well (at least for a first timer I think) and the clatter/clicking noise was less obvious in the beginning. We have a sturdy bracket on the back-end of the motor that transfers weight and movement into the chassis (including motor mounts to absorb torque and respond without 100% rigidity to the motor mounts on the transmission end of things.
 

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Discussion Starter · #14 ·
Is the "interference fit" coupler made of aluminum, which is heated and pressed onto the motor shaft?...
Does the steel flywheel bolt directly to this coupler? (eight bolts around center)
Yes, indeed it is an aluminum interference fit coupler.

If so then you have two problems.

1. The coupler is not stiff enough to carry the weight of the flywheel and pressure plate, and hold them concentric to adequate tolerance.

2. You are relying on the thrust-carrying load capacity of the radial ball bearings (6207 drive-end bearing?) of the warp motor to carry the reaction force for the pressure plate throw-out bearing. Typically the axial load capacity is not very much for a radial bearing and it will be easily damaged and fail.

It may run for awhile if you don't use the clutch. Either start in higher gear, or clutchless-shift while at speed.
Wow, you have brought up some interesting concerns that I had not exactly thought of.

Did you intend to say that I likely have ONE of these two problems or BOTH of these problems?

... if, as you say the flywheel and clutch assembly are not "concentric to adequate tolerance" is that then the possible cause of a reaction in the bearing of the Warp 9's inner shaft? Possible we could be damaging the WarP bearings before we destroy the clutch disc (I think unlikely)... or were you referencing that just the noise we hear as coming simply coming from the WarP shaft's bearings/connections?
 

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i see two problems.

Flexibility of the coupling allows flywheel-clutch-pressure plate wobble (mass imbalance, alignment, etc). Likely source of noise.

Axial load into radial bearings. Eventual source of bearing failure. This subject was discussed some years ago, may not be an issue but i don't like the axial load path. Turns out i made a good guess on the bearing size,
http://www.diyelectriccar.com/forums/showpost.php?p=118057&postcount=35
 

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The new release bearing is unlikely to be the source of the noise, but using it (disengaging the clutch) may be the cause of the noise problem, since the axial force on the motor shaft could damage motor bearings, as kennybobby explained. It's still worth listening to the clutch engaged/disengaged noise, because a damaged bearing can sometimes be make more quiet by loading it - the same force from the release bearing that damages a motor bearing may muffle the bad bearing's noise.

The shaking or vibration seems unlikely to have anything to do with the release bearing, although perhaps a motor bearing problem could cause it.

For those with more experience in this sort of setup:
What is normally done - if anything - to handle the axial load on the motor shaft of using the clutch release? This isn't an issue with an engine, which is designed to take substantial axial thrust, but an electric motor would typically not need to be able to handle that thrust.
 

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Is the "interference fit" coupler made of aluminum, which is heated and pressed onto the motor shaft?

Does the steel flywheel bolt directly to this coupler? (eight bolts around center)

If so then you have two problems.

1. The coupler is not stiff enough to carry the weight of the flywheel and pressure plate, and hold them concentric to adequate tolerance.
...
I wouldn't have thought that this sort of interference fit would be used, because it seems to me that it would be a problem to remove, but my understanding of this discussion is that it is at least somewhat common.

kennybobby - or anyone - why would this not be stiff enough? It seems to me that this approach would have zero play and the best possible concentricity; the aluminum coupler only needs to be dimensionally suitable to be stiff enough. What is there about this setup which makes either stiffness or concentricity an issue?


I keep learning interesting new things in this forum... and wondering why a motors built for EV conversions wouldn't just have an output flange like almost every engine. Even a keyed taper with a thread on the end for a big single nut (like a Wankel rotary from Mazda, which couldn't be assembled if the mainshaft had a flange) would be better than a straight plain shaft... for handling a flywheel of a clutched installation, and for adapting to various transmissions. A spline (as used in production EVs) would work, too, but doesn't seem like the best choice for a flywheel (although the Mazda R26B 4-rotor uses an output "gear" or spline).
 

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Discussion Starter · #19 ·
...using it (disengaging the clutch) may be the cause of the noise problem, since the axial force on the motor shaft could damage motor bearings, as kennybobby explained. It's still worth listening to the clutch engaged/disengaged noise
Thank you for the suggestion brian. We made a video yesterday of the clutch disengaging and engaging repeatedly. You can here the serious noise come when the clutch engages.

Our team's consensus so far is that the noise comes out of the transmission bellhousing, and seemingly the trans is getting slowly getting destroyed from very small misalignment-jerking on the shaft.

Here is a 34 second video link (through dropbox) that shows what is going on a lot better than any typing here.

https://www.dropbox.com/s/zjl201adhx0l1hh/WarP9- clutch in and out.MOV?dl=0

Let us know what you think :(:(:(
 
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