Jump to content

Rear end clunk


Recommended Posts

4 hours ago, TR Paul said:

Hi Dan, I had a similar 'clunk' with my '6' ('Troy') a couple of years ago;  the steel tubes had un-glued themselves from the insides of the diff mounting bushes. This took someone of my limited intelligence quite a while to work out, but ended up being a fairly cheap & easy fix!

Hope this helps,

Cheers,

Paul.

 

Thanks Paul, I will take a look.

Link to post
Share on other sites

Dan - with everything being so much quieter than a normal car, you will undoubtedly hear a lot more noises coming from the back than in a normal car. Given how many UJ joints ( 6 in the driveline) and the sliding driveshaft joints, you don't need much play in any of those items for clonks to start emanating.

However I would expect those noises to be be particularly apparent under acceleration and deceleration and not necessarily affected by unevenness in the road, which is what you initially suggested as to when these noises were most noticeable.

If you are confident it isn't loose lever arms, and the remaining bushes and joints are all OK, then the last remaining culprit could be the diff, but again I wouldn't expect any clonks from this to be related to the road surface.

Given the torque of electric motors, I would have thought the whole of the rear end of these IRS cars would be a bit on the marginal side, as they often struggle to cope with the standard cars! The diffs themselves are not the weakest link ( check that the front bracket on the diff isn't cracked), but they can and do regularly wear with resultant clonks - my concern would be, if this was the case, would a rebuilt diff be man enough to cope with all the extra torque for a reasonable service life?

Just some thoughts, but still a great project - if you are going to put a sound track on the car, then use a triumph 6 cylinder sound track, as it's pretty unique, with a great sounding exhaust - there are some fantastic noises about!!

cheers Rich

 

Link to post
Share on other sites

Dan,

The rear lever arms are difficult to tighten up correctly, even when you've tried really hard. On the earlier cars the lack of space between the head of the bolt and the lever arm "shroud" means using a socket there to tighten it gives the impression it's torqued up whilst it's the socket interference with the shroud which makes it stiff ! Maybe worth checking to see if the TR6 has the same problem, if so replace the bolts with cap head bolts and then you can tighten them correctly using an allen key drive in a socket from the front, this has sorted out many peoples mystery "clonks" over the years.

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites
29 minutes ago, Motorsport Mickey said:

Dan,

The rear lever arms are difficult to tighten up correctly, even when you've tried really hard. On the earlier cars the lack of space between the head of the bolt and the lever arm "shroud" means using a socket there to tighten it gives the impression it's torqued up whilst it's the socket interference with the shroud which makes it stiff ! Maybe worth checking to see if the TR6 has the same problem, if so replace the bolts with cap head bolts and then you can tighten them correctly using an allen key drive in a socket from the front, this has sorted out many peoples mystery "clonks" over the years.

Mick Richards

Thanks Mick, I was able to get 2-3 turns on the bolts on one damper - hopefully this is the issue 

Good suggestion on the capheads, someone else had also suggested a nyloc on the back using longer bolts

Link to post
Share on other sites
1 hour ago, rcreweread said:

Dan - with everything being so much quieter than a normal car, you will undoubtedly hear a lot more noises coming from the back than in a normal car. Given how many UJ joints ( 6 in the driveline) and the sliding driveshaft joints, you don't need much play in any of those items for clonks to start emanating.

However I would expect those noises to be be particularly apparent under acceleration and deceleration and not necessarily affected by unevenness in the road, which is what you initially suggested as to when these noises were most noticeable.

If you are confident it isn't loose lever arms, and the remaining bushes and joints are all OK, then the last remaining culprit could be the diff, but again I wouldn't expect any clonks from this to be related to the road surface.

Given the torque of electric motors, I would have thought the whole of the rear end of these IRS cars would be a bit on the marginal side, as they often struggle to cope with the standard cars! The diffs themselves are not the weakest link ( check that the front bracket on the diff isn't cracked), but they can and do regularly wear with resultant clonks - my concern would be, if this was the case, would a rebuilt diff be man enough to cope with all the extra torque for a reasonable service life?

Just some thoughts, but still a great project - if you are going to put a sound track on the car, then use a triumph 6 cylinder sound track, as it's pretty unique, with a great sounding exhaust - there are some fantastic noises about!!

cheers Rich

 

I wont start talking about the drive shafts - they need replacing due to play in the splines, you can hear them very well at 0-5mph, they go quiet after that.

As I don't have the gearbox anymore, the original engine would have put more torque through the diff in 1st & 2nd gear, this is now effectively locked in 3rd gear using the overdrive for 4th. Early in the planning phase I decided I didn't want the gearbox as it saps power, adds weight and its another thing to break. So it takes the edge off the performance in the 0-10mph range ever so slightly, but once its rolling and in real world driving for these cars 20-60mph its quite rapid, it almost gets a second wind at 60mph and wants to go but hopefully some more throttle pedal mapping will help with that.

I'm also a firm believer its about the rate of change of torque has that a bearing on parts breaking, the motor gives very controlled and smooth application of torque and there is no clutch to suddenly apply it. Years ago playing with mini's a Turbo A-series would always blow gearboxes but a supercharged version with similar torque wouldn't break the box because its a much more smooth and gradual application of torque compared to a spiky high boost turbo - just a theory of mine 

Link to post
Share on other sites
4 hours ago, DanTR6 said:

thanks for everyone's help - it was the damper bolts, nice and silent now!

Cheers

 

Dan

FWIW I always use longer bolts and fit nylocks to the rear of the bracket as the thread in the mounting plate isnt the best and has often suffered due to overtightening over the years.

Stuart.

Link to post
Share on other sites
16 hours ago, stuart said:

FWIW I always use longer bolts and fit nylocks to the rear of the bracket as the thread in the mounting plate isnt the best and has often suffered due to overtightening over the years.

Stuart.

Cheers Stuart, its now on the to-do list.

Any tips on how you stop the doors knocking/creaking on their latches? minor annoyance but would be good to quieten up

Link to post
Share on other sites
50 minutes ago, DanTR6 said:

Cheers Stuart, its now on the to-do list.

Any tips on how you stop the doors knocking/creaking on their latches? minor annoyance but would be good to quieten up

What door rubbers have you got fitted? How good are the receiving plates on the "B" posts? How good are the hinges?

Stuart.

Link to post
Share on other sites
On 8/21/2020 at 9:03 AM, stuart said:

What door rubbers have you got fitted? How good are the receiving plates on the "B" posts? How good are the hinges?

Stuart.

I have new door rubbers from Moss, hinges don't have any noticeable clunk in them if lifting the doors .  What specifically would I be looking at on the receiving pates? the passenger side is a pain to shut and needs a good slam 

Link to post
Share on other sites
1 hour ago, DanTR6 said:

I have new door rubbers from Moss, hinges don't have any noticeable clunk in them if lifting the doors .  What specifically would I be looking at on the receiving pates? the passenger side is a pain to shut and needs a good slam 

I use these rubbers from Woolies as theyre a better fit and closer to the originals https://www.woolies-trim.co.uk/product/1285/door-seal

Stuart.

Link to post
Share on other sites

+1 for Stuart’s suggestion of the door seal and long bolt and nylock on the dampers. Have both on mine and work great. 
tim

Link to post
Share on other sites
On 8/20/2020 at 9:34 AM, DanTR6 said:

I wont start talking about the drive shafts - they need replacing due to play in the splines, you can hear them very well at 0-5mph, they go quiet after that.

As I don't have the gearbox anymore, the original engine would have put more torque through the diff in 1st & 2nd gear, this is now effectively locked in 3rd gear using the overdrive for 4th. Early in the planning phase I decided I didn't want the gearbox as it saps power, adds weight and its another thing to break. So it takes the edge off the performance in the 0-10mph range ever so slightly, but once its rolling and in real world driving for these cars 20-60mph its quite rapid, it almost gets a second wind at 60mph and wants to go but hopefully some more throttle pedal mapping will help with that.

I'm also a firm believer its about the rate of change of torque has that a bearing on parts breaking, the motor gives very controlled and smooth application of torque and there is no clutch to suddenly apply it. Years ago playing with mini's a Turbo A-series would always blow gearboxes but a supercharged version with similar torque wouldn't break the box because its a much more smooth and gradual application of torque compared to a spiky high boost turbo - just a theory of mine 

Yes it's called dynamic overshoot, a rapid increase in forces can result in much higher transient loads than in the steady state situation. It was a problem for the Space Shuttle due the asymmetric nature of the shuttle at launch and hadn't been considered in its design.

Link to post
Share on other sites
  • 3 weeks later...
  • 2 weeks later...
On 9/16/2020 at 6:21 PM, SteveB21 said:

Hi Dan - I also enjoyed the article. It all looks very impressive - are you planning to get it to the IWE next year? It would be great to see it in the flesh one day!

Cheers

Steve

Hi Steve, glad you enjoyed it, I hope to get it out and about as much as I can, people seem to enjoy seeing and talking about it at the shows its been to, although most things seemed to have been cancelled for the time being so we will see what 2021 brings!.

Dan 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.