RichardK
Member Since: 18 Jan 2006
Location: Western Australia
Posts: 295
  
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| Report on Timing Belt Replacement |
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Well I've done 200 kms and these are my thoughts:
* Definitely more get up and go
The difference in standing start pickup is unbelievable, goes off the mark like a bullet...........absolute joy 
* So much smoother
the gear changes are ultra smooth, hardly feel them
* Changes down so much quicker under acceleration
* Engine is so much quieter and idles more smoothly
* And last but most interestingly
The shuddering that I thought was a gearbox issue which had become quite bad has disappeared, and, although I have tried to create the circumstances in which it started previously, I can't at this stage make it shudder 
The only explanation I can come up with is that the worn belt was causing erratic timing under acceleration thus causing the shuddering 
So all in all it's like driving out of the showroom
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 2nd Feb 2009 12:58 pm |
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RichardK
Member Since: 18 Jan 2006
Location: Western Australia
Posts: 295
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Same as this thread, which is I think the same symptoms as the one you have mentioned
http://www.disco3.co.uk/forum/topic27326.html
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| 2nd Feb 2009 1:21 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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| Re: Report on Timing Belt Replacement |
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RichardK wrote:Unnecessary quote edited
* And last but most interestingly
The shuddering that I thought was a gearbox issue which had become quite bad has disappeared, and, although I have tried to create the circumstances in which it started previously, I can't at this stage make it shudder
The only explanation I can come up wit....
Presumably you also had the battery disconected for a while which has reset everything back to empty/unlearned/factory starting position etc.
I honestly can't see the cam timing having been far enough off beforehand to cause all these symptoms...purely due to stretch.
Out of interest is the tensioner fixed once tension applied at fitting or continously tensioned throughout the life of the belt?? Cheers
Simon
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| 2nd Feb 2009 2:21 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
 
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Gearbox & engine 'adaptiveness' is stored in the relevant ECU and are not cleared by disconnecting the battery, the engine cannot be cleared but the gearbox can using a specific routine in IDS or Autologic
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| 2nd Feb 2009 3:04 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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Unnecessary quote removed
Ah OK, still can't believe there was slack in the belt to cause that lot and not be enough to jump a tooth and cause major problems - had it on a petrol once and it was nearly undriveable... Cheers
Simon
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| 2nd Feb 2009 3:09 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
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Doesn't mean that they didn't clear the adaptiveness, I was just saying that it isn't cleared just by disconnecting the battery
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| 2nd Feb 2009 3:16 pm |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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 Cheers
Simon
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| 2nd Feb 2009 4:19 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
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What I assume is being referred to as the 'timing belt' is the fuel injection pump belt, is not timed to the engine ... the belt tensioner is spring loaded like the FEAD belt so I can't see how changing this would affect any gearbox shudder 
edit.  just realised - been looking at the wrong belt the timing belt is at the front of the engine and the tensioner has a certain amount of pre-load but is not like the FEAD belt tensioner
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| 2nd Feb 2009 4:51 pm |
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RichardK
Member Since: 18 Jan 2006
Location: Western Australia
Posts: 295
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Where I was coming from was:
If the timing belt had stretched (not jumped a tooth) perhaps it is possible that under acceleration, loaded up belt, is there the possibility that the timing could go out a minute amount to cause a difference in the engine timing, as the engine reaches peak load for the amount of throttle opening provided by the drivers foot on the accelerator or deceleration then the belt shifts (once again a minute amount) to unloaded belt then could it cause a variable timing thus engine causing the so called "gearbox vibration"
I'm sure there are many here who are much more qualified than me, so I would be interested in your comments
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| 2nd Feb 2009 11:07 pm |
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10forcash
Member Since: 09 Jun 2005
Location: Ubique
Posts: 16534
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Hmmmm.... think if that was the case pistons & valves would make contact - not sure of the TDV6 clearances but the 1.7D GM Diesel had a piston-to -valve clearance of 1/100" , the test after fitting a timing belt was to run the engine at full chat for 30 seconds if it survived that then the tech had got it right! 
not saying you're not right, just wondering why this only occurs randomly and only on auto boxed vehicles
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| 2nd Feb 2009 11:20 pm |
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RichardK
Member Since: 18 Jan 2006
Location: Western Australia
Posts: 295
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I'm don't think it would be the only cause but in my case it seems to have made a difference, could it be the auto box has a "shock absorber" effect to the engine "shuddering"
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| 3rd Feb 2009 12:08 am |
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simonsi
Member Since: 14 Oct 2007
Location: Auckland
Posts: 1264
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The loads on the cam wheels and hence timing belts are not even, consequently in my experience, any slack in the belt would cause jumped teeth, shredded belt and engine damage long before any timing alteration on the cam wheels would take effect. lots of the belt grip on the wheels comes from the tension, not like a chain where it comes from the links.. Cheers
Simon
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| 3rd Feb 2009 9:14 am |
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RichardK
Member Since: 18 Jan 2006
Location: Western Australia
Posts: 295
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Yeah...........well..............as I said there are many more people much more qualified than me in these matters, unfortunately the shuddering did come back today although not as bad as before, the gearbox double flush is on in the next couple of weeks.
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| 3rd Feb 2009 1:54 pm |
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ronp
Member Since: 29 Nov 2006
Location: North Yorkshire
Posts: 15214
 
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RichardK wrote:... the gearbox double flush is on in the next couple of weeks.
Keep us posted on that one please, Richard.
I was a normal heterosexual chap, but in these new woke awakenings I now identify as a Wardrobe.
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| 3rd Feb 2009 2:03 pm |
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