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Accelerated Cam Belt degredation using stop start
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Robbie
 


Member Since: 05 Feb 2006
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United Kingdom 2013 Discovery 4 3.0 SDV6 HSE Auto Baltic BlueDiscovery 4

That's encouraging. I drive my own MY13 more than anything else so I guess I find the MY14+ a bit of a shock. I find myself attuned to when it stops and the sense of intrepidation as to all the things that have to work in a timely manner to sprint across a roundabout.
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Post #13515172nd Oct 2014 1:38 pm
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D3Savage
 


Member Since: 30 May 2014
Location: Lancashire
Posts: 100

England 2015 Discovery 4 3.0 SDV6 SE Tech Auto Montalcino RedDiscovery 4

Hi good posts on this, from an engineering perspective - I agree restarting is stressful on components and accelerates wear, to do the job properly would involve storing oil - at pressure to ensure oil galleries are precharged before the restart .... this is complex and I doubt if this has been done. I am also willing to bet a wedge of money the cam belt has not been beefed up.

I totally agree with an earlier post ....this system - I belive is an engineering work around ..... to achieve a relatively easy reduction in omissions and theoretical mpg.

It appears to work ok ..... but only time will tell ...... and I think issues will arise outside warranty.

Cheers
 MY 2015 Se tec SDV6 auto
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Post #13517933rd Oct 2014 7:48 am
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mse
 


Member Since: 27 Jun 2005
Location: Shropshire
Posts: 2704

United Kingdom 2015 Discovery 4 3.0 SDV6 Landmark LE Auto Indus SilverDiscovery 4

Having had my D4 now for 10 months, I almost turn it off now on every journey. sometimes I forget but most of the time its instinctive, into drive eco off.

A few times ive missed and it hasn't restarted quick enough to quickly move out of side roads etc...its awful on all our cars that have it - the only difference is in a manual you have the extra moment when you put it in gear.

Always keep it off. I also noticed it seemed to make the mpg worse too.
 Mike  
Post #135637611th Oct 2014 10:29 pm
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Pedros
 


Member Since: 25 Jun 2011
Location: Cumbria
Posts: 454

United Kingdom 2010 Discovery 4 3.0 TDV6 XS Auto Santorini BlackDiscovery 4

My understanding is that it is, as intimated above, a measure to reduce things to the extent that the vehicle falls into a lower category for vehicle excise. Whether the increased wear of continual stop/starting over a period is compensated for by the £250 or so less of tax per year is somewhat debateable.

I don't have it on mine, but I drove one recently and it was somewhat off-putting, although I guess you get used to it.

I'm all for it though if it means less tax if you can switch it off!
  
Post #135641412th Oct 2014 2:24 am
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amazing
 


Member Since: 05 Mar 2011
Location: chengdu
Posts: 1542

China 2011 Discovery 4 3.0 SDV6 HSE Auto Santorini BlackDiscovery 4

my old smart has it and it would work if you could drive up to an empty junction,stop,drive off. The reality is bumper to bumper stop start traffic self disables the unit as the battery gets too low after a few hundred yards of constant restarting.
I just turn it off
I gave it to my father in law who also had same issue..he also just turns it off.
maybe ok for quite trafffic areas
 It is better to have and not need it then need and not have it.  
Post #135641512th Oct 2014 4:28 am
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D3Savage
 


Member Since: 30 May 2014
Location: Lancashire
Posts: 100

England 2015 Discovery 4 3.0 SDV6 SE Tech Auto Montalcino RedDiscovery 4

Hi I still have grave concerns re cambelt - service life. I have seen commercial petrol engines with a cam belt service life of 40k/3yrs ..... fail after 12 to 13k (12months) as the vans were used for multiple stop start journeys ......... when examined the teeth were ripped off belts - due to premature fatigue - this happened on 3 vans. I strongly suspect this could become an issue on SDV6 ..... at around 25 to 30k.
 MY 2015 Se tec SDV6 auto
Extras added:
Electronic diff
Meridian 17 speaker audio
Cool cubby box
Full size spare
Tow bar
Surround Cameras
Black rear tints
Cosmic grey interior panels 
 
Post #135787414th Oct 2014 11:17 am
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D3Savage
 


Member Since: 30 May 2014
Location: Lancashire
Posts: 100

England 2015 Discovery 4 3.0 SDV6 SE Tech Auto Montalcino RedDiscovery 4

We really need landrover to comment on the tests undertaken ... re duty cycle.... I could be speaking out of turn and maybe they have tested it to the limit .... and modified accordingly.
Are the belt part numbers the same????
 MY 2015 Se tec SDV6 auto
Extras added:
Electronic diff
Meridian 17 speaker audio
Cool cubby box
Full size spare
Tow bar
Surround Cameras
Black rear tints
Cosmic grey interior panels 
 
Post #135787514th Oct 2014 11:20 am
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Numpty
 


Member Since: 18 Aug 2012
Location: Bolton
Posts: 673

England 

Good point. If the belt part numbers are the same before and after stop/start was introduced then unless some other solution has been implemented a bit like modern ejection seats which go off softly then the shock loading on the teeth will be occurring much more frequently.
  
Post #135804014th Oct 2014 5:08 pm
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D3Savage
 


Member Since: 30 May 2014
Location: Lancashire
Posts: 100

England 2015 Discovery 4 3.0 SDV6 SE Tech Auto Montalcino RedDiscovery 4
Some further thoughts

It was explained to me that - quite often engines come to rest in/at the same crank angle - or there abouts due to engine coming to hault due to the static compression - so the instantanious start stresses a limited row of teeth very frequesntly (this may not be quite so bad on a 6 cylinder). I know years ago when I had a citroen.....they did TU petrol and diesel engines of the same capacity - with many of the parts being identical .......... however the timing belt on the diesel was about 25% thicker. When I asked about it I was told that the instant starting turning forces required a thicker belt.
 MY 2015 Se tec SDV6 auto
Extras added:
Electronic diff
Meridian 17 speaker audio
Cool cubby box
Full size spare
Tow bar
Surround Cameras
Black rear tints
Cosmic grey interior panels 
 
Post #136112720th Oct 2014 7:25 am
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