Member Since: 05 Mar 2019
Location: Reading
Posts: 13
TDV6 cam chain failure...attempting rebuild!
Hi all,
So ive been used to rebuilding porsche's but thought id try my hand at a range rover sport with the tdv6 3.0 2011. I have to say I wish I hadn't but im in too deep now!
So body is off etc engine not seized as turns over on bottom pulley fine so I went ahead assuming timing belt failure. This is fine and actually looks to have been changed recently. Checked through oil filler cap to see if cams were turning and they werent so now ive gone ahead and taken cam covers off and as suspected cam chain has snapped (1-3). The tensioner had failed badly and upon removing cams there is some scoring.
I thought I must go ahead and remove cam cover for 4-6 to see if any damage in there. - chain hadnt snapped but tensioner has started to go with plastic runner on the bottom disintegrating, so basically about to go!
Now I can go ahead and repair but I have to think about why this has happened (car has 87k miles). For both sides to fail there has to be an underlying issue and this is where i'm unclear and hoping for some possibilities/ideas to check.
- Oil starvavtion causing the cams to grip snapping the chains etc but why? if the tensioners fail does it then restrict oil flow to the cam housings
- Or is my next step (which i really dont want to do) to remove engine, remove sump and see if there is an issue with oil pickup?
- Oil pump (new style with extra support on casing) do these fail internally?
- Ive read about incorrectly fitted oil filter causing oil restriction to top end - i havent checked oil filter yet but surely not....
- Failed bottom end wouldnt cause this would it? engine still turns over by bottom pulley.
Anyway, any help or suggestions to check would be greatly appreciated.
I know everyone says failed tdv6 engines are basically scrap but surely it can all be rebuilt, albeit if it ends up being triggers broom scenario!
Thanks
5th Mar 2019 7:51 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10361
You need to ensure the crank hasn’t snapped before you wasting any more time.
Tensioners can fail if it’s not had frequent oil changes
5th Mar 2019 9:06 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10361
It only takes about 10 minutes to see the oil pickup pipe akaik and you could see if any metal present.
5th Mar 2019 9:09 pm
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
Have you checked for bent valves as some must have been open when the chain failed?
5th Mar 2019 9:11 pm
willstrang
Member Since: 05 Mar 2019
Location: Reading
Posts: 13
When i was turning it over it felt like there was some compression at least from 4-6 where the chain hadnt broke so hopeful that crank is good still. If it had snapped wouldnt it be likely there would be some resistance or not? I think sump has to come off to be 100% sure then unless there is another way of checking?
Where is the oil pickup pipe? is it not internal?
Could potentially be some bent valves but initially looking it seems no broken rockers and all valves seem the same height. If the valves are flat against pistons then rocker damage would be more likely id have thought.
Thanks for replying to my post!
5th Mar 2019 9:54 pm
willstrang
Member Since: 05 Mar 2019
Location: Reading
Posts: 13
I also suspect this has had infrequent oil changes!
5th Mar 2019 9:56 pm
sputnixb51
Member Since: 23 Apr 2013
Location: Morayshire
Posts: 833
The 3.0 V6 has a different oil filter to the 2.7 so shouldn’t have the miss fitting problem.
5th Mar 2019 10:05 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10361
Well if there is no lateral crank movement it maybe ok.
You need to decide if you are going to remove the head or just put new tensioners on and see what happens
5th Mar 2019 10:22 pm
willstrang
Member Since: 05 Mar 2019
Location: Reading
Posts: 13
Do you mean remove the head to check for valve or piston damage?
I think there has to be a bigger reason as to why both side cam chains/tensioners have failed and im thinking along the lines of pickup blocked with sludge etc although doesnt look like a lack of oil in the heads and tappets have oil in them.
Id be tempted to check sump first and if okay then leave heads on/repair and put back together.
Are the oil pumps prone to failing? If i put power to starter to turn engine over am i able to check if oil pump if functioning if oil comes up to where the filter is?
5th Mar 2019 10:34 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8075
I would suggest you take the injectors out put new tensioners on, turn the engine over by hand if ok then check compression by turning engine with starter and a pressure gauge, fill with new oil and check oil pressure again with starter motor, if ok fit new timing chain.
I have known this to happen on a 2.7tdv6 Sport with similar mileage, the chain snapped, LR repaired FOC.It can when others can't,
It will when others won't,
It goes where others don't.
Last edited by M3DPO on 5th Mar 2019 11:15 pm. Edited 1 time in total
5th Mar 2019 10:57 pm
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10361
In the hopefully unlikely event you have oil starvation then the whole engine really is scrap. Why would it just cause or show a problem to tensioners?
It takes ages to get oil pressure on these. So cranking over to test for it isn’t a sensible way forward
5th Mar 2019 11:12 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8075
Could the clue as to why it happened be in the fact the timing belt has recently been changed?- timing out one one bank?It can when others can't,
It will when others won't,
It goes where others don't.
5th Mar 2019 11:22 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4628
I don't think it would have run properly if at all with timing out on one bank! I'd tend to agree with Pete K, lack of oil changes causing premature wear on BOTH cam chain sets.yµ (idµ - eAµ) ψ=mψ
6th Mar 2019 3:16 am
lynalldiscovery
Member Since: 22 Dec 2009
Location: Maidstone
Posts: 7274
Cheap usb boroscope down the injector holes to check valves, lot of work to put it back together only for a bent valve to fail big time.
6th Mar 2019 12:42 pm
willstrang
Member Since: 05 Mar 2019
Location: Reading
Posts: 13
I have got boroscope and tried down the injector holes but it wouldnt fit through the hole. I pulled the oil filter and there is a small amount of metal shavings around it so not looking good to be honest! Also turned it over with starter and it blew the tissue out the injector holes on 1 and 2 and 4 and 5 but not 3 and 6 (think ive got that right - the two cylinders at the back of the engine.)
Anyway, too many alarm bells for me so going to remove engine, strip heads and remove sump to see what exactly is going on. I'll update with my findings incase its of interest to anyone else and then go from there with the repair-if possible!
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