Michal969,

I understand your logic - though I am extremely surprised that low oil pressure would cause rockers to shear - unless this is the result of exaggerated clearances caused by unpressurised followers and then provoked with higher revs.

This does not explain however the underlying low oil pressure that initiated the problem. It is the order of events that still require scrutiny - assuming your argument holds true.

Regards Toadshall

Alex : OK Alex you are right - slightly retarded intake camshaft should not bent the valves - may be only under some oscilations during start-up or engine stopping but this is rather theory...I think we agree that all rocker arms broken on an intake cam in one time can most likely be caused by incorrect timing.It is quite hard to find the exact problem from my armchair with my notebook


Toadshall : I am not sure if I properly understand what you ask because of my poor English. If the timing of the shaft changes for any reason it will often happens that the piston hits the valve.This impact is then passed to upper part of the valve where it can damage the component above the valve - rocker in this case.

OK, I'll try to explain what we think has happened and the causes for the rockers to shear in two, It might help or forewarn people in the future when it comes to servicing your own vehicle, please remember that at this point, we have come to this conclusion by process of elimination and back tracking.

It seems that when the oil filter was changed, the old filter was removed and because of the tight space, the chap who removed the filter had disturbed the valve which sits in behind the filter within the housing. This sprung mounted valve has a gallery feed which sits in a small inlet pipe, we think that this was dislodged and was not sitting true hence the low oil pressure! As it is sprung mounted, the new oil filter was able to be fitted without leaking and no one was aware of the problem.

After start up, the oil warning light being illuminated and the engine cutting out, the oil and filter was checked by me, I removed the filter to make sure oil has passed through and that it hadn't collapsed. I am presuming that when I removed the filter from the housing, I must of inadvertantly disturbed this valve once again but this time, it moved itself back into its proper position......this would explain why on trying to restart the engine, the oil warning light would go out whilst cranking and why oil pressure was then found to be good.

By the mechanics own admission, he had 'blipped' the throttle several times originally to try and get oil pressure, because the TD4_e engine has hydraulic lash adjusters which operate by new oil forcing old oil out of them, no old oil was expelled and so they didnt retract. This is turn kept them 'jacked' up which caused excessive tension.....an irresistable force meets an inmoveable object so to speak! The weakest part gave way and hence the lash adjusters sheared as they are not all that strong. (each went by the collar by the needle bearing).

I am still waiting for the lash adjusters to turn up so am unable to confirm that the engine now operates as it should but I have good oil pressure now, all the valves are sitting at the same height and it's timed up in safe mode without needing to adjust anything.

Next time someone does an oil change, stick your hand in the oil filter housing and push down on the plastic circular plate and you'll feel the spring tension! As is the case with paper cartridge type filters, sometimes they can stick in place, if this happens, make sure the pressure valve hasn't been pulled outwards and twisted!

For me it's a case of lesson learnt, dont let your vehicle get used for training.....even if it is under surpervision!

I'll let everyone know if she starts when the new parts arrive.

offroadit wrote:

the TD4_e engine has hydraulic lash adjusters which operate by new oil forcing old oil out of them, no old oil was expelled and so they didnt retract. This is turn kept them 'jacked' up which caused excessive tension.....

I am no engine expert but the principle of HLA's are to reduce noise in the drive train, is that not the case?

With the HLA's under oil pressure this is their design running condition, when not pressurised they rattle like mad until they come under pressure.

For me, as a layman, it would appear necessry for the valves to be struck by the piston for a breakage to occur, something that would only happen if the timing was incorrect, the gap, or lack of, caused by a tappet without oil or with "too" much oil wouldn't be enough to cause a rocker to snap?

I think Alex is correct and his understanding what is wriiten is correct

michal969 wrote:

Alex : OK Alex you are right - slightly retarded intake camshaft should not bent the valves - may be only under some oscilations during start-up or engine stopping but this is rather theory...I think we agree that all rocker arms broken on an intake cam in one time can most likely be caused by incorrect timing.It is quite hard to find the exact problem from my armchair with my notebook


Toadshall : I am not sure if I properly understand what you ask because of my poor English. If the timing of the shaft changes for any reason it will often happens that the piston hits the valve.This impact is then passed to upper part of the valve where it can damage the component above the valve - rocker in this case.

Toadshall :

I fully agree with you and I also remember "hunting" the right cam belt tension on old Opels...

I think the most interesting things on this issue are that ONLY intake camshaft was involved and the low pressure light was on.

This reminds me exactly the same issue on VW / Skoda 1.2 3cyl.petrol engines (chain driven cams) where after an oil change the oil lets out from the chain tensioner and despite its spring pre loaded the engine gets extremly noisy after start-up until the oil pressure is biuld.And now comes the most interesting part - if a mechanic blips the throttle during this phase there is high probability of piston/valve collision

Of course this is different engine and the main part of this problem is in poor design of chain tensioner but the rest is almost identical.

I think the problem was that for any reason the oil pressure was low (carboned pick-up screen on oil pump which didn't self primed,faulty instalation of oil filter,by-pass valve stuck open etc.) and bliping the throttle in this phase caused intake camshaft timing off and piston/valve collision........

offroadit, thanks for being so frank and honest about the lead up to your rocker failure. It's great for us all to watch out for those things when we do the same jobs.

For the hydraulic tappets...

rockhopper wrote:

I don't know how a jacked up adjuster situation happens. Surely it would be shorter without oil pressure?

Alex, Contributors,

If you have access to a line drawing with a parts discription or photographs, it would be a post that might just be rewarding to this issue.

Two areas:

. The engine filter bowl assembly showing the by-pass relief valve system.
.The camshaft and valve rocker cylinder head assembly


Regards, Toadshall

Toadshall, do you mean this sort of thing?
This was pulled from http://lrparts.net.ru/ have a look at that site and you should find what you are looking for, the image below is the latest TD engine so there may be differences but it gives ytou an idea of what you can get, hope it helps you.

Here's the cylinder head design:

Click image to enlarge

At risk of sounding dim...isn't there a procedure for building oil pressure after an oil service without starting the engine?? The common factor here is low oil pressure, whether through human error or not, and a method of building oil pressure without starting would be beneficial. Mine: 2012 Golf GTI Edition 35
Family's: 2009 Freelander 2 HSE TD4 Auto, Stornoway

Yorkshire - God's County

Left behind a little with all the techy jargon but it seems to me that it is important for whoever does my service in the future to be au fait with the idiosyncrasies of FL2 engine layout. How can a simple oil change cause so much of a problem

Or have I missed something. MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings

tenet,

Exactly that - FL2 engines designed by Ford/Peugeot/Citroen are used by many vehicles. The unacceptable design in terms of access to the oil filter bowl on FL2's, makes the bowl difficult to remove and the bowls base impossible to view without the use of a mirror. Thus you locate the paper filter element blind.

Big Dave,

In a simple world after an oil change, you turn the engine over using the starter until the oil pressure light on the dash goes out. Ermm - firstly on a diesels you require to loose engine compression to do this, (or have a spare battery) The solution is to remove fuel injectors. Nobody does.

Thank you for the cylinder head diagrams Alex and taztastic.

TO STICK MY NECK OUT - AN ALTERNATIVE ARGUMENT.

I suggested earlier that I thought it unlikely (unless already damaged) that cam belt or chain drive tensioners would have failed to operate, and that the potential for valve and piston collision would be avoided. What therefore has caused the 8 inlet valve rocker arms to break?

The percussive nature of rockers operating onto an increased gap, plus a significant blip of the throttle, provide a mechanism for inlet valve rocker failure. Could it be that the gap was less for some reason regarding the clearances between rocker, valve and hydraulic valve lifters (lash) on the exhaust valve rocker side

This, of course is supposition on my part, we will have to wait and see.

Regards, Toadshall

Toadshall wrote:

makes the bowl difficult to remove and the bowls base impossible to view without the use of a mirror. Thus you locate the paper filter element blind.