Engine rebuild post snapped cambelt - pics for your enjoyment.

[JFWerkstatt]

Found the belt

Belt melted through cam cover and front main, needed to replace before timing for a ‘test spin’

Charge cooler removed

6x broken rollers/rockers

Cam/cam cradle removed

Front end removed for better access

Old head

New head gasket

New head

New cam cradle

New timing belt after 10 rotations, all 3 tools slid in lovely at tdc

Customer and I agreed that due to the valves impacting the pistons (all 16 valves left tiny impressions on the pistons) that head gasket upward would be renewed. Big job for a garage that opened only 3 months ago.

Enjoy, Josh.

 

[Dellmassive]

Awesome work.

Got any close up pics of the damaged bits?

Did it bend valves? What about the pistons?

What was the van spec?. Millage? Etc?

Any idea what caused the belt to fail,?... Water pump leaking?- causing bearing to fail?

 

[Mocko1962]

How did the belt go .. was it re-newed previous in scheduled time / miles or missed or other reason .. just for future reference for others

 

[Deleted member 47379]

Yeah like the previous two comments. Would love to know the van's history and mileage since last cambelt change for reference.

 

[Dellmassive]

This is a follow on from this...

Oil pressure issues after top end rebuild

Morning, I’ve recently done a top end rebuild of a 2018 T6 2.0tdi with 104,500m after a cambelt snap. I’ve had all sorts of issues since doing the rebuild one of which was a misfire due to stuck injectors. This is now sorted. Now she’s up and running I’ve got an oil pressure fault at idle. So...

www.t6forum.com

....
Quote:

I’ve recently done a top end rebuild of a 2018 T6 2.0tdi with 104,500m after a cambelt snap.



...

 

[Deleted member 47379]

Thanks @Dellmassive. I'll check that thread out

 

[Deleted member 47379]

Hmmm .... This might be a stupid question. But I'm guessing from that original post that the van has 104k miles from new. But it didn't state whether the belt was changed at 85k (which is the recommended interval I think? I'm new to the T6 community so forgive my ignorance).... This is critical information isn't it? Or did it do the 105k miles on the original belt?

 

[DXX]

Was the lower timing belt cover replaced with the latest version? I seem to remember reading that the latest version is stronger to prevent a failed auxiliary belt fouling the timing belt.

 

[JFWerkstatt]

Ok, I apologise for the lack of info. Here goes.
The van is a 2018 2.0tdi eu6 5 speed on 104,500m. It has never had the belt replaced.
The van had a dodgy remap when I took over the fleet maintenance for the company, I’d recently replaced the dual mass due to a rattle I believe was caused by a ‘no boost, all the boost’ remap. This may be related, excess belt stress due to the crank knocking back and forth and a sudden wave of torque.
I haven’t actually got to the root cause however I have an inkling the aux belt may have caused it. The belt doesn’t sit correctly in the tensioner, I have a genuine tensioner being delivered in the morning from TPS.
Waterpump removed was fine, tensioner and both rollers were both fine too. All aux belt driven pumps were also fine.

As there is no definitive cause for the belt to snap, I believe it was due to it being 20k overdue and overstressed whilst the remap was file was installed.

The same business have a 6.1 that was remapped by the same person who had the file supplied by the same place. As soon as I drove the 6.1 I stopped, the remap was completely unnatural for a diesel, it wheel span in second gear in the dry when the boost kicked in. That was swiftly removed but cost them the second dual mass replacement. This had 60k and has a leaking front main, I believe the crank giving it stacks and knocking back and forth on an un dampened flywheel probably accelerated the leak here too.

Both remaps have been removed now.

 

[JFWerkstatt]

I don’t really have pictures of the damage as I took videos and sent to the customer. There were very slight imprints in the piston heads from the valves which is why we just replaced the head. The van isn’t earning any money in the workshop and believe me the thing earns when it’s on the road…. The decision was made to replace the head without confirming bent valve through removal. Also, by the time the head was decked etc the van would have been off the road for an additional couple of weeks.
I believe that exhaust valves would have been questionable as 6 or the 8 rollers shattered on impact however, all 16 contacted the pistons.
I recommended that the cam cradle was replaced purely due to the impact through the rollers. There was no visible damage to the cams (to test them fully would have been a job I couldn’t perform so time was also a factor), so they were also replaced.

 

[JFWerkstatt]

Was the lower timing belt cover replaced with the latest version? I seem to remember reading that the latest version is stronger to prevent a failed auxiliary belt fouling the timing belt.

It’s the only part they had listed so I assume the newest revision

 

[bluezie]

The rocker elements are the weak link on these engines, so you shouldn't have any bent valves. This probably could have been repaired just by replacing the rockers and compensators. So far not heard of one with bent valves, but plenty with shattered rockers!

 

[JFWerkstatt]

I might, with admin permission start a thread on the stuff I get up to in the shed. I’ve got all sorts on the go, 2.5 shuttle for injector seals, t4 autosleeper for re-conversion, t6 (forum members) in for a few niggles and an overall health check. That’s the stuff in the shed now, I’ve also got my 3rd Transporter in there at the beginning of a heart transplant. She’s getting a 3.2 out of an A3.
Due in I’ve got a T6 for a dual mass, T6 for coilivers and wheels and a T5.1 in tomorrow for a ‘doesn’t run right’ fault, 2012 2.0 which is a version of the CR diesels I’m keen to learn more about. Also, a 1.9 Vivaro with suspected head gasket issues.
Best thing I ever did was to set up on my own, I am in my absolute element at 23:00 at night playing with Transporters!

 

[JFWerkstatt]

The rocker elements are the weak link on these engines, so you shouldn't have any bent valves. This probably could have been repaired just by replacing the rockers and compensators. So far not heard of one with bent valves, but plenty with shattered rockers!

I told the customer this but they wanted to play it safe, as did I. Time was a huge factor in this job, it will earn the cost of this job in less than 2 weeks when factoring in them not paying for a hire van etc.
I’ve got an iveco daily to have a look at soon with the same sort of fault, I think the tensioner has failed as the belt is slack (guessing, done no research or diagnosis yet) First thing after finding out why the belt is slack is to whip the cover off and check the rockers, there are rumours around the patch that these aren’t just a weak link but actually designed as a sacrificial component. Not sure that’s true but worth a look

 

[DXX]

It’s quick to check the camshafts are true if you have a surface plate, a pair of V blocks and a DTI.

 

[JFWerkstatt]

It’s quick to check the camshafts are true if you have a surface plate, a pair of V blocks and a DTI.

Yeah you’re right, used to do a lot of dti work on helicopter spherical bearings and train tyres so it makes sense measuring for run out of the shaft. The concern was more that the cam might have moved on the shaft as they look to be separate, you’ll probably tell me a really obvious way of measuring now but as far as I am aware I do not have the ability to do it.
I do need to order a dti though, 3 reasons now. My lathe, t4 belt and not camshaft runout

 

[Dellmassive]

welcome to the Trade Members Club @joshuaaitken

 

[DXX]

Yeah you’re right, used to do a lot of dti work on helicopter spherical bearings and train tyres so it makes sense measuring for run out of the shaft. The concern was more that the cam might have moved on the shaft as they look to be separate, you’ll probably tell me a really obvious way of measuring now but as far as I am aware I do not have the ability to do it.
I do need to order a dti though, 3 reasons now. My lathe, t4 belt and not camshaft runout

If you have a lathe you could put the camshafts up between centres.
Good luck with the new business.

 

[Ayjay]

@joshuaaitken. Where are you based? There's a few of us on here in Gloucestershire and it's always nice to know that there's another expert in the area.

 

[Gavinda]

If you have a lathe you could put the camshafts up between centres.
Good luck with the new business.

I think it's the cam lobes, which are possibly a shrink fit on to the shaft and could have spun out of position. I'm not sure how you might go about measuring that? Especially if you don't know which lobes have or haven't moved.