Hi Guys,

I've had a bit of a search and couldn't find the specific info I'm after so please bear with me if this has been covered elsewhere.

Quick questions:
1. Can a failed intake cam adjuster allow cam timing to advance and retard to the point where valves can hit pistons or other valves? (I note that the adjuster has travel stops that allow about 20 degrees of movement)
2. Is it likely or even possible that a cam adjuster that is showing minor issues can suddenly fail catastrophically while the car is in a workshop?
3. Can a cam adjuster be caused to fail if timing is set incorrectly, placing load into the adjuster after valves meet pistons?

Longer story:
I bought a 2010 R36 with 110,000km showing on the odo approx 9 months ago which I got a bit cheap as it had a check engine light showing. The car started and drove beautifully other than about 3 seconds of valve train noise on startup and it would occasionally throw the cam position/crank position synchronisation error. After I did a bit of reading I started suspecting the cam chains, guides and tensioners may need replacement.

I did a warm engine compression test to check the state of the engine and got the following results-cylinder 1-6 in order:
200psi, 210psi, 200psi, 210psi, 190psi, 190psi. "You beauty!", I thought, and I decided that this thing was worth going to some effort with.

I started disassembly and after getting the cam cover off I realised that the locking slot on the end of the intake camshaft did not line up horizontally, even when the timing marks on the cam sprockets were in the reassembly position. In retrospect, this should have indicated to me that the intake cam adjuster was not 100% but I made the decision to have the chains, tensioners and guides supplied and replaced by a local VW dealer.

I dropped the car off and called back a week later to pick the car up and I was advised that the engine refused to turn over after being reassembled. Valves into pistons was my initial concern, especially after the guy on the service desk advised that the technician had then "re-timed" the car and it still wouldn't fire. It is now showing compression test results of 40-50psi on all cylinders and absolutely does not run. It's clear that the intake cam adjuster has completely failed as the cam can be rotated from stop to stop before putting any torque onto the cam chain itself.

I had a meeting with service manager who is insistent that the "adjuster was on the way out and happened to completely fail while the car was at the workshop". He contends that it was probably the loss of oil pressure that caused it. I explained that the car had regularly sat for up to 3 weeks at a time over the last 9 months and the startup noise and performance of the car had never changed in the slightest.

My main query is whether the failed tensioner will allow pistons and valves to meet. Any help or even a referral to someone who might be able to point me in the right direction will be massively appreciated.

Thanks,
Ben