Failed CAS = blown RB26

Hey guys, my engine has unfortunately lost compression and will no longer run. Prior to this there were no issues, sounds, knocks ect. Started and drove as expected until it shut off unexpectedly at idle under no load and couldn’t be started.

The workshop has told me the CAS drive had snapped, leading to timing jumping and a loss of compression in all cylinders as a result. I understand a CAS can fail but I’m struggling to understand how I’ve lost an engine as a result, at idle with no load or warnings.

Im not suggesting it’s impossible, however the car had recently been serviced which included doing the timing belt. As there was limited usage from the time of the service to engine failure I’m now beginning to question how and why this has happened.

My gut is telling me something has gone wrong during the timing belt install resulting in the engine failing but I’d love to hear from those more experienced with RBs as to how that explanation stacks up. I’m not trying to point the finger at anyone, just hoping to understand more about the situation I’m facing and gain more knowledge so I can ask the right questions.

Thanks!

Unless the belt has failed I would assume you would have felt a significant difference in driving behaviour and idle quality if the cams weren't timed correctly.

I think it's unlikely that significant damage would be caused at idle even with worst case ignition event and if it did that all cylinders would have no compression as a kickback on one would probably stop it.

Did it drive as beforehand after the timing belt change?

If the belt failed or timing was wrong you could have has valve to piston contact which could cause loss if compression on all cylinders if there was only light contact that allowed running at low rpm but gave heavy contact on the exhaust/intake overlap at high rpm. To my understanding the CAS should not effect physical crank/cam timing, only sequence of fuel and ignition.

If you got really unlucky and the CAS failed in such a way that you ran on load for an extended period with significantly advanced or retarded ignition you could have cracked/holed/melted pistons but you should probably have heard/felt something wasn't right.

You really need to eyeball everything (crank/cam timing, CAS, piston tops) ideally before anyone else gets their hands on it if you think you are being lied to.

You can buy inspection cameras to plug into phones/tablets for ~$20.

Thanks for the response mate. The car was running perfectly prior to shutting off. Zero signs of anything going wrong. Idle was perfect, started as normal until it died. I thought it was the fuel pump that has failed. I just can’t understand how a few weeks after a timing belt service I’ve lost an engine!

Does it sound like a sewing machine when you crank it?

Sounds like a belt or tensioner fail.

Been a while since I tried started can’t recall. It cranked but no sign of life