CAYC Valve Train Wear Criteria

[Overdose]

Hi again,

I have what I believe to be a valve train wear problem and I am looking to see what exactly is worn. I have yet to see anything horrid, but have yet to remove the cams.

The car is my Fabia II Monte Carlo (again) 1.6TDi with CAYC engine.
The problem is a loud ticking/tapping at half engine RPM, it was reasonably quiet, but getting progressively louder over the last couple of months and came on much louder this week, with a noticeable power loss. No fault codes and no EML

Would someone please be kind enough to point me in the direction of any dimensions or information so that I can determine what has actually worn significantly? I have never seen other CAY engine camshafts and have no reference.

you.

[Crasher]

Pretty simple setup, usually it is worn cam to cam gears, the inlet has been revised… about £1k in parts genuine.

[Overdose]

Thank you, I'll take a closer look at the gears in a minute. The tappets are nearly all seized with sludge, presumably and only one or two have any spring action, I'm certainly no expert, but that looks like the smoking gun to me.

[Overdose]

So, reading further, it appears that 'springy/squishy', is bad and No.3 cylinder has two squishy lifters, so quite likely the issue. Camshaft lobes and gears show no significant damage to my eyes, so a set of lifters and rockers would seem in order.

Presumably, if the lifters have collapsed, there is effectively a valve to rocker gap, closed only by a spring, so hence the tap. A functional lifter must stay rigid and have no gap between valve and rocker. Is this correct?

[Crasher]

The lifters and rollers are easily available aftermarket but you have to get the oil system clean, LongLife oil changes… FFS!

[Overdose]

I've done a couple of changes in the year that I've had the car, it was clearly neglected in the past, but at least the really expensive parts seem ok. I think it would be prudent to replace all lifters and rockers as a set, drop the oil and start with fresh again.

Thanks for your input BTW.

[Overdose]

OK so, good news, the lifters and rockers have been replaced, injectors refitted, engine fire upon.

Bad news, the noise is still there, injection deviations on 1 and 3 are way out and I'm beginning to suspect the bottom end. A while back, I had a low oil pressure light come on and proceeded to remove the sump to find metal chips and debris blocking the pick-up. I didn't see any damage at the time, but the metal must have come from somewhere.

I haven't driven more than two miles with the current knocking noise, but whilst it was running, I heard it squeak a couple of times, like a belt slipping. Could this be bearings slipping?

I think I need to revisit the bottom end and with a lack of garages near to me that would be either capable, or willing to do the work, I might have to do it myself, which doesn't fill me with much joy.

I would like to know if it is possible to replace the main and big end bearings in situ, or does the crank need to come out? Having just gone through the rigmarole of dismantling half the engine to get the cams out, I don't really want to be going down that route again, if possible.

[Crasher]

End of the road for me, not worth the money required. I wont rebuild modern VAG engines, they are *****. A new unit is 5K plus VAT and fitting.

[Overdose]

Can the bearing shells be replaced in situ though?

And on the topic of these cr@ppy engines, does anyone have any suggestion as an alternative?

[Crasher]

You can replace the shells with the sump off but it may be too late. As for none cr@p engines? No, they are all *****, way way to complex and fragile… VAG haven’t made a decent engine since the 1.8 20 valve.