Take a seat, this is a long one! In February 2020 we had a Scirocco come in with the CAVD version, it was smoking and misfiring so I gave it to one of my lads to do a compression test which showed two cylinders down so he dropped the sump, chain cover and chain system off and pulled the head, when the cam carrier was off we found one of the fingers out of position and it had mangled the inlet cam and the carrier, it was clear it had been apart before. He flipped it over and filled the chambers with brake cleaner and all the exhaust valves leaked so he stripped it and took it to the engineers for exhaust guides, vales, skim and pressure test. I noticed the bores were so shiny you could do your makeup in them so whilst the head was away we got permission to pull them and hone the bores plus fit new rings and shells but when we put the pistons on the bench our mobile visiting engineer noticed the ring land of two had gone, and I mean gone, no trace of the missing metal!
So, I ordered a set of Nural pistons, KS bearings, Elring gaskets, head and rod bolts, Febi lifters, fingers, oil cooler, FAI timing chain kit, oil pump and inlet cam plus second hand cam carrier (I know, I know) and he built the engine back up. Plugs out primed and then started, it sounded like a skeleton masturbating in a biscuit tin and a quick check showed barely 2 Bar oil pressure when revved, sod all at idle. Yes it had a new VVT hub, solenoid and oil tube as well!
The only thing we could think of was the oil jets as we had removed them for honing and reused them, sump off, new jets (difficult to do with the crank in the way and ran it up... no difference, so we dropped the sump AGAIN and decided the KS bearings felt sloppy so we fitted Glyco, built it up, no difference...FFS! We put the original pump on, again, no difference. Then the world went into meltdown and everyone except me and my business partner went on a three month holiday on full pay as we topped it up out of our own pockets.
As there wasn't much work in (thank God for our eBay shops) I pulled the whole engine out and gutted it on the bench, I found the block was badly warped so our engineers decked and hot tanked it, then I meticulously inspected it, core plugs out, and smoke tested for leaks. I built it back up with a genuine new oil pump, Glyco bearings, the new jets, new bolts, the new pistons, engineer checked and polished crank which I Plastigauge checked the clearances on and brand new FULL genuine head with new lifters and fingers again plus a new genuine cam carrier with the pervious cam setup and basically built it as I always do, no compromises except I didn't paint the block as normal... even a new Febi rear crank oil seal; literally the only original parts of the base unit were the cam chain cover, bare block, crank and rods but all meticulously cleaned and checked.
I fitted and primed it and when I started it it sounded awful and STILL had no oil pressure, I was baffled, never experienced anything like it in 42 year of building VAG engines. I just gave up, ordered a new base unit from TPS and ****ed it off, I calculated that cockup cost us £25k and just at the worst possible time.
What REALLY hurt is to get the exchange the engine had to go back but we did put the original head and cam carrier on plus the old oil pump. One interesting point with the new engine was it cam with a brand new block and recon head but also a new timing chain cover and this had been a suspect during build but I could not see a fault.