Clattery when cold
Join Date: Feb 2012
Location: United Kingdom
County: Greater London
I got the head off finally, just as it was getting dark, so these are only first dim impressions. I seem to have got away with only slightly visible impact damage on the piston on cylinder #3. A few slight indentations, but it's hard to tell as the piston has more carbon than the other three, which have virtually none. I'll need to clean the carbon off the piston crown before really knowing how much of a beating its had, but at first glance just a few superficial marks.
#3 was at TDC when I lifted the head, so I've not yet looked for bore damage.
The extra carbon is interesting. There's not a lot, but more than the others. I can only think of three possible reasons.
- Once the flap has gone, the combination of no flap/open port and EGR result in a sootier burn at low revs. I'd sort of expect that, if flaps do the job they're supposed to.
- Another is that #3 injector isn't working right - or wasn't, it was noisy before the Wynnes injector treatment but isn't so much now. I haven't looked at the nozzle for impact damage, or at all.
- Or bore or piston damage is allowing engine oil into the cylinder.
No trace of the missing flap. I couldn't see any impact damage on the head itself, but need to check more carefully.
I've not yet searched for flap #2 which is in the inlet port somewhere. Very, very lucky I decided to tear it down when I did. I saw it when I first removed the inlet manifold and it wasn't jammed in the port, just sitting there waiting to cause mayhem.
I had to take the catalyst off. I couldn't get access to remove the lambda sensor because the shield was in the way, and the only way I could remove the shield, catalyst and lambda was to undo the large circular ring clamp that holds the catalyst onto the turbo. Then they all come off together. Actually undoing the nut was easier than expected, I had a small deep spark plug socket (16mm) that fit perfectly, but the clamp itself was both corroded to the turbo and also had strong spring pressure holding it in place. A combination of tapping it and forcing the jaw apart did the trick eventually. That alone took me over an hour of trying different tools and approaches, for a 5 minute job. If I ever have to do all this again, it'll take me a third of the time.
I haven't yet got the manifold and turbo off the car, just off the head, as the inlet hose has one of those foul single-use clips which some Milanese sadist has arranged so that the clamp part is completely hidden and out of reach. I spent an hour trying to get that off too, but in the end I just left the whole lump of crap dangling to deal with later. It will now have to come off so I can check the turbo for damage and at least cleaning, as the actuator is sticky. I tried to cut through the band with a Dremel from above, but couldn't get access. From underneath, maybe. TBC.
I'll post some pics tomorrow.