That is not good news as you know so I would imagine if the guides failed and the chain jumped then the action of the cams trying to turn but being prevented by the pistons would damage the vanos and potentially undo them, there is a torx bolt that tightens the vanos units and then the trigger wheel is held in place by the nut and all threads are left handed and the vanos units are only held in place by the torx bolt pressure , when it is loose they just turn and the same for the trigger wheel. If they become loose then there is nothing timing the cams and that's when everything collides, but i would imagine you knew that ..
You need to know if the heads were pressure tested and skimmed also as they could have cracks
have a look at this thread for an interesting read and the most gummed up engine in the world
http://www.bimmerfest.com/forums/showthread.php?t=516669
The pistons being forced into the valves would put a tremendous load on the con rod and bearings.
The compression could be down to the new head gasket not sealing correctly, are the misfiring cylinders next to each other ?
They probably didn't compression test it after they did the work and they wouldn't have been able to do it before so now there is a problem they are investigating
I think mine is ok, I was concerned about head gasket after losing the top hose but i think it was just problems bleeding the air out of the cooling system and had discolouration in my oil which i think was the remnants of the engine flush being dissolved by the new oil. I took it for a couple of good runs over the weekend and it is running the best it ever has.......so far
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Excellent write up. It's frustrating when you see how much punishment the M62 can withstand and yet I seam to have the lemon of the Solihull plant!
You hear of these running for 150k+ without missing a beat and yet mine seams to have busted its Vanos units and knackered its timing components all under 62k.
As I have not has the chance to drive it properly, I felt it to be really underpowered (I know why now with the low compression) but it also seamed to rev really high before chainging up a gear. Could the gearbox oil be degraded and need a flush or are these L322's like this to drive anyway? It just just sounded really low geared and hang in the gears too long.
