MikekiM@PureMS

Ooh that looks nasty.

turbo944s2

I dont know how true this is, but a I read on vwvortex that the stock valves are two pieces pressed together and the heads of the valves can come a loose. My buddies a6 dropped a valve and his engine was mangled like yours too.

qfrog Ti20

In my experience some valves stems which respond to magnets but flared ends which do not. The turbocharged engines get sodium valves, I'm not sure how these valves are produced as sodium is highly reactive with oxygen which is why samples of sodium are kept in oil. I believe the sodium is used to cool these valves.

I suspect that there are two dimensionally similar exhaust valves for the 058 cylinder head casting, I think the ADR and other 1.8 non turbo variants got non-sodium filled valves much like the 30v non turbo 078 engines which IMO share much of the same head architecture/design/engineering.

2.0GT35

from the dealer. Not exactly something I need to do since I am running a ported AEB head.

A400

part of the engine failure, then the head must have lifted from the block and a chunk filled the gap momentarily, at least long enough for 1 rev.. What did the cam and retainers look like? I still think you had extreme detonation and melted qa piston and dropped a valve, but would have to see the head to be positive. I think that if you dropped a valve 1st that you would have definately heard the stuff banging around. The #2 piston looks melted rather than beaten on the upper side. I have always felt that when you track a car, you want to be rich rather than spot on because the block will begin to become heat soaked as well as the IC/turbo/ex.mani. all being taxed because of the continual accel. and decel. from a road course. A car that runs fine on the street will get leaner as the session go's on unless enriched as it gets hotter. Also there are some heat risers on these heads which should be smoothed at a minimum as they alone will cause detonation during hard running. You should have someone smooth these down before assembling your next engine.

So you may want to size a slightly larger injector or get a new tune for more fuel volume when needed. Also you probably would have seen this coming if you had been runing an EGT and WB A/F meter. These are a minimum for road course turbo cars.
Rod

BJC::wokka wokka

I'd imagine by the color of the pistons?

pointby

Would the color/appearance of the plugs give any indication?

BJC::wokka wokka

You're running rich.

When they are real white, you're running lean.

They should have just a little brown color to them. Like a well done roasted marshmellow : )

pointby

Since the three piston heads also look like they are that nice brown "toasted marshmallow" color I wonder if a lean condition caused the failure. I had the car dyno'd with a wide band read out and it was borderline lean but nothing dramatic. Unfortunately I just changed the downpipe and they didn't reinstall the EGT guage. That may have given a better picture or stopped the failure altogether.

ScratchRob13

but thats where alot of guys have theres