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Discussion Starter #1
I was coming back up through France last week when after a period of hard driving, I noticed Vmax could no longer be achieved... When I pulled over for a fag break, the car was idling slightly lumpily, and slower than usual causing the valve train to chatter a bit.

Now, when I crank it over it spins quicker on one compression than on the other 5- and it's a compression problem, I've swapped injectors, plugs and ignition coils around, and have sparks on each plug.

Has anyone else lost one cylinder before? I am suspecting a burnt exhaust valve because the inlet plenum and pipes are still clean, and it isn't using any oil.

Also, There was no hesitation when trouble occurred, just a slight decrease in performance, which I initially put down to having picked up some dirty fuel, after a full fill on SP98.

So, valves, or rings- any experience?

Chris
 

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Discussion Starter #3
They're all good thanks- had the rocker cover off on the afflicted bank, no flat cam or obviously sticking valve, no swarf floating around.
 

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Could one of the pistons be holed?
 

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A holed piston is unlikely, but possible, so are broken rings. If you have the engine at idle and remove the oil filler cap, is there excessive blow-by? (there is always a bit).

More likely to be a damaged valve or seat. Did you decuce which cylinder it was be removing each coil pack and seeing which one didn't affect the idle speed?
 

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You'd notice oil smoke and by now have a violently sick cat on a holed piston, or probably rings. Disabling each cylinder is a good starting point as Chrispy says.
 

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Discussion Starter #8 (Edited)
Hi all, thanks for your replies. Swapped the coil packs around, new plugs etc, and found, as you look at the engine from the front, it's the right hand cylinder on the back bank that ill. And when I start it, it kicks over a lot quicker on that cylinder than on the other 5. Pretty sure it's not rings, as I had a look at a section of the bore by taking the air pipe off, and it's not puffing out of the oil filler at all.
So, I reckon I burnt an exhaust valve out, because it's not forcing air back up into the plenum :)

Burnt valve.
 
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Could be the head gasket thats gone. Any water in the oil etc???
Must Be worth a pressure test. A pain to get to on the v6 though.
 

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Discussion Starter #11
No, not watery oil or oily water. It's great weather to do it, only I'm washing the boat down, and the car's a million miles away :( The upside is, I'm gonna go out for a ride after work to the mountains and wind down. I may not wear boots or shoes or socks, cos the acid wash last week has made all the skin come off my feet this week...
 

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Discussion Starter #13
Its what makes them so big! Also, the polonium leakage from the starboard hyperdrive is making them easier to catch at night.
 

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Discussion Starter #15
Th state of play now is that the wee beastie's going into a local independent on monday to be sorted. I decided it after getting home for a whole day and takig her out for a good run- started first time sfter being sat for about 6 weeks!
My dilemma is how far to go- the cambelt is going to be changed, and maybe clutch, injectors pulled and checked and replaced or reconditioned if necesary, mass air flow sensor replaced, bushes and maybe exhaust. Do Alfa do a sports exhaust for the v6? Then, I don't know what corrosio protection is like on the GTV. It's going to be pretty much unused until the end of the year and left outside under a arport on hard standing. Comments please...
 

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Discussion Starter #16 (Edited)
Well, I bit the bullet, and it proved to be: 2 burnt exhaust valves, and whilst I was at it, new cambelt, clutch pack, MAF sensor, injectors checked, MOT, headlights reset for UK, new PAS hydraulic hoses and some other stuff I think. I told the garage not to hurry it, and err...4 months later it's getting done. Hahaha, well I'm not around to use it and it's out of the parents' way. Looking forwards to using her again next year :)
 

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Cool! At least you're fixing it.

If you're not using it for ages, I'd say at least stick it on axle stands. Otherwise under a carport is okay. If you wash and wax it before you jack it up, it'll be easier to clean it when you get back out there.

4 months should be okay to not drain the fuel etc. and all those other car-storage tips.

Ralf S.
 

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Yes, good to hear its (slowly) on the mend :thumbs:
 
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