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[Andy H]

The damage to the pistons doesn't look new to me - there appears to be carbon build up hiding the shiny aluminium that I would expect to see

Unless someone carefully dropped some small stones or metal objects down each of the 2/4/6 inlet ports I think the piston crown damage is historic.

I think Taxi Al might be on the right track looking for something electrical but I think it is (or was) something more basic - say a connector that was just touching rather than clicked together or a wire that is making intermittent contact - enough to break the low tension circuit to the 2/4/6 coils at a critical moment (about 50deg before TDC by the sound of it)

[Andy H]

If it was running like a bag of spanners before the heads came off there could be significant bore wash. That would kill the compression without immediate ill effects to the cylinders or piston rings (wouldn't take long before it did do some damage though)

[JamesV6CDX]

The damage to the pistons doesn't look new to me - there appears to be carbon build up hiding the shiny aluminium that I would expect to see

Unless someone carefully dropped some small stones or metal objects down each of the 2/4/6 inlet ports I think the piston crown damage is historic.

I think Taxi Al might be on the right track looking for something electrical but I think it is (or was) something more basic - say a connector that was just touching rather than clicked together or a wire that is making intermittent contact - enough to break the low tension circuit to the 2/4/6 coils at a critical moment (about 50deg before TDC by the sound of it)

I don't disagree Andy there is no way to tell when the piston damage occurred...

Are we basically saying it could run ok 100 psi down on a cylinder and that the misfire that occurred after the service is unrelated?

If we can restore compression, we will at least have a brilliant slate to start from

[JamesV6CDX]

If it was running like a bag of spanners before the heads came off there could be significant bore wash. That would kill the compression without immediate ill effects to the cylinders or piston rings (wouldn't take long before it did do some damage though)

It did 400 miles between the work and me taking the head off , plus, it didn't improve with oil  :/

[Andy H]

If it was running like a bag of spanners before the heads came off there could be significant bore wash. That would kill the compression without immediate ill effects to the cylinders or piston rings (wouldn't take long before it did do some damage though)

It did 400 miles between the work and me taking the head off , plus, it didn't improve with oil  :/

I missed that bit 

[Steve B]

Forget the rings talk...Bores look Just dandy 

[JamesV6CDX]

Forget the rings talk...Bores look Just dandy 

They aren't suggesting the rings as such, just the possibility Unburnt fuel could cause the low compression

[05omegav6]

When I did my compression test... first run at pot 6 was 4 bar instead of 9.2 bar of the second run, but that was  with a flat battery...

[JamesV6CDX]

When I did my compression test... first run at pot 6 was 4 bar instead of 9.2 bar of the second run, but that was  with a flat battery...

Yeah we thought about that, but we started at pot 6. Also revisited it again to find low compression.

We even checked cyl 135 after that to make sure the low reading wasn't flat battery, and the 135 bank was 200psi still

[05omegav6]

Fair enough

[JamesV6CDX]

Fair enough

Cheers for the thought though. Bottom line is, I really want to get this sorted for Steve

[Steve B]

First of all i would like to thank everyone on here for putting there thoughts into this one.. And i mean everyone... James for putting his time in... Al.. who must get sick of me picking his brains over the loom ...MarkDTM ...Chris..aaronjb..Andyh..Emd..Kevin wood,,ITs dragged on for 13 pages Of TBs Hard drive 

So its been over 24 hrs of james findings ......

Its time to vote 

My first thoughts were that a foreign part entered the cam 246 area From the thermostat Chisel out and got smashed up by the cams and then passed by the lifters and entered the bores....i now see that has a real stupid thought 

The main on this thread keep jumping onto Spark plug electrodes So i am going to go with that idea For now

So therefore 3 plugs lost there electrodes.....If so it was way before i bought the car... So is it they were crap plugs like Al says...Is it That a YTS put the wrong plugs in and they were too long and the piston hit them and snapped the electrodes (Then the crown will show this)And i think they would just bend.

OK So these 3 electrodes have bounced around in the cylinders Like mentioned   tickover 10 sec on the key And done this damage then the mistake was realised ...That would explain the minimal damage

And thats where i come to a end with this Fantasy post Owing to when i looked at the car prior to buying i put the code reader on it ...100 Maf Only

[JamesV6CDX]

First of all i would like to thank everyone on here for putting there thoughts into this one.. And i mean everyone... James for putting his time in... Al.. who must get sick of me picking his brains over the loom ...MarkDTM ...Chris..aaronjb..Andyh..Emd..Kevin wood,,ITs dragged on for 13 pages Of TBs Hard drive 

You're very welcome. As I said before I've no interest in who if anyone has made any potential mistakes in the cars past. I'm just trying to focus on facts with a view to getting you on the road

My first thoughts were that a foreign part entered the cam 246 area From the thermostat Chisel out and got smashed up by the cams and then passed by the lifters and entered the bores....i now see that has a real stupid thought 

I may have asked this before, but just confirm the 2-4-6 plugs were definitely not removed (exposing the bore) during the chiselling out of the stat housing/pipe? As it would be easy for a particle to fly around and enter the holes. Or the inlet ports - were they exposed or stuffed with rags?

The potential for such debris to fly when chiselling brittle alloy is high, and the smallest amount in the inlet ports or plug holes might explain what we are seeing, especially if the plugs removed during the service were definitely intact, and it was running ok before.

The main on this thread keep jumping onto Spark plug electrodes So i am going to go with that idea For now

So therefore 3 plugs lost there electrodes.....If so it was way before i bought the car... So is it they were crap plugs like Al says...Is it That a YTS put the wrong plugs in and they were too long and the piston hit them and snapped the electrodes (Then the crown will show this)And i think they would just bend.

OK So these 3 electrodes have bounced around in the cylinders Like mentioned   tickover 10 sec on the key And done this damage then the mistake was realised ...That would explain the minimal damage

Thing is. If the plugs that were removed were intact, combined with the fact it was running fine before the work, means electrode damage isn't possibly the cause. It's some other sudden event causing the sudden running problem.

We'll put it back together later and see what happens. Shit or bust, no balls no glory, hope you have lots of tea bags still

[05omegav6]

First of all i would like to thank everyone on here for putting there thoughts into this one.. And i mean everyone... James for putting his time in... Al.. who must get sick of me picking his brains over the loom ...MarkDTM ...Chris..aaronjb..Andyh..Emd..Kevin wood,,ITs dragged on for 13 pages Of TBs Hard drive 

So its been over 24 hrs of james findings ......

Its time to vote 

My first thoughts were that a foreign part entered the cam 246 area From the thermostat Chisel out and got smashed up by the cams and then passed by the lifters and entered the bores....i now see that has a real stupid thought 

The main on this thread keep jumping onto Spark plug electrodes So i am going to go with that idea For now

So therefore 3 plugs lost there electrodes.....If so it was way before i bought the car... So is it they were crap plugs like Al says...Is it That a YTS put the wrong plugs in and they were too long and the piston hit them and snapped the electrodes (Then the crown will show this)And i think they would just bend.

OK So these 3 electrodes have bounced around in the cylinders Like mentioned   tickover 10 sec on the key And done this damage then the mistake was realised ...That would explain the head damage

And thats where i come to a end with this Fantasy post Owing to when i looked at the car prior to buying i put the code reader on it ...100 Maf Only

Fixed

Had the engine been running faster, the combustion forces would have been greater and blown the debris out of the exhaust valves before they made such a mess of the heads

[05omegav6]

I vote on plug debris... anything smaller would have been irrelevant and anything bigger, such as a cam cover bolt would still be present having cracked the pistons

Hopefully the fresh head and replacement loom will see it sorted for once and all

Good effort btw