Sprinting at Debden today, had a bit of a problem, just coming up to the finish line on my second pratice run, foot flat down on the throttle pedal and bang. Came across the line with smoke, steam, oil pouring out everywhere. My helmet and visor were covered in gunk, it was everywhere. Pulled off to the side and got out sharpish as there was smoke pouring from under the bonnet and there was a nasty looking oil and water mix dripping from everywhere. Got towed back to the paddock and found a damn great hole in the crankcase.
Rescued attachment Crank.jpg

Obviously done for the day so we trailered it home and started poking about, number 2 carb looks like this, bits of metal everywhere, both sides of the butterfly (we've now cleaned it up and it actually appears undamaged)
Rescued attachment Carb1.jpg

ooffff, least you did it properly

Number 2 plug looks like this
Rescued attachment Plug.jpg

ouch, you're also in a game over for this summer position. I destroyed my rear axle 2 weeks ago.

At least it's all repairable.

Haven't seen many zetecs go bang like that, you know the cause already?

replied too fast and didn't see th eother pictures, that looks nasty, possible head damage too. Metal stuff coming throught the valves = not good

Guess when you drop the sump you'll get to see a disaster

[Edited on 11/7/10 by Werner Van Loock]

And the sump could do with a clean
Rescued attachment Sump.jpg

Something air filter side disintegrated and got into the engine?

Good job zetecs cost pennies.

Did you win?

[Edited on 11/7/10 by iank]

quote:

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Originally posted by norfolkluego
And the sump could do with a clean

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Simple question really, is there something wrong with it?
Seriously, when I saw the hole in the crankcase I assumed the bottom end had gone but it seems the piston has let go. If you shine a torch in the hole in the crankcase(it's that big!!!) and lookg down the spark plug hole you can see the con rod apparently intact, the mangled remains of the pin and no sign of a piston at all, none.
1. What would cause that kind of failure.
2. Anyone want to buy a Zetec (slightly used - £500 ono )

piston desintegration could be caused by it running lean and having high speed knock going on, as you have injection throttle bodies it could mean 1 of the injectors not delivering the same amount of fuel as the others at high speed. mostly a hole is burned into a piston, but it can also desintegrate when going well wrong

Does the zetec have oil squirters aimed at the bottom of the piston? If one of those got blocked it could also be the cause icw runnig lean

quote:

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Originally posted by Werner Van Loock
piston desintegration could be caused by it running lean and having high speed knock going on, as you have injection throttle bodies it could mean 1 of the injectors not delivering the same amount of fuel as the others at high speed. mostly a hole is burned into a piston, but it can also desintegrate when going well wrong

Does the zetec have oil squirters aimed at the bottom of the piston? If one of those got blocked it could also be the cause icw runnig lean

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quote:

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Originally posted by iank
Something air filter side disintegrated and got into the engine?

Good job zetecs cost pennies.

Did you win?

[Edited on 11/7/10 by iank]

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ouch that is very bad.

hope you get it sorted, or maybe a new or seconded hand engine in soon.

stuart

Looks like oil control problems to me, lack of oil pressure, has caused the big end to fail, causing the damage to the block, the piston will have then hit the valves and spark plug etc, pushing/blowing debris back out through the carbs
Could be down in part, to the extra grip you would have been getting on a hot day, on the new R888.

In my experience running lean tends to burn a hole in the piston.

My bet would be on big end failure allowing the piston to hit the head.

Davie

Feel for you, looks like time for a upgrade. Was it a silvertopor a blacktop.

Was a Blacktop, more than happy with another one as it's a cracking (no pun intended) engine in that car

The normal failure for a zetec is the con rod bolts letting go hence the need for arp bolts. If as you say the bottom end is ok then you must have been running very lean and detonated the piston. Oil supply causing the little end to dry out?

Bottom end looks OK, obviously haven't stripped it down but looking through the new 'viewing window' the bottom end looks OK, the piston however looks to have been totally destroyed.
Edit.
Just prior to it going pop we'd taken the plugs out to have a quick check on how the engine was running (a rough and ready check I know but still not a bad indicator) and the plug colour looked spot on. Having said that, the engine did feel very hot, temp gauge was reading around 100.



[Edited on 11/7/10 by norfolkluego]

have you taken the head off yet? this can also be caused by a dropped valve..

quote:

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Originally posted by mookaloid
have you taken the head off yet? this can also be caused by a dropped valve..

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What pistons (Cast or Forged) ?
What revs when it let go?

Standard pistons so cast.
We had a soft rev limit set on the Megajolt at 7200 and I'm assumung thats what it was doing as I was accelerating as hard as possible towards the finish line and didn't want to change up.

Hi

Anyone wondering where the center electrode of that plug has gone - or am I being simplistic?

Regards Mick

quote:

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Originally posted by Mix
Hi

Anyone wondering where the center electrode of that plug has gone - or am I being simplistic?

Regards Mick

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I'll throw out another vote for a dropped valve.

Been there, done it before. The piston was annihilated and smashed to pieces but the lower portion of connecting rod was pretty much perfect.

Finally got inside it today. Not a dropped valve, they're fine, piston has disintegrated completely, nothing left of it at all, not a trace, con rod actually looks pefectly heathly, pin is still in place and looks in remarkably good nick considering.
Looks like it was fuelling or ingition or a combination of both (of course I'm making the assumption there was a piston in there to start with )
Just possible I suppose that the piston had an inherant fault that was waiting to go. Interestingly one of the MSA officials down at Debden who saw me blow up came over just to check I was OK, said before we even lifted the bonnet, 'bet it's number 2 cylinder, quite common', he was right.

[Edited on 17/7/10 by norfolkluego]