what killed this 1242cc 16v FIAT engine?

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GeX

GeX

GeX

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Anyone take a guess at what went wrong to kill the engine because i don't know.

It happened at low speed, approaching a junction, car stalled, PAS was lost (suggests bottom end was stationary to me)

belt_teeth.jpg


Teeth stripped, that must've been the crank pulley?

Belt is only half the width it is meant to be, and has a groove in the back of it

belt_groove.jpg


that groove matches the damage on edge of the tensioner;

tensioner_damaged.jpg


looks like it had been rubbing on something, but there was nothing there for it to hit. i couldnt get the tensioner to go anywhere near close enough to the head.

tensioner.jpg


inlet manifold was full of water / oil

inlet_oil_water.jpg


as was the pipework from the airbox to TB.

All 8 inlet valves are bent; (exhaust prolly are too, but not pulled the head yet - didnt have the right RIBE tool :rolleyes: )

bent_valves.jpg


had been driven for about 15mins before this happened and after the car stopped, it blew its coolant out the cap.

So what caused it, and what are the results of that. I can't work out which is which! (i know bent valves is cos the belt stripped, it didnt snap though). Engine is not siezed solid, and can be turned over with spanner on the respective pulleys.
 
yeah, hence why the valves are bent. But i dont get what caused that damage to the belt or its tensioner.
 
thats possible, i've only seen the car after all this happened to it - i have already sourced a new engine got the old one ready to drop - but am just curious about what killed it!
 
I've had an alternator belt cut nicely thru my cambelt/alternator belt cover in the past... I guess it could be anything really...

Good luck with the engine swap! :)
 
Could just be that the tensioner is shot and was causing the belt to run over it at a slight angle and hense rub. Is it not a Fire enginge (safe) or is that just the 8v engine ?
 
Whats the state of the fanbelt? a large portion of cambelt failures are caused by broken fanbelts getting behind the crank pulley.
 
Yep auxiliary belts (no such thing as fan belts these days :D) are a prime suspect. You say the PAS stopped, is the pump drive belt intact (that is, if it's hydraulic, if it's a Punto it will have an electric column I guess).

Is it possible something could have have been rattling around inside the cam cover (e.g. e.g. a nut/bolt or a stone)? Was the tensioner and any idler pulleys fully tightened up?
 
I think the answer is *cough* Fiat made it?

Which one is it out of curiosity? My mate had a brava that went through 3 head gaskets by the ripe old age of about 55,000 and 6/7 years old! The water might suggest that this was happening to this one as well.
 
If the head gasket failed and water got into the cylinders, because water cant compress like air, it can cause this kind of problem i think, momentarily ceasing the engine (which could damage the cam belt) and the valves contacting the pistons. Because theres so much water and oil in the inlet, it seems like the head gasket failed first.
 
teulk said:
Could just be that the tensioner is shot and was causing the belt to run over it at a slight angle and hense rub. Is it not a Fire enginge (safe) or is that just the 8v engine ?
Click to expand...

it was new 2 years ago, and looks to be in good shape. Like i said though, there is no way that the 'furred' edge on the tensioner could have come from hitting the head as it was at least 10mm away from it. I need to get the belt covers and look at them.

Its off a 16v, so it's not safe (as you can see in the picture!). Any FIRE engine is (stock) safe.. but the 16v is SuperFIRE..so not safe at all!


Dogbreath said:
Yep auxiliary belts (no such thing as fan belts these days :D) are a prime suspect. You say the PAS stopped, is the pump drive belt intact (that is, if it's hydraulic, if it's a Punto it will have an electric column I guess).

Is it possible something could have have been rattling around inside the cam cover (e.g. e.g. a nut/bolt or a stone)? Was the tensioner and any idler pulleys fully tightened up?
Click to expand...

the aux belt is fine, and car is a Brava which has a hydraulic PAS. The loss of PAS, and the stipped teeth which match the crank pulley suggest to me that the bottom end seized momentailiry (as if it had been hydro-locked).

As far as i know there was no fod in the inside the head, and the belt tension was all correct.

Like i say though, what i dont understand is the water / oil. If the HG had failed and hyrdolocked the engine then it would have all this damage, bar the tensioner and belt cut down to half width. Unless it was just coincence?
 
The only way that a snapped belt would cause the water in the cylinders would be if the damage to the valves/head was so bad as to rupture the cooling jacket. Once you have the head off you should be able to see where the water got in. However it would be more likely that the head gasket failed causing the engine to hydrolock and thus snapping the cambelt.
 
which couldn't have damaged the tensioner, or belt in the way it has been.

My theory;

Tensioner failed, collided with the cam belt cover. The belt was pulled over toward the edge of the tensioner and was worn away by the belt cover with the edge of the tensioner (hence the groove). It pulled it over far enough to pull it off the coolant pump (has ridges on the pulley to prevent, will inspect for debris). As it came off the coolant pump, the tensioner managed to keep enough tension in the belt whilst their was load on the engine. No coolant flow cooked the head (enough to jam the HT leads to the plugs), blowing the headgasket, hydrolocking the engine, stripping the teeth and smacking the valves into the pistons.

The damage to the belt is from it rubbing on something, there are fibres from it all over the place, and jammed into the 'vents' on the alternator - suggesting it was spinning as the belt was failing. The belt never snapped, only wore down and then stripped teeth off it.
 
The fluid in the inlet tract may well be a result of the damage which was caused by the belt failure which was caused by whatever.

Oil could have got down a damaged valve sleeve, or any one of a number of methods...
 
GeX said:
had been driven for about 15mins before this happened and after the car stopped, it blew its coolant out the cap.
Click to expand...

Just noticed this. Does the timing belt drive the water pump? If so bearing failure in the water pump, or something caught in the impeller vanes could have caused this.
 
I'm not so sure about the bottom end seizing causing the cambelt to strip. Surely nothing that is driven off the belt has sufficient inertia that it'd be able to do that, particularly at low engine speed.

EDIT - Dogbreath's post makes more sense, with a seized water pump you've still got the crank driving the belt which would then strip it.
 
kaiowas said:
I'm not so sure about the bottom end seizing causing the cambelt to strip. Surely nothing that is driven off the belt has sufficient inertia that it'd be able to do that, particularly at low engine speed.
Click to expand...

Force of the valve meeting the piston in the FREE engine usually causes a big end bearing failure. So it's not far fetched actually.
 
Dogbreath said:
Just noticed this. Does the timing belt drive the water pump? If so bearing failure in the water pump, or something caught in the impeller vanes could have caused this.
Click to expand...

Yes it does drive it. The waterpump at the moment spins freely, but thats not to say something didn't jam it. I will take it out and check for damage. Its pulley is of similar size to the crank pulley. Will be stripping the engine tonight, atm its all sat there ready to come out but i didnt have the tools to get the head (just got some now).

Whilst the cam / coolant pump couldn't pull enough load to strip the belt, remember that this belt has been worn down by something is less than half the width of what it is meant to be. It's quite seriously comprimised.
 
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