Trying to diagnose whether my timing has slipped.

[Ryannn982]

Hi everyone, I’m a bit stumped with this issue so hoping someone can help!

Got a 2003 172 that I’ve been planning to use for motorsport. Unknown timing belt history and I’ve only had it a few weeks.

Driving it particularly hard today and under deceleration I hear a large metallic rumbling noise and the car cut out. Tried to restart on the key and it just turns over with no compression.

On further investigation, the alternator belt is frayed with strands hanging down below the pulley but the timing belt is still on. When rotating the engine by hand, all 3 visible pulleys move however the engine does lock at a specific point.

Is it possible that one of the pulleys has moved causing the valves to meet their neighbours? I’ve had a timing belt go before and this has the same characteristics but the belt appears to still be round all the correct pulleys!

If anyone could offer any advice that would be great, I’m just in the process of getting the head off.

 

[NorthloopCup]

That sounds like a idler pulley has failed or the aux belt tensioner is seized and made the belt come into contact with the cambelt. That'll have fucked the head mate.

 

[Ryannn982]

Never had a pulley fail which is annoying! Belt is still tight aswell.

Need to source a new head sharpish!

 

[NorthloopCup]

Tbf mate, it may have just dropped a valve.

 

[Dr HMS Derv Destroyer]

Aux belt strand has probably found its way behind the bottom pulley , jumped the belt a tooth and smashed a valve ( or more )

Only other explanation is a dropped valve

 

[bloke]

rip 8 valves.

 

[Ryannn982]

I’m going to get another head rather than get this one repaired for now, just for a quicker turn around. The engine was great before so I’m loathed to buy another, depending on the state of the pistons obviously!

Before I waste too much time, is it far quicker to take the engine out to change the head and belts? I’m handy with a set of spanners but I’m working to a short time scale.

Cheers

 

[JB21]

Sounds similar to what happened to mine first time around.

https://www.cliosport.net/threads/just-broken-down-aux-belt-part-gone.813161/

 

[Ryannn982]

Spent the last couple of days stripping the car down to take the engine out as it’s clearly loads cheaper to get a complete unit than a head!

Part way through and I’ve found the cause of the shredded alternator belt... a sheared air con pipe. I think it’s been snapped by my radiator which is very loose, how exactly should it be secured?!

Anyway... least I know now...

 

[Ryannn982]

That’ll do it...