Technical Cambelt snap

[Davies23]

Have this 2008 Fiat multipla.

Cambelt snapped, unknown circumstances as to wheather it was just starting or if it was running at high speed or the circumstances.

Decided that having it having been turned over a few times that the chances are very high a valve has bent potentially.

I’ve got a cylinder head spare that is good.

How do they do with head gaskets being changed?

Would I be better off with a complete new engine?

Is there any chance of the valves being intact.

 

[ZaphodB]

Is there any chance of the valves being intact.

There's only way to know for sure , get the head off , or use an endoscope to have a look around inside each cylinder

It turns over very quickly but no compression.

With or without a properly timed belt fitted?

I doubt you'll get any compression if the belt is not on, random chance you're gonna get any cylinder at the right point of both valves fully closed

 

[348azeus]

Often the rockers just break and the valves are ok. If you find broken rockers you may be lucky. You will need to check the water pump hasn’t seized. The circumstances are unlikely to be unknown, it’s either overdue a change or something else has seized or cause it to fail so do a good check.

 

[Davies23]

There's only way to know for sure , get the head off , or use an endoscope to have a look around inside each cylinder



With or without a properly timed belt fitted?

I doubt you'll get any compression if the belt is not on, random chance you're gonna get any cylinder at the right point of both valves fully closed

With the cambelt snapped.

Only the bottom end of the engine is turning.

 

[ZaphodB]

With the cambelt snapped.

Only the bottom end of the engine is turning.

Yeah, so wherever the top end was left at , it's odds on no cylinder is gonna have both valves closed (even if they were undamaged) so you're not gonna get any compression (with no belt or an untimed belt), and you're not gonna know if valve gear is damaged until it's inspected.

 

[Davies23]

Yeah, so wherever the top end was left at , it's odds on no cylinder is gonna have both valves closed (even if they were undamaged) so you're not gonna get any compression (with no belt or an untimed belt), and you're not gonna know if valve gear is damaged until it's inspected.

In terms of removing the cylinder head,
How do these sort of engine cope being a desiel and with the compression ratios is it more viable to replace the whole engine?
I wouldn’t want to do the head gasket for further issues to evolve further on.

 

[ZaphodB]

The engine's stuffed at this moment , you need to get the lid off to see what level of damage there is (if any)

 

[AnthonyH]

The car is vvt as far as I know so the engine is destroyed beyond economic repair.