If one was to snap how much damage could you expect to find?

I ask because some engines are made so that the valves and pistons can't meet each other, not knowing this engine too well I wondered if it will smash itself up or just come to a halt.

I can't think of any diesels that are not interference designs as it is the easiest way to get the high compression ration required for ignition in a sensible space.

If one snaps in a 1.9PD you are talking total engine write off or at least a couple of thousand pounds to fix it.

Valves will impact the pistons and it won't be pretty.

Yep, I agree with Mr Monkhai.

Surely the only way you could do that would be if the pistons didn't ever extend further than the combustion chamber? Other than antiquated sidevalve and hemispherical units, I can't see how this is possible???

Lots of old petrol engines didn't have interference designs.

The compression needed wasn't that high, so essentially with the pistons at TDC they were not high enough in the cylinder to impact the valves when they were fully down.

You can easily do this, but when you need to start putting the compression ratios up quite high you need to move to an interference design.

Thx guy's, it's what I thought, but it's better to confirm than guess.

I remember years ago I came off a motorway in my MK3 Cavalier and at the next traffic lights the engine died as I went to pullaway. Cam belt had gone. Got AAed to my local garage. 2 hours later i was back on the road. I had had the repacement cambelt on sitting on the back seat as I had been meaning to get around to doing it for ages!!! Very lucky escape and I learnt my lesson.

Always wondered why it didnt go on the motorway at high revs rather than pulling away from the lights.

I remember years ago I came off a motorway in my MK3 Cavalier and at the next traffic lights the engine died as I went to pullaway. Cam belt had gone. Got AAed to my local garage. 2 hours later i was back on the road. I had had the repacement cambelt on sitting on the back seat as I had been meaning to get around to doing it for ages!!! Very lucky escape and I learnt my lesson.

Always wondered why it didnt go on the motorway at high revs rather than pulling away from the lights.

You get most stress on a belt while pulling away. Were the old Cavs not known for snapping the belts as IIRC the AA used to carry them in their vans.