A friends punto broke a cam belt on the motorway and I know it can cause serious damage to the valves etc but what are the odds, as the garage she bought it from fixed it in a couple of hours. What should i look out for if it is damaged anywhere?

Find out what engine it is and have a search to see if it's an "interference" engine.

I'd imagine the first things to check would be valves/guides, but that means taking the head off. Try a compression test to see if the valves are seating properly ?

If the engine runs ok then it is probably ok

Not all engines self destruct if the cam belt breaks - it depends if the valves can actually hit the pistons on full lift.

If there was no contact then it will be ok.

Cheers

Mark

Hi, Some engines are deigned in a way that the valves do not contact the piston once out of sync. You should be able to find this somewhere on the net. In which case all you would need is a new cam belt and away you go. If it is an interference engine then it will more than likely have damaged the piston crowns and hence will be detectable with noise and lack of power.

I agree, I have a fiat with the same engine as the early punto's which had a similar failure and no contact was made.
It is one of those situations where, had contact been made, you would have known about it!!!

Andy

[Edited on 7/10/05 by andylancaster3000]

if its the "fire" engine they are safe,16 valve jobs...take out a mortgage

If its been fixed and runs ok whats the prob? If its an 8 valve which i assume it is, theyr not a hard engine to have apart so if it did bend some valves it could easily be repaired quickly.

As conrod said if its the fire engine which i believe puntos are based on then its not a contact engine.

If even one of those valves make contact with a piston, it would almost certainly have "stuck a leg out of bed", i.e. the trauma of mashing a broken valve head around in the combustion chamber tends to "upset" the conrods, and normally one buckles and breaks, which then flails around in the crankcase, and normally makes its exit through the side of the block.

Woops.

Beware the cambelt service interval!!

AS an aside, I once saw a BMW M6 engine where the driver had gone from 5th to 3rd for a dust-up on the motorway, got over zealous in the process and hooked 1st at about 80mph. Well, the engine TRIED to do about 15,000RPM. Redline is 6,700 IIRC...

The camchain snapped, and let me tell you that an M power engine is definitely an interference engine. 2 conrods through the block, 1 piston was so badly mashed that all that was left was the gudgeon pin and a small amount of metal around it!!

The sump was full of metal powder, and i believe one of the cams had broken.

We salvaged the rocker cover.

Ed.

Thanks lads it's just a bog standard s reg and it's got no power lose or rattles so should be fine.

aaaaaaaah the joys of owning a fiat
(yes i do own a fiat)