burned out valve, change them all?

Well by the time you've disassembled it all the marginal cost should be quite low. I can'rt remember ever only getting one done. But thereagain I'm not old enough to remember valves burning out in 62K. Any idea why it was sticking?

It is relatively low, just wondering whether to apply the if it aint broke don't fix it ethic, given that one wouldn't imagine valves would have an issue at this sort of mileage.

I dunno. Mechanic reckons it may have overheated, I have never noticed but then Fiat saw better of putting a thermometer on it.

If they look fine they probably are, but you wouldn't expect a duff valve at all & they'll all have come from the same batch.

I could be wrong but I though the jtds stored fault codes.

I have a fault code reader, there was a stored fault but it came up as some sort of manufacturer specific code and I cleared it so we'll never know :(

Personally I'd fit a new set of exhaust valves & check the valve guide clearances before putting it together again, then hope for the best. If it got that hot there'd probably be some other evidence.

the burn out could just be due to a tight valve clearance, it is almost never checked on ohc engines. If all the other valves look in good condition then by all means just give them a clean, light grind and reset the clearances.

Mrcheerful

So what are the others like? If you can get a good seat on them, there's no reason to change.

The likely cause for a burnt valve is that it was already sticking, owing to crud buildup on the stem. Any others with crud may already have burned, any that are clean are most unlikely to have suffered at all.

I dunno, I haven't seen them.

I'm just trying to qualify what the mechanic is telling me, getting the usual 'while its in bits might as well do them all' thing.

With the best will in the world, a 'mechanic' isn't really the best person to be advising you. An experienced engine builder and machinist will be able to tell if there is a specific fault that can be attributed to that one valve and whether the rest look fine or not. Mechanics actually get to look inside engines fairly rarely and what they understand of what they see while doing so is debatable.

Hence the suggestion to change them all, as that'll be cheaper than getting somebody competent to look at it.

As someone is probably (ideally) going to have to cut the seats and reface the valves anyway, if that person has the requisite experience the advice will come free of charge. The mechanic will only farm that work out anyway.