Dropped Tappet - Update

Initially they thought it might be the tappets, but could see nothing

Almost certainly consequential on the head job they carried a few months ago. Try and prove it though! 'Plug/key' whatever that is- corroding when it's completely and continuously swamped in oil? Tappets are barrel shaped devices that are pushed by the lobes on the camshaft to open the valves. They are cushioned by oil pressure-hence the clicking sound at startup with a worn engine when there is low pressure. They cannot contact the pistons but valves can when the timing goes out- such as when a mechanic forgets to check for wear in the sprocket keyway and key when replacing the camshaft. DaveK.

Thanks Dave - the confusion between tappet and valve is probably my fault. They have also mentioned trying to drill the end of the camshaft and drive-in a pin, apparently to compensate for the corroded plug/key. Does that mean anything to you?

Regards Jools

If we are talking about the key which the camwheel is located by on the outer end of the cam shaft: This key is purely for location, once the bolt securing the cam wheel is correctly fastened then it plays no further part, in fact if everything is done up properly then you don't even need a key at all. Therefore if the key has become damaged in any way then the camwheel securing bolt has been left loose. It would usually have been removed and replaced during a head job. If the garage don't offer to fix it completely free then you can ask for (and pay for ) an independent engineers report and sue them for the repairs. You 'should' win , but nothing is certain :)

mrcheerful

After five months! You're having a laugh Mr Cheerful? If such long liability was to become a reality then the cost and risk of any remedial work would become unsustainable for any business and most importantly for the customer. S*it happens. Get over it and move on to find a practical and economical solution.

Huw

S*it happens. Get over it and move on to find

Good advice. In most situations that end up with lawyers-there's two winners, neither of them being you. DaveK.

A reasonable person would expect that a repair would be carried out to a reasonable standard, that would include doing things up properly. I agree that if for instance the head gasket had failed unaccountably again then there would be difficulty in a claim, but this 'sounds' like poor workmanship.

mrcheerful

Sounds like they're taking you for a ride.

The crankshaft sprocket is located in position with a woodruff key (half-moon shaped bit of metal, fits in a cut-out in the crankshaft and the sprocket itself), but as another poster said, once the pulley has been bolted on it would be clamped firm anyway. The camshaft(s) have a roll pin (quite literally, a pin made of rolled steel) inserted into a hole on the camshaft end to locate the sprocket on. These can work loose and fall out, but only when the sprocket is removed as the retaining bolt has a large washer which cover the pin. I suppose it is possible they could corrode, but again, the sprocket retaining bolt and washer should be enough to hold firm.

If the timing had slipped as they suggest, and the noise was the valves hitting the pistons, then your engine wouldn't be scrap anyway - as it still runs at the most it would probably need 8 valves replacing. However, if the pistons and valves were meeting then I wouldn't expect your engine to run at all - the inlet or exhaust timing would be so far out, and the noise would be terrible and probably accompanied with backfiring, etc.

Assuming they are right though, the garage would have had to remove the camshaft sprockets in order to do a proper head job on the car (how else could they replace the camshaft oil seals!?), so surely they should have noted the corroded roll pins? The roll pins don't corrode right through that quickly in that environment and I'd expect them to have noticed them starting to when they removed the sprockets. However, five months does count against you...

I'd still be tempted to get some s/hand tappets from the scrapyard and do it myself just to see if that improves it - much cheaper than a new engine or head and you could also check the state of the roll pins, etc. whilst you're at it.

Darren

If the valves hit the pistons then the engine would have stopped, you may well have a shagged camshaft but you'll be wanting to try a different garage with a clue.

I'm with mrcheerful on this one. The garage replaced the head 5 months ago. They say the timing slipped due to something failing due to corrosion. Even if that were true, which I doubt, it suggests that the item was already corroded when the head was fitted, as it's doubtful that significant corrosion would take place within

I think 5 months is a little long for a problem to develope. I would have thought it would happen long before then. I'm not family with the this engine, but would like to know is it a tapered shaft that camwheel is fitted. Is there any damage however small (if tapered shaft) Does the keyway LOOK corroded, or does show signs of damage to one side. Have you acually seen the key with your own eyes. Is there any damage to it, and does the damage MATCH the damage on the keyway.

Theory 1, if the camwheel locating diameter is tapered and has damage on it, it could work it's loose due to vibration, even if bolted. Once loose enough it would set about damaging the keyway and key.

Theory 2, Was the key actually fitted when locating camwheel to shaft.? I have know engineers to 'line up' the edges of keyways in shaft and camhwheel when the key is lost and bolt in position.

IIRC that engine has a plain shaft end (no taper) and the wheel position is located by a roll pin.

mrcheerful

Why was the head replaced on such a new car? Was this also the garage's fault? Was`the replacement head a new one or an used one of unknown provenance? Only the OP and the garage know this and they must decide on what remedial action to take in the circumstances. I see s*it hitting the fan in this way on a regular basis, sometimes effecting me directly as a consumer, and most of the time absolutely no one is to blame. Unless there is a clear basis for allocating blame, then one is on a hiding to nothing but possibly causing ill-feeling all round.

Huw