piston gone on just bought car

Iand1

poppasmurf_bewdley wrote: »

Piston broke?

like me on a Friday night

Strider590

Ok..... Realistically to know a piston has broken, you'd have to strip the engine down..... There are too many other possible faults that would look like a piston failure, compression tests could indicate anything from HG failure to a sticking valve.... Unless the person who's told you this has actually removed the head (or used a pin hole camera down the spark plug hole) and possibly stripped out the bottom end (A seriously MAHOOSIVE JOB), then I don't see how they've come to this conclusion.


Edit ~

Let me just add that I have experienced a broken piston (caused by 3rd party negligence) and when a piston breaks it usually misaligns, this bends the con rod, shatters the piston, cracks the engine block and as the piston breaks up it hit's the crankshaft, it gets launched through the sump at high velocity, creating holes that look like gunshot exit wounds and a nice big pool of engine oil.

marlot

Strider590 wrote: »

Ok..... Realistically to know a piston has broken, you'd have to strip the engine down..... There are too many other possible faults that would look like a piston failure, compression tests could indicate anything from HG failure to a sticking valve.... Unless the person who's told you this has actually removed the head (or used a pin hole camera down the spark plug hole) and possibly stripped out the bottom end (A seriously MAHOOSIVE JOB), then I don't see how they've come to this conclusion.

I was just thinking the same thing!

If the engine was running fine when the car was purchased then its very unlikely that the seller can be held to blame. And unless the engine has been stripped down, I'd doubt a diagnosis of piston failure.

atrixblue.-MFR-.

ive know ford festa's 1.3 to have piston failure and not go like strider has described but as a percentage they mostly go as strider describes.

ford fester piston failure, 1.3 endura engine, push rod slipped past rocker jamming valve person drove with it for ages as garage (ford dealership) told customer that all ford festers of that age have loud tappets 1 smashed piston top and no compression later, garage wanted to fit new engine.

mattyprice4004

karen2947 wrote: »

friends son bought a car from a private seller (£4000 cash) a week ago and today the piston head has gone on it, friend rang the seller but he basically said 'tough' bought as seen and he had no problem with it as far as he was concerned its now her sons problem. is there anything my friends son can do?

The seller is right, you have no comeback.

If you want a warranty, you buy a car from a dealer. If the car had gone bang on the way home, you'd have no redress.

Tetley_the_Cat

Strider590 wrote: »

Ok..... Realistically to know a piston has broken, you'd have to strip the engine down..... There are too many other possible faults that would look like a piston failure, compression tests could indicate anything from HG failure to a sticking valve.... Unless the person who's told you this has actually removed the head (or used a pin hole camera down the spark plug hole) and possibly stripped out the bottom end (A seriously MAHOOSIVE JOB), then I don't see how they've come to this conclusion.


Edit ~

Let me just add that I have experienced a broken piston (caused by 3rd party negligence) and when a piston breaks it usually misaligns, this bends the con rod, shatters the piston, cracks the engine block and as the piston breaks up it hit's the crankshaft, it gets launched through the sump at high velocity, creating holes that look like gunshot exit wounds and a nice big pool of engine oil.

Not true.

It's possible to determine exactly what has happened by pressurising the cylinder with compressed air and looking for the leakage. Now this is ages old diagnostic stuff. Modern wise one woud use a boroscope, quite cheap now to film the cylinder internals.

Broken pistons do not also mean the rod is bent in all circumstances or that it blows the engine apart. With respect I don't think you know a lot about internal combustion engines other than what you see. Engines with piston failures do so with many causes but by design you would not see a piston through the sump. A rod may be where the big end has let go.

Strider590

Tetley_the_Cat wrote: »

Engines with piston failures do so with many causes but by design you would not see a piston through the sump. A rod may be where the big end has let go.

My Westfield has an alloy sump with a large patch welded to it, which im afraid would argue with that statement.... Piston shattered into small pieces, fell down into the crankshaft and bust their way through the sump. All because the fool at the rolling road, lost a bolt inside my inlet manifold and decided not to go looking for it.....

atrixblue.-MFR-.

had a 95 mondeo, blew a huge hole in the engine that big the piston complete with conrod flew out of it.

mad an absolute mess to the front of the car and bonnet where metal shards peirced the bumper, grill radiator ,lights and the rest followed upwards putting dents in the bonnet, i knew it was on its way out at the complete racket the valves were making and knocking, took a chance and drove it less than a mile to put it off road made it just shy by about 400yards. needless to say i slammed a 1.8 zetec engine in it complete with everything needed to complete the conversion, run sweet as a nut then i sold it on bad bits had a metalic purple silver bonnet bumper and grill on a navy blue car donor car was a rear ended s reg with 45k on it.

mikey72

Strider590 wrote: »

My Westfield has an alloy sump with a large patch welded to it, which im afraid would argue with that statement.... Piston shattered into small pieces, fell down into the crankshaft and bust their way through the sump. All because the fool at the rolling road, lost a bolt inside my inlet manifold and decided not to go looking for it.....

A bolt down the inlet manifold would fall into the inlet valve, and get stuck in the valve seat. It's unlikely to make it into the engine.
Either way, if it sticks the valve open, or sits on top of the piston, it will stop the piston dead on the upstroke, before tdc.

The con rod will bend , the piston may shatter, the crank may go, as will the big ends, the con rod may go through the block, and yes even the sump.

Not because the piston shattered, but because of the shock of stopping it dead on the bolt.

boyse7en

mikey72 wrote: »

A bolt down the inlet manifold would fall into the inlet valve, and get stuck in the valve seat. It's unlikely to make it into the engine.
Either way, if it sticks the valve open, or sits on top of the piston, it will stop the piston dead on the upstroke, before tdc.

The con rod will bend , the piston may shatter, the crank may go, as will the big ends, the con rod may go through the block, and yes even the sump.

Not because the piston shattered, but because of the shock of stopping it dead on the bolt.

I helped a mate strip his 1340cc Mini engine back when I was at university.
When we got the head off, you could see a perfectly hexagonal hole punched through the top of one of the pistons. A nut had gone down the inlet manifold, somehow got through the valve and then acted as a cookie cutter when the piston came up.
Unfortunately the nut and the bit of piston crown fell down into the gearbox and made a right old mess of it.