Pistons - Scratching, still useable?

[UncleLol]

Are these still useable? Or will I need a new set.

I have a few photos so uploaded them to a gallery on dropbox:

https://www.dropbox.com/sh/a7p8iqm1r9jwtuz/6eS5M7rgtE

Thanks for your help guys.
Another question, not sure how to tell if my pistons are a different size. Does M2008 D12 mean anything to anyone? Hoping they're standard size.

[UncleLol]

I'm changing the rings obviously, and the scratching is only on two pistons of 4.

[MarkyB]

How are the bores, are they marked and is there a ridge at the top?
You need to clean the tops and look for something like +20 stamped into them, that would be an over size.

I've reused pistons like this in the past after filing the scores with a fine file till they feel smooth.
On motorbikes when money was tight!

[UncleLol]

The bores are perfect, thats why its confusing me why there is no +20 or other kind of readings on top, because it suggests its been rebored because the pistons are damaged but the bores are perfect. The top only says m2008 D12.

[philthehill]

Personally I would replace the pistons with a new set especially as you say the bores are perfect. If the pistons are over size they are normally as you stated stamped with the oversize on the crown (top). If you have or can borrow an internal micrometre you can determine the size of the bore accurately.

[MarkyB]

Take the oil filter apart and make sure there is a spring and large washer under the filter, damage like this isn't normal.

[GBond]

Those pistons don't look healthy, I'd check the bores for roundness and look for a couple of used pistons in better shape.

If you can do it, a new set of pistons and rings will save you money in the long run I think.

[UncleLol]

Take the oil filter apart and make sure there is a spring and large washer under the filter, damage like this isn't normal.

Why would I need a spring and large washer under filter? Sorry i'm a bit of a noob when it comes to cars, only 16 and its my first car so learning.

Those pistons don't look healthy, I'd check the bores for roundness and look for a couple of used pistons in better shape.

If you can do it, a new set of pistons and rings will save you money in the long run I think.

Bores are in perfect condition, although I guess it is worth looking for a couple of good pistons to replace the damaged ones!

[MarkyB]

Why would I need a spring and large washer under filter?

They are easily lost and without them no filtration happens.

[GBond]

Just making sure, bores could look perfect to the eye but still be out of round when measured with a micrometer.

About the filter without that washer the oil can just go around it instead of through it, leading to fast deterioration of the engine insides.

Make sure you're not missing any parts of the oil filter and if possible now that your engine is dismantled check that the oil pump is still ok.

[daveyl]

If the bores are good, it could be that the oversize pistons were second hand when fitted.

[MarkyB]

I think it's just overheated badly at some time.
No + markings on the pistons says they are standard but the big end shells look pretty new.

[bmcecosse]

These pistons have been at least partially seized......hard to believe the bores are not marked. Basically they are scrap - but you can try cleaning them up - and clean away any metal that has 'strayed' into the ring grooves..... Let's see the crankshaft and the bearing shells........ Could be caused by unfiltered oil - so certainly do as advised to check the filter -and the condition of the oil pump - pictures of that would be good too....... But also could have been caused by serious overheating....... Measure the bore diameter to confirm piston size.