Bought a set of cp pistons and have just been cleaning them up when i noticed this.
Assuming it's caused by det?
Is it ok to use? Crown is mint no damage whatsoever
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Bought a set of cp pistons and have just been cleaning them up when i noticed this.
Assuming it's caused by det?
Is it ok to use? Crown is mint no damage whatsoever
Sent from my SM-G900F using Tapatalk
New rings and a bit of a polish and it should be fine.
When you say polish, Does the area need to be smooth?Originally Posted by Actual_Ben_Taylor
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Just use some Fine (1500+) emery paper and light oil, it doesn't need to be "Mirror" polished, just smooth to the finger nail. Don't use polish and a buffer wheel for instance as it will take off too much material and round off edges.
Be sure it is scrupulously cleaned before rebuilding though.
if it is only one mark on the piston,possible two or more piston ring gaps were lined up,if it was det there would be more damage at the top edge of the crown
like some sort of pitting /metal loss to the ringland above the top ring but that looks ok (in that blurry pic) ,
maybe the bore was marked? as it is strangely bang in line with the oil squirter cut out
imo leave it alone as trying to remove the mark will create a tiny flat edge, the rings seal the piston is 'just' filling the bore
The oil jets spray under the crown and the oil is channelled so it runs off on the side away from the jet. If the jet was part blocked the spray pattern can be deflected.
You won't get det at the top ring, it will be at the top of the piston and the shock goes though the gap, that hits the top ring which breaks the 2nd ring land. The top edge of the piston and anti-det grooves are intact. It does look like something has been wiped up and down the bore between the piston and bore wall. From the gold colour it looks like turbo bearing but I don't think you have enough material to do a spectroscopic analysis.
If you had the block.
I'd suggest looking for something embedded in the bore wall.
And are the oil filter housing pressure relief valves intact? The balls can be knocked out and then it by-passes un-filtered oil. If the filter blocks the by-pass opens.
If you had the turbo I'd say inspect it.
but with just a set of pistons you don't have access to all the evidence.
Get a high magnification lens, x20 or better and a good light, inspect the whole mark for foreign material. Groove at 2nd land looks like it needs very close inspection as there is something a bit brighter in there.
Unfortunately i dont have the block nor turbo.
Their is some pitting there.
There is nothing at the top near the crown it's just above the the ring.
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Where did you get the pistons from?
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