Piston Marks

[garethcolley]

Ive just taken the head off to change my gasket and checked the tops of the pistons. 2,3 & 4 all have a highly polished area for some reason but the rest is covered in carbon. Any ideas what this is or what could cause it? I think that because its running slightly rich maybe they excess fuel is cleaning up the piston? Piston 1 is just starting to do it.

Images can be found on the following link,,,

http://i154.photobucket.com/albums/s280/monocult/Gaz/PistonPic.jpg

[meritlover]

thats pretty normal. under the plug is where the fire starts so its usually warmer there and carbon wont stick at a higher temperature.

it looks quite healthy and no det. perhaps the rings are worn causing a bit of carbon round the crown, but like meritlover says, its pretty normal.

[garethcolley]

thats pretty normal. under the plug is where the fire starts so its usually warmer there and carbon wont stick at a higher temperature.

it looks quite healthy and no det. perhaps the rings are worn causing a bit of carbon round the crown, but like meritlover says, its pretty normal.

Why would having worn rings cause excess carbon on the crown mate?

[jimbob-mcgrew]

the oil mixes with the fuel and air on the molecular level and forms a substance called cyclon-b, its prety much a recipe for coke

[jimbob-mcgrew]

lol that sounded semi-convincing

[white2lSR]

thats pretty normal. under the plug is where the fire starts so its usually warmer there and carbon wont stick at a higher temperature.

it looks quite healthy and no det. perhaps the rings are worn causing a bit of carbon round the crown, but like meritlover says, its pretty normal.


eh?

[garethcolley]

Anyone else got an opinion on the polished marks?

[Stuart]

Anyone else got an opinion on the polished marks?


as said, its where the flame front starts, and also under the inlet (iirc) meaning the fuel will clean it up a little and also the heat will keep it clean.

[Stuart]

the oil mixes with the fuel and air on the molecular level and forms a substance called cyclon-b, its prety much a recipe for coke

Thats the something new learnt for today :thumb:

[garethcolley]

Cheers lads