PHIL928

I just got my new boroscope
What do you guys think of this piston? It seems like it's pitted and cracked, but the car was running fine. The second cylinder looks the same, I haven't looked at the others yet.

Is this normal?
http://youtu.be/WMG58PLJw40

Rob Edwards

Looks like the light show at a Pink Floyd Sound gig in 1967. Looks also like a mix of carbon and (normal) machining marks up close. My vote is it's fine, 'specially if it's running fine.

atb

"That's one small step for man....."

BC

Is that broken aluminum?

Herman K

Carbon build up - Time to decarbonise

brutus

Does the gasoline in Dubai have any additives for cleaning ?

toofast928

Detonation, cylinder is runnig lean. !

Dave928S

I'm battling to make a lot of sense of it. It's not until you can see the valve reliefs that you can put things in perspective, and in context/scale of things around them. It's also hard to know whether we're seeing pitting or build up ... the black bits could be either.

I'm thinking probably just normal carbon build up.

I have an optical borescope that has a wide field of view and looks at right angles to the shaft, so that you can see across the pistons, see the bore, and also the valves and head chambers, head gasket and valves. You'll get way more information if you can you put a mirror adapter on yours to look sideways, or adjust to get a wider field of view.

milkman383

Which scope do you have, this is a pretty nice unit, but agreed the right angle ones are helpful as well.

This definately looks like just normal buildup, and no problems. Carry on! :-)

toofast928

39 seconds in shows great pic of piston pitting. Cylinder ran lean or is lean. If not corrected those pits will become a hole in the top of the piston.

milkman383

Yeah, that picture is not super clear, but I can see that as pitting, and I can see that as just build up/deposits. Only way to know for sure is to ****** the head off and check it out, or see if you're getting a lot of aluminum flakes on the plugs. That's a decent scope, but it's by no means ideal. :-(

PHIL928

That's not good to hear :/
I don't think they run any additives in the fuel, I think it's just pure petrol out of the refinery, nothing is advertised anyway.
I'll drive it for a while with some decarbonation additives to see if it improves, any recommendations for these? are there alu specific ones?
The scope is actually pretty cheap, it's called "super eyes", didn't come with a mirror attachment though.

Here's a pic from the second cylinder. I think you can clearly see some pitting in this one

Dictys

Phil,

When we took your intake apart we noticed a lot of oil in the intake, this may have accerated the carbon build up in your cylinders.

Not sure about the fuel out here do you use special or super? I use the super which is meant to have a higher octane and some cleaning stuff in it.

PHIL928

ahh yeh good point! there was alot of oil, i reckon that the oil I was running was too thin, causing lots of oil vapours. I just just bought some thick oil
I tend to use 98, but there was a period a couple of months back where the stations only had 95, so I had to run that.
The other thing that could have caused running lean was that all my injectors were blocked, so not enough fuel was getting in.

GregBBRD

Carbon.

Look closely. You can still see the lathe marks from machining the piston, where you think there is pitting.