Carbon build up on cylinder wall.
Carbon build up on cylinder wall.
(OP)
I'm just looking for some quick input. I operate a fleet of Caterpillar 3500 series engines and have cylinder heads off of one engine for other reasons but noticed a build up of carbon on the cylinder wall thick enough the piston crown is hitting it. It is only in one portion of the cylinder and there are no other unusual deposits elsewhere. Is there a chance the injector is not atomizing properly out one port and fuel is hitting the cylinder wall? The wet appearance is because I hosed everything down with wd40 to prevent corrosion over night.





RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
If a fuel injection spray jet was impinging on the cylinder wall you would probably see thermal distress at the location.
RE: Carbon build up on cylinder wall.
MikeL.
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
The hard black carbon deposits on these engines is typically from incompletely burned fuel. If they were due to excessive oil consumption they usually have tan to brownish colored areas in the deposits from the lube oil ash. I assume you are using a multigrade DEO?
If you had raw fuel from a bad injector hitting the cylinder wall it usually results in vertical scoring of the cylinder liner. Does the crown of the piston indicate the injector spray pattern? In a lot of these engines you can see equally spaced oval "discolorations" in the bowl of the piston, number of these are dependent on which injector you have, Eight holes is most common, but also injector tips with 7, 9 and 11 holes were made.
What does your servicing CAT dealer have to say about it? The report of excessive blowby is also a concern. I have not had any experience with the new piston. I spend most of my time these days around the gas engine products when I do work around the engines. I would suggest you get your local dealer to put in a DSN ticket on it and see if CAT has any input. You can also try the CAT forums here, http://forums.cat.com/ and see if any one else is having similar issues. It would be helpful if you provide your engine serial number and the piston part number for the best possible answers.
Hope that helps, MikeL.
RE: Carbon build up on cylinder wall.
For more info, the engines run Chevron Delo 400 MG 15w40 oil. They are serial number 4TN 3512 engines. They were recently converted to epa tier 2 which involved a firing order change, new cams, and a switch from Abb turbos to Garrett. I'm not happy with any of the Garrett turbos I have in service so I am not ruling them out as a problem either.
And the white spots. They are not pits. Fretting seems the better way to describe them. If I took a sharpened pick and dragged it across the spot it would not snag.
Oddly the turbo on this bank had much oil residue in the outlet ducting while the other had a light coating of soot. I expect at 350F discharge temps most oil residue would burn. I have not had a chance to look into why one duct was oily and the other not.
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
je suis charlie
RE: Carbon build up on cylinder wall.
RE: Carbon build up on cylinder wall.
je suis charlie