: carbonized pistons what does it mean ?



ThumperPup
12-08-10, 12:34 PM
ok this might sound dumb since i dont understand it im gona ask
just curiouse because the Shop i called to find out if the caddy would be doen in time for my road trip this weekend or if id have to rent a car
he said that chanses are he wont have it doen untill Monday since i nore him want the job to be rushed
he also mentioned to me that he spend most of yesterday Carbonzing the pistons or something liek that what does this mean exactly
what is it that he did could someone explain to me in word i could understand thank you

Submariner409
12-08-10, 03:33 PM
During the normal combustion process carbon is formed by petroleum fuels - think of it as a hard deposit of ashes on the bottom of your woodstove. Modern gasolines are formulated to chemically break down carbon deposits in everyday driving. No-lead fuels make the process even easier, and Ethanol is a powerful cleaner.

Carbon deposits which remain on the piston crowns - completely normal - are as hard as diamond - and are an unholy bitch to clean off with the engine assembled - you sure don't want to either scratch the piston crown, the cylinder wall, or get abrasive grit down by the piston rings.

So proper cleaning is tedious.

vincentm
12-08-10, 06:07 PM
Will a good premium fuel such as Shell's Or Chevron's with Techron clean the deposits over time?

Ranger
12-08-10, 09:41 PM
you sure don't want to either scratch the piston crown, the cylinder wall, or get abrasive grit down by the piston rings.
Sub, I can certainly understand the cylinder walls and grit by the rings, but how would scratching the piston crowns hurt anything? Color me confused. :hmm:

Submariner409
12-09-10, 11:28 AM
Sub, I can certainly understand the cylinder walls and grit by the rings, but how would scratching the piston crowns hurt anything? Color me confused. :hmm:

I'm a cleanliness freak - scratched piston tops look unprofessional, nothing else.

I usually put each piston at TDC, do the crown cleanup with a power wire brush, put a ring of oil around the crown and lower the piston down the bore. Any cleaning grit or carbon sticks to the oil left on the cylinder wall so it just wipes out.

TECHRON will clean or reduce combustion chamber deposits which is why GM recommends Top Tier gasolines. A 20 oz. jug of TECHRON in a fillup of 93 octane every 5,000 miles is a fuel system cleanup, not much else.

ThumperPup
12-09-10, 06:22 PM
cool thanks guys i get it and understand it better now
thanks sub for explaining like you did

ThumperPup
12-10-10, 09:56 AM
oh also just curiouse with all thats going on and i guess the cabon built up being goen totaly i know i was already getting like avg 25 to 26 mpg on the highway can i look forward to my MPG getting better atleast for a little bit of time ?
or chances are is 26 gona be the best i will do

Ranger
12-10-10, 11:57 AM
26 is about the best you will do. Maybe a tad better under ideal conditions like a good stiff tailwind.

ThumperPup
12-10-10, 12:55 PM
there was one time running on 90 heading to idaho i picked up 32mpg stedy for about 70 miles on Cruise Control
i thout it was playing games with me but since i only filled up 70 miles ago when i stoped for bathroom break i filled up again and low and behold it relaly only took like 2.2 gallons to fill up