Valves stuck open from carbon
Valves stuck open from carbon I just got done preping a engine that I thought I was going to stuff a cam in and pump and put in my 99ss but now were heading off track .The engine has so much carbon crap that its on the valve face(seat) and when I put some air pressure into them (with the rockers off) allmost all of them were leaking major amounts of air past them ..so I pulled the heads and holy **** they were loaded tops of the pistons and the combustion chamber and the valves only on combustion side of the valves not in the runners with a very small amount in the intake runners and it looked wet ...what would cause this it looks like flaky black oily carbon and the trail come from the intake ports and they are clean were the fuel sprayed into the head the engine does not look beat or blow by bottom end is nice, bores are clean no piston rock or major scores or any stuff that looks like it would have done this .......................
Launching!
Joined: Sep 2008
Posts: 234
Likes: 0
From: Ashland,VA
I just got done preping a engine that I thought I was going to stuff a cam in and pump and put in my 99ss but now were heading off track .The engine has so much carbon crap that its on the valve face(seat) and when I put some air pressure into them (with the rockers off) allmost all of them were leaking major amounts of air past them ..so I pulled the heads and holy **** they were loaded tops of the pistons and the combustion chamber and the valves only on combustion side of the valves not in the runners with a very small amount in the intake runners and it looked wet ...what would cause this it looks like flaky black oily carbon and the trail come from the intake ports and they are clean were the fuel sprayed into the head the engine does not look beat or blow by bottom end is nice, bores are clean no piston rock or major scores or any stuff that looks like it would have done this .......................
I was planning on doing the ls6 pcv set up I have all the stuff to do it and its part of what I was planning . this is normal on these engines to have this much crap going in to the combustion chamber
Launching!
Joined: Sep 2008
Posts: 234
Likes: 0
From: Ashland,VA
yep its normal. some are worse than others. Is the car a daily driver or what. I mean the LS6 setup is better but if eliminating the system is an option for you that would be better. you have to put a breather where your oil fill cap is.
Its a 99 SS 6spd build got it blown up putting in a s ls1 w/ 241 an ls6 intake TREX cam ported ls6 oil pump textraila OZ700 clutch new pacesetters no cat / magnaflow ect...I feel the need to build a toy
Launching!
Joined: Sep 2008
Posts: 234
Likes: 0
From: Ashland,VA
PCV was just put into place because some EPA people decided that crankcase gasses were too harmfull for the atmosphere so lets suck it back into the intake to burn it off. PCV is not used to lube anything. That much oil being sucked in could actually carbon coat the rings and cause them to get stuck in the ring groove. The newer DOD 5.3s and stuff are having a problem with oil spray from the valve in the oil pan coating the rings too much and making them stick. Its causing them to burn 2-3 qrts every one or two thousand miles. Little different from your case as the oil problem is from the bottom of the piston and not the top. still the same idea. doesnt sound like you will be driving it everday as it is a toy so i would remove the pcv system and put a breather on. alot of guys on here have done it with no issues.
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PCV was just put into place because some EPA people decided that crankcase gasses were too harmfull for the atmosphere so lets suck it back into the intake to burn it off. PCV is not used to lube anything. That much oil being sucked in could actually carbon coat the rings and cause them to get stuck in the ring groove. The newer DOD 5.3s and stuff are having a problem with oil spray from the valve in the oil pan coating the rings too much and making them stick. Its causing them to burn 2-3 qrts every one or two thousand miles. Little different from your case as the oil problem is from the bottom of the piston and not the top. still the same idea. doesnt sound like you will be driving it everday as it is a toy so i would remove the pcv system and put a breather on. alot of guys on here have done it with no issues.
The best bet for him would be a good catch can if it's the pcv, not a cheesy empty can with two hoses running into it, but a good can. PCV's were not just for emissions, it also was to help ring seal, and remove condensation and water (after it boils out of the oil), it also removes other vaporized contaminants.
There are unfortunately alot of people who think pcv's are for emissions only, they arent.
To get back to the original poster, I have seen nitrous motors that looked like that after the rings got fried.... there is more than one way for oil to get in the cylinder (valve seals, rings, pcv) Just saying pcv without diagnosis is ignorant.
TECH Senior Member
Joined: Feb 2009
Posts: 5,445
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you can have carbon build up on the valve seats also from a over rich tune up.the factory tune up is over rich.I had 1 intake valve leak when aired up and changing springs.the car had 10,000 miles.I removed the heads cleaned them up ,not removing the valves or springs and it sealed up.use water or solvent to check for valve leaks.
