Carbon Build up? - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Buschman · 03-11-2017, 06:16 PM

My 1LE is in the shop getting some work done, and I was just emailed this picture. It's a 2015 LS3 with 14k miles on it. It looks overly excessive to me, and I'm told that the valves are not sealing.

Any thoughts on what would cause it? I'm guessing that the car has been running rich. It has had high flow cats for the last 5k or so miles.

The heads are coming off, checking for bent valves. I just want to make sure we locate and fix the issue causing it.

The car has had a catch can and clean side since new (2 miles on the odo).

15rs/ss · 03-11-2017, 06:22 PM

all of them look the same?

Buschman · 03-11-2017, 06:23 PM

I was told yes, but this is the only picture they sent.

Russell James · 03-11-2017, 07:47 PM

Compression and leak down tests.
Scanner readings.
Any check engine light?
Any driveability issues?

All before teardown so you know what to look for. Scanner readings will call out how it's running. Compression and leak down will tell the mechanical condition.
Also good to read the spark plugs.

Without a cranking compression and leak down test, and scanner observations while driving.... that carbon could be meaningless or something.

Could have just been not romped on enough lately. Putz around, do a bunch of cold starts in the winter... can carbon up quick. Then it blows out on a highway romp. Sensor issues like a bad O2, coolant temp... can carbon up stuff quick.

There's no way to tell what if anything is wrong by a sooty ext port. Might have just had a few cold starts and not driven much before the manifolds removed. Something seriously wrong would have set a light/code, most likely.

AFR is controlled by O2 and MAF while in closed loop. Coolant temp sets the cold start AFR. So those are the sensors to watch on a cold start and transition to closed loop. A mechanical problem like a valve would be a misfire.

Russell James · 03-11-2017, 08:06 PM

I put headers on my 1LE at 6000 miles. Just looked at the manifolds, pretty sooty like they all look.

I doubt there is anything wrong with it. Pull a couple spark plugs. If they look great, doesn't burn oil, misfire, or set codes...no problemo.. Exhaust ports are suppose to look sooty.

Buschman · 03-11-2017, 08:24 PM

Quote:

Originally Posted by Russell James

Compression and leak down tests.
Scanner readings.
Any check engine light?
Any driveability issues?

All before teardown so you know what to look for. Scanner readings will call out how it's running. Compression and leak down will tell the mechanical condition.
Also good to read the spark plugs.

Without a cranking compression and leak down test, and scanner observations while driving.... that carbon could be meaningless or something.

Could have just been not romped on enough lately. Putz around, do a bunch of cold starts in the winter... can carbon up quick. Then it blows out on a highway romp. Sensor issues like a bad O2, coolant temp... can carbon up stuff quick.

There's no way to tell what if anything is wrong by a sooty ext port. Might have just had a few cold starts and not driven much before the manifolds removed. Something seriously wrong would have set a light/code, most likely.

AFR is controlled by O2 and MAF while in closed loop. Coolant temp sets the cold start AFR. So those are the sensors to watch on a cold start and transition to closed loop. A mechanical problem like a valve would be a misfire.

No codes and the car drove great for the 120 mile trip to the shop. They confirmed the leaking valves with compressed air. the heads are coming off to be milled and ported so it will be fixed soon.
They were not too worried about it, I just want to make sure I address any issues.

L99CAMA2011 · 03-11-2017, 08:30 PM

This is mine at 127000 miles with cam. Questions, what oil do you use,how often do you change your oil and also do you have a lot of bumper to bumper traffic to contend with that can lead to extreme carbon buildup. Is the calve not sealing because of the excessive carbon?

L99CAMA2011 · 03-11-2017, 08:35 PM

One more picture. Engine feels very strong though and honestly in my case a new set of ported heads would fix this issue in my case.

Buschman · 03-11-2017, 09:42 PM

Oil was changed at 2,000 5,000 10,000 and at 14,500 just before I put the car up for the winter. They think the carbon build up is causing the valve to not seal, but the heads are coming off anyways so they can check it all over.

I ran it for about 30 minutes once a month since December (in hind site most likely not a good idea). Temps were close to freezing on the 120 mile drive to the shop I'm using. So I took it easy, I still think it was running rich but it kind of makes sense now.

I'm pretty sure if I would have got on it a few times most of it would have cleared out. I'm guessing that the build up is because of the long idle times over the winter. No worries though, like I said the heads are going to be milled and ported anyways.

Thanks for the help!

InFiD3ViL · 03-12-2017, 08:26 AM

Wow, that is nuts for the mileage.

Good luck man!

JD555 · 03-12-2017, 08:52 AM

With the amount of black I get on my exhaust tips from a long ride and a couple romps I am not surprised they look like that. I have a Tundra that has 120,000 on it and the pipe is clean. These engines run rich.

NC_SS · 03-12-2017, 10:02 AM

Try some WOT pulls a few times a week, then check back and see if it's not blowing that garbage out

Scotty D · 03-12-2017, 11:39 AM

The dealer replaced my pistons ,rings, cam , liftes cause of carbon build up !!

pir4te · 03-12-2017, 10:27 PM

For comparison pics are after running flex fuel (rich) for 100k miles. The headers are almost 10 years old, were rusted and sooty inside on install.

On tear-down all the internals were spotless and in good order, this sort of explains it:
[ame]https://youtu.be/jdW1t8r8qYc[/ame]

03-11-2017, 06:16 PM	#1
Buschman Drives: 2018 ZL1 2015 1SS 1LE Join Date: May 2013 Location: North Eastern Michigan Posts: 772	Carbon Build up? My 1LE is in the shop getting some work done, and I was just emailed this picture. It's a 2015 LS3 with 14k miles on it. It looks overly excessive to me, and I'm told that the valves are not sealing. Any thoughts on what would cause it? I'm guessing that the car has been running rich. It has had high flow cats for the last 5k or so miles. The heads are coming off, checking for bent valves. I just want to make sure we locate and fix the issue causing it. The car has had a catch can and clean side since new (2 miles on the odo). Attached Images __________________ 2018 ZL1 2015 1SS 1LE Stock...ish

03-11-2017, 06:23 PM	#3
Buschman Drives: 2018 ZL1 2015 1SS 1LE Join Date: May 2013 Location: North Eastern Michigan Posts: 772	I was told yes, but this is the only picture they sent. __________________ 2018 ZL1 2015 1SS 1LE Stock...ish Last edited by Buschman; 03-11-2017 at 06:35 PM.

03-11-2017, 08:06 PM	#5
Russell James Drives: '15 SS 1LE, '69 Z28 drag car Join Date: Dec 2009 Location: Mich Posts: 4,483	I put headers on my 1LE at 6000 miles. Just looked at the manifolds, pretty sooty like they all look. I doubt there is anything wrong with it. Pull a couple spark plugs. If they look great, doesn't burn oil, misfire, or set codes...no problemo.. Exhaust ports are suppose to look sooty. Attached Images

03-11-2017, 08:30 PM	#7
L99CAMA2011 Drives: One of the baddest handling Gen 5s Join Date: Feb 2011 Location: Masachusetts Posts: 4,177	This is mine at 127000 miles with cam. Questions, what oil do you use,how often do you change your oil and also do you have a lot of bumper to bumper traffic to contend with that can lead to extreme carbon buildup. Is the calve not sealing because of the excessive carbon? Attached Images Last edited by L99CAMA2011; 03-11-2017 at 08:43 PM.

03-11-2017, 08:35 PM	#8
L99CAMA2011 Drives: One of the baddest handling Gen 5s Join Date: Feb 2011 Location: Masachusetts Posts: 4,177	One more picture. Engine feels very strong though and honestly in my case a new set of ported heads would fix this issue in my case. Attached Images

03-11-2017, 06:22 PM	#2
15rs/ss Drives: 2015 Yellow 2SS LT Z28 cai tune Join Date: Aug 2015 Location: Tallmadge,Ohio Posts: 208	all of them look the same?

03-11-2017, 07:47 PM	#4
Russell James Drives: '15 SS 1LE, '69 Z28 drag car Join Date: Dec 2009 Location: Mich Posts: 4,483	Compression and leak down tests. Scanner readings. Any check engine light? Any driveability issues? All before teardown so you know what to look for. Scanner readings will call out how it's running. Compression and leak down will tell the mechanical condition. Also good to read the spark plugs. Without a cranking compression and leak down test, and scanner observations while driving.... that carbon could be meaningless or something. Could have just been not romped on enough lately. Putz around, do a bunch of cold starts in the winter... can carbon up quick. Then it blows out on a highway romp. Sensor issues like a bad O2, coolant temp... can carbon up stuff quick. There's no way to tell what if anything is wrong by a sooty ext port. Might have just had a few cold starts and not driven much before the manifolds removed. Something seriously wrong would have set a light/code, most likely. AFR is controlled by O2 and MAF while in closed loop. Coolant temp sets the cold start AFR. So those are the sensors to watch on a cold start and transition to closed loop. A mechanical problem like a valve would be a misfire.

03-11-2017, 09:42 PM	#9
Buschman Drives: 2018 ZL1 2015 1SS 1LE Join Date: May 2013 Location: North Eastern Michigan Posts: 772	Oil was changed at 2,000 5,000 10,000 and at 14,500 just before I put the car up for the winter. They think the carbon build up is causing the valve to not seal, but the heads are coming off anyways so they can check it all over. I ran it for about 30 minutes once a month since December (in hind site most likely not a good idea). Temps were close to freezing on the 120 mile drive to the shop I'm using. So I took it easy, I still think it was running rich but it kind of makes sense now. I'm pretty sure if I would have got on it a few times most of it would have cleared out. I'm guessing that the build up is because of the long idle times over the winter. No worries though, like I said the heads are going to be milled and ported anyways. Thanks for the help! __________________ 2018 ZL1 2015 1SS 1LE Stock...ish

03-12-2017, 08:26 AM	#10
InFiD3ViL Drives: 2010 CGM 2SS/RS LS3 Swapped A6 Join Date: Sep 2016 Location: Spring Hill, FL Posts: 4,570	Wow, that is nuts for the mileage. Good luck man! __________________ 2010 CGM Camaro 2SS LS3 Swapped A6 - GPI LS3 SS1 .647/.638, (224/237, 112 +4, 7º overlap) on CamMotion 8620 core, BTR Platinum .660" Dual Spring kit w/titanium retainers, CHE bronze trunnion upgrade, stock heads milled @ .015, Melling HV 10296 oil pump, TSP 1-7/8" long tube headers (W/Catless Off-road Pipes), Corsa Xtreme 3" Catback, GPI Ported/Rod Mod Intake, Stage 2 Ported Throttle Body, Vararam OTR CAI, Mike Norris Gen 2 catch can + GM 1LE clean side separator, 160º thermostat - Megan Racing adjustable coilovers (lowered 1.75"), MRR M017 10/11" wheels-Tuned by Ryan @ GPI

03-12-2017, 08:52 AM	#11
JD555 Drives: 2014 2SS RS, 6 sp man Join Date: Feb 2016 Location: Marlton, NJ Posts: 461	With the amount of black I get on my exhaust tips from a long ride and a couple romps I am not surprised they look like that. I have a Tundra that has 120,000 on it and the pipe is clean. These engines run rich.

03-12-2017, 10:02 AM	#12
NC_SS Drives: 2012 M6 Camaro SS (RIP) Join Date: Nov 2014 Location: Virginia Posts: 1,684	Try some WOT pulls a few times a week, then check back and see if it's not blowing that garbage out __________________ Speed engineering 1 7/8 LTs, CAI inc Cold Air Intake, offroad connectors, Solo performance axle back with J pipes, tune, and in need of a driver mod LOL

03-12-2017, 11:39 AM	#13
Scotty D Drives: 2014 1le 1SS CRMT Join Date: Apr 2014 Location: Boston mass Posts: 1,178	The dealer replaced my pistons ,rings, cam , liftes cause of carbon build up !!

03-12-2017, 10:27 PM	#14
pir4te Moonshiner Drives: Holden SS-V L77 flex fuel Join Date: May 2012 Location: Sydney, Australia Posts: 166	Carbon Build up? For comparison pics are after running flex fuel (rich) for 100k miles. The headers are almost 10 years old, were rusted and sooty inside on install. On tear-down all the internals were spotless and in good order, this sort of explains it: [ame]https://youtu.be/jdW1t8r8qYc[/ame] __________________ Compression is King. Naturally as-pirated, all-motor, all alcohol.