Need help post cylinder head swap....this cant be normal?!?
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Le Mans Master
Joined: Sep 2002
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From: Redacted
Need help post cylinder head swap....this cant be normal?!?
FINALLY finished up swapping a set of Livernois Stg 3 heads onto my 2003 Z06. After triple checking everything last night, I started her up and she ran just fine. No bad lights, no leaks, holds 40 PSI oil pressure between 8-900 RPM at idle. I let it run for about ten minutes just to get it up to operating temp. What concerns me is the amount of smoke coming from the engine compartment. Now having had this thing apart numerous times, Im very familiar with the smoke generated as the car heats up and all the oil, coolant, dirt, grime burns off the headers but after that stopped, I still had a good amount of smoke coming from what looked like behind the intake by the firewall. Additionally, the exhaust was red hot from the headers back, see below.....
Ive honestly never looked at the exhaust under the car while it was running, but those cats are glowing red.
Lastly, there was a bit of black smoke puffing out of the exhaust. Im assuming that is largely due to the lack of updated tune yet. I will be making an appointment at Virginia Speed to have them do a full dyno tune. Any thoughts are much appreciated.
Ive honestly never looked at the exhaust under the car while it was running, but those cats are glowing red.
Lastly, there was a bit of black smoke puffing out of the exhaust. Im assuming that is largely due to the lack of updated tune yet. I will be making an appointment at Virginia Speed to have them do a full dyno tune. Any thoughts are much appreciated.
Thread Starter
Le Mans Master
Joined: Sep 2002
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From: Redacted
so what about the tune is causing the exhaust to get so hot? It already had a cam in it, which had a tune when I did the install years ago, and again last September. The only change I made this go around was the cylinder heads...has the added airflow really thrown things out to the point that the exhaust is getting that hot?
Thread Starter
Le Mans Master
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From: Redacted
Melting Slicks
Joined: Jul 2012
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Heads alone should not be making the cats glow like that, especially just idling. They are supposed to get up in the 5-600 degrees F range I seem to recall to work correctly. Shoot an infrared thermometer at the and see what temp they are.
Burning Brakes
Joined: Mar 2005
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My question to the op would be did he own the car and live in the same area all along or did he buy it modded already from some other part of the country and not retune it in new area. If thats the case it could have been close to lean because of altitude. Too many factors at play to just say it wont make that big of a difference.
Thread Starter
Le Mans Master
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From: Redacted
On a stock engined car, I doubt you would get that big of a difference with just a head swap. But this car was already cammed and tuned for that came and previous heads. From my experiance a custom tune will not be as flexible as what the general puts on factory stock cars. I have seen this before, especially on a car that may have been running the ragged edge.
My question to the op would be did he own the car and live in the same area all along or did he buy it modded already from some other part of the country and not retune it in new area. If thats the case it could have been close to lean because of altitude. Too many factors at play to just say it wont make that big of a difference.
My question to the op would be did he own the car and live in the same area all along or did he buy it modded already from some other part of the country and not retune it in new area. If thats the case it could have been close to lean because of altitude. Too many factors at play to just say it wont make that big of a difference.
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Tech Contributor
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From: Dyer, IN
Not knowing exactly what you did, i.e. looking over your shoulder, it's impossible to make that assessment. Sounds like you need to take it to a qualified shop for evaluation.
Racer
Joined: Jun 2012
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From: LAUREL MD
Lean
Did you check to see if all of your vacuum lines and were reconnected properly? Clean MAF? Check fuel pressure regulator/filter? I would try these first before running engine and, if OK, then take it to a mechanic.
Thread Starter
Le Mans Master
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From: Redacted
I ordered FAST 36lb injectors but havent installed them yet because I was planning on driving it down to the shop to have it tuned and was told that you dont want to install bigger injectors withou tuning it immediately. With the current lean condition, Im just going to trailer it down anyway so Ill probably install those tonight and let the tuning gurus at VA Speed sort it out.
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Le Mans Master
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From: Redacted
Drifting
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From: Florida
St. Jude Donor '09
On the contrary, catalytic converters typically glow red as a result of unburned hydrocarbons (oil blow-by, raw fuel) entering the converter and burning within it.
Team Owner
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Thread Starter
Le Mans Master
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From: Redacted
so what would cause the timing to suddenly be way out from a simple head swap? The motor was turned over by hand a few times during the torquing sequence on the rocker arms per the maintenance manual, but the timing chain was never removed, hell the cover wasnt even taken off.
Thread Starter
Le Mans Master
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From: Redacted
ok, well either way, at idle, it runs fine with no indications of anything being off mechanically so its going on a trailer down to VA Speed late next week and Ill let the tuning experts sort it out. Ill post results once I have them. I do appreciate the input 
Team Owner
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From: Central PA. - - My AR15 identifies as a muzzleloader
I believe in the Beer Fairy
with this. Ok, internal engine parts hot because of lean condition, fine. But, the Cats? I'm not buyin it. They have to have fuel burning inside them in order to get red hot, and red as they are, they're at 12-1300F. Absolutely a dangerous condition, and I am glad to hear you're trailering it to get it looked at. There's a boatload of unburnt fuel going out the exhaust.
Originally Posted by 3boystoys
Heads alone should not be making the cats glow like that, especially just idling. They are supposed to get up in the 5-600 degrees F range I seem to recall to work correctly. Shoot an infrared thermometer at the and see what temp they are.
Le Mans Master
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From: Farmington CT
Cruise-In VII Veteran
1. you commented on EGR, C5's never had EGR(unrelated to topic here)
2. Tuning, your in VA Beach area.........simple, Ed Hutchins http://www.hitechtuning.com/contact/
2. Tuning, your in VA Beach area.........simple, Ed Hutchins http://www.hitechtuning.com/contact/