Wellll.....
Thread Starter
Instructor
Joined: May 2019
Posts: 126
Likes: 11
From: ARIZONA
Wellll.....
Temps outside were 106f that night and car was running cool around 215. Had good oil pressure and 50%ethanol. Car ran through 3rd like a champ felt so strong. Hit 4th and it fell on it's face. No sounds of breaks, booms, grinding. Just a flashing check engine light and a p305 code for #5 Cylinder misfire. I was near home and because I heard no sounds or saw and drastic changes on the dash. I limped it there.
Got home no leaks, no visible signs of damage. So I was thinking I have a bad coil, plug, or wire.
Drove it around the next day just to verify and Temps got warm fairly quick and I noticed debris on the windshield so I pulled over.
The pics are what I witnessed 🙈😬
Pulled #5 plug and this is the damage
Any input or suggestions would be great as I haven't pulled it apart yet.
Thanks,
Joe 👊
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,149
From: SW Florida
2021 C6 of the Year Finalist - Modified
I don't see any damage ... All I see is a photo of the front bumper cover and hood with engine oil splattered over it.
Where is the photo of the damage ?
Is the car a GS, Z06 or ZR1 ? . . . There is nothing about the car in your profile
Where is the photo of the damage ?
Is the car a GS, Z06 or ZR1 ? . . . There is nothing about the car in your profile
Thread Starter
Instructor
Joined: May 2019
Posts: 126
Likes: 11
From: ARIZONA
Thread Starter
Instructor
Joined: May 2019
Posts: 126
Likes: 11
From: ARIZONA
Sorry all the pictures didn't upload
Safety Car
Joined: May 2016
Posts: 4,609
Likes: 1,802
From: Erlanger, Kentucky
Where is all the oil coming from? What do you mean debris on the windshield?
To me it looks like catastrophic engine failure. Only way I can think as to why the electrode of the spark plug is bent is something let go like a connecting rod or piston. Add in the oil all over, you likely need a new engine.
To me it looks like catastrophic engine failure. Only way I can think as to why the electrode of the spark plug is bent is something let go like a connecting rod or piston. Add in the oil all over, you likely need a new engine.
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Le Mans Master
Joined: Dec 2005
Posts: 6,994
Likes: 1,677
From: Southeast TX
My guess would be piston related. Don't think it would be running smooth if the problem was in the valve train. Detonation will bugger up spark plugs. That, or a piece of the piston slamming into it before exiting out the exhaust. A broken piston will increase crankcase pressure and oil will be forced in a lot of different directions that oil wasn't designed to flow.
Intermediate
Joined: Feb 2011
Posts: 27
Likes: 2
Time for a compression test. If No. 5 is low, just start pulling the motor apart. See if the heads can be saved.
I had one where the lands on the piston gave way - top of piston looked OK. Car idled OK, compression was way off (about 1/2 the other cylinders).
I pulled the oil pan and looked up, still looked OK. I went to clean the oil pan in the parts cleaner and I found bits of piston rings and some small aluminum ring lands. Note: this was a deep sump racing oil pan and the bottom was welded square/right angle and the bits were disguised and dirty oil hiding in the corners.
Light hone on the wall, new piston, back in business.
I had one where the lands on the piston gave way - top of piston looked OK. Car idled OK, compression was way off (about 1/2 the other cylinders).
I pulled the oil pan and looked up, still looked OK. I went to clean the oil pan in the parts cleaner and I found bits of piston rings and some small aluminum ring lands. Note: this was a deep sump racing oil pan and the bottom was welded square/right angle and the bits were disguised and dirty oil hiding in the corners.
Light hone on the wall, new piston, back in business.
Team Owner
Joined: Dec 2012
Posts: 30,427
Likes: 1,609
From: Outside the Quick Stop N.J.
Drain the oil and cut open the filter, I suspect that you will find plenty of metal in there.
Just out of curiosity, why would anyone continue driving without at least taking a look under the hood ?
Just out of curiosity, why would anyone continue driving without at least taking a look under the hood ?
Pro
Joined: Apr 2019
Posts: 690
Likes: 415
From: Armonk, NY
Looks like a dropped valve, probably exhaust. Severe detonation is not going to bend the ground strap without peppering the ceramic and rounding the edges. That looks like mechanical damage. If it pinched a ring land the piston would hold together. That looks like the valve finally broke apart and punched it up into the plug. Perhaps the pieces stayed in #5 and didnt go up into the intake manifold and back into another hole!
Hopefully you got lucky with minimal damage.
If I had an LS7 I would 100% go with a non OEM casting. It is just not worth it as the "fixes" seem to not last more than 25k miles!
Hopefully you got lucky with minimal damage.
If I had an LS7 I would 100% go with a non OEM casting. It is just not worth it as the "fixes" seem to not last more than 25k miles!
Race Director
Joined: Mar 2011
Posts: 13,262
Likes: 3,149
From: SW Florida
2021 C6 of the Year Finalist - Modified
Titanium is great for manufacturing jet engine turbine wheels, but I don't want titanium valves or connecting rods in my engine.
EDIT: . And, I agree with you that it might be better to just use aftermarket heads (such as Trick Flow, etc) and stay away from trying to 'fix' GM LS7 heads.
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Last edited by Turbo6TA; Aug 12, 2021 at 04:41 PM.