Does My Engine Need To Be Rebuilt
Thread Starter
7th Gear
Joined: Feb 2022
Posts: 7
Likes: 0
Does My Engine Need To Be Rebuilt
So the way this happened was I was at a stoplight idling and the car just shut off. I tried to restart the engine it did I pulled into the nearest parking lot and then got it towed. I ripped the whole thing apart and found out I have a bent valve and the piston hit it do you guys think I need to replace the piston I do not a race and I am fairly gentle with the car.
Instructor
Joined: May 2022
Posts: 136
Likes: 66
From: Long Island, NY
So the way this happened was I was at a stoplight idling and the car just shut off. I tried to restart the engine it did I pulled into the nearest parking lot and then got it towed. I ripped the whole thing apart and found out I have a bent valve and the piston hit it do you guys think I need to replace the piston I do not a race and I am fairly gentle with the car.
Drifting
Joined: Feb 2017
Posts: 1,274
Likes: 399
From: Tacoma WA
2024 C4 of the Year Finalist - Unmodified
That looks more like the valve spring retainer let go and the valve dropped into the cylinder hitting the piston resulting in the bent valve stem. I have had that happen on a car previously and it did not need anything done to the short block. Repaired the head and valves and it ran until I sold it much later. It might also work in this case. You were also very lucky you were at low rpms. I had a valve drop like that at a race at about 6800 rpm and it pushed the piston out of the side of the block.
No Hostility Be Happy
Joined: Aug 2018
Posts: 10,080
Likes: 7,398
From: South Hill Wa
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified
The real question is why did the valve hit the piston? You didn't say if you found that culprit.
That is an odd pattern on the piston.
That is an odd pattern on the piston.
Le Mans Master
Joined: Feb 2021
Posts: 6,503
Likes: 4,348
From: Florida
2025 Corvette of the Year Finalist - Unmodified
2024 C5 of the Year Winner- Unmodified
2022 C5 of the Year Finalist - Unmodified
Hard to tell the extent of damage to the piston from that pic. Could be a deep scratch, or a direct hit capable of creating a weak spot.
Thing is we don’t know if the valve dropped and hit the piston and bent, causing the repeated scars. Or, if some aspect of the piston/rod broke loose ramming the valve, out of time.
I wouldn’t rule out reusing that piston just yet. Let’s get more info.
Thing is we don’t know if the valve dropped and hit the piston and bent, causing the repeated scars. Or, if some aspect of the piston/rod broke loose ramming the valve, out of time.
I wouldn’t rule out reusing that piston just yet. Let’s get more info.
Administrator
Joined: Mar 2001
Posts: 368,319
Likes: 24,777
From: In a parallel universe. Currently own 2014 Stingray Coupe.
C7 of the Year - Modified Finalist 2021
MO Events Coordinator
St. Jude Co-Organizer
St. Jude Donor '03 thru '25
NCM Sinkhole Donor
CI 5, 8 & 11 Veteran
Moved to C5 Tech.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Drifting
Joined: Apr 2007
Posts: 1,517
Likes: 159
From: Lafayette Louisiana
Do you know car’s history? Just wondering if it might have been raced or had engine work in the past. I would pull the pan and inspect bottom. Plan to replace piston and get the head reworked. Think I would also pull other side valve cover and check all looks good. Good luck! 
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,667
Good question!! I have another; is it me, or does anyone else think the extra swirl marks are from a de-carbonizing tool that was spun in a drill motor? Either that, or some PO broke a valve spring, shut it down quickly, saving the piston, changed the spring, and sold it?? An engine should run with one bent valve. I recently forgot to plug in one coil pack after I had the valve covers off, and the car fired right up, and idled mighty rough, but it did run......
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
Good question!! I have another; is it me, or does anyone else think the extra swirl marks are from a de-carbonizing tool that was spun in a drill motor? Either that, or some PO broke a valve spring, shut it down quickly, saving the piston, changed the spring, and sold it??
To answer the OP title question, yes, at this point, I would want to pull the engine apart and see what else lurks. But this is defintitely the result of a valve train issue.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,667
NEVER......Try assembling engine parts when you're over-tired! Wish I had a video of the look on my face when I did almost the same thing. I installed a melling HV Oil pump on my wet sump LS7. So, I wanted to make sure everything cleared under the timing cover. So (have you guessed it yet?) I installed the timing cover w/o the gasket, to see if the pump held it away from the block. It didn't, so it was all good. It was like 9:30pm, after a 10 hour day at work, and the wife came out to the garage wondering when I was coming in. So....I centered and torqued the cover down, and even put the rack back in, then I went inside. The next evening, I went out, and PRESTO-Theres the new timing cover gasket, laying on the bench!!!! DOHHHH!!!!!
Le Mans Master
Joined: Feb 2021
Posts: 6,503
Likes: 4,348
From: Florida
2025 Corvette of the Year Finalist - Unmodified
2024 C5 of the Year Winner- Unmodified
2022 C5 of the Year Finalist - Unmodified
NEVER......Try assembling engine parts when you're over-tired! Wish I had a video of the look on my face when I did almost the same thing. I installed a melling HV Oil pump on my wet sump LS7. So, I wanted to make sure everything cleared under the timing cover. So (have you guessed it yet?) I installed the timing cover w/o the gasket, to see if the pump held it away from the block. It didn't, so it was all good. It was like 9:30pm, after a 10 hour day at work, and the wife came out to the garage wondering when I was coming in. So....I centered and torqued the cover down, and even put the rack back in, then I went inside. The next evening, I went out, and PRESTO-Theres the new timing cover gasket, laying on the bench!!!! DOHHHH!!!!!Thats classic.
I once built a BBC and the very last detail was installing the balancer. They’re a bitch to get on and you’re not supposed to use the crank bolt to push it on. It’s late, I’m tired, didn’t have the correct tool, and…. I broke the bolt off in the crank! Had to completely disassemble the engine to have the crank snout sorted out, and then put it all back together.
Sometimes it’s just better to finish the next day.
No Hostility Be Happy
Joined: Aug 2018
Posts: 10,080
Likes: 7,398
From: South Hill Wa
2022 C5 of the Year Finalist - Modified
2021 C5 of the Year Finalist - Modified