When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Decided to tear the LQ4 down that was in my Jeep to freshen it up. Had some noise previously but i narrowed it down to lifters, and MMO freed them up. Motor had zero noise after this, just burned a bit of oil.
# 5 was replaced about 15k ago. Thats why the piston is a little cleaner.
Anyways, everything looked good, til i pulled the pistons out.
#2, #5, and #7 are all cracked in pretty much the same spot. Upper corner closest to the front of the motor.
No real signs of wear in the bore, bearings all looked great. Lifters were good, and cam bearings were slightly worn.
I'm running less timing than stock on 93oct. Couldn't add any timing due to knock retard popping up. Motor is bone stock.
My guess is it was majorly overheated in a front end collision.
Not sure if thats sarcasm or not, but funny that you say that...
Came out of an 01 denali that rolled 7 times. I've put 30k on it since.
However, about 15k ago, I cracked the upper ringland on #5. No damage other than the piston. Swapped it out, and changed out the injector too. So being that all 3 of these cracked in the same spot, I'm thinking that it happened in the last 15k miles.
Its also overheated once on me. Threw the belt after hitting a snow drift and I didn't notice it until it was too late.
I was totally serious. The overheating causes the ring ends to close and butt together. The aluminum breaks from the pinch.
When hot rod twin turbo'd that 4.8 to over 1200 HP with the JY short block, the only mod they did was to open the ring gaps.
"Came out of an 01 denali that rolled 7 times"
Had a lo mile Silverado that rolled. The dumass wrecker driver got it up on the wheels, and tried to start it. Kicked 2 rods out due to oil in the cyls. Yours could have suffered the same fate, sans the rod damage.
I was totally serious. The overheating causes the ring ends to close and butt together. The aluminum breaks from the pinch.
When hot rod twin turbo'd that 4.8 to over 1200 HP with the JY short block, the only mod they did was to open the ring gaps.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
LQ4 3 Cracked Ringlands 
