LQ4 3 Cracked Ringlands
#1
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Join Date: Sep 2012
Location: Armada, MI
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LQ4 3 Cracked Ringlands
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.
# 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.
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Stock compression 9.4:1
Heads and tops of the pistons don't look about normal for a high mileage engine. I haven't had a chance to closely inspect the heads yet.
Heads and tops of the pistons don't look about normal for a high mileage engine. I haven't had a chance to closely inspect the heads yet.
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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.
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