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i have a lq4 with 243 heads along with a 228r cam, long tube headers along with a nubs intake with ls7 throttle body. I drove with it for almost a year with no issues until recently. I added a stall and built trans in it and under wide open throttle would break the spark plugs. Never have had this issue before. Well after I got back home and drove the truck it died and locked up. Tore it apart and cylinder 7 piston was destroyed, #5 piston was deteriorating and #8rod snapped. Any ideas what would cause this?
Last edited by Daniel817; Jun 7, 2018 at 01:56 PM.
You built up the trans and then didn't hold back as much as you used to and it finally gave up. I'm wondering if you dropped a valve or 2 and it became a battering ram in the cylinder.
You built up the trans and then didn't hold back as much as you used to and it finally gave up. I'm wondering if you dropped a valve or 2 and it became a battering ram in the cylinder.
no valves dropped. Only damaged due to prices of piston hitting the head and valves
Could be many many scenarios, stretched rod, worn rod bearings, broken piston. I'm gonna guess it went something like this.........WOT piece of a piston breaks off and whacks the spark plug-plugs. You replace plug-plugs continue running it hard WOT next time more piston breaks off jams piston against the head breaks rod. Could go a few other ways too. Moral of this story is GAP THE RINGS LOOSE if you are going to flog the crap outta it. Especially the top ring, the top ring got hot didn't have enough end gap and had to go someplace so it broke the piston ring land.<very bad
I've done the same thing BUT when it broke the piston I stopped driving it. You my friend made sure there was no doubt where this was going. When EVER you have a broken mashed spark plug you know big trouble is lurking.
Last edited by RockinWs6; Jun 7, 2018 at 02:10 PM.
Had launched it and it was at 6k about to shift into second. The first time it happened I used a scope inside cylinders and nothing out of order. And it was at full line.
Where did the engine come from and what did you do to it before putting the performance parts in it? If it was a junkyard motor with no known history it may have just been waiting to blow. I've seen a few junkyard motors that seem fine until you run them hard and they start to show how beat they are.
Could be many many scenarios, stretched rod, worn rod bearings, broken piston. I'm gonna guess it went something like this.........WOT piece of a piston breaks off and whacks the spark plug-plugs. You replace plug-plugs continue running it hard WOT next time more piston breaks off jams piston against the head breaks rod. Could go a few other ways too. Moral of this story is GAP THE RINGS LOOSE if you are going to flog the crap outta it. Especially the top ring, the top ring got hot didn't have enough end gap and had to go someplace so it broke the piston ring land.<very bad
I've done the same thing BUT when it broke the piston I stopped driving it. You my friend made sure there was no doubt where this was going. When EVER you have a broken mashed spark plug you know big trouble is lurking.
that's what is was wondering if the bearings were wore letting **** go farther than it should. But with the rings pushing together man can something simple like that mess a lot up. Wow! Would this be from heat shrinking the clearances together?
The factory ring gaps are set too tight, its so common to have that top ring land come off. Plus number 7 cylinder runs hot to start with. If it were me I'd be adding quite a bit to the ring gaps if you are going to run hard WOT all the time. Happened to me number 7 broke the land and it happened fast. Of course I didn't run it after I seen the plug was mashed. Once the piston looses a ring land its not long till the piston fails<see results above>
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Destroyed engine question 
