OK-Some of you might of remembered that I put the 4.8 out of its misery or should I say I put my misery of the 4.8 away. I killed a TR-6,piston,valve,and had some head damage so I put in a low mileage LS1(10k miles). 4 days after I got the truck up and running I started to get a nasty knocking. Everyone thought lower end somehting to do with a rod most likely a spun bearing. Well after completely disassembling the LS1 the problem was found but the cause is still up in the air. The rods and bearings were in great shape but 2 pistons had some dimples 1 of them had like 3 or 4 small dimples but the other one looked alot nastier than it really is. Some how a piece of metal of some sort got on top of these two pistons and eventually went out the exhaust(it was nowhere to be found). The knocking was the sharp edges of the dimples hitting the heads. Im real happy about dimpling the piston tops in 4 days!

If I would have to guess at what the peice of metal was I would say it was either that original TR-6's ground strap maybe got caught somewhere in the heads or when the heads were getting repaired originally maybe the guy at the machine shop chipped something and it finally broke free. I dont know its just real crappy. It could ahve been a whole lot worse I guess. I should be back running tomorrow or Wed! Im gonna go ahead and start saving for a Lunati rotating assy! All I want now is to be able to enjoy the LS1 for more than 4 days this time and get some track and dyno #'s

 

well good luck to you. may there be no more problems so you can enjoy it as you so choose.

 

Yea, good luck.. Im keeping my fingers crossed for ya.

 

Damn, that sucks. So i am assuming you the dimples were not too bad and it all got put back together?

 

Interesting that you had more than one chamber with that symptom. Glad its nothing worse. Make sure the shop completely checks out the heads and cleans out any debris left inside. Check the intake while its off too.

 

Yeah everything was disassembled-intake and all. The thing is one of the piston tops had like 2 or 3 small dimples and then two psitons away had 10+. I think it was #1 and #4. The only think I could see what happened there wa smaybe it was getting sucked in and pushed out the valves. What ever the case it ahd to of happened real quick. The heads had some minimum marks on them but nothing that is really going to matter. Weird deal though! Good news is at least I know the rods,bearings,pistons(mainly cosmeticlly damaged now),etc... are all up to par. I should be driving Tomorrow!

 

in this situation, i would carefully inspect the valve straightness on the affected cylinders. it would cause a low power problem and may be otherwise hard to troubleshoot.

 

was it a cig. lighter in your motor ??? (rgvsierra)

 

The place that is doing the repairs checked everyhting out thoroughly and they were actually suprised at the shape of everything. So one good thing I got out of this is to know that the lower end is in good shape!

 

Hurry up and get that thing back in there, I wanna go for another ride!!!