Hey, so I recently bought a 2004 lq4 short block for 800 bucks. After assemebling the block we put in my truck. A few minutes later we hear a ticking nosie. Turns out to be that piston 5 bearing spun. So I take the motor out fix it and put it back in. Started up the truck and ran fine for about an hour. Park in and I happen to see smoke comming out, open the oil cap and Blow by is present. Did a compression test and all cylinders were at 150 except for cylinder 7 which was at 100. SO could this be bad piston rings, or bad valve guides. Im Stumped..

 

Seeing as how it's #7 I'm going to guess that it's got a broken piston. That's a common cylinder to have go lean. Seen a lot of guys here with broken ringlands from detonation.

 

Exactly what I didnt want. Bummer!! Thanks for the quick reply. I spoke with the guy whom I bought the motor from and he said that they will take care of it. Keeping my fingers crossed!!

 

Good luck, keep us updated!

 

That sucks man. good luck!

 

Cracked ring or broken ring land, good luck!

 

Man that sucks someone must have ran the **** out of that thing. Do you know what they were doing with it in it's previous life?

 

The motor was out of a burned truck. The yard wanted 500 for it and he told me for another 300 he would put new rings and bearings. So i thought i got a pretty good deal for 800. I guess not right...

 

My motor was running lean for awhile. I have ~66k miles and just did my rings and had a valve job done. Do a leakdown test to be sure where you are losing compression

 

well here is a video of how the smoke looks... I am going to do change out the valve guides..

http://www.youtube.com/watch?v=iVQ40qRUoeg