/My dad and I rebuilt my the LT-1 in my '95Z in '03. A rod bearing had spun. We replaced the crank, put in a comp cam, rebuilt the heads, put in new rings, but kept the original pistons. There was some light scoring in the bore, but the guy who put the cam bearings in said it wasn't enough to warrant boring. I've since put 90k on the motor.. fairly hard miles, but always kept the maint. up, reg oil changes. A year or so ago I noticed some haze in the headlights of cars behind me after I had gotten on it.. i was hoping it was my car running rich.
I"m not running a cat, but I am running a muffler. I was autox'ing the car this summer on a day when I was about 98 deg. out.. and I noticed the oil pressure dip into the red while I was waiting in line for another lap.. And.. after letting my sit about a week, when I fired it up it blew blue smoke out. and if I reved it, it would blow more out. I realize that is probably from the oil seals leaking, however even after the motor has been running for 20 mins it will still blow some smoke at WOT.. and you can see a puff in between gears... wtf?

I thought I would get 180-240k on this motor before it needed another rebuild..

 

It depends on break in and quality of parts used.. How often were you racing or auto crossing the car??

 

You have well over 100K on the original pistons and run the car hard. 7 years on the rebuild doesn't sound all that bad to me...

If you get oil smoke on shifting, it's likely due to valve seals....

 

the car its self has 210k on it.. supposedly the motor had been replaced at 80k due to a punctured oil pan causing a lock up.

I didn't think valve stem seals could cause smoke at WOT? I thought only.. at start up after they had let oil leak into the cylinders.

The car has only been autox's once.. but I take it out on the twisties now and then and treat it like a race.

I did have a friend who had a mitsu gallant that would smoke going down the road and it was valve stem seals.. That was an OHC motor though.. I don't see it happening on a OHV motor..

 

Stem seals don't do the smoke at WOT...that's rings. On shifting, with the throttle closed, cylinder vacuum climbs and sucks oil through the valve seals and you get the puff....

 

I also see the smoke when I blip the throttle in neutral. I guess I need to go to WOT.. and not let off.. and see if it smokes then, it may only be smoking as soon as I let off. That'd be nice if it was only valve stem seals..

 

So today.. I reved, then held it for about 10 seconds..without letting off the throttle. It still blew smoke out.. so I guess that means its the rings...

 

That's what they invented a leakdown tester for.

 

Ya... reving to high hell in neutral isn't the way to test the rings. Do a leak down test and you will know for certain if you have an issue or not.

 

Although, revving to high hell in neutral is a great way to test the bearings...

Stop taking advice from whoever told you that the light scoring wasn't enough to warrant boring. Sounds like you got quite a bit of use out of your rebuild. This time do it better. A good build is stock crank w/ forged rods and pistons bored .030 over. put in a decent cam and now you have reliable power.

 

This.

Your pistons and bores were worn out the first time around, only a fool thinks they can eye ball the size on a cylinder bore and say it's ok to use again without tools.

 

Thanks for the advice.. I may go with a 383 cast crank.. larger cam and ported heads.. this car had been my daily driver so I wanted to keep it mild.. but I'm now DD'ing an '87 cherokee that's been a project over the last year. I need to repaint my camaro.. and I'll probably leave the motor as is of for a couple years and save up for the rebuild.

 

VIDEO!!!!

yes haters i have a single exit muffler that comes out behind my rear tire.. I put it on to pass inspection..

http://s192.photobucket.com/albums/z...t=MVI_1575.flv

The car had been sitting for 4 days before I started it. After driving the car around.. it only blows out a small puff at WOT.