Trying to make a long story short, purchased an 01 Z with 25xxx on it. Information from the buyer was forged lunati 383 bottom end , stock reman 243's from GM, MS3, boltons. Car burns a little oil, which was visible at idle and was a small amount. Got a good deal so I bought the car.

800 miles later and 6 months this car smokes at idle only like its on fire. Once this car reaches 120 degree oil temps the clouds begin. No visible smoke on accel, car runs like a champ and just put down 445rwhp 428 rwtq. Dosent miss a beat.

Finally got time to work on it, pulled all plugs out, electrode look normal however oil was on all threads and 2 of the 8 were saturated on the threads, no valve cover leaks. Car has a catch can, I pulled the intake and it was soaked. Oil appeared to be dripping out from behind the throttle body blade from the vent tube on the passenger valve cover. The intake valves appeared to have a coating of oil around them that was visible. Cleaned everything out with high hopes, blocked off the vent tube and ran the catch can to vent to atmosphere. Started the car reached 120 degrees and what do you no still smoking like hell. It is blue in color, and after removing the oil filler cap when it was running it was having some white smoke that was visible from there.

Any ideas from there, I am really hating to have to pull the motor right at the beginning of the season as it will be down for a period of time due to my work schedule, and at same time I cant trade it in because of the smoking issue.

Could the white smoke from the filler cap be from capping off the pcv system and not having the intake vacuum to remove the gases or is this rings? OR can the oil issue still be in the head rather than the rings?

 

Pulling the valve covers and visually inspecting the valve seals to see if any of them are crushed or have pulled off the guide top/perhaps damaged or broken guides.
Aside from that; older built 383s tended to have oiling issues as the forged pistons have a much greater piston to wall clearance and the piston pulls out of the bottom of the sleeve which unsupported skirts causes it to rock in the bore. This quickly beats up the skirts and flutters the rings which makes it difficult for them to seal off the compression and control the oil. Wiseco apparently has a better piston design and with the correct rod length it is more supported at bottom dead center and with proper machining (bore clearances) does not use oil.
I'm not saying this is yout issue but could be a poosibility.

 

Sorry I forgot to mention I already pulled the valve covers, everything that I can see looks brand new. Valve seals are blue in color and none appear to be damaged. Just purchased a compression tester so I will have those numbers sometime today.

 

Compression Test Reults

All cylinders between 170 and 180 psi.

 

Bump...

 

What kind of catch can? Some of the cans on the market really suck *** and are far too short to be effective. Is there any oil being caught in your can? I would also consider replacing the exhaust and intake valve seals on the 2 cylinders that had oil on the spark plugs. The factory seals are black (intake) and brown (exhaust)

I like the Saikou Michi dual can setup

http://www.saikoumichi.com/Stage1_LS1_page.html

http://www.saikoumichi.com/Config_LSx_2013_ver1.pdf

 

Another update. Before my last post I had pulled the intake and cleaned it out. I ran the car for maybe 10 minutes and put 1 mile on it. I pulled the intake again just now to start tearing it down and a few of the ports going into the head have a stream of oil going into them. ( This was all just cleaned a few days ago and ). During that run the catch can was vented to atmosphere and the vent tube from passenger valve cover was vented to atmosphere. With all possibilities blocked off could there be that much blow by its forcing it up into the intake from the valve and then running back down the runners?

 

The catch can has no name brand on it. The oil is also fresh, clean oil running down the runners. The heads are stock ls6 heads no port work, and were purchased reman from GM within the past few thousand miles, everything inside still looks new.

 

Bump... and another update.

Pulled passenger head off today since it was easiest. Every head bolt was covered in silver grey im assuming anti sieze and the center bolts were dripping in oil. Is this normal for an LS? The pistons are virtually spotless for how much oil is burning. However every intake valve on the head is covered in hard gritty substance almost like sand paper and can not get it off by scratching it. Cylinder 2 had oil in the CC of the head. I am hoping at this point rings are ruled out and its an issue with Head Gasket or Cylinder Head.

Not much feedback from many at this point so any ideas or comments would be greatly appreciated. I am an LT guy so LS motors are new to me.

 

The factory TTY headbolts go in dry, there is some GM orange thread locker on them, but that is it. I do put a very small dab of ARP assembly lube on the bolt heads though. I would have the heads cleaned/tanked and pressure checked. May not hurt to have the valves lapped either.

BTW can you tell if they were ported? Rocker boss/threads exposed in the intake ports? If sealant was not used on the rocker bolts with exposed threads in the intake ports, you would lose a lot of oil there.

 

These are stock unported 243 casting. Purchased from GM reman.

 

I would check the valve-valve guide clearance on cylinder 2 and any other where there is oil in the combustion chamber.

 

Ok its valve seals. Some of them are torn, some are missing the spring and others on the driver side are completely up the stem.

These are PRC .650 springs with Texas Speed Stem Seals. ( Blue top )

Question on the seating of the seals. After tapping them on the guide, should they be sitting flush with the spring seat or up a bit higher? There was about a 1/4 in gap between the bottom of the old valve stem seals and the spring seat making me believe not 1 of them was installed correctly.

 

Even a first timer knows to push the seals on as far as they will go. However something a first timer may not do is properly shim the dual valvesprings to within .060" of coil bind. This step prevents the inner spring from experiencing surge/occilation which is what happens when the valves are opening/closing about 55 times per second. Hence, destroyed valve seals.