tmonttt

iTrader: (10)

Here's a run down on the car...

It's a 05 LS6 V, it has PRC 2.5 heads on it, Pacesetter LT's, magnaflow mufflers, unknown spec'd cam (previous owner said it was a custom grind and he lost the cam card...), K&N intake, tune, yadda yadda.

I'm having issues with it smoking under WOT and want to know exactly where to start looking for the issue. It seems to be blue smoke and it burns about 1/2 - 3/4 of a quart over oil change intervals, which with LS motors doesn't seem to abnormal from what I've seen.

I guess step one would be a compression and leak down test and see what those results yield me prior to moving forward from there. Can someone give me the numbers that I should see for compression? Also, approximately what % of leakdown is acceptable?

It doesn't smoke after sitting over night and starting up or any time at idle or start up, which leads me to believe that it's not the valve seals or I'd have the issue during start up or prolonged idle, correct?

Could it be something in relation to the PCV system? It doesn't have a catch can setup on it and maybe that's part of the issue?

I'm looking to see what the best and most logical approach to this is going to be. If it's something as simple as the PCV system, that would be awesome; if not, where do I go from there?

I've been looking into a forged setup recently due to the higher mileage on the stock short block (~140k) and the fact that it smokes under WOT leads me to believe the rings are nearly shot, which only makes upgrading the even more logical approach. With that being said, I know there are vendors like Texas Speed and Thompson Motorsports that sell pre-built short blocks, but what is the thought that goes along with those? I'm not opposed to reusing my block, but I need to have minimal downtime which is why the pre-built short block sounds perfect for the situation.

If I do choose to go with the forged short block setup, what kind of pistons (cc, dish, etc) and I'm looking for? At some point in time, I hope to put together some sort of boost application on the car whether it be a procharger or turbo setup, which demands the lower compression ratio, but how low is proper for an LS motor that might see 7-15 lbs of boost at some point.



I know this is a bit long, but many of you on here have gone down this same route at some point, maybe not the blue smoke but going to a built/forged motor. Tell me what you did that you wish you would of changed or if you're happy with your setup and what that setup is. Show me what y'all recommend for a build that's at about a $3500 budget.

Thanks for the help, pals.

NIKDSC5

iTrader: (10)

Does it have converters on it? They will hide oil consumption smoke very well. If it has no cays then pcv may be a problem but unlikely. The best thing is to def start with compression and leak down.

My v at 96k does not burn a lick of oil per 10,000 mile amsoil change. That lsx eating oil bs is just that, bs. If it eats oil (more than just pcv vapors minimal) then there is a problem.

itsslow98

iTrader: (18)

That much smoke I would guess rings for sure. Since it hasnt popped yet your in a good spot as far as havign a useable block and crank and havent damaged the heads. Compression test I would hope for anything over 150 but the more important factor is that all of the cylinders are within 5-10psi. Leakdown I wanna say is 5% or less but dont quote me on that.

Here is what I would do........

Stock block, stock crank, wiseco pistons, callies compstar hbeams,ARP rod bolts and head studs. I would do a 10:1 motor for a procharger or turbo and you can get away with around 12psi on 93 octane but have great throttle response. The days of 8:1 compression for boost are over for street cars.

BTW like Nik said, my 98 SS had 130k hard nitrous miles on it and never burned a single drop of oil.

07CTS-V

iTrader: (6)

I wish that I would have checked to see if the company I bought my 418 LS3 shortblock from bought and used blems. Blems are blocks that do not meet spec (blemishes).

punishmentcycle

iTrader: (6)

first thing i would do would be pull the plugs and see if u can tell which cylinder is burning oil..then a compression test. etc

this what i did when i melted a piston.. stock block, stock crank, eagle h beams,diamond pistons with 8.5 cc dishes. (9.5/1) stock heads, ls9 cam and valve springs. new gaskets all around and hardened push rods.

wish i woulda left the compression higher and built a 383 while i was in there but my motor is very sound the way it is so its staying this way. i prolly built my motor for around 26-2800 with me doing all the work besides the machining of the block.

thompson

iTrader: (4)

We can definitely help you with a great motor that will get you out of the smoking car. Let us know if you need any help deciding what you need. From your description you will probably find a ringland broken. It is very common with the stock pistons.

vmapper

iTrader: (8)

I could not agree more and is the route I took (though im using a TSP block studded mains etc) - 10.1:1 procharged.
Having higher compression would also mean you are running thicker top ringland as the pistons will be 'flat' pistons, not dished.
Not to get into too much of a discussion, but dynamic compression and cylinder psi is the key... but no problem running 10-11:1 static compression to have great low throttle response and better fuel mileage w/ reasonable boost.