Well so my car puffs out a nice cloud of white smoke when u first start it so I did a compression check and everything looked good but I did a leakdown and cyl 7 has 12% so is the ringland? Or? Thanks ahead of time for opinions

http://www.youtube.com/watch?v=_A-R0...er_profilepage



heres the video to see whats going on!!

 

Ohh yea...car is a cam only car..longtubes....ported fast 92/92..100mm maf.. 100mm lid...underdrive pully...vig 4k stall tuned with ls1 edit..car made 417rwhp 409ftpt on 116k mile longblock...

 

12% isn't that bad for factory stuff with 100k on it white smoke can be condensation or water on first start up. Its the blue smoke you have to worry about. Also check your coolant level just to make sure your not burning coolant.

 

K...it smells like oil when u first start it up...could it be a valve seal or somthing in the head to make it smoke ...the local shop that dyno tuned it said 12% in cyl 7 and it's toast and needs a rebuild...but 4k for a built 346ci shortblock sounds high to me...

 

When you did the leakdown did you hear the air coming out? Sometimes you can hear where the air is coming from. You may have to use a stethoscope but you may be able to tell. It's worth a try. Could be a bad valve seal leaking down when the car is off.

 

That's what I thought because it's like oil is getting on top of the piston and it started doing this about 20 miles after cam and parts....car was bone stock with not even a k&n and I did everything at one time...now it big cloud of blueish whit smoke comes out when u start it then goes away after the motor runs for a min then every once in awhile puffs it out when idling in the driveway

 

i know mine puffs out some oil cloud when i punch it WOT but from what i've heard sometimes 243 heads will do this especially with the fact i got used ones. Also The PCV system in them sucks and sometimes dumps oil into the intake which in turn goes into the cylinders with the air in the intake

 

This could be an issue as well. But I would bet the valve seals first.

 

So I should change the valve seals or just drop the motor out?

 

mine used to consume about a quart every 3k miles until the catch can and PCV redo(LS6 setup) and it's not consuming it anymore but does puff it out from time to time

 

All I have on the valve cover are the little cone filters...so not sure if the PVC is working right maybe that has something to do with it

 

ohh yea my car had 113k miles when i did all the mods even cam and we did not put new valve seals or guides in i dont know if that matters...im gonna post a video on youtube tomorrow of it starting so you guys can get a better idea of how much smoke and what color it is....

 

I would replace the valve seals first. Worse come to worse if the engine is bad you can still save the heads.

 

yea i hope it is the seals i would be so stoked.....i have not even really got to drive this car too much yet cuz i did all the mods at one time then why we were doing the drivabilaty tune not even getting on it just cruzing it started smoking and i parked it so i did not mess anything else up and that was march this year it been in the garage...i get my yearly bonus in feb and thats when i was gonna put the new shortblock in but it would be nice to just put seals in and drive it for awhile...

 

Smoke on start up is usually a sign of bad valve guide seals but probably not related to your high leak down reading on the number 7 cylinder.
Although 12% is getting to the high side it doesn't mean your motor is toast, It does mean that your losing a little power on that cylinder. When doing a leak down test you use it as a tool to not only find if your motor is hurt but where it's hurt.
If you hear air escaping out of the intake the it's intake valve problem...If it's coming out the crank case ventilation system then it's rings...if it's coming out of the exhaust then it's an exhaust valve problem. Here is a video showing how you can pinpoint the problem using a smoke machine...If you can find someone with one it's much easier to locate the problem. http://www.youtube.com/watch?v=9JQSQlnWuF0.

It's not uncommon for a high mileage motor to get carbon buildup on the exhaust valve keeping it from sealing completely or the valve seat getting worn and losing seal.
Keep in mind that a shortblock rebuild won't fix your problem if it's something in head related. Pinpoint the problem first and go from there.

 

Wow awesome video!! Thanks for that info that helped alot now I need to find a smoke machine lol

 

im uploading a video to youtube right now so u guys can see exactly whats going on and maybe will have a better idea if whats the deal....

 

12% ant **** on leak down!

 

Listening for the escaping air is the best way to figure out which direction to go.

I burnt up 2 valves in my yoda a few months ago an I could hear the air coming out of the exhaust...

 

http://www.youtube.com/watch?v=_A-R0...er_profilepage


k heres the video tell me what u think....