Car Trouble. Please read and advise!
 

SO here is the breakdown of what it is. I have a 96 z28 as you can see by my name. 5.7, 6 speed yatta yatta... bought the car about two years ago, only get to drive it for about 3 weeks a summer because of being away for work. So it was puffing blue smoke, so i took it to a garage and he thought it was the valve seals. The garage is highly recommended among LT1/LS1 owners from here. So he replaced the valve seals, plug wires, and installed a CAI, and two new magnaflow cats and a magnaflow exhaust.

That was fine, it did eliminate some of the smoke, but now all. I also just had the gearbox rebuilt, new clutch, flywheel resurfaced. And NOW I have more smoke issues.

The garage that did the clutch and stuff say the car has a vacuum leak.

The problems i am having now are, a little bit of a high idle. Once the car is warm (eg. a 2 hour drive) it runs as if it only has say 6-7 cylinders working. LOTS of blue/white smoke. Some sputtering and backfiring. Also it will drop about a litre or so oil in the same distance. so what i have done in the past is once it cools, i try to see if a plug wire is loose, and most seem ok. and then car works OK again until warm usually. (this has only happened twice on me, because i have only driven it twice in the last two years)

So my question is would a vacuum leak cause smoke and loss of oil? Or does it sound like the optispark?

Sorry for the long explanation, but if anyone has an idea please let me know. I have it to my uncles garage right now, but he hasn't had a chance to look at it yet. Thanks fellas

it sound like either a very bad vacuum leak or a blown head. if you blew the head just right you'll burn oil lose compression in cylinders and sputter, without mixing water and oil. I blew the 5.7 in my truck that way. have the vacuum leak checked, if they don't find anything have them run a compression test... oh and check to make sure your oil filter is seated right... it could be that its not, and its leaking oil onto something hot and smoking.

i would get a second opinion in the future. your gona need to do a compression test on all the cylinders. are you leaking oil or losing coolant, could be intake maniflod gasket is bad or the manifold itself is lose. at worst could be a bad pistion, pistion ring or rings or crack in head.

coolant is fine, oil is fine unless i drive it for a long period of time. But even after the drive the coolant is still ok, just not the oil. And this is the first time that i have had the car at my uncles garage. So this will be the third opinion, hopefully the right one!

I would also have the PCV system checked. I will show signs of a vacuum leak (like the high idle) and will consume oil if something is wrong with it.

Look at your under carriage see if oil is sprayed all the way down. I have so many small drops it's unreal to count
In your case pull the dipstick out and oil cap off and see if it's chugging smoke
If you have any exhaust leak you might not see any smoke if your pcv has failed or worse rings