I first flushed the engine with gunk motor flush then drained the old oil and changed filter and swithched to 10w30 supersyn....it smokes light blueish between 1/2 and full throttle. Recently gutted the cat and i have no pipe after my cat so is the lack of cat converter making it smoke more? 144,000 on engine. The trannys shot so i cant drive it around...i just noticed it while messin around in the garage. It smoked a little on start up before but thats it. Im thinkin that maybe the flush and synthetic is wearing away the crud around my valve seals. Dosent leak a drop though....yet! What yall think i should do?

 

if you're worried about the smoke, i'd try a heavier oil....

 

It's entirely possible that your cat was burning the smoke before. Now that you dont have one it just comes out the pipe. Coincidence because of doing 2 things nearly at the same time.

 

V8,

Maybe a coincidence, maybe not. Synthetics clean very well. It isn't uncommon to find sludge, varnish, and carbon coking on piston rings with engines at that mileage. If the engine flush cleaned some of the deposits away, and the synthetic is doing what is should (cleaning varnish and sludge) you may be seeing the result. The sludge and coking may have been sticking the rings in their grooves, but also filling the gaps and providing some sealing and oil control.

Give the situation some time. Check the oil frequently. Don't be surprised to see it turn very dark very quickly. This should be a sign that the time to change is getting near. I'd stick with the synthetic for at least a couple of changes, and give it a chance to do some thorough cleaning until the oil rings can move freely and again seal themselves (instead of being stuck and sealed by varnish). If you've removed some of the varnish already, changing beck to mineral oil won't fix the problem now - it will only smoke until more varnish and sludge are created.

As for the viscosity, 10W30 should be adequate, but I wouldn't go much lighter.

The situation may be aggrevated slightly by the abscence of a cat, but even oil burned in the cat will produce some smoke.

 

That very well could be the problem vader. I just didt understand how it could go from smoking really only at startup..to smoking so much at 1/2 and wot that quickly. I cant drive it cause th trannys gone so i just startit about twice a week and today it seems like its starting to calm down a little. I know that i really cant tell alot untill i get out in real world conditions but ill keep an eye out for any improvements.

Brandon

 

Light blue smoke = burning oil. Plain and simple.

The smoke at start up is the result of worn valve seals and SBC's are notorious for it. The added smoke is from both the motor flush and synthetic oil.

The flush removed any desposits and gunk around the rings. Since synthetic oil is "more slippery" than conventional oil, it's slipping past the rings under load. You could try leaving it alone and see if the smoke calms down or switch to a heavier weight conventional oil.