Oil recommendations?

[RedZMonte]

So, I get a little bit of buring oil smoke when idling and occationally after i rail on it... Good friend of mine who we just built his motor and turboed in his vette was getting simmilar smoke issues just switched from Moble 1 5w30 to Moble 1 15W50 now has no more smoking issues (his motor was built a little "lose" intentionally)... Mine is just getting old and after a while of being turboed im sure has become a little lose...

Anyone run the 15W50? what oil do you guys use? ive been running 10W30 and she still smokes a little bit... It looks like alot of the turbo vette guys run the 15/50 with good success. It gets cold in colorado sometimes in the winter but its not ever too cold for very long, im mildly concerned about cold starts im sure that 15/50 is like mollassis lol.

S

[robertisaar]

yeah, 15-50 is WAY thick...

i would honestly try some 10-40 before going to anything heavier...

[1988GTU]

I run 5w30 normally, but 10w30 is what is being used now due this past summers temps.

I wouldn't go any higher than 10w40. You might find it will work good with it too, but being a DOHC it might not be that great for flowing.

[asylummotorsports]

Ok do you actually understand the numbers?

The low number is the viscosity (thickness/lubricity) constant when cold.

The high number when hot.

You never need anything "bigger" than 10 when cold.

You can run about whatever you want when hot, but you are just fooling yourself as the motor is hurting if it needs more than 40 to sustain oil pressure.

Our engines work well on 5W30.

When you start deviating from that to maintain or control smoke/pressure/usage, you have a problem.

My .02

[robertisaar]

Eric: thanks for adding in that last bit, i was just coming here to mention it.

i run Pennzoil conventional all the time, 5W30 in the winter and 10W40 in the summer, if you need anything outside of that, SOMETHING needs rebuilt, be it the turbo, fried rings, bad valve seals, something needs it...

[Joseph Upson]

So, I get a little bit of buring oil smoke when idling and occationally after i rail on it... Good friend of mine who we just built his motor and turboed in his vette was getting simmilar smoke issues just switched from Moble 1 5w30 to Moble 1 15W50 now has no more smoking issues (his motor was built a little "lose" intentionally)... Mine is just getting old and after a while of being turboed im sure has become a little lose...

Anyone run the 15W50? what oil do you guys use? ive been running 10W30 and she still smokes a little bit... It looks like alot of the turbo vette guys run the 15/50 with good success. It gets cold in colorado sometimes in the winter but its not ever too cold for very long, im mildly concerned about cold starts im sure that 15/50 is like mollassis lol.

S

Smoke from a turbo motor especially after running it hard is usually associated with oil getting past the turbine ring seal due to worn bearings, high oil pressure, or obstructive oil return. When the bearings are worn there is a greater chance of the oil going past the bearings fast enough to fill up the return line at high revs and going into the turbine exhaust. I believe heavier oil just moves a little slower through the passages slowing the rate of seapage past the seal. You can get smoke on startup from a failing turbo that comes and goes at anytime. That's what my experience has been.

When the issue involved piston rings a lot of smoke (blow-by) exited the PCV valve and entered the engine which then began to smoke as it was burned off, requiring disconnection from the intake altogether to stop the smoke from the exhaust.

[asylummotorsports]

In addition, it is always a good idea to let a turbo engine run at idle for a minute or two to allow cooler oil to get pumped up to cool things.

It's not a good idea to shut off a hot turbocharger.

You can actually buy shut off systems to let the engine run for a bit after you shut it off to cool the turbo.

And I'm just starting to learn this stuff!

[robertisaar]

i've always toyed with the idea of using an electrically fired accumulator/pump that holds a good amount of oil in it, that way, in a turbo engine, you shut it down, wait for a minute, then have the accumulator pump a good amount of oil through the center housing to remove a lot of heat...

same idea for start-up as well, have it start pumping a bit of oil through before cranking....

probably a plumbing nightmare though...

[Joseph Upson]

i've always toyed with the idea of using an electrically fired accumulator/pump that holds a good amount of oil in it, that way, in a turbo engine, you shut it down, wait for a minute, then have the accumulator pump a good amount of oil through the center housing to remove a lot of heat...

same idea for start-up as well, have it start pumping a bit of oil through before cranking....

probably a plumbing nightmare though...

Water cooled center sections have eliminated the need for these gadgets. Use a good oil with a water cooled center section and you shouldn't have any problems reaching more than 100K with a turbo.

[robertisaar]

call it a fail-safe measure...

but the shot of oil at start-up would be nice...

[asylummotorsports]

'splain to me these water cooled center sections of which you speak.

[robertisaar]

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech101.html

about 3/4 down the page...

[RedZMonte]

lol i know something is Fudged up... I understand its a bandaid... looking for nothing more.. the car sat for ~2years im sure its my valve seals more then anything... i wouldnt doubt its a little blow by as well(turbo+high mile engine=blow by... Sooner or later). My turbo is a "Dry" turbo and if i drive it hard i do let idle for a few min.. (same result as a Turbo timer). the bearings on the turbo feel tight and i do have a "oil restrictor" on the oil feed line so pressure shouldnt be an issue. Most of the smoke is at idle if i idle for more then a min or 2. My PCV is not hooked back into the intake so under hard boost it does spitt a little in the engine bay (not to bad tho). My oil dump is smooth and free flowing, No kinks or restrictions returns high up on the oil pan.

I understand the thick oil moving slower ect.... also leaks slower and fills the rings up to help slowdown blow by... its a bandaid but its an effective one.

S

[RedZMonte]

'splain to me these water cooled center sections of which you speak.

Dry turbo= Oil cooled and lubricated.
Wet Turbo= oil cooled, lubricated but it also has a water jacket (simmilar to an engine) that coolant passes threw and out of the turbo to keep the temp of the turbo down to prolong life of the seals and stuff. Most OEM turbos are "WET" turbos.

[60dgrzbelow0]

call it a fail-safe measure...

but the shot of oil at start-up would be nice...

Echoed in the last line of this article...

http://www.stockcarracing.com/techarticles/1594_oil_accumulators/index.html