Question for TP/LTH users, oil smoke @ high RPM?

Sh0velMan · 08-27-2013, 07:45 PM

So for as long as I have been without cats on my car, at high rpm (6K+) on throttle close I get some oil smoke.

The video makes it look pretty bad, and it's noticeable for sure, but I'm inclined to think it's not that big of a deal.

It changes a bit with which oil I use, some oils have been much worse, others not as bad as what you see there... This is Mobil 1 0w40.

The engine had been warmed up for around 20 minutes, including some revving, before this video was taken. I don't know if it does it as badly when it is cold, but I won't be revving so high when the engine is cold no matter what, so I guess I'll never know haha.

The question for me is:

A - Valve Seals?
B - Rings?

I know it isn't PCV blow-by as my PCV tubes are clean and dry after the catch cans, checked that first.

Again, it's ALWAYS done this, this is just the first I've asked about it.

Edit: Just to clarify, I specified TP/LTH users because with cats, the oil smoke was never observed, presumably because the cat takes care of it, or something. That's why I called out those with similar setups, because presumably if you have cats, you won't see the smoke.

Boost_lee · 08-27-2013, 08:02 PM

If you let the car sit overnight, is there any smoke at startup? That's a usual sign of valve seal wear

luigi90210 · 08-27-2013, 08:13 PM

you are running M1 0W40, did you let the oil get up to temp before revving? if you didnt then it will burn a little bit and afiak it is normal because the oil is like water when cold

Megan370z · 08-27-2013, 08:22 PM

What I see from the video is the smoke appear when you let go of the throttle and then the intake goes into full vacuum which would pull the oil in by the valve stem seal.

Normal wear and tear.

Megan370z · 08-27-2013, 08:24 PM

Quote:

Originally Posted by luigi90210

you are running M1 0W40, did you let the oil get up to temp before revving? if you didnt then it will burn a little bit and afiak it is normal because the oil is like water when cold

he did mentioned this.

Quote:

Originally Posted by Sh0velMan

The engine had been warmed up for around 20 minutes, including some revving, before this video was taken. I don't know if it does it as badly when it is cold, but I won't be revving so high when the engine is cold no matter what, so I guess I'll never know haha.

luigi90210 · 08-27-2013, 09:20 PM

Quote:

Originally Posted by Megan370z

he did mentioned this.

a warm engine can still mean cold oil

just because your engine is no longer idling high doesnt mean your oil is up to temp, it just means your coolant is up to temp, i know when leaving my car running for 20mins, my oil temps are nowhere near 160F

Megan370z · 08-27-2013, 09:30 PM

no where near 160F after 20mins ?
I guess mine get up to temps quite faster than yours then.

Sh0velMan · 08-27-2013, 10:01 PM

Part of the warm up process, for me, is to gently rev into VVEL land ~5500rpm (after it's idled a few minutes) because that's how you can put heat into the oil.

It was around 165-170 indicated when I started this video, right at tstat open ~183 when I stopped. Dropped back to ~170 immediately.

No smoke on start up, only on full vacuum. I'm thinking it's intake valve seals as well, Megan.

Sh0velMan · 08-27-2013, 10:25 PM

Maybe I'll get one of those fiber optic scopes and pull the intake plenum. See if I can get a peek down at the intake valves and see if there's oil gunk all over the stems from leakage...

Or maybe I'll just ignore it until I blow up, rebuild or swap out the engine. lol

DEpointfive0 · 08-27-2013, 10:36 PM

Quote:

Originally Posted by Sh0velMan

Maybe I'll get one of those fiber optic scopes and pull the intake plenum. See if I can get a peek down at the intake valves and see if there's oil gunk all over the stems from leakage...

Or maybe I'll just ignore it until I blow up, rebuild or swap out the engine. lol

You cannot look through the intake valves when the car is off, they'll all be closed
Thanks VVEL!

synolimit · 08-28-2013, 12:36 AM

Unless I see it under load on the highway I can't comment.

What I will comment is revving and engine without load is just asking for trouble! That video was a huge no no by almost every engine builder in the universe and should be avoided.

Sh0velMan · 08-28-2013, 08:52 AM

Quote:

Originally Posted by synolimit

Unless I see it under load on the highway I can't comment.

What I will comment is revving and engine without load is just asking for trouble! That video was a huge no no by almost every engine builder in the universe and should be avoided.

LOL

Was for the purposes of this video only, not something I do regularly.

Wasn't bouncing off the rev limiter, the valves aren't going to float at the RPMs the engine was seeing and it's got over 38K miles of break in done, it's not going to hurt anything at all.

Doesn't do it under load, only on lift. Never noticed it on the highway, but did notice it on the dyno, again only after lift.

Sh0velMan · 08-28-2013, 08:53 AM

Quote:

Originally Posted by DEpointfive0

You cannot look through the intake valves when the car is off, they'll all be closed
Thanks VVEL!

I just meant the valve stems and the backs of the valves. If it is sucking substantial amounts of oil, I would think there would be evidence of it there? I dunno!

DEpointfive0 · 08-28-2013, 09:37 AM

Quote:

Originally Posted by Sh0velMan

I just meant the valve stems and the backs of the valves. If it is sucking substantial amounts of oil, I would think there would be evidence of it there? I dunno!

Makes sense now, and I guess if there is enough oil being burnt or dripping down, you might see darker valves, but not sure

synolimit · 08-28-2013, 10:32 AM

I guess I can only say piston rings then, maybe valve. The vacuum increase at high revs could be sucking oil into the chamber. Under wot you should have a lot of bow by but since you don't go wot 24/7 you're probably not seeing a big drop in oil or filling the catch can up fast. At this point I'd go buy a compression kit from autozone for like $40 and test the cylinders and see what you get. The manual should post a range for healthy motors.

08-27-2013, 07:45 PM	#1 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 20	Question for TP/LTH users, oil smoke @ high RPM? So for as long as I have been without cats on my car, at high rpm (6K+) on throttle close I get some oil smoke. The video makes it look pretty bad, and it's noticeable for sure, but I'm inclined to think it's not that big of a deal. It changes a bit with which oil I use, some oils have been much worse, others not as bad as what you see there... This is Mobil 1 0w40. The engine had been warmed up for around 20 minutes, including some revving, before this video was taken. I don't know if it does it as badly when it is cold, but I won't be revving so high when the engine is cold no matter what, so I guess I'll never know haha. The question for me is: A - Valve Seals? B - Rings? I know it isn't PCV blow-by as my PCV tubes are clean and dry after the catch cans, checked that first. Again, it's ALWAYS done this, this is just the first I've asked about it. Edit: Just to clarify, I specified TP/LTH users because with cats, the oil smoke was never observed, presumably because the cat takes care of it, or something. That's why I called out those with similar setups, because presumably if you have cats, you won't see the smoke. __________________ Buy My Car! \| Build Thread Last edited by Sh0velMan; 08-27-2013 at 07:50 PM.

08-27-2013, 08:02 PM	#2 (permalink)
Boost_lee A True Z Fanatic Join Date: Feb 2009 Location: SATX Posts: 2,813 Drives: 09 370Z TT 6MT Rep Power: 29	If you let the car sit overnight, is there any smoke at startup? That's a usual sign of valve seal wear Megan370z likes this. __________________ My TT Z

08-27-2013, 08:13 PM	#3 (permalink)
luigi90210 A True Z Fanatic Join Date: Apr 2012 Location: San Diego CA Posts: 1,103 Drives: Classified Rep Power: 15	you are running M1 0W40, did you let the oil get up to temp before revving? if you didnt then it will burn a little bit and afiak it is normal because the oil is like water when cold __________________ SOLD 370z New Car:classified DD:2011 Mini Cooper S stock

08-27-2013, 08:22 PM	#4 (permalink)
Megan370z A True Z Fanatic Join Date: Oct 2009 Location: Canada Posts: 1,156 Drives: 370z Rep Power: 24	What I see from the video is the smoke appear when you let go of the throttle and then the intake goes into full vacuum which would pull the oil in by the valve stem seal. Normal wear and tear. __________________ Megan Journal Click Me ....................One Man Team Motorsport Click Me

08-27-2013, 09:30 PM	#7 (permalink)
Megan370z A True Z Fanatic Join Date: Oct 2009 Location: Canada Posts: 1,156 Drives: 370z Rep Power: 24	no where near 160F after 20mins ? I guess mine get up to temps quite faster than yours then. __________________ Megan Journal Click Me ....................One Man Team Motorsport Click Me

08-27-2013, 10:01 PM	#8 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 20	Part of the warm up process, for me, is to gently rev into VVEL land ~5500rpm (after it's idled a few minutes) because that's how you can put heat into the oil. It was around 165-170 indicated when I started this video, right at tstat open ~183 when I stopped. Dropped back to ~170 immediately. No smoke on start up, only on full vacuum. I'm thinking it's intake valve seals as well, Megan. __________________ Buy My Car! \| Build Thread

08-27-2013, 10:25 PM	#9 (permalink)
Sh0velMan A True Z Fanatic Join Date: Jan 2012 Location: Dallas/Ft.Worth Posts: 3,349 Drives: Noisily. Rep Power: 20	Maybe I'll get one of those fiber optic scopes and pull the intake plenum. See if I can get a peek down at the intake valves and see if there's oil gunk all over the stems from leakage... Or maybe I'll just ignore it until I blow up, rebuild or swap out the engine. lol __________________ Buy My Car! \| Build Thread

08-28-2013, 12:36 AM	#11 (permalink)
synolimit A True Z Fanatic Join Date: May 2013 Location: Columbus, OH Posts: 5,051 Drives: 2013 Silver 370z Rep Power: 3389	Unless I see it under load on the highway I can't comment. What I will comment is revving and engine without load is just asking for trouble! That video was a huge no no by almost every engine builder in the universe and should be avoided. __________________ 13 370z-

08-28-2013, 10:32 AM	#15 (permalink)
synolimit A True Z Fanatic Join Date: May 2013 Location: Columbus, OH Posts: 5,051 Drives: 2013 Silver 370z Rep Power: 3389	I guess I can only say piston rings then, maybe valve. The vacuum increase at high revs could be sucking oil into the chamber. Under wot you should have a lot of bow by but since you don't go wot 24/7 you're probably not seeing a big drop in oil or filling the catch can up fast. At this point I'd go buy a compression kit from autozone for like $40 and test the cylinders and see what you get. The manual should post a range for healthy motors. __________________ 13 370z-

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