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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. :D |
If you let the car sit overnight, is there any smoke at startup? That's a usual sign of valve seal wear
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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
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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. |
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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 |
no where near 160F after 20mins ?
I guess mine get up to temps quite faster than yours then. |
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. |
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 |
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Thanks VVEL! |
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. |
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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. :tup: 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. |
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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.
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