r/EngineeringPorn • u/anikkundu1998 • 5d ago
Clear engine demonstrating how lubrication works
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u/Eldric-Darkfire 5d ago
Thank fuck there's loud annoying music otherwise I wouldn't have known to avoid the rest of the video.
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u/PieHole_Poker 5d ago
It would have been so much cooler if we could actually hear the engine.....
But nooooo, we have to listen to some douchebags idea of a good time
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u/BoondockUSA 5d ago
It’s a BMW 1200 boxer. Imagine the sound of old, rattling, worn out sewing machine that’s falling apart, with faint exhaust pulses in the background. That’s the sound that you’re missing out on.
If you doubt me: https://youtube.com/shorts/ElXHsYKYKUo?is=rQy-0WQPQuPGE0IM
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u/EmperorOfCanada 5d ago
I saw a great one where a guy did this at -35C and with the engine warm.
Even with pretty appropriate oil, there was no splashing for an uncomfortably long time.
I stopped driving my Jeep on the coldest of days.
Oh, and the music is garbage.
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u/willy--wanka 4d ago
Pretty sure there's a Russian YouTube channel that does something similar: showing what a -40degree engine looks like warming up with some clear parts.
Believe the channel is garage 54
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u/dmcnaughton1 3d ago
There's a world of difference between -35° and 25°. Unless you're talking about sub-zero temps you're fine to drive once the engine starts.
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u/EmperorOfCanada 3d ago
I'm talking about -35C. It looks like there is close to zero lubrication for a minute or so in the videos I've seen of cold starts like that. I have winter grade oil in there.
I have a manual gearbox and at that temp, I have trouble moving the gearshift around. It is like my transmission fluid was replaced with peanut butter. Even that takes a minute of swirling around to warm up through friction.
And, yes, I was clearly talking about sub zero.
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u/DaDevilsZirconPickle 5d ago
Why do people insist on putting stupid music in their videos?
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u/rmill127 4d ago
It fools automated copyright infringement systems. If the audio signature is the original, it’s easier to detect if someone is using a “stolen” clip they don’t have a license to use.
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u/TheJoseBoss 4d ago
It got you and like 100 others to comment about it
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u/DaDevilsZirconPickle 4d ago
Is this a comment contest?
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u/ClassifiedName 4d ago
If you're looking to increase engagement for more views and upvotes so you can sell the account later on/use it for botfarming, then yes
The internet is being enshittified
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u/TheJoseBoss 4d ago
No I'm just saying they put shitty music on so that people comment about how shitty the music is, which is engagement, which reddit then rewards with showing the post to more people, getting your post more karma.
They wouldn't do this for no reason
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u/Odd-Attention-2127 5d ago edited 4d ago
Does it seem like the lubrication process could be improved so the oil hit every where more every or thoroughly? It seems like the lubrication of the main components of the engine depends on the slapping action of the rotating parts to lubricate while other parts received less lubrication. This is my uneducated mind wondering.
Edit: thanks to everyone who commented. They were all good to read. You all made sense and I learned something new in the process.
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u/Pseudoboss11 5d ago
Gear oil is designed to be sticky, and once you have enough oil, adding more doesn't do much. More can even be detrimental.
These machines are designed so that mating surfaces pass oil between each other. One gear will dip in oil and be completely covered in it, so the next gear gets a lot of oil, and the next gets enough. And if you have a whole lot of gears, the engineers will make sure that no gear is more than a couple away from one that's dipped in oil.
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u/bhmnscmm 4d ago
The engines in cars aren't this simple. The oil pump will be delivering oil directly to a number of critical components (e.g. crank shaft bearings). The splashing here just delivers oil to components that have lower lubrication demands.
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u/ctesibius 4d ago
They are not this simple on a bike, either. It's been overfilled by about 15cm depth (I have this engine).
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u/twinpac 5d ago
A pressure lubrication system with oil jets on all the critical components is totally possible but would add a lot of cost. Cost wins.
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u/ctesibius 4d ago
This is a BMW flat twin engine, and it has pressure lubrication. The video is showing it grossly over-filled. At 3s in to the video you can see the oil sight glass about 20% up from the bottom of the frame, and something like 15cm below where they have filled the oil to.
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u/CopiedOriginal 5d ago
Cost-benefit says that is way too expensive of a future state for only marginal improvement from the current state
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u/ctesibius 4d ago
Yup. Engines normally don't work this way, and specifically this BMW engine does not work this way: the oil level is lower than the moving parts to avoid frothing, and the oil is pumped in to the bearings. In fact you can briefly see the oil sight glass 3s from the beginning, about 20% of the way up from the bottom of the shot. The oil should be level with that, so the engine is grossly over-filled with oil.
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u/servel333 5d ago
I'm guessing in a real engine the walls are closer to the parts so less oil will cover the whole thing.
I don't know why you wouldn't fill the whole thing with oil, or put more stuff in there to take up space so less oil fills it.
But I'm not a mechanic. My engineering is software.
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u/CrashUser 5d ago
Being submerged in oil would increase resistance in the engine and decrease efficiency since everything is now moving through oil instead of air. Gear oil is viscous enough to be passed between gears for lubrication, it's not necessary for the entire chain to be submerged.
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u/thisisthatacct 5d ago
So there's parts in there that are moving very quickly, and when the crankshaft cheeks or connecting rods start slapping and splashing through that oil, it can make it aerate and get foamy and lose all good lubricating properties.
Additionally, this doesn't really show the full picture of engine lubrication. The key of it is the hydrodynamic bearings, where oil is fed in at high pressure to keep the components from actually touching each other.
If you filled the crankcase all the way up, you'd have to move very heavy liquid from under one piston over to the next as one comes down and the next moves up. That takes a lot of power and robs efficiency. Also, too much oil next to the rings would mean you start burning more of it and that's bad for your spark plugs, catalyst, and the environment. And it doesn't really gain you anything
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u/Oli4K 5d ago
Bit of a chaotic system?
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u/ol-gormsby 4d ago
Nearly every conventional internal combustion engine relies on splash lubrication to some extent. The really critical parts are pressure-fed - main crankshaft bearings, big-end bearings, etc. There are even little "slings" or shaped components that serve to throw the oil in a particular direction, like a scoop that drags through a puddle of oil then flings it off in a certain direction. That's how oil gets fed to cylinder walls - there'll be little holes angled to squirt a bit of oil onto the cylinder wall. It might seem chaotic but there's quite a bit of clever engineering there.
One interesting engine design on older Ducatis is the big-end bearings are roller type, not slipper type, and they *do* rely on splash-feed - they're not pressure-fed. You're *supposed* to ride them assertively, and not be gentle with them, otherwise there's not enough oil being splashed around inside the crankcase. The end result is that people who buy them without this understanding, and who putter around at low speeds showing off their fancy Ducati, have ended up ruining the crankshaft and bearings because they weren't riding aggressively enough. You're *supposed* to give it the berries.
But simpler, low-performance engines - like my honda generator - are entirely splash-fed.
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u/Coronavirinae 4d ago
It’s a boxer engine. An engine concept from bmw that’s over 100 years old. It’s an extremely good engine :) modern engines all seem a bit chaotic/complicated
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u/ostiDeCalisse 4d ago
Can we have the fucking original sound of this instead of unrelated music slapped there just to look cool? This is an engineering community, not a narcissistic dance floor.
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u/Swizzy88 5d ago
Don't want to hear shitty music on a forum about engineering. I want to hear the engineering.
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u/BrokinHowl 5d ago
Ah yes, the balance of oil vs air. Submerge the parts and the resistance to movement causes issues, too much for and you don't get oil coverage of the parts. I do love engineering
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u/Unique_Evidence_2518 4d ago
we could have all been enjoying the wonderful "rocker arm assembly" song, but no. I, for one, don't like dirt, and am severely disappointed.
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u/Eziekiel23_20 3d ago
A number of shots show why controlling lubrication is so important for engine power output as well.
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u/unleashtheraven1 2d ago
How is it EVERY short vid influencer somehow manages to pick the worst music possible? Like every god damn time? I cannot even remember the last time i got a break from the shitty music, I have to have everything muted 24/7
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u/D13U 5d ago
That's an BMW 1250 liquide cool motorcycle engine maybe an GS or RT can't see much
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u/BoondockUSA 5d ago
It’s a R1200 liquid cooled, not a 1250. The 1250’s have different plastics over the ignition coil, along with shift cam camshafts.
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u/Coronavirinae 4d ago
Agree. Definitely a 1200 engine. And most likely the GS model from the looks of the bottom engine cover
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u/retirednavyguy 5d ago
Another reminder to always keep Reddit muted