too much oil

[Blueknyt]

Ok, your basicly saying its like 5 quarts in a 4 quart system well above windage trays, is getting frothed/ foamed by the crankshaft splashing oil making the oil cavitate around the pickup effectivly sucking air (poor oiling) so the crank comes incontact with the bearing serface and this causes a spun bearing?


ok then, going on that, how does a spun bearing happen in a splash lube enviroment?

how does it happen in a dry sump system?




while i can agree some headaches will come of an overfilled crank case, this would be power loss and weeping or blown seals as the crankcase breaths.   that much oil even frothing would seep out (just like bubbles of milk over the rim of the glass) of the breathers and either run down the outside of the engine, or get sucked back into the intake and burned makeing smoke.    this would happen untill the level of overfill has dropped in which case the frothing would stop.  there would still be 75-80% of the oil in the sump.  

. Now take a 20ozbottle, put about 2oz of milk in it

but thats not the case with an over filled sump, your discribing an underfilled sump.  If infact your 20oz bottle, is spose to hold 7oz and you put 10 in, shake it, it would foam to the top, but you will still have 5oz or more, and once the foam is either burned off, pushed out the top, or blown out a seal that normaly doesnt see that kind of level you will still have a close to normal level remaining.

[makenzie71]

Ok, your basicly saying its like 5 quarts in a 4 quart system well above windage trays, is getting frothed/ foamed by the crankshaft splashing oil making the oil cavitate around the pickup effectivly sucking air (poor oiling) so the crank comes incontact with the bearing serface and this causes a spun bearing?

First I'm not saying that would happen...commercially available motor oil that would hasn't been available since before I was born, I think.

Second, there's a sump sucking oil out.  I didn't really go into adequate/propper detail earlier:

Way back when we were being paid to use gasoline...the oil pump would be sucking oil out of the pan.  If the pan was too full, however, a lot of it would froth up.  When this happened the lubricating system stood a chance of emptying the oil pan of it's liquid content and the rest of the system would lose it's circulation.  On a vehicle that used an oil cooler or a more elaborate oiling system, not only was there a risk of starvation at the crank but in the valve train and cylinders as well.

A splash-lube enviroment would be adequate, but if the crank only had access to froth'ed oil it'd burn it up real quick in a 4000lb running about 2100rpm.

[Blueknyt]

but if the crank only had access to froth'ed oil it'd burn it up real quick in a 4000lb running about 2100rpm.

the only way this could happen is a very shallow sump, no windage tray, and low oil to begin with.

even over filled and being foamed, the crank will sling the foam about even up into valve covers, it will still gather on the walls and run back into the sump. the crank will only foam what it can reach .  

your basicly discribing the oilpump cavitating (sucking air) this results in lack of oiling/low oil pressure. this doesnt happen with an over filled WETsump system.

in a drysump system its not even a possiblity but spun bearings happen there too.

If you wanted, you can fill the crank case untill it reaches the top of the fill hole, when you crank (it might not turn at all with no breathing room in the crank case) all its going to do is push the oil out anyplace it can. it may not run well fighting all that oil,  the crank will foam it up again pushing more out.   the pistons pumping to bottom dead center would push oil past shaft seals (pistons move air under neith to)  again, once the level drops this too will stop (unless the seal was damaged)

overfilled with oil may foam and may cause leaks without much doubt. but its very very improbable to be the cause of a spun bearing.

[makenzie71]

hey I have no experience myself...just got the he said she said words of the old-schoolers.

[Blueknyt]

i dont think the oldschoolers you talked to fully understood the problem.  i will never knock an oldschooler as ive been taught by many.  however, i know most oldschoolers wont try to explain something they dont know about.

By all means, pass along factual info and experience you gain unto others.

hey I have no experience myself...

you seem to have a decent amount of greymatter but...
trying to support an explanation without knowing forsure is foolish.

[makenzie71]

Old school logic.

trying to support an explanation without knowing forsure is foolish.

I never said it was correct, nor did I advocate it as such.

[Blueknyt]

Old school logic. Way back when oils didn't have the same kind of addatives they do today. If you take a cruder variety of the standard 5w40 a lot of folks use and add too much the oil level will contact the crank. When the crank hit the oil and started splashing and sloshing it around at 5000+rpm, the oil would begine to "froth" and turn into a foamy variety of it's former self.

Imagine it like this: Your oiling system sucks oil out of the pan much like you'd suck milk from a glass with a straw. Now take a 20oz bottle, put about 2oz of milk in it, shake the total hell out of the bottle for a moment then try and suck out the milk with a straw. You won't get much. Why? Because you've turned the milk into huge bubbles instead of a steady, liquid substance...much like a crank would do to oil 15~20 years ago.

Way back when we were being paid to use gasoline...the oil pump would be sucking oil out of the pan. If the pan was too full, however, a lot of it would froth up. When this happened the lubricating system stood a chance of emptying the oil pan of it's liquid content and the rest of the system would lose it's circulation. On a vehicle that used an oil cooler or a more elaborate oiling system, not only was there a risk of starvation at the crank but in the valve train and cylinders as well.

There in your own words you are explaining how this spun bearing happens do to frothing oil in an overfilled sump.

yet

hey I have no experience myself...just got the he said she said words of the old-schoolers.

I never said it was correct, nor did I advocate it as such.

now im really confused, what are you saying exactly?  

why would you pass on info that you are unsure about or dont personaly support?   Even if the info Right or Wrong.  


saying "I'm not sure but i heard this and this because of this..." is one thing  but going into a full on explanation like you did above, and not supporting it. thats just scarey dude.


Bob B, Pablo, Geep, or Werase, If im reading all this wrong step up and say so, correct me or give me a 3rd person veiw on this thread.  Am i really missing the forest for the tree?

[makenzie71]

why would you pass on info that you are unsure about or dont personaly support?   Even if the info Right or Wrong.

Because you asked why.  I explained to you what was explained to me and stated half a dozen times that it wasn't an applicable example to anything we'd be able to experience ourselves.

[makenzie71]

Want a reason applicable today?

According to the auto manufacturers themselves, overfilling the crankcase accellerates the consumption of oil because of contact with the crank.  Also, instead of burning off, like the marginal amount the crank would normally see, the oil could thicken around the journals and prevent propper flow to the bearings.

That work for you?

...edited for typo...

[Mk1inCali]

I'm not one of the ones mentioned above, so I'll keep this short, but I do believe that over-filling is not nearly as drastic of a misstep as this thread overall would have an uninformed individual believe.

I'm not an old-timer, but I've made my fair share of mistakes while taking care of my GS and the dirtbikes I raced successfully (meaning no mechanical failures over the time I was racing), for 5 years, and never has having too much oil been high on my list of things to be concerned about.


Question for mak-

Why would the oil continue to be frothed/beat up by the crank after it (the oil itself) has dropped down out of the reach?  It would seem to me, that after a certain amount of the oil is foamed, the crank will have nothing else to grab, and will instead return it's focus to it's regular daily schedule of 40-some horsepower.  Wouldn't you agree?


I don't think the spun bearing idea mentioned by whoever it was, has ANY merit whatsoever, and I don't see how this high oil level could be harmful beyond perhaps messing with the clutch's actuation.  I personally have over-filled my GS a couple times when doing a quick get-ready-for-the-weekend-ride-in-5-mins-or-all-your-buddies-will-leave-you-at-home-for-the-day kind of thing, and I've never even experienced any sort of clutch problems.

[makenzie71]

Question for mak-

Why would the oil continue to be frothed/beat up by the crank after it (the oil itself) has dropped down out of the reach?  It would seem to me, that after a certain amount of the oil is foamed, the crank will have nothing else to grab, and will instead return it's focus to it's regular daily schedule of 40-some horsepower.  Wouldn't you agree?

Again...I'll state that I have no idea becuase oils that would do this haven't been available in my lifetime.  Plus, I've already answered this a few posts back.

[Blueknyt]

Because you asked why. I explained to you what was explained to me and stated half a dozen times that it wasn't an applicable example to anything we'd be able to experience ourselves.

but it has been, a few folks on here have dealt with over filled cases, and spun bearings (specialy the racers)

even i have dealt with it numerous times with engines ive had or repaired for others, i know how it happens.  what i wanted to know was how an overfilled sump causes a spun bearing.  fact stands that it does not. spun bearings are caused by oil over heated and broken down, over reving, or pump cavitation brought on by low levels/improper oil return, AND/OR Full Volume SLoshing brought on by hard accerlation,braking or cornering (mainly cars)

i know a few racers that overfill alittle just to keep the slosh starving down to minimal.




you repeating something explained to you and knowing its not a viable explanation or rather  

that it wasn't an applicable example

it doesnt make sense really.

According to the auto manufacturers themselves, overfilling the crankcase accellerates the consumption of oil because of contact with the crank. Also, instead of burning off, like the marginal amount the crank would normally see, the oil could thicken around the journals and prevent propper flow to the bearings.

Ok,  Show me your facts. give me links and text, hell scan and post the ASE bulletin that even hints this.

Also, instead of burning off, like the marginal amount the crank would normally see, the oil could thicken around the journals and prevent propper flow to the bearings

you run straight STP?   even using old Dino oil of the 30's.  Overheating will cook the oil makeing it thicken into sludge. this is do to poor cooling and low oil levels.  the sump does allow the oil to cool abit, this helps cool the internals like the cranks,cams,gears,rods and bottom of pistons.
Sludge build up on the outside of the crank doesnt interfer with oil pumped through the bearings.  Sludge build up in the pickup screen will starve the system for oil, sludge blocking oil returns would starve the pickup and thats about it.

as to oil consumption by hitting the crank, again this will only happen till the oil doesnt hit the crank anymore then it stops

dude, sofar it looks like you just enjoy typing and seeing your name on the screen. show me some facts, HARD facts and perhaps you wont look like an idiot. so far, you fail.

[makenzie71]

...look like an idiot.

Have fun with it, guy.

btw, I wouldn't mind seeing a little bit of proof on your part that overfilling can in no way lead to bearing damage.  Just for kicks, ya know?

[Blueknyt]

btw, I wouldn't mind seeing a little bit of proof on your part that overfilling can in no way lead to bearing damage. Just for kicks, ya know?

i dont think there is a recorded case of an engine letting go due to being overfilled.  ive seen one or two that wouldnt start or turn over verywell due to the oil blocking everything including the pistons moving in and out of the cyl's.  

hell ive even seen a 1600cc VW engine that sat uncovered for over 6 months in rain, hooked up a batt, tryed to crank it, nothing. pulled the drain plug and almost 2 gal of water and oil come out. pulled the spark plugs, put fresh oil in it,cranked it over and water come out the plug holes.  we stuck the spark plugs back in it poured some fuel down the carb and it fired up. once the carb was cleaned it ran for 2 years on and off untill it was sold.

and i tend to over fill most my stuff cuz i hate 1/2 quarts laying around.
i think my lawn mower is about the only thing i dont overfill as it will sit for 2 weeks and that leaves plenty of time for oil to seep past the rings so it smokes alittle when starting.

[GeeP]

You're looking at only part of the problem.  As has been stated, the crankshaft will whip up the oil.  It will splatter over all surfaces within it's range and whip air into the oil.  This will lead to increased oil consumption by itself - Filling the valve covers and saturating the cylinder walls.

Not all the air forms a "froth" on the surface.  While this is a problem of containment and possible increased oil consumption, it's not the whole problem.  Some of the air becomes entrained in the oil.  This is called aeration.

The API has a standard test for for determining oil aeration levels.  It basically consists of running an oil in an engine representative of the type of engine the lubricant would be expected to operate in.  The oil aeration levels are then measured at specified intervals and cannot exceed certain maximum levels.  The maximum aeration level is 8% by volume for API CH-4 and CI-4 as an example.

http://www.swri.edu/4org/d08/DieslTst/engoil/default.htm

It can be expected that sump oil contact with the crankshaft will result in the entire oil sump being kept in constant movement.  Not only does the whipping motion of the crank help to entrain air, but by mixing the whole sump it does not allow the oil settling time for the entrained air to escape.  This situation lends itself favorably to high amounts of entrained air.

The result of entrained air is a reduction in the lubricant film layer thickness which causes a slight increase in friction and a large increase in bearing load.  This can increase the bearing temperature markedly.  Interestingly, the amount of entrained air is inversely proportional to the bubble size.  i.e. the smaller the bubble the greater the entrained air content.

The Effect of Eccentricity on Aerated Oil in High-Speed Journal Bearing"

So, my thought has been that overfilling the oil sump will result in high levels of entrained air.  The "froth" on the surface is of secondary concern.  The results of high aeration are increased bearing loads and temperatures.

Obviously, this is not good for the bearing.  Whether it causes spalling, some other contact damage, or spins is partly a matter of temperature...

To answer your question as relating to spun bearings, it has been my experience that spun bearings result from high temperature.  Specifically, high temperature differentials between, say, the crankshaft journal and the rod.  This could occur due to a high rate of temperature rise such as one would expect if a bearing was cut off from it's oil supply.  Normal running friction, or increased running friction due to oil starvation will not by itself spin a bearing.  It takes the entire journal to expand to fill the bearing - like a clamp.

To elaborate:  The standard running clearance on a small journal bearing is .0015".  Steel expands at the rate of .0000068" per degree F.  A two-inch diameter journal bearing will therefore seize if the temperature differential  exceeds 110 degrees between the running member and the object holding the bearing.  (.0000068)(2)(110) = .0015"

Now whether all these variables come together is a matter of the particular engine and oil combination.  As an example, large radial aircraft engines have extreme oil aeration problems even during normal operation.  This is due to the small amount of oil carried on board (reduced settling time), the large number of journal bearings, and the service factor.  

The GS could be similarly susceptable.  Not so much because of the bearing loads, but the speed of the crankshaft.  At 11,500 RPM, the crankshaft is moving at blender speeds.  

Now, half a quart is unlikely to be enough oil to bathe the crankshaft.  So if you over-fill a little I wouldn't go worrying because GeeP said it's the end of the world.   :lol:   However, in the airplane business we worry about whether it meets specification or not.  If it doesn't meet spec, the airplane doesn't fly.  It's not a question of whether it will work, it's a question of whether it is right or not.  Take that view when maintaining your GS and it will out-live you.  

My wordy technical post for today...  

[Blueknyt]

Geep, gotta love ya man            

If it doesn't meet spec, the airplane doesn't fly

dont let spirit or delta here you say that. ive followed them down the runways and taxiways with a dustpan and kittylitter.  

Not all the air forms a "froth" on the surface. While this is a problem of containment and possible increased oil consumption, it's not the whole problem. Some of the air becomes entrained in the oil. This is called aeration.

even then oil consumption will be a factor untill the level of oil has dropped that aeration (caused by the crank whiping oil) no longer occurs. which point consumption should be typical (leaks aside)

[GeeP]

dont let spirit or delta here you say that. ive followed them down the runways and taxiways with a dustpan and kittylitter.  

haha!  Too true.  You work at MIA in airfield maint. right?  No doubt you have a better collection of  hardware in your streetsweepers than some airlines have in their shops!   

Yeah, oil consumption can be expected to remain abnormal in a wet sump engine until the oil level drops below the reach of the crankshaft.

[Blueknyt]

Nah, work for FLL.  mainly i take care of airfeild grunt work, but when a airframe misses the litterbox everyone jumps out to sweep,mop and fabreeze the runway. 9L-27R gets the most.

[groff22]

I did an oil change this weekend and ended up putting a bit too much oil back into the engine. It's just a quarter inch over "F"... I'm wondering, is it acceptable to turn the engine over a few times while topping the oil off? Otherwise it would distort the view and possibly end up putting too much/too little in?

[galahs]

Overfilling it alittle wont hurt it for two reasons.

1 = manufacturers have a msall allowable tolerance for accidental overfills.

2 = once the engine is running some oil is pumped to the top of the engine to the camshaft ect. which lowers the level in the sump ensuring enough clearance for the crank.