What are the effects of putting too much oil into an engine? I've been checking my oil level with the engine running at idle where as I’ve found
out the manual says let it idle for a few minutes and switch off then measure. I then put in an extra 1/4 litre. It seems I’ve been over filling,
then overfilling a bit more.
A friend’s brother is an engineer at Triumph and reckons that over filling froths the oil. What affect might this have on my engine?
If you overfill the engine, the crank splashes into the oil in the sump. This has two effects, drag on the crank, and causing the oil to froth up with
bubbles. These bubbles will make the oil appear thinner, leading to lower oil pressure.
I think!
Mike
... and if you fill it up further, you'll get the pistons smacking in to the oil, if the engine runs at all.
not a good idea and can cause damage, generally frowned upon
I was having an argument with my father on this one. He is a long serving engineer with proper engineering qualifications and memberships and I'm
the young upstart.
His theory was that crank oil seals are not designed to run in oil and that they should only see oil splash. He claimed oil would be blown past them
if the engine was overfilled or the sump shortened and filled to the usual quantity... The debate rages on.
The oil levels I’ve had may have been enough for the crank webs to dip into but certainly not up to the crank centre line and nowhere near the
pistons.
Would frothy oil float on the top in the sump or could the air bubbles be drawn in through the oil strainer at the bottom of the pan? The reason I
ask is that my engine has recently suffered big end failure and I’ve found no apparent cause. If frothy oil = low oil pressure then it might go some
way to explaining it.
I think you've answered your own question.
Too much oil = fcuked engine
windage
I'd think there may be a danger that on corners that the throthed up oil (which when running will be alot more than when not) could get sucked up. Bubbles in the oil would be as bad at building up pressure as air in the brakes.
quote:
Originally posted by Hammerhead
windage
I doubt you'll get windage in a bike sump, the oil feeds the gearbox as well and the crank is usually pretty high up in the casing. From the pictures you showed previously you only suffered one bearing picking up which was more likely due to the bikes previous history than anything you have done. Some bikes levels alter just by running while on the side stand due to the change in oil level when stood at an angle.
i have overfilled cars with oil before, my saabs v4, that i managed to put 11 litres of oil into (don't ask, but it was when i was just starting
working on cars) and that still ran some how, though it didn't sound happy and oil was coming out of the relief value quite quickly!
the other time was recently with my micra that started throwing it out of the exhaust, it doesn't seem to have done any damage to either though
admittally the cars were never driven over filled. I would imagine significant over filling would damage the engine and slight over filling would not
cause too much of a prob, especially on cars that leak oil.
I've always heard that overfilling with cause main seals to blow out at speed...leading to loss of oil...leading to no oil pressure at
all...leading to
With the R1 you do need a slight overfill compared to that recommended for the bike.
General consensus seems to be to fill it to the top of the sight glass when the engine is actually idling. Thats certainly what I do and have had no
issues at all.
Too much of an overfill will cause problems though, as well as some of the above, if the oil line is above the bottom of the clutch plates, they can
struggle to squish the oil out when re-engaging, thus causing slip.
[Edited on 26/4/07 by ChrisGamlin]
Yamaha recommend filling to the middle of the sight glass on a level road when the engine has been idling for a few minutes and has then been
stopped.
I filled to slightly over the top of the sight glass with the engine still idling on a slight slope (sight glass at the top of the slope), so not
massively over full.
The only other thing I’ve done is drive round the “clover leaf” in Redditch at enough speed to make the brake fluid light come on due to surge rather
than low level. The cloverleaf is a junction where 2 dual carriagways join. It has 4 sliproads that are 270° left handers. They are 140m in diameter
so 0.2 miles long each. The speed limit is 70 MPH though I’m too much of a scaredy cat to try it. If there was brake fluid surge, then there would
be oil surge as well. I have a baffle plate but I guess that only slows oil surge.
How steep is this slope? If the glass is at the upper end of the slope then you'll be over filling by way more than you realise, due to the glass showing less oil than is actually in the engine. Imagine tilting a half empty pint glass over, and watching the level at one edge. The more the tilt, the less the apparent level. But if you were to then top up to the old level, the galss would be much more than half full. Hope that makes sense
quote:
Originally posted by DIY Si
How steep is this slope?
if you overfil you aerate the oil..
result, blown bearnings as the air can be compressed and the crank meets the soft metal of the shells..
