Community Forums

sal avitabile · 08-26-2007, 03:54 AM

The only advantage I would see with larger filter ,more oil a little longer oil life,with normal oil changes I dont see the benefit to larger filters ( My Opinion)

Thanks Sal Avitabile

eandy · 08-26-2007, 08:49 AM

Isn't the real danger with filters made in China that they're painted with lead based paint?

TandW · 08-26-2007, 09:37 AM

Bear in mind that any condition that raises oil pressure in an automotive application tends to bypass dirty oil around the filter. This is a fact of life you all need to consider. If you want to blow on down the hi-way you better have some idling time to do your filtering. Think about it. Good luck!!

Ron & Dee · 08-26-2007, 09:48 AM

T&W,

Just out of curiosity, how often did they change the oil in the engine of those big ships?

Ron

edgray · 08-26-2007, 11:25 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I'll just say that I don't know of any of our customers that use it since our equipment can cost from $150,000 to $10,000,000. </div></BLOCKQUOTE>

RUSTYJC: Thank you for your straight forward answers. IF you are involved in selling any of this pricey equipment....please tell me you DON'T wear that tasteful sport coat you wore in Branson!

ED

TandW · 08-26-2007, 11:45 AM

I don't recall ever hearing of an oil change on a Gearing class destroyer. They were twin 30000 h.p. G.E. or Westinghouse turbine driven thru 17000 to 1 double reduction gears. The sump held 800 gallons of Sun 100 turbine oil which was purified of water and contaminants by a single Delaval cone disc type separator. I think at a rate of approximately 100 gpm. The separator was also used to transfer oil, dirty or purified to and from the turbo-electric generator and the main feedwater pumps for the boilers. It was also possible to transfer oil between engine-rooms. There was no testing done on the oil. The replacement rate was sufficient at approximately 200 to 300 gpy. And there is no combustion component. It was recognized that the permatex-like material that was cleaned from the 60 separator cones every nite at midnight was the oil break-down component. Glad you asked!!

RustyJC · 08-26-2007, 12:04 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by T&W:
Bear in mind that any condition that raises oil pressure in an automotive application tends to bypass dirty oil around the filter. This is a fact of life you all need to consider. If you want to blow on down the hi-way you better have some idling time to do your filtering. Think about it. Good luck!! </div></BLOCKQUOTE>
If your comment relates to higher oil pressure with a larger filter, the reason the oil pressure at the engine's oil feed gallery might be higher is that there's less pressure loss across an oil filter with a larger surface area, all else being equal. Since the filter bypasses based on differential pressure, the larger filter, having a larger surface area and less pressure drop, is less likely to bypass than a smaller filter.

Rusty

RustyJC · 08-26-2007, 12:11 PM

Oil in reciprocating gas compressors, centrifugal compressors, steam turbines, etc. isn't exposed to combustion temperatures and gasses. This service is so "easy" relative to engines that ISO 32 or ISO 46 turbine oils may only have an R&O (rust and oxidation) additive and may have changeout intervals based in years, if ever.

We build a 2-cycle integral engine/compressor that lubricates the power cylinders, compressor cylinders and compressor rods and pressure packing with lube oil drawn from the crankcase. The make-up rate of fresh oil to the crankcase keeps the crankcase oil "sweetened" with fresh oil and additives. Many of these engines have run years between changes, but lube oil analysis is still performed.

Lube oil analysis on our equipment serves two purposes:

1. It determines the condition of the oil

2. Even more importantly, it helps determine the condition of the equipment via wear metal analysis, ferrography, detection of fuel dilution, coolant contamination, etc.

Rusty

TandW · 08-26-2007, 12:38 PM

Integral automotive oil pumps are positive displacement pumps. Any condition leading to high oil pressure will cause the oil to bypass. If pressure was not relieved the pump would fail. On the other hand when an engine has aged, and is worn in tolerance, the pump has also loosened up and can no longer pump up to an overpressure condition. This is when you need to dilligently replace filters; perhaps more frequently than prescribed by schedule. I hope you can understand now. Good luck!!

RustyJC · 08-26-2007, 12:47 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by T&W:
Integral automotive oil pumps are positive displacement pumps. Any condition leading to high oil pressure will cause the oil to bypass. </div></BLOCKQUOTE>
With a larger filter surface area downstream of the oil pump, system resistance is lessened, not increased. Since the pump is attempting to move a fixed volume at a given RPM, the discharge pressure of the pump would be lessened with less system resistance, not increased. The scenarios might look like this (just picking arbitrary numbers):

Small filter:

Lube oil pump discharge pressure - 70 PSIG
Filter differential pressure - 10 PSIG
Engine header pressure - 70 - 10 = 60 PSIG

Large filter:

Lube oil pump discharge pressure - 68 PSIG
Filter differential pressure - 6 PSIG
Engine header pressure - 68 - 6 = 62 PSIG

If the filter bypass is spring loaded to open at 20 PSID differential pressure, the small filter has 20 - 10 = 10 PSID margin to bypass while the large filter has 20 - 6 = 14 PSID margin to bypass.

Rusty

RattlenRam · 08-26-2007, 01:34 PM

Boy I am sure getting more than I expected on my origanal post {which is good thing}. Thanks to all for your imput, keep it coming.

Mutha · 08-26-2007, 02:37 PM

Rusty, Thanks for all the great post! Your explanations are not only correct, and understandable, they are also more clear and concise than many of my old engineering tech traning classes.

Best to you - Glenn

TandW · 08-26-2007, 05:59 PM

If you insist on using an oversized oil filter please consider the increase in time necessary to get two quarts of cold oil moving and the lag time involved in developing vital delivery of moving oil to the furthest of the engine running gear. If you are bent on doing this you should go all the way and install a prestart prelube pump with starter enable on proof of pressure. Install solid motor mounts so that it simulates a stationary engine and won't require excessive overtightening to keep that filter from rattling loose. Good luck!!

max49 · 08-26-2007, 06:05 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by T&W:
A BIGGER FILTER IS A BIGGER TARGET FOR STONES AND GATORS!! </div></BLOCKQUOTE>

Finally, some one has thought of an advantage for the 'little filter'. I hate it when a gator bites my oil filter.