bottleworks said:
I have been running dual remote 51970XD filters sense February. I am getting aprox 3 seconds until pressure.
Therein lies the rub. The remote filtering system by design CAN allow less oil to flow back to the oil pan, thus less oil to refill the system, thus less time to refill the system and achieve normal oil pressure.
Consider these points:
1. The stock Deuce LDT oil pump, in good repair, and in a sound engine, is rated to deliver 22 GPM using OE/HDO-30 at 180F (ref TM 9-2815-204-35-2-1, MAINTENANCE DIRECT SUPPORT AND GENERAL SUPPORT LEVEL ENGINE ASSEMBLY, DIESEL, (MULTIFUEL), page 1-14)(engine rpm not stated, but assumed to be at 2600 engine RPM, as the max oil pressure is rated at 2600 RPM).
2. The Deuce oil pump is a gear type pump, thus oil delivery is approximately proportional to engine RPM.
3. Considering point 1 and 2, at an engine idle speed of approximately 800-850 RPM, the oil delivery is in the neighborhood of roughly 7-8 GPM.
4. Most Deuce owners, with a stock oil filtering system, report a time lag of 14-15 seconds from engine start to start of oil pressure rise.
5. Considering points 3 and 4, a 14-15 second lag time for oil pressure to build indicates an oil delivery of roughly 2 gallons of oil to fill the entire lubrication system (oil filters, oil galleries, and connecting passages) from engine start to start of oil pressure rise.
6. The oil filter cannisters themselves require 1.5 to 2 quarts of oil each to fill (considering the oil filters occupy a fixed volume within the cannister, the volume required to fill each cannister is the absolute volume of the cannister less the volume of the wetted filter). For arguments sake, I will assume 2 quarts net per cannister, or 1 gallon total, to refill both cannisters.
7. Considering points 5 and 6, if roughly two gallons of oil are required to fill the ENTIRE oil system, and one gallon or less is required to refill the oil cannisters, then roughly one gallon of oil is required to fill the oil galleries and connecting passages.
8. Considering points 3, 5, 6 and 7, roughly one gallon worth of oil galleries and connecting passages to fill on engine start up requires UP TO 7-8 seconds of engine run time to fill before engine oil pressure begins to rise.
So what is my point? If you look closely at Bjorn's installation, his remote filters are installed ABOVE his personnel heater, and the supply lines are ABOVE the level of the oil passages in the oil filter base and the oil cooler, so ALL of the oil in his oil galleries and connecting passages, EXCEPT for the oil in the filters themselves, will drain back into the oil pan, as Bjorn noted. Bjorn reports 6-8 seconds of engine run time before engine oil pressure begins to rise, which corresponds EXACTLY with my point #8, given the accuracy of my assumptions of oil volumes and oil flow delivery rates.
On the other hand, were an individual to mount their remote filters BELOW the oil filter base and the oil cooler, LESS oil will drain back, and he engine run time before engine oil pressure begins to rise will be LESS than what Bjorn reported. Thus a 3-6 second lag before engine oil pressure begins to rise is entirely possible with a properly installed remote filter system, regardless of whether such installation is by design or fortunate chance.
I have no disagreement with John Tennis' claims. Properly installed, a remote filter system can reduce the lag time before engine oil pressure begins to rise to a few seconds, but cannot reduce the lag time to zero because the oil galleries will ALWAYS drain back to the oil pan, and there will ALWAYS be a slight lag in oil pressure untill those galleries are filled. But to give John the credit he deserves, a 2-6 second lag is MUCH better than a 14-15 second lag!
Banshee365 said:
After sitting for about 3 weeks the truck took 14 seconds to build pressure from the first indication of ignition to the needle moving. Seems like it takes a lot less if you start it at least once a week.-Kelly
Not possible, unless you have discovered some new laws of physics. It takes roughly two hours for the Deuce oil system to drain completely back into the oil pan. Thus, whether the truck sits two hours, two days, two weeks, two months or two years, it takes EXACTLY the same volume of oil to refill the system and for oil pressure to start to rise. Thus, for all intents and purposes, idle time on the engine has no effect on oil pressure build time. However, there are three variants which can affect the oil pressure rise lag time, oil temperature, oil time at temperature and battery condition.
The first is obvious - warm oil flows faster than cold oil. If you restart a warm engine, or start an engine in a relatively warm environment, say 80F, the oil will flow faster and time to pressure will be quicker than were you to start an engine with oil at 20F or 0F.
The second factor is not well understood. Engine oil has a memory. The longer engine oil remains at a given temperature, the more viscous (thicker) it becomes, within a very limited range. Thus, an engine oil which has been at say 20F for 24 hours will appear less viscous (thinner) than the same engine oil which has been at 20F for two days or two weeks. This effect is more noticed by those of us who live in the cold north. If I start my car every day in very cold weather, it will start fairly easy. However, if I wait several days before starting my car, it will take a bit more cranking before it starts. This is partially due to the oil time at temperature factor and partially due to the battery temperature. A cold battery (or a battery which has sat for a while) will not deliver the cranking amperage of a warm, fully charged battery.
Thus, I would suggest the phenomenon you noticed is a result of the combination of oil which has reached its maximum viscosity due to sitting for a long period of time and batteries which have lost a portion of their charge due to disuse, resulting in a slower cranking speed, both of which will affect oil pressure lag time.
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Could you take him out, you couldn't even see a whole bunch of 'em circling for the kill 
