I was looking at a booklet on bypass filters from Fleetguard. It reads as follows. "The majority of wear occurs during cold starts. The question is, what is the impact of the add on system on cold start wear?" Although wear points will still have a residual coating of oil even when the sump has been drained during oil change full oil pressure is required to prevent additional wear. The pressure drop associated with the filtration system impact the time it tales for full oil pressure to reach all components."
They go on to say that their bypass filter compared to the full flow filter only gives 30% less wear to the upper conn rod bearing shell 63% less wear to the lower conn rod shell 49% less wear to the upper main bearing shell and 64% less wear to the lower main bearing shell.
Awhile back I put their best bypass filter on a 8.3 Cummins engine in a yard mule. As you might expect I converted the LF 750 housing to take two rolls of Kleenex Viva and three rolls of Scott TP. I am hoping to get 1000 hrs between filter changes with no oil drains. I just got back results from 320 hrs. The oil analysis shows 20 ppm iron, 1 chromium, 1 lead, 2 copper, 0 tin, 2 aluminum, 0 nickel, 0 silver, 4 silicon, 50 boron, 3 sodium, 11 magnesium, 3165, calcium, 1172 phosphorus, 1503 zinc, 42 molybdenum. Fuel (% vol) under .5 water under .1 (% vol), soot under .1 (% vol), glycol neg.
I think this is a good report. This engine gets started a dozen or more times on one shift and works every day spotting trailers. I have a similar report on a 8.3 in a motor home after a trip to Alaska.
I might be wrong but I doubt that the numbers would be a lot better if the engines had a pre oiler. Both engines use Delo 400 15-40.
Using Motor Guards old formula of one hr equals 30 miles 320 hrs would be 9,600 miles. If I can keep the numbers looking good until 1000 hrs I will be happy. I was changing a much smaller filter every 500 hrs on a Detroit 8.2 in another yard mule. Fleetguard uses an orifice that is too large for these engines and is at the outlet. I put a 1/16th orifice at the inlet. The big LF 750 is a do it your selfers dream. It doesn't take me long to roll an element. I run a secondary filter on these big filters. I will change the secondary filter when I change the big filters. A secondary filter is the only way I can be 100% sure that no paper fibers will get into the oil.
The stock elements are shredded newspapers and are loaded with paper dust. They have a built in filter to keep this out of the oil. When you have a lot of rolling paper you are going to generate loose paper fibers.
Ralph