I will ask and look into this
Thanks for your insight
Edwin
Changing cold oil leaves much of the dirt in the oil pan and passages. I've seen oil pans that only held 1/3 of the oil because of particle buildup. The owner was oblivious.
I have a centrifuge and plumbed my engines to drain via a gear pump. Occasionally I drain the engine oil after running and centrifuge it. My plan is to greatly extend the engine life. When I have the oil tested, it comes back as almost new oil. I haven't actually changed oil in 5 years.
Depending on installation level engines may use oil until they get to the proper level for the installation angle. Dip sticks are not always calibrated properly for the install and factory capacity is for a flat install. You may want to try letting the oil go down a bit and see if it continues to go lower or stops using at that level.
Eric try wrestling a 1 quart big hot oil filter from the outside of an engine and you may reconsider.
I pump mine out hot after an extended cruise as I feel it's more likely to have any particulate suspend in the oil and it's easier on the pump. Change the filter the next day when it's cool and pour in the new oil.
Older Perkins can be really fickle about their oil.
I have twin 6.354 na's. I was burning oil, about 1 qt per 8 hrs at 2400 rpm's on each engine, since brand new. The local yard suggested switching from single weight (30W) to multi weight (10 -30W) and the oil use actually went up.
I continued to run it on 10-30W for two seasons and nothing changed.
I switched back to single weight and was back to 1 qt per 8 hrs.
I did notice that if I ran a little slower, oil use went down. At 2250 RPM's oil use was nearly zero. Only explanation anyone could offer, was that is "the sweet spot for those engines in that boat."
So use a single weight oil and experiment with your engine speed and maybe you can find the "sweet spot" for your engines.
Eric try wrestling a 1 quart big hot oil filter from the outside of an engine and you may reconsider.
Detergent keeps the big crud in suspension so the oil filter can grab it.
The fine stuff that passes the filter still requires removal for longest engine life.
A long 5-8+ hour run allows the detergent to re grab the fine stuff stuck to the sides and bottom of the oil pan and get it back in circulation.
This happens with every long engine run , weather you are changing the oil or not.
"Best Practice" would seem to remove it every time the oil is changed.
Or use a centrifugal bypass filter system and catch it as its formed.
I would think running those engines at 2400rpm would be running them a bit hard...no???
So mechs can't work on a running engine?
chris: I use a nail to punch a hole and drain the filters into a bucket. Some tape or a metal screw will plug the hole so you avoid drips. An empty big filter is much easier to deal with.
Only once did I try the plastic bag routine. Now I know what wrestling a greased pig must be like.
Yeah, I meant to try the drain hole thing... but worked out that a big zip loc bag works well enough on our port filter. "Greased pig" is what happens if there's a slip-up, but mostly the big-a$$ bags are big enough so it's all manageable. And I'd probably need to use a bag anyway, even if the filter were mostly drained in advance.
I use a bag on the starboard filter, too, but that's very straightforward.
Usually the result is that the bag/filter goes into the bucket, and the bucket itself never even gets oily.
-Chris