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Old 08-13-2022, 03:32 AM   #1
dmbraaten's Avatar
City: Luxembourg
Vessel Name: Anna Sørgaard
Vessel Model: Selene 49
Join Date: Dec 2018
Posts: 17
Oil Bypass Assessment

I have a single John Deere 60668SFM on my 49 Selene and am planning a circumnavigation starting from Barcelona that will start in earnst next spring. One consideration of many is changing oil along the journey. Earlier this year, I installed a Jackmaster oil bypass filter (2 micron) and it has been functioning without incident. My reasoning behind installing it was to reduce the number of times i will do a full oil replacement - or eliminate a full change completely.

My plan that I am starting this summer after our extensive crusing on the Med (320 hours so far) will be to drain and replace 10 liters of oil (John Deere Plus 50 II 15/40)and continue to do this 3 times a year. The oil capacity of the engine is 34 liters so I will be replacing almost 1/3rd of the oil every 4 months. I will get an oil analysis after each of these changes to monitor wear and will replace the normal oil filter every year and the oil bypass filter twice a year. My hope is that this will result in adequate lubrication (verified by the testing) and will be a simple process while under way.


I attached the last 2 oil analyses for FYI
Attached Files
File Type: pdf John Deere - Aug 2019.PDF (237.0 KB, 6 views)
File Type: pdf John Deere - Feb 2022.PDF (50.9 KB, 3 views)
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Old 08-13-2022, 04:54 AM   #2
O C Diver's Avatar
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 11,246
A few thoughts:

I've never liked Cat oil analysis. To me, it's hard to read and I'm not sure it's as accurate as a specialty lab. From reading that report, there's no iron or aluminum in your oil. In the other report, the levels of iron seemed elevated and clearly a significant amount of aluminum. A bypass filter only filters a portion of the oil. I find it hard to believe there is zero iron or aluminum in your oil.

I like the concept of a bypass filter, but you don't get the cleaning effect that comes from centrifuging oil. I would feel better changing all the oil when I did oil changes.

On a side note, I have a John Deere 4045TFM75 in my boat. Religiously used JD plus 50 II 15W/40 and wasn't happy with the wear metals. Ended up switching to Rotella T4 15W/40 and have substantially lowered the wear metals, ymmv.

I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
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Old 08-13-2022, 09:12 AM   #3
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City: Port Townsend Washington
Vessel Name: " OTTER "
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On the 2019 analysis were the numbers for water and glycol high?. Did you investigate this any further?
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Old 08-13-2022, 11:16 AM   #4
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48
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Originally Posted by dmbraaten View Post
I have a single John Deere 60668SFM on my 49 Selene and am planning a circumnavigation starting from Barcelona that will start in earnst next spring. One consideration of many is changing oil along the journey. Thoughts?
There is considerable discussion on the Nordhavn site about John Deere oil change methodology when doing long passages. Several TF members have access to that site and I'm sure could chime in on what are the preferred routines. Also, the 6068 is a favorite for large yacht gensets running 24/7 with oil changes up into the 400 hour range when burning ULSD.

The ultimate question of course is are you comfortable shutting your engine down for an oil change every two to three weeks when in mid ocean? My guess is you'd be in a port somewhere every few weeks where an oil change could be easier accomplished thus avoiding a mid ocean change out. That being the likelihood, a complete oil change every few weeks can be accommodated - by far the preferred thing to do as compared to becoming an onboard chemist..
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Old 08-13-2022, 11:49 AM   #5
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City: Between Oregon and Alaska
Vessel Name: Charlie Harper
Vessel Model: Wheeler Shipyard 83'
Join Date: Jun 2016
Posts: 2,767
I've been using bypass filters since the 1960s. Before 1955, most car oil filters were bypass only. Older Detroit Diesels (Gray Marine) engines were bypass only. Bypass filters best effect is reducing particle size and that leads to less wear. I've run several engines thru multiple rebuild cycles with bypass filters and always get more hours than others using the same engine in the same way. Usually close to double hours.
If you cut open your filters after changing you'll find they retain some water in the bottom. Adding a bypass filter holds a little more. It's good to get water out of the oil system.

Now I use a centrifuge and haven't actually changed oil since 2011. Just make up oil. I do change the filters about once a year and do oil tests. My oil is transparent.
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Old 08-13-2022, 01:08 PM   #6
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City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,559
I’m also a fan of by-pass.

And clean oil.
I mostly get that from more frequent oil changes.

I suspect “full flow” filtration could have been a bit of an advertising gimmick. What a horrible thought .. the evil chunk of hard metal destined to ruin my engine got passed by the filter by dumb luck.

Obviously ideal would be a 30 micron full flow filter with a 10 micron by-pass filter. OK not ideal but much better than either one alone.

North Western Washington State USA
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Old 08-13-2022, 01:52 PM   #7
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City: Saltspring Island
Vessel Name: Retreat
Vessel Model: C&L 44
Join Date: Nov 2007
Posts: 5,277
years ago I visited a mountaintop generator location. The gens were:
#1 in use, Deutz diesel, bypass oil filtration,
#2 ready, auto start if #1 fails, same engine, same bypass filtration.
Maint was annual, so 24x365, 8760 hrs, #1 would be shut down, #2 would run the next cycle.
The only oil and filter change was at annual shutdown.
Rebuild scheduled at 30000 hrs.
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Old 08-13-2022, 04:37 PM   #8
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48
Join Date: Apr 2008
Posts: 9,422
Dependent upon the engine oil burned and leaked, oil needs to be added up to the fill mark between changes. For newer engines oil burned is between 0.05 to 0.10 % of fuel used. Older or higher hour engines can be a higher %. The necessary added oil when combined with top notch filtering can indeed extend oil change intervals.

In a previous lifetime where very large motors were provided a manufacturer's warranty for hours, oil change intervals were based upon chemistry. The dual and triple oil filtering setups on the engines got a lot of attention, with change intervals seldom going above 400 hours. The operating conditions were rigorous with dust, water and fully loaded engines conspiring to really test these diesels.

In a recreational boat, no doubt the conditions are benign. Sometimes too much so with low engine hours and sitting time then taking its toll with internal corrosion silently occurring. The "worst case" for Anna's circumnavigation is to do a complete oil change every 400 hours or so which is right in the ball park JD recommends. If the engine's lube system and current health allows longer intervals as indicated by analysis great. No harm in being conservative with oil usage to start the journey.
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