Does anybody use a bypass oil filter system?

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f508

Senior Member
Joined
Jun 20, 2017
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117
Location
USA
Vessel Name
MaryAnn
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48 DeFever
I friend of mine that runs some diesel trucks at work swears by a dual filter bypass system.

It sounds like it consists of a fitting and a couple of hoses where the oil filter normally goes and the oil transits a more elaborate filtration process externally and then is returned to the engine.

He says he gets much longer intervals between oil changes, and his oil never looks black. I am pretty sure the filter gauge is much finer than the normal FRAM filters I usually see fitted.

A search for bypass oil filter system Lehman didn't turn anything up, so I am wondering.

Thanks,

Frank
 
Our NT855 has what is called bypass oil.
Its just a fleetguard lf777 with smaller hoses running into the main larger filter.
We are due for an oil change within the next 60 hours.
Oil is still clear on the dipstick.
 
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I used bypass filters plus the full flow filter on many engines since the mid 60's. Older engines, before 1960, use a bypass filter not full flow as common in todays engines. They work by allowing the oil to pass thru the filter very slowly. The slower the pass, the smaller the particle is captured. Full flow filters only capture 30+ micron dirt. Most bypass filters capture below 5 microns and some below 1 micron. Less dirt, longer engine life. My last gas pickup truck got 350,000 miles before engine overhaul. Oil stayed transparent in gas car engines. When running commercial boats, I usually got double life between overhauls when compared to users with similar setups. But, I also don't beat my engines. Now I use a centrifuge, but would have bypass filters if I didn't.
Something that helps is to buy a longer full flow filter - slows the flow, or dual filters.
 
I've used them on non marine applications in the past. We ran a fleet of generators driven by Caterpillar 3516's. The first engines were originally rigged up with large volume bypass filters.
We ended up ceasing the use of them after determining that the oil life was limited by the oil becoming acidic (TAN and TBN out of spec) Extra filtration had little effect on this so the substantial extra cost of the bypass filters was not worth it.

Other engines and applications may have results.
 
Our DD 6-71 was a "war reserve" unit from the 1950's.

It has factory bypass filtration , no full flow .

At 50 hours the oil looks clear , at 100hrs (change time) it is slightly golden.
 
With what you guys are saying, combined with my friends comments, I am sold on the idea.

Is anyone aware of bolt on kits for 120 Lehmans, or are the kits generic?
 
I've used them on non marine applications in the past. We ran a fleet of generators driven by Caterpillar 3516's. The first engines were originally rigged up with large volume bypass filters.
We ended up ceasing the use of them after determining that the oil life was limited by the oil becoming acidic (TAN and TBN out of spec) Extra filtration had little effect on this so the substantial extra cost of the bypass filters was not worth it.

Other engines and applications may have results.

:iagree:

Oil is more than just the particulates and color. Considered bypass filters and synthetic oil. Decided to stick with more frequent oil changes and standard filtration. My Dodge pickup with a Cummins 6BT 220 HP diesel engine has over 430,000 miles using standard Wix filters and 15w-40 Rotella T oil. Still going strong after 15 years. Hard to improve on that.

Ted
 
With what you guys are saying, combined with my friends comments, I am sold on the idea.

Is anyone aware of bolt on kits for 120 Lehmans, or are the kits generic?

Pretty generic. I installed a Puradyn 1 micron bypass filter on our Cat 3306B and use synthetic Rotella oil. 1 micron is a whole lot smaller than the tightest tolerance on the engine so theoretically wear is almost eliminated.

I had to build a bracket to hold the filter housing and mounted it over the gear and you will likely have to do or have done some fabrication yourself. Puradyn sells filters with supplemental additive packs to replace what gets depleted, allowing you to go quite a long time between oil changes, if you wish. I don't so wish, and change it normally since saving $100 a year on oil is not that relevant when compared to the cost of repair.

I have no doubt that if I just used regular dino oil and OEM filters this engine would outlive me regardless but I have never quite understood the argument against having cleaner oil so will stick with what I'm doing.

Incidentally, you can frequently find Puradyn filter bodies on eBay, as well as filters, for quite a lot less money than retail.
 
google Gulf Coast filters for a bolt on kit.

My cummins 5.9 has used this depth style filter since new.

I change the filter at 100 hours, add about a gallon of new oil for additive depletion and have the oil tested regularly.

Additionally, every 500 hours I do a full oil/filter change.

The oil stays transparent.
 
With what you guys are saying, combined with my friends comments, I am sold on the idea.

Is anyone aware of bolt on kits for 120 Lehmans, or are the kits generic?

AMSOIL has kits and filters. Adapter spins on the existing filter mount. In and out lines routed as appropriate. I have one of their kits mounted on my Chevy Duramax. With synthetic oil and oil testing drain intervals are greatly extended. I also have Lehman 120's but I won't be installing bypass filtration. I do however use AMSOIL filters that are much larger than the standard Fram PH8A or equvilant. I use their synthetic and oil testing for the simple reason of extended oil drains. Cost is no more cuz the oil is not changed as often. But testing is recommended to make sure TBN remains adequate and the soot levels are within limits.
 
I don't think it is worthwhile to add a bypass filter to an engine that did not come equipped with one. Very few of these trawler engines are going to suffer any significant wear based on things that might be caught in the bypass.

Some engines come from factory with such: Yanmar 6LY (some), Cummins 6CTA (really, there is a separate tight pore element in the big can!), some Volvo's, and then the bigger engines of various brands.

Unless you are logging zillions of hours, the scheduled normal oil change interval will take care of your engine.

One local owner put a bypass filter on his Cats and did not engineer his plumbing well. A fitting blew off and he blew an engine. That did not work out so well for him.

If you want to do it for fun, nothing wrong with that, but don't expect a payback. Also, be very cautious if you extend change intervals. Particulate is not the only reason to change oil, and particulate is the only thing the bypass will improve.
 
Ski,
Do you have any idea how much of that "particulate" is carbon? It would seem that any significant amount of carbon (being an abrasive) that is removed would be a plus. A plus depending on how much black carbon was removed. And if one's oil ran clean w the by-pass operating and black w/o it .........
 
Most folks just want the engine to run happily while they own the boat.

I have never known a recreational boater to have worn out an engine.

But I have seen lots that were killed.

A bypass filter MIGHT create longer engine life , just as crap oil seldom changed MIGHT kill the engine.

A properly installed bypass to me is insurance , for me, worth the effort.

Only with lab work can the oil change be extended , why bother?

Oil is cheap , do the oil sample with each change (for your boats records) .

Many boats never get to the operating engine hours per year to require a change ,
but time in the engine is also a requirement for change.

Additives wear out.
 
Speaking about oil analysis, any advice for one lab in Canada?
 
Soot, however small will clump into larger and larger particles. Eventually causing damage.
My goal with bypass filters is to extend the time between overhaul. Extending the oil change interval requires oil testing. I've been testing since the early 70s.
In my experience what wears out first is the sleeve cross hatching and the rings. They wear out from dirty oil and high exhaust gas temperatures. Once the cross hatching is gone, the rings no longer carry oil to the top rings and they wear like crazy. From no cross hatching to compression loss can be in a few 100 hours. If at the first sign of oil use or compression loss the engine gets re-cross hatch honing and new rings, usually the engine runs like new.
I overhauled or oversaw many engine overhauls. Much of the time I got to know the history of the engines and how they were maintained. It didn't make me an expert, but gave me tons of info. I became a believer in clean oil and keeping the throttle under 80%. In my book, the oil can never be too clean.
My current boat has Detroit (Gray Marine 1947) mains that were known to have at least 20,000 hours before being overhauled. I suspect they were used engines when installed. They have the original bypass setup. I bought the boat partly because of the engines. I overhauled them. With normal care, no matter how much use, they'll still be running for some owner long after I'm dead.
Picture is cross hatching on Detroit sleeves.
 

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I once visited a prime power generator site on a mountaintop near Campbell River.
The generators were on Deutz engines. One running, one ready to go should the one running fail, and a third that hopefully would be used when one of the others was out for a rebuild.
The site was accessible by Helo in emergencies in teh winter, by road in the late summer and early fall, so all maintenance was scheduled to be done annually, during the accessible time.
Between annual maintenance that would take place every 8760 hours, the oil cleaned itself, in a bypass filtration system.
The schedule for rebuild was after 30000 hrs, replacement after 60000. Premature failures were not mentioned.
 
My engine came with a bypass filter, V555M, so I use it. Do I believe in it, maybe, since I don;t put the hours on the engine to make good use of the bypass and change the oil yearly regardless of hours.
I also do the oil tests yearly and they keep coming back good.


Lou,
Caterpillar operates their SOS oil test labs and they have them all across the country. Local Cat dealer should be able to help you.
My Cummins dealer sells the Cat SOS kits.
Just tell them you want it for your marine engine as they sell other sample kits for other types of machinery which are much more expensive and won't add anything of real value.
 
By Pass Flow Oil Filter - Gulf Coast

F508,
I can help you I think.
They do work very well.
I believe I have a good used "Gulf Coast" bypass flow oil filter I can set you up with at a reasonable price.
It uses a "BOUNTY" brand Paper Towel filter element and end flow filtration & I used it on a Detroit Diesel 6-71 engine for 20 years with great success.
They definitely work. Sold engine & it was still running fine.
Filters down to about 2 microns or so as I recall.
I still leave the full flow 30-50 micron standard oil filter element in place as well as put the bypass filter on.
I have heard of guys going a million miles on an Diesel engine with these filters changed regularly.
Don't have to change all the oil if you use synthetic oil.
Just change filter & top off to full with fresh oil.
PM me & we can talk if your interested.

Alfa Mike :thumb:
 
I think using by-pass filters is a good thing but I question if I'd want the QC of household products in fuel or oil filtration. Parts of paper towels could go where you definitely don't want them. I would want a small in-line filter to catch pieces of paper towels ect. Or ideally a filter designed to do that.
 
Large trucks also keep the oil clean with a centrifugal oil filter

Easier to clean than tossing roles of toilet paper or paper towels .
 
We all did in 1950.
"Full flow filters were yet to come.
It was felt one couldn't be made that would flow all the oil and provide adequate filtering. So to have both makes sense.
 
"It was felt one couldn't be made that would flow all the oil and provide adequate filtering."

The worry was if the filter got plugged from crap the engine would be starved of oil.

Problem solved by putting in a 5c spring that would allow oil to pass a blocked filter.
 
F508,
I can help you I think....


Alfa Mike :thumb:

That is very helpful. I am afraid I have 2 engines and I think in the long run it will be simpler if both sides match, so I won't be able to take you up on your kind offer.

But thank you very much!

Frank
 
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