Views on John Deere 6125AFM75

[FF]

"We have base engine selection done, and are working on marinisation now."

What did you finally chose?

The number of base engines world wide is declining rapidly , because of the Air Police and their testing , and the endless time and cost of the testing.

Has any mechanical injection engine come close to being modern-legal?

 

[pacopico]

There are no mechanical engines available in the 70-300HP range we are looking at that are meeting Tier III.

The new engines will be common rail injected.

As far as the manufacturer of the base engine, I need to keep that confidential until we are further down the road.

 

[FF]

"The new engines will be common rail injected. "

How do you handle the problem of std. fuel being too dirty (as noted in PBB) for use in a common rail system with nornal filtration?

Alfa Laval ,a centrifugal filter , the small one , comes to mind , although 18 wheelers have a small $700 system for lube oil that might work as well.

A great fuel cleaning system would be a good stand alone product , as it is currently needed by the entire planet.

With only a paper cup to toss instead of a dozen old fuel canisters , the greenies would love ya!

 

[twistedtree]

"The new engines will be common rail injected. "

How do you handle the problem of std. fuel being too dirty (as noted in PBB) for use in a common rail system with nornal filtration?

Alfa Laval ,a centrifugal filter , the small one , comes to mind , although 18 wheelers have a small $700 system for lube oil that might work as well.

A great fuel cleaning system would be a good stand alone product , as it is currently needed by the entire planet.

With only a paper cup to toss instead of a dozen old fuel canisters , the greenies would love ya!

This is a long-ago solved problem. Common rail engines have been in boats for the better part of a decade now. The only real issues is getting techs to read the instructions and NOT pre fill the on-engine filter(s) when the manufacturer says not to. Pre filling can introduce unfiltered fuel which is bad.

 

[CPseudonym]

The only real issues is getting techs to read the instructions...

This is a problem across all disciplines, not unique to boat techs. Simply R'ingTFM has advanced me to the top of my field.

 

[pacopico]

Twistedtree is correct: biggest issue is filling the secondary filter with "clean" fuel out of the tank to prime the system which does allow small particles to get into the common rail injectors.

The proper way with any high pressure injection system is to use a secondary pump to pull fuel through the primaries and push through the secondaries, bleeding air from he filter head prior to starting.

if one desires a centrifuge filter can always be added, as they do often on commercial watercraft.

My personal recommendation for single-screw fuel system is duplex primaries with a selector, and vacuum gauge to check filter health, and duplex secondaries with a pressure/vacuum gauge and a selector. With this and some additional valving on the priming pump you can do under-way filter changes. This is how many single-screw commercial operators run...allows for filter changes due to dirty fuel without losing full operational capability.

Also on the note of dirty fuel in secondaries, the nominal rating for secondary filters on high pressure injected engines is 2microns. No one can see two microns!

 

[twistedtree]

This is a problem across all disciplines, not unique to boat techs. Simply R'ingTFM has advanced me to the top of my field.

So true. This is why we usually end up spending good money to have these guys come on our boats and break stuff. I think my new business slogan will be "we break twice the stuff in half the time, all for half the price". Feels like a winner to me

 

[Transaxial]

Twistedtree is correct: biggest issue is filling the secondary filter with "clean" fuel out of the tank to prime the system which does allow small particles to get into the common rail injectors.

The proper way with any high pressure injection system is to use a secondary pump to pull fuel through the primaries and push through the secondaries, bleeding air from he filter head prior to starting.

if one desires a centrifuge filter can always be added, as they do often on commercial watercraft.

My personal recommendation for single-screw fuel system is duplex primaries with a selector, and vacuum gauge to check filter health, and duplex secondaries with a pressure/vacuum gauge and a selector. With this and some additional valving on the priming pump you can do under-way filter changes. This is how many single-screw commercial operators run...allows for filter changes due to dirty fuel without losing full operational capability.


Also on the note of dirty fuel in secondaries, the nominal rating for secondary filters on high pressure injected engines is 2microns. No one can see two microns!

I like where this thread is going with the 2 micron absolute rated filters, vacuum gauges in line, and dual parallel primary and secondary filters to allow changes with the engine running. To make this work really well, you need to have low pressure from an in line supply pump or gravity feed to be able to bleed the filters after a change and get all the air out of the filter head while filtering all fuel that is passing through. Some of these common rail setups can be a bear to get primed and restarted after a filter change due to air in the system. That is a source of contamination while trying to bleed air and refilling filters manually several times until the enginestarts.

I did some research on fuel systems in a 6.7 common rail Cummins in a 2009 Dodge 3500. In those early years of the 6.7s they only used one tea cup size fuel filter that had a rating of 5 microns IIRC. They had fuel system problems but of course Dodge would not admit it but on later models added a second filter. On my truck I tried to prevent a problem before it ruined very expensive and brand new fuel system by adding extra filters. I am familiar with filters from bigger trucks, HD equipment and ag applications and have them in stock in bulk quantities at reasonable prices. It was suggested the a water separator filter be first followed by a 2 micron absolute secondary. Çommonly used filters on Cummins N14 common rail electronic engines is a Fleetguard FS1000 with a water drain on the bottom of a full sized cannister, about 9 or ten inches long. It is rated as one of the best water sep filters. The best secondary units I found were the full sized series of Cat filters for their 3406 engines in many modern configurations like C15, C18, and multiple filters for the larger C32 etc. Cat 1R 0749 and a few others are very common in trucking. These are 2 micron absolute, which means that no particle of 2 microns or larger can pass through. There are other filter companies that have this claim but few that can àctually reach that standard. Next is finding a filter base to fit these threads. Good old Napa had the right base, 1 inch 14 thread per inch for the right price, about $25 each. I installed these in line ahead of the stock filter under the deck along the frame and they have worked out well for me. No problems with fuel!! I would think this would be a great setup on a boat to be sure about your fuel supply. Good luck!

 

[FF]

"Pre filling can introduce unfiltered fuel which is bad."

Which one reason why most wrenches will use a can or two of ATF to prime filters..

According to my reading a 2 micron filter will pass a few 20 micron particles and lots of smaller diameter particles.

PBB claims the only method today getting cleaner fuel is to use a series ,3 or so of the 2 micron filters in series.

"followed by a 2 micron absolute secondary."

the Euro gov fuel testing seems to show that an Absolute filter does not yet exist, hence the reason for the series.

 

[bayview]

IMO the support and parts availability in your area are as important as the engine history.