2 micron filters on Racor Dual Spin-on 75/B32009

[Tenedos]

Our boat came with a nice Racor Dual Spin-on 75/B32009. It has S3209S (2 micron filters) on both slots. 2 micron feels too granular and I am a little worried it will clog at some point. But it has worked very well for 1.5+ years without any issues (diesel taken in numerous US PNW and British Columbia/Canada ports) so I also don't want to change it since it is working. So I have a carry 2 micron spares but wondering if I should consider changing this to 10 or at least carry a spare.

Also it would be nice if these were connected in a series, meaning I could put one 10 micron and one 2 micron and diesel gets through 10 first and then 2 later. But I may be wishing too much.

What do others do?

[Lepke]

If it worked for a year and a half then it's ok. Your tanks and fuel system is cleaner for it. Injectors and injector pump lasts longer.

I've been using 2 micron for 11 years w/o issues. 2 Detroits. About 70 gallons an hour pass thru.

[mvweebles]

Not possible to plumb these in series so that's off the table with the Racor dual filter.

Engine manufacturers universally recommend 10 micron ad the on-engine secondary filter is almost always 2 micron. Many DIY folks figure they want to protect the secondary filter and therefore run 2 micron. Thinking is they don't want to have to change the secondary and bleed the engine.

I run 10 micron in my dual racors. I also have a fuel polishing system and use 30 micron in that.

[Bowdrie]

Originally Posted by mvweebles

Engine manufacturers universally recommend 10 micron ad the on-engine secondary filter is almost always 2 micron.

Perhaps the new(er,) common rail/computer engines are.
The engine mounted secondaries on the older Perkins/Detroit/Cat/Cummins, that I've changed filters on were lucky to have a 10, most were 20, a few were 30.
I always thought it was kind of counterproductive to have a 2, or a 10 filter as a primary when the secondary was no finer, oh well.
I too run the 2s in my Racor as a primary, the secondary is a 1, (one,) micron.
As far as I know the old Fram dual-cannister units, (that everybody hated and got rid of,) were the only ones I've found in which 1-micron elements are available.
Actually, the old Detroits, where they circulate far more fuel than they use seem to run pretty good as long as you keep the rocks and water out.
PS, Truth be told, I detest engine mounted secondaries, it's a travesty having filters mounted where even one drop can spill on the engine.
The same for oil filters.

[mvweebles]

Originally Posted by Bowdrie

Perhaps the new(er,) common rail/computer engines are.
The engine mounted secondaries on the older Perkins/Detroit/Cat/Cummins, that I've changed filters on were lucky to have a 10, most were 20, a few were 30. .

Arw you sure youre not thinking of primaries? Vast majority of on-engine filters I've seen are 2-micron, and that goes back 30+ years (DDs may be different). An article for a definitive source, Steve D'antonio on common setup and filtration, and myths seems go corroborate this.

https://www.passagemaker.com/channel...ings-explained

Another article - with quote extracted below with highlights.
https://www.cruisingworld.com/how/sensible-fuel-system/

Secondary Filter: The final line of defense is the secondary-filter element. Commonly located on the engine, this filter is usually either a spin-on filter or a replaceable-cartridge element. The filtration rating varies among manufacturers; it’s usually in the range of 2 to 7 microns.

Most primary-filter manufacturers recommend using 10- or 30-micron elements, which means they’ll catch anything bigger than that size. The idea is to catch the water and coarse dirt here and let the secondary filter take care of the finer grit.

Some cruisers prefer to use a finer primary filter to catch all but the finest particles before they reach the secondary
filter. This may work for some, but in my experience, it isn’t any more effective. With this system setup, filters typically don’t last as long, and the engine is more likely to shut down due to acute fuel starvation from a clogged primary filter.

[Roniszoro]

I have a 10 micron filter in my Racor and a 2 micron filter at the engine on my Yanmar. I had the same setup on my previous boat's Volvo. So far, good success with this set up over close to 30 years.

[Orion Jim]

Originally Posted by Roniszoro

I have a 10 micron filter in my Racor and a 2 micron filter at the engine on my Yanmar. I had the same setup on my previous boat's Volvo. So far, good success with this set up over close to 30 years.

This is what I’ve had for over four decades in eight to twenty-five horse diesels.