10mic or 30mic for primary racor filters? Cat 3116TA 300HP

[inquisitivej]

You all have been great with my newbie questions, here is another one.

I thought I was all ready to do my primary fuel filter change, tools, diapers, couple small containers, drain hose for petcock valve, ... I open up the lid and find that the filter I'm pulling out is a 2040N-10. I bought 2040V30.

So the first thing is that the prior owner used a 10micron filter. The second thing I realized I didn't buy the 2040SM I should have.

While I wait for a reply from the prior owner I thought I would ask this audience about this.

Like with most Grand Banks I've seen, I have a primary racor 900MA that sits between the fuel tanks and the secondary Cat brand fuel filter on the engine, starboard is the same. There is also a backup 900MA on each side with a set of valves so one can flip between filters quickly if there is a problem while out and about. Thats how this boat is setup (the 900MAs do not run in parallel as I've seen on some).

When I saw the 10 micron filter my first thought was, "of course, the cleaner the fuel the better, why not", my second thought was "I wonder if that puts undue stress on the fuel pump system or has much of an impact on flow rate", my third thought was "really, another trip to fisheries supply?"

I would love your collective wisdom and thoughts on going with 10 vs 30 micron on the primary racors in this sort of setup. Someone put those red 30 micron stickers on there for a reason.

 

[Comodave]

Personally I would go with the 10 micron element, if the choice is between 10 and 30, 2 is my preference in real life. The 10 micron will flow the same rate as the 30 but you will have to change it sooner. But the secondary filter will last longer with cleaner fuel getting to it. The Racors are easy to change elements in.

 

[Lepke]

I run 2 micron, but my tanks are clean and kept that way. I don't buy fuel from marinas unless they are a major supplier. And I use a fuel additive that helps my Racor separate water better and kills fuel bugs. And my filters go 500 hours +.

 

[tiltrider1]

10 over 30. 2 is better than 10 if your tanks are clean. If in doubt start with 10mic.

 

[inquisitivej]

I run 2 micron, but my tanks are clean and kept that way. I don't buy fuel from marinas unless they are a major supplier. And I use a fuel additive that helps my Racor separate water better and kills fuel bugs. And my filters go 500 hours +.

Thanks, you have a 3116 Cat? Which additive?

 

[inquisitivej]

10 over 30. 2 is better than 10 if your tanks are clean. If in doubt start with 10mic.

You have a 3116?

I am assuming not all diesel engines expect the same amount of vacuum or resistance to pull fuel into the pump. But maybe I’m wrong and it’s such a small amount of difference. It doesn’t matter?

 

[Comodave]

I run 2 micron, but my tanks are clean and kept that way. I don't buy fuel from marinas unless they are a major supplier. And I use a fuel additive that helps my Racor separate water better and kills fuel bugs. And my filters go 500 hours +.

Agree. I run 2 micron on my boat. Doesn’t really matter which engine you have fuel filtration is fuel filtration.

 

[inquisitivej]

Agree. I run 2 micron on my boat. Doesn’t really matter which engine you have fuel filtration is fuel filtration.

I have done a little more reading and came across this 2017 article by Steve D'Antonio Fuel Filter Micron Ratings Explained

Probably already known to most of you. Reposting it here for the other newbies that will come behind me. I think I'm going to go with the 10 micron like prior owner had in there. I'm going to add drag needle gauges to the racors in my system that don't have them already.

 

[MarkPaul]

This topic gets almost as much attention as "the best anchor"!

Two points are worth repeating:
1. Steve D'Antonio's article summarized it aptly: " sequential filtration is scientifically proven to be more effective than single stage, fine micron filtration". But then again there is a strong modern movement against all things scientific. Sorry Steve, the article is so "pre-Covid".

2. If your fuel is uncontaminated, your tanks are pristine and everything else is surgically sterile, why not go for a 0.1 micron filter? Actually, you don't need to filter your fuel at all.

 

[BruceK]

Good to think about issues like this. Any problems using the existing 10s? If no, your system copes. The water removal function is as desirable as the filtering.

 

[inquisitivej]

Good to think about issues like this. Any problems using the existing 10s? If no, your system copes. The water removal function is as desirable as the filtering.

The only problem is they were due for replacement based on hours and based on the vacuum level on the gauge. I figured a finer filter would mean extra burden on the fuel pump, which it could if they get plugged up (per the article). So its another reminder to watch the vacuum gauge drag needles for measurements above 7 inHG and just change them before its an issue.

 

[kapnd]

Under ordinary circumstances, it doesn’t really matter much what micron rating you choose for your primary filter, but I prefer to set up my system to work to my advantage in the event that contaminated fuel is introduced.
This entails a bulk water separator followed by a 30, then a 10, and the final filter of 2 microns.
If your primary filter is a fine rating, it will clog incredibly quickly, leaving you dead in the water, whereas the graduated filter system will get you a lot further without choking off the fuel supply.
Careful monitoring of vacuum gauges should be done as a matter of course.

 

[Comodave]

Usually the primary filter is easier to change. Getting to the port secondary is a real PITA. Also I can usually change the Racor element without bleeding the system. The secondary filter requires bleeding every time. So I do 2 micron in the Racor. They flow as much as the 10 or 30 but will block faster. I watch the vacuum gauge and change them as it rises before it can get blocked. But my tanks are clean and I am careful where I buy fuel.

 

[Lepke]

I have Detroit 2 cycles. Running really clean fuel saves wear on the fuel components. There is no injector pump. The injectors make the pressure. Fuel is constantly flowing thru the injectors cooling the tips between firings. The gear lift pump moves 35 gallons/hr at speed, natural engines. Injectors are operated by a 3rd rocker arm for each cylinder. Inside the injector is a piston and cylinder that makes pressure on the down stroke. Other parts determine how much fuel is needed. Any fluid carrying debris causes wear. So limit the debris to limit the wear. Current injectors are 12 years old.
Speaking of engines, I just put another $5k in my diesel pickup fixing no start problems. If I was younger I'd swap in a Detroit.

 

[Comodave]

One of the nice things about Detroits is the amount of fuel pumped, a lot so it gets filtered well.

 

[O C Diver]

It depends on your change schedule and hours or operation in between. I changed mine (Racor 1,000) annually and did no more than a thousand hours per year. I used all 3 micron ratings without any difference. How often will you do it and how many hours between changes?

Another consideration is the secondary filter. Many older engines have a 2 micron fuel rating on their secondary filter. Depending on the engine, this can be a quite small filter. As a result, if you use a 30 micron in the Racor, you may clog the secondary filter on the engine before the Racor filter (depending on the amount of sub 30 micron particulate).

Either 2 or 10 micron would be my choice. Remember, always change all filters for the engine at the same time. A 2 micron Racor doesn't block all of the 2 micron particulate. Some amount will be collecting in the engine filter. In the relative cost of boating, fuel filters are all but free.

Ted

 

[BB-marine]

If you use a vacuum gauge as the indicator of when to change your primary filter there is no reason to worry about damaging the low pressure lift pump. 30 micron, 10 micron , or 2 micron have the same flow when new and clean. A 30 micron will allow larger particles to pass through and the secondary filter will be next inline to collect the finer debris in the fuel. The purpose of the secondary filter is to protect the high pressure components of the fuel system pump and injectors. The primary purpose is to remove water and larger particles essentially polishing the fuel before reaching the secondary filter.

A 30 micron does let a lot of crud pass through which will increase the need to replace the secondary filter more often. As I stated already 30, 10, and 2 Micron filters when clean have the same flow and same restriction. The dirt, crud, oxidation residue collected by the filter causes the restriction in the fuel system that will reduce the fuel flow through the filter and increase the vacuum. As this debris collects in the filter a 30 micron it can become a 10 micron filter and a 10 micron a 2 micron. So a 30 micron filter that is causing the lift pump to pull a 7 in Hg is filtering the same as a 10 micron filter that is causing the lift pump to pull a 7 in Hg. The difference between the two filters is you may have to change the 10 micron more often. You have 900 series Racor filters in dual series. I believe the 900 series have a flow rate of 90gph with a clean filter. The is plenty of surface for the filters to collect debris. I would choose to use the 10 micron racor element in the primary filter location.

The secondary filter element used for most mechanical injection engines is 10 micron to 5 micron. Most mechanical injection systems do not require a 2 micron in the secondary location. The pumps and injectors can tolerate larger particles. The new diesel engines that are electronic common rail can not tolerate particles larger than 2 micron. Most of theses newer elctronic engines have electric lift pumps and require 10 micron to be used in the primary filter and 2 micron in the secondary.

Step filtering is a recommendation of most engine manufactures. Racor recommends step filtering. If your secondary filter is 10 micron it would be a recommendation of the engine manufacture to use a primary filter with an element courser than the secondary. In this case the use of a 30 micron would be recommended. If the secondary filter is an easy change out than this would be a good choice 30M primary, 10M secondary. In most cases the secondary filter is not an easy change out in some cases it is a PIA. In theses installations it is IMO better not to use the step filtering recommendation and use the equal to filter element of the secondary in the primary location.

The key IMO is to monitor the vacuum. 7 to 9 in Mg is the same measurement regardless of the filter element used 30, 10, 2 micron filter. Requiring the lift pump to pull a vacuum at that vacuum value it is time to replace the filter.

IMO use the 10 micron and monitor the gauge as you stated.

Brian

 

[inquisitivej]

It depends on your change schedule and hours or operation in between. I changed mine (Racor 1,000) annually and did no more than a thousand hours per year. I used all 3 micron ratings without any difference. How often will you do it and how many hours between changes?

Another consideration is the secondary filter. Many older engines have a 2 micron fuel rating on their secondary filter. Depending on the engine, this can be a quite small filter. As a result, if you use a 30 micron in the Racor, you may clog the secondary filter on the engine before the Racor filter (depending on the amount of sub 30 micron particulate).

Either 2 or 10 micron would be my choice. Remember, always change all filters for the engine at the same time. A 2 micron Racor doesn't block all of the 2 micron particulate. Some amount will be collecting in the engine filter. In the relative cost of boating, fuel filters are all but free.

Ted

To date it’s experienced 100-150 hrs per year and annual filter changes unless vacuum shows earlier need. I expect my usage will be similar.

Agree on the filter cost and benefit.

For the secondary filter on the 3116 cat specifies a 2 micron filter.

There is no priming pump on the marine 3116TA from the factory. I believe all one has to do to bleed the air is crack the plug on the top of the filter mount and crank until the air is gone. This is following a prefill of the filter with already cleaned fuel. Sounds too easy if not messy. At least that’s what I’ve gleaned from my reading so far. Educational replies encouraged!

 

[inquisitivej]

Usually the primary filter is easier to change. Getting to the port secondary is a real PITA. Also I can usually change the Racor element without bleeding the system. The secondary filter requires bleeding every time. So I do 2 micron in the Racor. They flow as much as the 10 or 30 but will block faster. I watch the vacuum gauge and change them as it rises before it can get blocked. But my tanks are clean and I am careful where I buy fuel.

I’m due for a tank cleaning/polish so going with 10mic for now.

 

[O C Diver]

To date it’s experienced 100-150 hrs per year and annual filter changes unless vacuum shows earlier need. I expect my usage will be similar.

Agree on the filter cost and benefit.

For the secondary filter on the 3116 cat specifies a 2 micron filter.

There is no priming pump on the marine 3116TA from the factory. I believe all one has to do to bleed the air is crack the plug on the top of the filter mount and crank until the air is gone. This is following a prefill of the filter with already cleaned fuel. Sounds too easy if not messy. At least that’s what I’ve gleaned from my reading so far. Educational replies encouraged!

I hope you are correct. To date, I've never seen a marine diesel engine without a lift pump. Just to be safe, follow the plumbing from the injector pump back to the secondary filter, and then back to the Racor. Some lift pumps are quite small and bolted to the block such that you wouldn't think it’s a pump.

I agree with your choice in another post to go with 10 micron and changing filters annually.

Ted

 

[inquisitivej]

I hope you are correct. To date, I've never seen a marine diesel engine without a lift pump. Just to be safe, follow the plumbing from the injector pump back to the secondary filter, and then back to the Racor. Some lift pumps are quite small and bolted to the block such that you wouldn't think it’s a pump.

I agree with your choice in another post to go with 10 micron and changing filters annually.

Ted

I will look again, but pretty sure no manual priming pump on these 3116, thing the prior owner said that too. The genset has one though.

 

[O C Diver]

I will look again, but pretty sure no manual priming pump on these 3116, thing the prior owner said that too. The genset has one though.

Maybe I misunderstood you. There should be a lift pump, but some aren't manual priming. Some just have a bleed screw that you crack open and then crank the engine.

Ted

 

[inquisitivej]

Maybe I misunderstood you. There should be a lift pump, but some aren't manual priming. Some just have a bleed screw that you crack open and then crank the engine.

Ted

I think this is the bleed port in lieu of a manual priming pump on this one.

 

[O C Diver]

I think this is the bleed port in lieu of a manual priming pump on this one.

I believe you are correct about that plug.

Most manual priming pumps have bleed ports also. My 4045 John Deere did as well as my B and C series Cummins engines.

Ted

 

[luna]

A lot of the Cats of that era had the manual pump mounted on the fuel filter mounting housing.
If so, there is no bleed port on the housing as you are just too far away from the high pressure pump or injectors for it to be useful. I guess you could use it to fill the filters.
I would not use bleed ports anyway as they are just too messy.
On mine, I can fill the 2 fuel filters and the rest of the fuel system in about 300 pump cycles and then, if you are quiet you will hear the fuel dropping into the fuel tanks from the return lines.

Here is an aftermarket one that the listing says fits on a 3116.

105-2508 Fuel Priming Pump Fits CAT 3406 Fits Caterpillar 1P0436 4N251

One New Aftermarket Replacement Fuel Priming / Primer Pump Fits the following Fits Caterpillar Equipment and Models:-- Marine Products: 3412C, 3176C, 3408, 3406C, 3408B, 3412, 3196, 3176B, 3304B, 3306B, 3406E, 3408C, 3116, 3306, 3406B, 3304-- Wheel Tractor-Scraper: 623F, 627E, 637E, 627F, 621E...

www.reliableaftermarketparts.ca

Where, I have no idea, but the backside of the flange that has the red circled so called "bleed screw" in it, shown in the picture attached to post # 23 would be my first guess.

 

[Portage_Bay]

Cat 3208 has the lift pump on the high pressure distribution pump body. Maybe other cats of similar size are the same?

Regarding primary filter micron size. I ran a boat with a Cat 379 for many years. That engine moved a LOT of fuel. We could use the excess return as a transfer pump to move fuel between the tanks. We burned thousands per year. I ran 2 microns in the Racor primary, a dual system running on one at a time so I could switch to the "spare" and keep on going. The Racors were changed annually or when the vacuum gauge indicated change was required. The on engine secondaries were changed annually. I see no problems with running 2 microns in the primary filters.

 

[Delfin]

FWIW, fuel from the refiner is already filtered to 30 micron, so using the same filtration spec only catches most of the stuff your boat contaminated the filter with greater than 30. Also, the OEM CAT filter is likely 2 microns, assuming it's the same standard as the one on my 3306. Given that, my suggestion is 10 microns if your tanks aren't clean, and 2 if they are since the Racor is easier to change than the OEM filter.

 

[heysteve]

On my Cat 3208, I run a 30 as my primary and the Cat filter as my secondary. My boat is single engine so reliable operation is my top priority. I subscribe to the idea of spreading the filtering out as much as possible between the two filters. I do have two primary filters so can switch between the two and the secondary filter is large and relatively easy to change. If I start having problems with the primaries then I know to change the secondary sooner rather than later. So far this has worked fine... knock on wood

 

[inquisitivej]

FWIW, fuel from the refiner is already filtered to 30 micron, so using the same filtration spec only catches most of the stuff your boat contaminated the filter with greater than 30. Also, the OEM CAT filter is likely 2 microns, assuming it's the same standard as the one on my 3306. Given that, my suggestion is 10 microns if your tanks aren't clean, and 2 if they are since the Racor is easier to change than the OEM filter.

This point about refineries is really great info and solidifies my plan to go with 10mic. This thread has been helpful, thanks to all who have engaged.

This has raised for me the question of tank cleaning. As a newbie I was surprised to find what companies charge for fuel tank cleaning. Not just a few boat dollars but many. I'm curious how you all think about tank cleaning, especially those who have something similar to dual 300 gal steel tanks like this GB 42C. I know there will be comments like buy clean fuel and stay on top of filter changes. Is there some minimum number of gallons, hours, or years that folks try to follow for tank cleaning? So many other things I can think of doing with that many boat dollars, struggling to justify it at the moment.

 

[Delfin]

If you have inspection ports, take a look. If you have sump drains at the bottom of the tank, see whether water/crud comes out when tapped. If you have neither, get the tanks down to 10 gallons or so and go out on a sloppy day. If you run bouncing around for 30 minutes and the pre filter isn't crudded up and no or little water shows up in the Racor bowl, don't worry about it. Diesel tanks don't need to be cleaned unless there is some design issue, intrusion leaks of water, bad fuel pickup, etc. I cleaned mine after 15 years or so, but they didn't really need it.