Primary Diesel Filter/Water Separator Recommendation

[sailorboy1]

Originally Posted by goboatingnow

I see no merit in having a very fine 2micron filter as primary. Best spread the filtration over the available set of filters.( if you have a 2 micron primary what's the point of the secondary )

Dave

it is so that the next filter downstream (whatever you decide to call it) stays nice and clean and never has to be changed

[donradcliffe]

Originally Posted by Don L

it is so that the next filter downstream (whatever you decide to call it) stays nice and clean and never has to be changed

+1

I can change the Racor and not have to bleed the system, but not the secondary filter--big incentive to go with 2 micron in the Racor.

[delmarrey]

Originally Posted by Don L

it is so that the next filter downstream (whatever you decide to call it) stays nice and clean and never has to be changed

Until it decomposes from age, sending paper fibers into the IP.

[model 10]

We use a big 2 micron primary and still need to change the secondary when the primary has clogged up as some stuff has gone through to the secondary and it does look dirty when you inspect it.. We just switched to a spin on secondary with a drain petcock so I am hoping for some relief there.

[captseamus]

I suggest if one filter plugs than one changes both just to be safe. If the first filter plugs chances are the second inline isn't far away. Is it better to change both filters if one plugs so not to "chase" the filters rest of the trip. My Hatteras has three fuel filters on each diesel - V8-92TA's. the final filters (one each) on the engines has the vacuum gauges going to the forward bulkhead. Each DD engines have Racor 1000's x 2, they are combined as one unit and clear bowls in the bottom as much diesels do. When the vessel was purchased all the Racor filter/separators were totally disassembled and cleaned and remounted with clean filters of course. The shipyard could not believe how the Racors' were so filthy inside. Just because the filters are cleaned doesn't mean the main areas of the Racors are clean.. It is called "Planned Maintenance Schedule" in the Navy. I glad I had it done. I know the filter/separators are as clean as new inside and redone to manufacturer specs. All my diesel fuel filters are now changed every two years including the gen sets. Disassembled and inspected and clean every five years.

captseamus

[colemj]

Originally Posted by donradcliffe

+1

I can change the Racor and not have to bleed the system, but not the secondary filter--big incentive to go with 2 micron in the Racor.

There is a reason why many diesel manufacturers specifically recommend only 10 or 30 micron primary filters and void their warranties if a 2 micron filter is used as a primary.

It is simply a bad idea to use a 2 micron primary.

I know it "sounds" like a good idea and maybe even logical, but it is not. No matter how strongly one feels about it or how many old salts tell you to do it.

BTW, a nominal 10 micron filter will be filtering out 60-75% of smaller particles also.

Mark

[colemj]

Originally Posted by goboatingnow

I would caution about using very large Racors . The turbine actions requires a certain fuel velocity. In a very large filter with low flows typical of small yacht engines Id question the advice to fit very oversized units. Racor spec gives the flow rate specs.

For most of us with relatively small diesels, we are not benefiting from the turbine action even on the small Racor 500 - there simply isn't enough flow. Water separation is occurring almost exclusively by the blocking facility of the impregnated filter media.

In these case, a larger filter with greater surface area would be a good thing.

We run a polishing system using a Racor 1000 and a 360gph gear pump and the turbine action is quite noticeable (and effective). The Racor 500 on our 30hp engine shows absolutely no turbine action at all.

Mark

[model 10]

Originally Posted by colemj

There is a reason why many diesel manufacturers specifically recommend only 10 or 30 micron primary filters and void their warranties if a 2 micron filter is used as a primary.

It is simply a bad idea to use a 2 micron primary.

I know it "sounds" like a good idea and maybe even logical, but it is not. No matter how strongly one feels about it or how many old salts tell you to do it.

BTW, a nominal 10 micron filter will be filtering out 60-75% of smaller particles also.

Mark

You say it's bad idea but why? Clean fuel is clean fuel.

[colemj]

The primary filter is located on the suction side of the engine lift pump. Trying to draw too much vacuum through this can damage the lift pump and cause fuel starvation in the injector pump.

This happens well before you notice the primary filter actually clogging. In fact, it is happening in a clean 2 micron filter.

But don't take my word for it. Find out why the engine manufacturers (and Racor itself) do not want this done. Or just recognize that they all tell you not to use 2 micron primaries, and take that at face value as a good reason not to.

Mark

[model 10]

Originally Posted by colemj

The primary filter is located on the suction side of the engine lift pump. Trying to draw too much vacuum through this can damage the lift pump and cause fuel starvation in the injector pump.

This happens well before you notice the primary filter actually clogging. In fact, it is happening in a clean 2 micron filter.

But don't take my word for it. Find out why the engine manufacturers (and Racor itself) do not want this done. Or just recognize that they all tell you not to use 2 micron primaries, and take that at face value as a good reason not to.

Mark

That makes sence.

[ErikFinn]

wow, a few days away and my thread has 4 pages of replies, thank you all for your comments, I really appreciate your time and effort!

Now back to my specific installation and situation; from what I've now read here so far I believe the way for me to go about with my old boat and tanks is the following:

1) get a dual turbine filtering primary system. Although much more expensive than a single. I believe this an investment to give me peace of mind when the weather turns rougher and the diesel (and all else ) in the tanks starts to move about.

2) Use 30 or 10 micron filters in it. 2 Micron is too small for the primary filter. (and yes, the "primary filter" I understand as the first one after the tank towards the engine. After which I still have the engine fuel filter (not sure yet what micron size I have)

3) the capacity of the primary turbine dual filter system is still somewhat unclear to me. My engine is a 1989 Perkins Prima M50 50HP normally aspirated engine, and I read that it might be a good idea to get a bigger capacity turbine dual system (to prevent filter clogging so quick when worst comes to worst) than for example the Racor 500MA Series
Racor 75500MAX30 - 500MA Series - Marine Turbine Series > - Marine Fuel Filtration

maybe the "midsize" Racor 900MA-series?
Racor 75900MAX30 - 900MA Series - Marine Turbine Series > - Marine Fuel Filtration

Or is the biggest Racor 1000MA-series too big for me?
Racor 751000MAX30 - 1000MA Series - Marine Turbine Series > - Marine Fuel Filtration

I'm not an expert but to me it makes sense with my 24-year old fuel tanks and Asian fuel to have something bigger than the 500MA series, but then, as someone pointed out I may not get the turbine action anymore with my 50HP diesel if combined with a bigger turbine filters; where is the line, what say you?

Regarding fuel polishing, I'm thinking maybe I could build something from the old CAV filter/water separator, but I'm not so far yet. And unfortunately my main tank does not have an inspection hatch. The Filter Boss mentioned earlier would certainly be nice but its just too expensive for me.

Thanks,
Erik

[colemj]

When "worst comes to worst" the 1000 will clog as fast as the 500. The larger filter will help you in those situations where things haven't hit the fan and you simply have lower quality fuel regularly. In this situation, it will be less likely to leave you in the lurch at an inopportune time, providing you monitor the fuel system regularly.

I would not worry about the "turbine action". MAYBE your engine is large enough to have sufficient flow on a 500 for this, but probably not. I think it is over-rated and possibly more marketing than anything. Your present CAV and others do not have it and work just fine.

The water separation is caused by the filter element itself and not the turbine. The turbine is to separate out large particles and free water. If you filter the fuel going in with a simple funnel filter, these should not be a problem for you.

Mark

[sabray]

I knew that some don't like my oversized 1000 series with 2 micron filter. I'm okay with their opinion. As said it works and I have a vac gauge. So I can see if I am working the pump and filter. Hasn't ever come close to getting out of the green before it gets its annual change.

[cheoah]

Originally Posted by ErikFinn

wow, a few days away and my thread has 4 pages of replies, thank you all for your comments, I really appreciate your time and effort!

Now back to my specific installation and situation; from what I've now read here so far I believe the way for me to go about with my old boat and tanks is the following:

1) get a dual turbine filtering primary system. Although much more expensive than a single. I believe this an investment to give me peace of mind when the weather turns rougher and the diesel (and all else ) in the tanks starts to move about.

2) Use 30 or 10 micron filters in it. 2 Micron is too small for the primary filter. (and yes, the "primary filter" I understand as the first one after the tank towards the engine. After which I still have the engine fuel filter (not sure yet what micron size I have)

3) the capacity of the primary turbine dual filter system is still somewhat unclear to me. My engine is a 1989 Perkins Prima M50 50HP normally aspirated engine, and I read that it might be a good idea to get a bigger capacity turbine dual system (to prevent filter clogging so quick when worst comes to worst) than for example the Racor 500MA Series
Racor 75500MAX30 - 500MA Series - Marine Turbine Series > - Marine Fuel Filtration

maybe the "midsize" Racor 900MA-series?
Racor 75900MAX30 - 900MA Series - Marine Turbine Series > - Marine Fuel Filtration

Or is the biggest Racor 1000MA-series too big for me?
Racor 751000MAX30 - 1000MA Series - Marine Turbine Series > - Marine Fuel Filtration

I'm not an expert but to me it makes sense with my 24-year old fuel tanks and Asian fuel to have something bigger than the 500MA series, but then, as someone pointed out I may not get the turbine action anymore with my 50HP diesel if combined with a bigger turbine filters; where is the line, what say you?

Regarding fuel polishing, I'm thinking maybe I could build something from the old CAV filter/water separator, but I'm not so far yet. And unfortunately my main tank does not have an inspection hatch. The Filter Boss mentioned earlier would certainly be nice but its just too expensive for me.

Thanks,
Erik

Hi Eric, I would prioritize installing an inspection/cleaning port in your tank. The filtration is necessary and important, but I would highly recommend a way to clean it all out and start fresh.

If chronic bad fuel is a problem, I would consider the two racor approach, with an installation that allows you hot swap filters. I would also think about using it to polish as well. Should be able to use valves and a fuel pump to accomplish this. I don't think you need the largest filters really. I think if you clean the tank and have two 500's with above configuration you'll be fine and save some $$.

[colemj]

Alternately, just keep your current CAV plumbed in parallel and get a valve to control fuel flow. The CAV would never be needed unless the Racor plugged, then it would be in use only as long as needed to change the Racor filter.

Mark