Fuel filter on 4-108 Perkins?

[MillenniumFalcon]

The filter on my 4-108 Perkins is a Perkins #26561117 and I am trying to find out what is the minimum particle size that this filter will catch?

The reason I need to know is that I want to put another filter up stream from it and I want it to be of a smaller size. My plan is for a 10 micron filter up stream with a bypass so that if it plugs up I can bypass it and let the engine filter do the job until I reach my next stop. Thus the upstream filter has to be finer than the downstream filter to make sure it is the first to plug up.

 

[Salty John]

I don't know for sure but it is about 10/12 micron. I'm sure you know that typically your primary filter is coarser than the final filter, up to about 30 microns compared to 10 microns, and should be a water separater type. I see what you are trying to achieve, my concern would be that your primary filter is ahead of the lift pump and when the filter clogs the engine may suck air and require bleeding. Better to have a vacuum gauge to tell you when the primary is getting clogged, but before it stops the fuel flow completely. That's the way I see it, anyway.

 

[omega2]

Get a Lucas/Cav 296 type filter with or without a glass bowl, and put it between the tank and the lift pump, you can then keep an eye on the colour in the glass bowl type and drain it periodically, we have this set up on our Sabre 180's and it works fine hardly any muck gets to the engine filters, and these are only twin Cav's also.

 

[ms1]

if you have same or finer filter upstream then the downstream filter will do nothing (until you switch your by pass). I would suggest 30 microns pre filter with 10 on the engine. If the pre filter has a glass bowl you can always see what is going on. 30 catches the worst then 10 does the rest.

 

[MillenniumFalcon]

Yes, the engine filter will do nothing until the primary filter is bypassed.

Heres the scenario I want to avoid:

running under power, loose power, critical time, have to remove and replace a filter.

With the course filter first there is no way of knowing fast which filter failed and there is no way to get going again fast in an emergency, especially if it is the engine filter that has plugged up.

With the course filter down stream then it is doing nothing until the fine filter plugs up. THEN by flipping a switch the fine filter can be bypassed...maybe even before the engine dies. The course filter will then protect the injection pump while someone goes below to swap out the primary filter and the boat goes on. In fact, you really don't have to go below to swap the filter if you are alone. The engine filter which should be quite clean will be able to get you to the next port where in less stressful situation you can then change the primary filter.

To me this makes more sense than having to change out an engine filter in heavy seas or in a traffic filled channel. My way you can go to a neutral corner to lick your wounds.

If you see a fallacy in this, speak up because I don't want to get caught with my pants down.

OBTW, glass or clear plastic bowls are no longer acceptable by insurance companies in the US. The complaint is that in a fire they will shatter ot melt and dump fuel into the fire. Of course I don't think they have thought this out very well since the rubber hose between the filter and the pump will probably be burned through before the bowl goes.

They are also making me put a 1/4 turn shut off valve on the fuel tank (which is in the engine room) so I can shut off the fuel if there is an engine room fire. If they think I will be going into the engine room when its on fire they have another think coming. I will empty my fire extinguisher(s) and if the fire is still going I will then prepare to abandon ship!!! But I will not go into a burning engine room to shut off the fuel tank!!

 

[jcmmarine]

At sea on a single diesel you certainly need to ensure a good quality fuel supply, if you are going to the extent of fitting extra filters may I make a suggestion.

Problems could be anywhere in the fuel supply chain, bad fuel, water in fuel, fuel bug, air ingress etc. A scaled down version of what many single engine ships have is the best idea.

Fit a separate fuel supply from a small separate tank with known clean diesel and its own filter along with a changeover valve. Ensure this emergency tank is above the fuel pump and the filling and vent cannot be contaminated with sea water.

Then, if you have any problem at all, you have a known good fuel source you can switch to for a short time whist you sort the problem out.

A bonus is that you also have a high level gravity fed fuel source for bleeding the system after work or problems.

For Perkins 108 engine I would only need a 1-2 gallon tank to give you a few hours running.