Filters for my CAV assemblies

[RichardS]

Never let a diesel engine run out of fuel because the injectors are lubricated by the fuel passing through them.

I understand that there are many reasons for not letting a diesel engine run out of fuel but please can you expand on that reason as it would seem that if the injectors are not being lubricated by fuel passing through them then the engine has already stopped so why do the injectors need lubrication?

Richard

 

[lw395]

A few years ago I had a problem with my fuel, and did considerable research before making my own fuel polishing rig for around £100, which has been a complete success and everything has been fine since.

There are some common misnomers about fuel filtration.
One is that a 5 micron or 2 micron filter will get everything out - it won't. As has been witmnessed in the threads above.
The big problem is moisture, and entrained moisture rather than "free liquid".
To get that out you need a coalescing filter, of the type used in modern common rail diesels.
The filter medium in the Fleetguard filter (1221, IIRC) I used gets about 90% of the mositure out, as well as holding about 6 times its own weight in crud before it blocks.

After filtering through this, the fuel went from a very dark almost brown colour to a light pink.
It was very obvious it was doing its job properly.

So forget the micron rating, it's how much moisture the filter removes that is the important bit.
If you remove the moisture, you remove the habitat for the diesel bug to live in, so you won't get any bug problems. Your standard CAV and engine filters will then be perfectly satisfactory to get on with their day job of getting the particles out. But on their own they won't remove moisture.

My suggestion would be for anyone to do some more research and fit moisture absorbing filters.
Get in touch with Fleetguard Technical Services to get details on the best filter & filter head for your application. Filters are cheaper than Racor and available at most truck & commercial vehicle factors & filter outlets.

By 'entrained' water, do you mean emulsion water droplets, or dissolved water?

 

[Trundlebug]

Dissolved water. Most people think that water would separate out, but in fact some does dissolve in diesel, hence many of the problems. Water isn't only present as "free" water, however surprising or unbelievable that sounds.

More apparent with modern diesel which has a bio element (up to 10-15%) which tends to have a higher water content, both as delivered and is capable of holding a higher moisture content than in the past.

 

[RichardS]

Dissolved water. Most people think that water would separate out, but in fact some does dissolve in diesel, hence many of the problems. Water isn't only present as "free" water, however surprising or unbelievable that sounds.

More apparent with modern diesel which has a bio element (up to 10-15%) which tends to have a higher water content, both as delivered and is capable of holding a higher moisture content than in the past.

Thinking back to my Uni studies, I don't think you are going to remove dissolved water from diesel with any kind of physical barrier filter. That would be like filtering a mixture of ethanol and water (vodka!) to remove the water.

You could remove water globules or water emulsion with a suitable hydrophobic physical filter but I can't see how that would remove dissolved content.

Richard

 

[pcatterall]

Thanks for all the responses to date. It is apparent to me that we will have to be more careful with our fuel management!
I will be looking at a suite of addetives from the marine 16 people to bring out on our next trip, these will include something to remove excess moisture in the fuel their injector cleaner and their general diesel protector.
First job, of course is to ensure no physical entry of water.
On coming to the boat after she has not been used for a while i will run a good amount through the polisher and check for water and colour before i even start the engine.
Thanks again guys!