CAV fuel filter

[LittleSister]

Thanks Roberto, all seems much clearer to me now.

In addition to the Framm PetiteFleur mentions, I now see some of the adverts state the Crossland 522 filter comes complete with 5 (?!) seals.

 

[Strathglass]

Thanks Roberto, all seems much clearer to me now.

In addition to the Framm PetiteFleur mentions, I now see some of the adverts state the Crossland 522 filter comes complete with 5 (?!) seals.

I recently bought a box of filters on Ebay.

I was not worried whether they were genuine CVA ones as I had a severe case of fuel bug and would be using quite a few of them to clear the system after I had stripped out everything.

This is the first filter I removed.

I have both a primary and secondary filter. The first one has a large metal bowl and the second one is the one normally fitted on a Ford 1.8 diesel.

The ones I ended up buying were.

http://www.ebay.co.uk/itm/200586963936

They came with all five seals in each box.

I have used Crossland 522 in the past but they were supplied with less seals at the time I bought them.

Iain

 

[savageseadog]

This nonsense comes up about four times a year on these forums. People that can't successfully change one of these filters have no business doing maintenance on an engine. For bigger engines, perhaps over 50HP I would suggest using a larger filter like the Racor. For 20 and 30HP engines the CAV units are fine.

 

[pvb]

This nonsense comes up about four times a year on these forums.

Bit like most questions on here! If only there was a search facility like Google. Oh...

 

[Chris_Robb]

Thanks everyone.

I deduce they supply the top and the one between bowl and filter and assume the bottom one is ok.

So I have four pieces, 3 gaskets between, and the small one on the central spindle. It should be fuel tight!

I am ashamed to admit that the last time I changed the filter was in 2004, and had not even noticed the sh20 in the bowl..

Emptied the tank out today, and agreeably surprised to find no water and minimal slime after using fuel additive..

John - you have been lucky so far! Just chuck the CAV away and get a decent system - the Racor 500 series. As said, filter change in 2 minutes, no bleeding, no mess. When you do finally have the misfortune to pick up a load of S$*t, you will be able to deal with it quickly - especially if you are on a lee shore in a F8!

 

[PetiteFleur]

ASAP Supplies do a conversion kit to convert CAV filters to spin-on type but the kit is quite expensive.
Also what micron rating should the primary filter be? 10, 20 or 30 micron? I'm tempted to go for the 20 micron as the engine spin-on filter is 10 micron(I think!) Does this sond OK?

 

[2Tizwoz]

The CAV filter comes in several varieties, with and without different types of metal and glass bowl.

Different rubber rings are needed dependent on the particular type.

Slightly larger at the top than the bottom of the filter element which makes it easy to reverse them and have a leak.

Some cartridges hold the rubbers in place more reliably than others depending on how well they are made. There are a lot of manufacturers and production.

Even more information is available here.

The design is poor as the water drain plug is nylon and swells when it gets wet so that the tongue/handle is often damaged. Don't over tighten it.

 

[Strathglass]

The design is poor as the water drain plug is nylon and swells when it gets wet so that the tongue/handle is often damaged. Don't over tighten it.

A metal water drain plug which is a direct substitute is available.

This is easy to remove and does not swell

 

[Stemar]

This nonsense comes up about four times a year on these forums. People that can't successfully change one of these filters have no business doing maintenance on an engine.

I have to disagree. Doing your own maintenance is the best way to become familiar with the systems on your boat, which could save your life one day.

The CAV filter system is a poorly designed bit of kit that could be intended to cause a maximum amount of grief to people who are unfamiliar with it, and I'd class someone who changes a filter once a year as unfamiliar. It may be fine on truck that's maintained by professionals, but I can make a decent case for it not being fit for purpose on a small boat.

Most folk with boats have a degree of mechanical knowledge and are quite capable of getting it right, but it's something that they do maybe once a year, with time to think about it. Head down in a smelly, hot engine compartment, while the boat's leaping up and down and SWMBO's panicking at the wheel is not the time to have to worry about stuff like which ring goes where. You need a something that can be sorted in a minimum of time with a minimum of fuss.

 

[LittleSister]

Excellent info 2Tizwoz. Thanks.

 

[TrueBlue]

AFAIK the CAV filter was designed for automotive use many, many years ago. Being of a rugged and inexpensive design it found its way into the marine market.

The original design had a shallow bowl - probably without a drain plug. The extended versions both glass and metal are an add on for markets where contamination is an issue; probably farm machinery and heavy plant where fuel contamination is an issue.

It's principal advantages are:-
flexibility - multiple in- and out- ports, allowing dual filters, hand primers and so on.
inexpensive cartridge filters, probably becoming more important with changes in diesel fuel regimes.

I don't understand why folks have so many problems. I mounted mine in the engine bay and very inaccessible. I cannot see what I am doing (at the best of times) and have to change the filter by feel.

Using an old baking tray to catch the surplus fuel and element works best for me. Perhaps its a matter of practice makes perfect.

Housings and filter are available from this guy £1.09 each for the 296 can't be bad.