Fitting a CAV filter assembly?

[Quidi Vidi]

Re my previous post, http://www.ybw.com/forums/showthread.php?366229-Engine-revs-won-t-remain-constant-any-advice-please
The CAV filter and hose etc have now arrived so it looks like I am in for a busy weekend. I know for most of you this will appear to be a simple job but never having fitted this sort of filter before (or any other for that matter) I'd appreciate any tips or tricks that would be useful to know before I get all the way out to the boat. For instance do I need fibre washers or O seals for the blanking plugs? The filter came without instructions, am I right in thinking that the central nut at the top is unscrewed to dismantle the filter and the nut next to it is used for bleeding?
As always your advice will be most welcome, you'll make a mechanic out of me yet!

 

[l'escargot]

This may help: http://l-36.com/manuals/CAV-Diesel-Fuel-Filter.pdf

 

[nigelmercier]

This may help: http://l-36.com/manuals/CAV-Diesel-Fuel-Filter.pdf

Interesting document. I've put a cleaned up version on my Bavaria Yacht Forum site: http://www.bavariayacht.info/downloads/CAV Diesel Fuel Filters.pdf

If anyone has Fig 6(a) and (b) in an original, I could clean it up a bit more.

 

[Twister_Ken]

Does it have a nylon drain plug? Mine did, and the thing became impossible to unscrew (swells in diesel?). I replaced it with a brass one (bought from ASAP) which solved the problem.

 

[geem]

Sorry to be a merchant of doom but I removed this type of filter due to the potential number of air leaks these things seem to create. I replaced the CAV type with a spin on fuel filter assembly. Prior to the fuel filter I installed a full size clear sight bowl. This allows you to see water in the sight bowl or sediment. The sight bowl rarely needs dismantling as you can drain it from the tap. In a blocked filter situation in a bumpy sea, you can spin a new filter on quickly without the hassle of CAV rubber o rings pinching and not seating properly.
A number of friends have also gone this route due to hassle with CAV type filter assemblies.

 

[Quidi Vidi]

Thanks guys, I'll print the document out later.
Geem thanks for the heads up, I've bought it now so will fit it anyway and take care over the O rings.
Yes it is nylon, I'll look out for a brass one
Thanks everyone

 

[NorthUp]

Finding a good position to mount the filter is critical to your continuing sanity-
Below the level of the fuel tank, so its easy to bleed the fuel ,
easy to reach,because you will be changing the filter in a hurry, in the dark, eventually,
and it makes finding the inevitable drip of fuel easier to find.

It a very dated design, would not have been my first choice nowadays, but there are millions in use, they dont all leak , and spare filters are available everywhere for a couple of quid.

Dont overtighten the centre bolt when reassembling!

 

[macd]

Dont overtighten the centre bolt when reassembling!

Would you mind awfully if I put that in bold for you?

 

[pcatterall]

How do you know when it is tight enough?

 

[nigelmercier]

It a very dated design, would not have been my first choice...

So what would?

 

[Quidi Vidi]

Perhaps i should have consulted the oracles of this forum prior to purchasing my filter but the CAV was suggested by someone in my previous thread so that why i went with it. Ignorance is bliss as they say and it was a good price.
I would be interested in others opinions/recommendations even if it is closing the stable door etc.

 

[macd]

How do you know when it is tight enough?

It doesn't leak
Mainly to do with feel: don't treat it like a big-end bolt. If there's room for a torque wrench, CAV suggest no more than 10 lb.ft.

 

[pcatterall]

10lbs a foot is a good guide.. so max 20lbs on the end of my 6 inch spanner.

It would be good to get that CAV 'manual' in a format I could print. I tried Nigels Bav link but it locked up my old PC

 

[Twister_Ken]

Another 'trick' with the CAV-style filters is that several O-rings are involved. Two are almost identical in size, but not quite. When you unpack it, make sure you know where each O-ring is supposed to go, and mark them in some way, or make a mental note.

 

[macd]

10lbs a foot is a good guide.. so max 20lbs on the end of my 6 inch spanner.

At the very most. Anything with those sort of O-rings doesn't need a lot of oomph. Think of a spin-on filter, which has similar 'square' o-rings: you do them up by hand.

 

[geem]

So what would?

Try this http://pages.ebay.com/link/?nav=item.view&id=160992212742&globalID=EBAY-GB

 

[macd]

Try this http://pages.ebay.com/link/?nav=item.view&id=160992212742&globalID=EBAY-GB

There's a link lower on the same page to a similar unit from the same seller, £10 cheaper.

 

[NorthUp]

So what would?

First choice would be one of the Racor spin-on types for a small engine, bigger engine I would go for a duplex design to allow an instant change over.

My own one- I have a Vetus type spin on, with water drain at the base. Gravity fed from the tank, so easy to bleed air from the new filter.....but I got it for free so might not count as 'first choice'!


edit- the post above links to one almost identical to mine...

 

[Laundryman]

Take the opportunity to fit a squeezy bulb somewhere in the line. It will show up any leaks and make bleeding quick and easy. Good luck Alan

 

[nigelmercier]

Try this http://pages.ebay.com/link/?nav=item.view&id=160992212742&globalID=EBAY-GB

Not convinced. Surely the advantage of the CAV is that it has a glass bowl?