Adapter CAV to Screw on filter

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pcatterall

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My recent flurry of SOSs concerns problems in bleeding my 4108 after a filter change.( engine filter)
I want to avoid this next time!! ( we may be at sea!)

I notice that ASAP do a conversion for the CAV type filter housing ( C£30)
Question 1... is this recommended?
Question 2.... My existing Cav type engine filter has only one 'hole' in the top, this is occupied by the return fuel line and I am having to bleed through this. The adapter only seems to have one hole as well so am I stuck with bleeding the adapted version through this connection?
Question 3 .... Bleeding through the return connector seems unsatisfactory, fuel flows without air but as I tighten up the connecter bubbles appear around the threads. I hope this is air being drawn around the threads but will appreciate comments on this.

I appologise if some of these questions appear in my sos threads but they are sort of 'side issues' which get lost and not responded to in long threads.
Thanks for your help and advice
 
pcatterall said:
My recent flurry of SOSs concerns problems in bleeding my 4108 after a filter change.( engine filter)
I want to avoid this next time!! ( we may be at sea!)

I notice that ASAP do a conversion for the CAV type filter housing ( C£30)
Question 1... is this recommended?
Question 2.... My existing Cav type engine filter has only one 'hole' in the top, this is occupied by the return fuel line and I am having to bleed through this. The adapter only seems to have one hole as well so am I stuck with bleeding the adapted version through this connection?
Question 3 .... Bleeding through the return connector seems unsatisfactory, fuel flows without air but as I tighten up the connecter bubbles appear around the threads. I hope this is air being drawn around the threads but will appreciate comments on this.

I appologise if some of these questions appear in my sos threads but they are sort of 'side issues' which get lost and not responded to in long threads.
Thanks for your help and advice
Click to expand...



I'm not answering your question but I have had great success in installing a Racor filter between the lift pump and the first, existing, CAV filter. This is mounted on the bulkhead. Very easy to get to. Clear sediment bowl, with a drain plug. T bar handle to tighten the lid. The filter can almost be changed with the engine running. :)
 
Thanks Frankie H. I was hoping to do a 'halfway house job' bearing in mind the cost and fitting of the Racnor ( and filter costs) The CAV adapter is a straight bolt on replacement and at least subsequent filter changes would be less fraught,
Cheers
 
pcatterall said:
My recent flurry of SOSs concerns problems in bleeding my 4108 after a filter change.( engine filter)
I want to avoid this next time!! ( we may be at sea!)

I notice that ASAP do a conversion for the CAV type filter housing ( C£30)
Question 1... is this recommended?
Question 2.... My existing Cav type engine filter has only one 'hole' in the top, this is occupied by the return fuel line and I am having to bleed through this. The adapter only seems to have one hole as well so am I stuck with bleeding the adapted version through this connection?
Question 3 .... Bleeding through the return connector seems unsatisfactory, fuel flows without air but as I tighten up the connecter bubbles appear around the threads. I hope this is air being drawn around the threads but will appreciate comments on this.

I appologise if some of these questions appear in my sos threads but they are sort of 'side issues' which get lost and not responded to in long threads.
Thanks for your help and advice
Click to expand...

Hi

I have just fitted the same after a few years of getting increasingly fed up with CAV filters (or their seals to be more precise).
The unit supplied by ASAP (circa £33.00) was simples itself to fit- took me about 15 minutes and guess what - NO LEAKS !
I'm happy even if the filters themselves cost about £7.00 each instead of just a couple for CAV's. Even at that cost I'll probably change them more frequently than I did with the CAV's as it is so much easier !

Jaba
 
filters

Hi...fit a Separ or Racor 500...as a prefilter as a previous poster stated....then the cav engine one will almost never need attention.......my guess...£140
 
The Racor conversion from ASAP is a lot more expensive than the simple CAV head replacement.

However, the Racor elements have options with a see though bowl and drain which allows water to be let out. I have a see through bowl on my CAV at the moment and it;s a great way of checking the fuel quality visually.

Are see through filters available for the £30 CAV head replacement? Otherwise it looks like the c£70 conversion and the £37 elements. Mind you that's a small price to pay for not having to mess around with three separate O rings and worrying that over tightening will crack the glass bowl.
 
My coarse filter ( a CAV) has a drainable glass bowl so Im not too bothered about another on the fine filter. Certainly worth the £30 for ease of changing though.
One problem at this time is that I have 5 spare filters which fit the existing CAV but their rubber seals are too big. Also the CAV I have has a very small rubber dished seal for the through bolt and non supplied with the filters.
Need to search for theright seals but I bet they only come with the filters.
 
My CAV is actually the coarse filter and water separator. There is a fine filter on the engine. As the CAV is the fiorst in line I like having a visual check on the fuel and wheterh there is any water in the filter which needs draining off.

Are there any drainable see though filters available for the £30 ASAP conversion?
 
pcatterall said:
My coarse filter ( a CAV) has a drainable glass bowl so Im not too bothered about another on the fine filter. Certainly worth the £30 for ease of changing though.
One problem at this time is that I have 5 spare filters which fit the existing CAV but their rubber seals are too big.the big one is the seal on the lid Also the CAV I have has a very small rubber dished seal yours is squashed, when new it is just an o ring, any small o ring will do, so long as it is tight fit on the bolt. for the through bolt and non supplied with the filters.
Need to search for theright seals but I bet they only come with the filters.yes they do normally, however i dont think everybody changes them evertime
Click to expand...
reply in red
 
thanks David I will check my other spare filters but he one I opened had 2 identical large seals both of wich were too large for the lower seal ( I confess I didnt change the upper one so perhaps that is larger. The o ring supplied was far too big for my bolt but it is a point that if any o ring will do then i can make sure I have that size on board.
Cheers
 
pcatterall said:
thanks David I will check my other spare filters but he one I opened had 2 identical large seals both of wich were too large for the lower seal ( I confess I didnt change the upper one so perhaps that is larger. The o ring supplied was far too big for my boltThat one is for the spigot the filter fits on in the lid but you probably knew that anyway but it is a point that if any o ring will do then i can make sure I have that size on board.
Cheers
Click to expand...
for the benefit of others

The biggest, slightly thinner seal is for the lid.

slightly smaller, but thicker for the bowl to filter bottom.

much smaller about size of thumb nail the filter spigot in the lid

the tiny one easily lost, the bolt.

The biggest problem with the cav filter is user abuse, being

wrong threads to the lid

wrong off cock assembly splitting the lid.

fear

probably others as well

Others have mentioned more modern filters have better water throwing, better filtration etc, which undoubtedly they do, but......

when the tank has been stirred and the **** is in suspension, I know I prefer to have 20 spares in the locker, and easily replaceable, not at marine price than just a couple of super mega expensive gizmos. That is just my personal preference. However if installing from new build, I would follow latestarters advice, that was well set out in a thread some months ago.
 
I run 135hp, currently at 10,000 plus hours, I go through about 2-3 tons of fuel a year. I have only a sediment trap before the lift pump and twin engine filters. The CAV glass bowl filter I found a problem as muck sits in the bottom of the glass, and does not get down to the drain in the alloy cup under the glass. I changed it to a transparent cone shaped bowl filter with a drain which lets everything go when opened. The fewer pipe unions in the line the better.
You mention the return line going to the filter. This is one thing I have always changed in the past, having once been disabled when the return line let in air, I redirected it to the tank.
 
david_bagshaw said:
for the benefit of others

The biggest, slightly thinner seal is for the lid.

slightly smaller, but thicker for the bowl to filter bottom.

much smaller about size of thumb nail the filter spigot in the lid

the tiny one easily lost, the bolt.
Click to expand...

Thats very useful info. After 20 odd years of using these filters I finally know how to fit them! :o:o And this year I had all sorts of leakage problems both air in and diesel out until I properly re-fitted the filter
 
SSL have one for £16 and another at £17 with different threads and a third with a primer pump also at £17, alL + VAT
All take spin-on filters including the 496 with a drain tap at the bottom but no glass bowl.
 
Quote from David
'much smaller about size of thumb nail the filter spigot in the lid'

I've dug out another spare filter and see the two large rings and now know where 'to put them'.. However still not sure about the thumb nail one (15mm ID) Is this 'spigot' on the lid of the filter ( where there is a raised bit but no way will my 15mm o ring stretch fit that) or is it in the lid of the filter casing somewhere?

The tiny one David refers to does not exist in my filter packs ( it would need to be about 6mm ID to fit the bolt)

I take note of the reference to SSL and have used them recently ( good service ) so I will check with them. ( Nigel... give them a go look at their site)

Engine still starting fine after another day standing, so (touch woood) the system bleed seems to be ok now.

Thanks all again
 
Last edited:
Just by way of a postscript on this. been back to the SSL site. They have a good photo of the replacement ( Nigel) £19.21 SFA 11 this clearly ( I hope) shows the spigot where the thumb sized O ring should go Up inside the cap and out of sight from above so I guess you just have to feel it into position!!
I have started another thread concerning the return pipe which looks like a real mares nest on mine
 
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