CAV filter issue

[Daydream believer]

leaving aside the awkwardness of getting the seals to bed properly, they have two seals that are similar enough in size for it to be easy to mix them up, which guarantees a leak. In my experience, a spin-on cartridge type is far more foolproof.

One would have to be pretty useless at DIY to mix up the 2 seals. Even the most basix DIYer should realise the difference. If they cannot then I would suggest that they get lessons pretty soon. before venturing out to sea.

 

[dunedin]

I have had CAV filters on all my yachts since 1993. Never had a problem with them, Two years ago I got diesel bug and so cleared everything out, I also replaced the CAV with a Racor 500 type as people kept saying how good they were.

I was amazed at how much cleaner and easier it has now become to change a filter.
Just dump the CAV and replace it with a Racor 500 type. less than £20 on ebay. You won't regret it.

100% agree. Also dumped CAV and replaced with Racor 500. Can check and/or change filter in under 2 minutes with minimal mess. Keep small bottle of diesel to top up before replacing lid, so no need even to bleed afterwards.

 

[rogerthebodger]

To change a CAV filter without mess simply use a cutdown plastic cold drink or milk bottle hung from the filter head.

The filter and base just falls in the into the container and you can tip any diesel back into the tank and clean the base dispose the filter and plastic container in the closest dumpster

 

[Daydream believer]

To change a CAV filter without mess simply use a cutdown plastic cold drink or milk bottle hung from the filter head.

The filter and base just falls in the into the container and you can tip any diesel back into the tank and clean the base dispose the filter and plastic container in the closest dumpster

Why would you put the contaminated fuel back in the tank?

 

[Freebee]

I have bought hundreds of the Facors and never had a problem, if you are squeamish about the chinese elements the housings will readily accept a genuine Racor element with out issue.

 

[goeasy123]

since nobody answered the OP question in the photographs are 2 different forms of the 296 element both are equally useable but one has about 10 times the dirt holding capacity of the other. The one with holes in the top has just one pleat but its rolled up like a toilet roll and sealed together top and bottom it has a massive surface area. the other is just vertically pleated, given the choice I would take the one with holes in the top every time ALTHOUGH I would really go with a small Facor which is far more user friendly.

Two thoughts. 1. Without the filter head, over a container fill the filter element through the holes and see if the fuel migrates through the paper and into the central anulus. If not the filter is a wrong'um. 2. If it does go through or it's marginal there might be enough static pressure down stream of the filter housing to stop fuel getting through. In which case crack a joint downstream to relieve the pressure.

I got these rather than Racor (alikes). Direct replacemen with Delphi 496A filters. Single filter head screw on filter type 1/2 | Filter parts

 

[rogerthebodger]

Why would you put the contaminated fuel back in the tank?

I put the fuel through a filter funnel so it has any cominates filtered out twice

When I fill my tanks I also pump to transfer the fuel from the can I use to the tank via a filter so polishing any fuel I put into my tank

 

[Stemar]

One would have to be pretty useless at DIY to mix up the 2 seals. Even the most basix DIYer should realise the difference. If they cannot then I would suggest that they get lessons pretty soon. before venturing out to sea.

When you do it regularly, on a well-lit work bench, I'd agree with you. Maybe even as part of a routine service alongside. but now your engine has stopped in a bumpy F8, on a lee shore at night. You're head down in the engine compartment and the crew is screaming that the rocks are getting closer. Now what do you think about the advantages of a spin-on filter?

 

[Daydream believer]

When you do it regularly, on a well-lit work bench, I'd agree with you. Maybe even as part of a routine service alongside. but now your engine has stopped in a bumpy F8, on a lee shore at night. You're head down in the engine compartment and the crew is screaming that the rocks are getting closer. Now what do you think about the advantages of a spin-on filter?

I was talking about telling the difference between the 2 sizes of seal & knowing in advance that such things are required.
Just lay one over the base of the filter & it becomes blatantly obvious - even to a total beginer - if it is the correct size or not. As I said , If one did not know, then one should not be out there, sailing near rocks in the first place.

 

[Stemar]

Having dealt with one, as I said, if you're familiar with them and are careful, it isn't difficult to tell which is which, but when you take one apart for the first time, or under stress, especially in a bad light, it isn't hard to confuse them which, in my book is poor design. There's a saying in process management that "every process is perfectly designed for the outcome it achieves". In other words, if a process isn't getting the desired results, it's the fault of the process, not the imperfect humans using it. The same applies to design.

Anyway, I doubt I'm going to convince you, so that's my last word on the subject.

 

[Daydream believer]

Having dealt with one, as I said, if you're familiar with them and are careful, it isn't difficult to tell which is which, but when you take one apart for the first time, or under stress, especially in a bad light, it isn't hard to confuse them which, in my book is poor design. There's a saying in process management that "every process is perfectly designed for the outcome it achieves". In other words, if a process isn't getting the desired results, it's the fault of the process, not the imperfect humans using it. The same applies to design.

Anyway, I doubt I'm going to convince you, so that's my last word on the subject.

In my view people who cannot complete basic maintenance on the boat when at sea should not go to sea

Anyway, I doubt I'm going to convince you, so that's my last word on the subject.

 

[snowbird30ds]

Basic maintenance is anything but basic under the wrong conditions, and stress/panic is a very bad condition to do maintenance under.
The easier you can make it the better.
Anyone that assumes a normally easy job will always be easy shouldn't go to sea.

 

[srm]

Many years ago, while running a skippered charter business, I started to understand that there was a lot of truth in the saying:

"If you do something long enough, everything that can go wrong will go wrong"

Having changed many CAV filters on different boats, both as routine and at sea, I finally got caught out in lumpy conditions on a long tiring passage. Not the lee shore mentioned above, but worrying with an air leak in one of the filters preventing the engine from running for more than a few minutes. Shortly after completing the passage I fitted spin on filters to that boat as there is also a lot of truth in the saying:

"KISS" - for the uninitiated "Keep It Simple Stupid"

 

[penberth3]

When you do it regularly, on a well-lit work bench, I'd agree with you. Maybe even as part of a routine service alongside. but now your engine has stopped in a bumpy F8, on a lee shore at night. You're head down in the engine compartment and the crew is screaming that the rocks are getting closer......

In that situation I wouldn't even try to change the seals. Bang in the new element and bleed.

 

[srm]

In that situation I wouldn't even try to change the seals. Bang in the new element and bleed.

and bleed . . . and bleed . . . . and bleed . . .

It might work, but then the seals may have hardened or been dislodged.

If you are going to do something it is usually worth doing it correctly the first time, - especially with CAV filters.

 

[penberth3]

and bleed . . . and bleed . . . . and bleed . . .

It might work, but then the seals may have hardened or been dislodged.

If you are going to do something it is usually worth doing it correctly the first time, - especially with CAV filters.

All I can say is when I was changing CAV filters by the dozen I didn't change many seals and rarely had a leak. If I was being driven onshore with no engine I wouldn't try.

 

[Daydream believer]

All I can say is when I was changing CAV filters by the dozen I didn't change many seals and rarely had a leak. If I was being driven onshore with no engine I wouldn't try.

Does not matter if you do get a small leak for a short while. Just get the engine running & get into safe water then you have time to play if you need to- Although you should not need to at all as you suggest

 

[B27]

My CAV filter has some rusty adaptors on it, and I want to tidy up the diesel system a bit.
I'm looking at the R12T type filter heads.
Only problem is, the filters are £7 or more each?
And of course, not as available as the CAV 296 type which is everywhere.
£7 is not a lot of money, but the CAV filters are so cheap in a pack of 10 that you can change them 'just to check' and don't mind throwing one away clean.

Being a bit more compact and not needing spanner access, I should be able to mount the filter in a better place, and still change it more easily.

I will also have simple glass bowl/gauze water trap like this:
Glass Fuel Sediment Residue Filter Bowl Assembly for Fordson Super Major Tractor | eBay
between the tank and the priming bulb.
That should protect the priming bulb from any gross lumps and give a visual check of what's coming out of the tank.

I have a Beta engine, which has a big fuel filter on it, compared to the little old Yanmar filters.

Does not matter if you do get a small leak for a short while. Just get the engine running & get into safe water then you have time to play if you need to- Although you should not need to at all as you suggest

A small leak will let air into the fuel and your engine will stop.

 

[rogerthebodger]

I will also have simple glass bowl/gauze water trap like this:
Glass Fuel Sediment Residue Filter Bowl Assembly for Fordson Super Major Tractor | eBay
between the tank and the priming bulb.
That should protect the priming bulb from any gross lumps and give a visual check of what's coming out of the tank.

I also added one of these segmentation filters between my tanks and the primary filter and made a world of difference to the ife of the CAV filters

 

[snowbird30ds]

With a longer 1/4" unc bolt you can fit 796 filters in place of 296 which are nearly twice as long so I would assume nearly twice the element area.
And with racor/facor you can just pop a filter out to have a look and pop it straight back in, as long as the fuel remains above the exit hole there's no need to bleed but a quick top up is easy.
For those carrying on with cav if you carry a vacuum oil extractor pump they make bleeding a doddle, no need to pump the primer bulb or lever and no worries about cam position assuming just bleeding up to main engine filter, obviously if air is in the system between engine filter and injector pump you still need to pump, I have self closing brake bleed nipples in place of the bleed screws in my engine filters and a bleed from tank to filter head via pre filter and lift pump takes no time at all with no diesel anywhere other than inside the oil extractor.