CAV Spin-on Adaptor

ASAP do them, but I got a complete compatible screw-on filter unit from ssldieselparts.co.uk , not expensive, with either original UNF threads or newer Metric threads. Uses common screw-on filters, also from ssl. Only fitted this year so not changed filters yet but should be MUCH easier and less messy than the original CAV filter. No see through bowl but filter does have a drain screw for any water drainage.
 
Every time I change the CAV filter crouching in the cockpit locker and wondering if I'll get stuck I decide to buy the spin in conversion from ASAP. Every time I look at the price I change my mind. I know all the arguments about 'you'll be glad you changed to a spin on filter when your engine stops and the filter needs changing in a force eight at sea..........' but in almost 20 years I've never had a blocked filter and I always use a a diesel additive to prevent diesel bug.
 
Like Bob, I've NEVER had a blocked filter. Even after 6 (SIX) years without changing the eliment! Just bloody diesel leaks grrrr....

Can anyone confirm the thread size of the ports on the original CAV head? 1/4" ???
 
Every time I change the CAV filter crouching in the cockpit locker and wondering if I'll get stuck I decide to buy the spin in conversion from ASAP. Every time I look at the price I change my mind. I know all the arguments about 'you'll be glad you changed to a spin on filter when your engine stops and the filter needs changing in a force eight at sea..........' but in almost 20 years I've never had a blocked filter and I always use a a diesel additive to prevent diesel bug.
I think the practicality of a traditional CAV filter depends on how easy it is to access it. I never have any issues with the two on our digger, but they are in clear view on the side of the engine. On the other hand on the boat the prefilter had to be accessed from above, lying on my side in the quarter berth. I changed to a spin-on after a lengthy wrestle to get the original CAV "Mini Filter" assembled and leak free the first time I changed it. It was so awkwardly placed that I only got it properly assembled by removing the whole thing, assembling it in the saloon, then re-installing. It was also so dirty that I thought a mid season blockage a distinct possibility, so the change to a larger capacity filter was welcome as well. I bought something similar to that suggested above, takes Delphi 496 filters which are readily available, although not as cheap as the "normal" CAV type (296).

Old ..
IMG_0189MingingFilter650.jpg
 
I think the practicality of a traditional CAV filter depends on how easy it is to access it. I never have any issues with the two on our digger, but they are in clear view on the side of the engine. On the other hand on the boat the prefilter had to be accessed from above, lying on my side in the quarter berth.

The location of the filter in my boat was similar, but required lying upside the cockpit locker, having first removed its entire contents and also the bolted on side panels in the bottom of it, and reaching across at arms length to get to the filter. Can't imagine why it was located there, but as it was fed and drained by flexible pipes I just had it moved (new pipes) and mounted on a short panel right in front of the engine. Sorted. Even having it moved by the boatyard probably cost little more than a screw on adaptor and a Racor filter. (It's still a CAV.)
 
In owning a boat the cost of a filter has never been of primary concern being lost in the expenses. I went for Racor because I did have a number of failures with CAV type and, while at sea, they were almost imposible to change without nipping an o-ring or dropping something into the bilge. On my latest trip to St Kilda (just short) we sucked air due to bad seas and I was able to go down, open the filter housing and see immediately what the problem is (dry), bleed and restart in a few short minutes. With a CAV I would have been upside down in the bilge for an hour cursing my saved pennies.
 
In owning a boat the cost of a filter has never been of primary concern being lost in the expenses. I went for Racor because I did have a number of failures with CAV type and, while at sea, they were almost imposible to change without nipping an o-ring or dropping something into the bilge. On my latest trip to St Kilda (just short) we sucked air due to bad seas and I was able to go down, open the filter housing and see immediately what the problem is (dry), bleed and restart in a few short minutes. With a CAV I would have been upside down in the bilge for an hour cursing my saved pennies.

But presumably not with a spin-on kit, the subject of this thread? Wouldn't the process then have been identical?
 
But presumably not with a spin-on kit, the subject of this thread? Wouldn't the process then have been identical?

No, I replaced the whole thing. I ended up with the top loaded filter. After a number of interesting occasions wrestling with the CAV I wanted to make sure I wouldn't have the same trouble again. I understand why people who have never had a problem in their fuel line will naturally wish to go for the cheap CAV but when it does go wrong you will curse yourself. I also took the oportunity to install a hand squeeze bulb for priming. This makes it super easy to bleed the system.
 
slight drift but has anyone ever changed the CAV filter tiny O ring at the top? I must admit I've never bothered as the RNLI video doesn't even change the upper O ring on the filter!
 
I'm getting a little confused here now (nothing new to me)... What I'm 'hoping' for is to find a filter unit (that accepts spin on filters) that will mount exactly the same way to the motor, and NOT involve changing any pipe work. Guess I need to assertain exactly what all my pipe fittings are. On the current CAV unit, there are 2 inlets and 2 outlets - all being used by the 4108, and now I realise, consist of at least two different connector sizes!!!
 
slight drift but has anyone ever changed the CAV filter tiny O ring at the top? I must admit I've never bothered as the RNLI video doesn't even change the upper O ring on the filter!

Since they came with the new filter, I've changed them all, because why not. You're probably fine if you didn't though.

P.S.: That SSL parts place somebody linked has great prices. I might upgrade my pre-filter after all! Thanks, somebody (too lazy to go back and look who).
 
Dougal

ASAP used to do a filter head that was an exact replica of the CAV head (same inlet/outlet port positions and sizes), but it took screw-on filters. I fitted one to my 4108, and it has made filter changes much easier; however, it doesn't appear to be on the ASAP website anymore, although some of the text still refers to it. It might be worth contacting ASAP to see if they are expecting to get any more in, or they might be able to suggest where you could get one.

Neil
 
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