Fittings for CAV/Delphi filter

[blackrose]

Did anyone know what fittings I should use to feed a small fuel pipe for a Webasto though one of these CAV/Delphi units? I think the pipe is 5mm OD but I'll check and measure it tomorrow. Ideally I'd want compression fittings for the pipes with tapered male threads at the other end.

 

 

[matty40s]

You shouldn't use a filter that size with a Webasto, use the filter designed for it. It will cause issues with fuel flow.

[blackrose]

54 minutes ago, matty40s said:

You shouldn't use a filter that size with a Webasto, use the filter designed for it. It will cause issues with fuel flow.

 

Which filter is that?

 

The installation instructions I've got just say "use a filter" but they don't specify which one.

 

Edit: The other thing is that an inline filter won't separate water which the CAV/Delphi unit will. How do we know it would cause fuel flow issues? I would have thought that for a given amount of fuel a bigger filter element means less resistance?

Edited August 29, 2021 by blackrose

[Awayonmyboat]

My boat has a similar CAV/Delphi filter. This is then followed by a further inline filter (similar to one's commonly found on cars) before feeding the Webasto pump. Whilst I've always considered this a bit overkill it's never caused a problem so I haven't changed it.

 

I too have seen nothing specific in Webasto instructions regarding filters and am interested to find out more details about what is the recommended solution and if there are any problems I might be storing up for the future.

[GUMPY]

I use one of these on my eber install.

 

https://www.asap-supplies.com/products/drive-force-mini-bowl-fuel-filter-short-bowl-1-4-bsp-302070

 

[blackrose]

Thanks Awayonmyboat. Well if your Webasto works with the the CAV/Delphi water separator/sediment trap and another filter then I should be fine.

 

4 minutes ago, Loddon said:

I use one of these on my eber install.

 

https://www.asap-supplies.com/products/drive-force-mini-bowl-fuel-filter-short-bowl-1-4-bsp-302070

 

 

Thanks. It looks very similar but without the water trap.

 

Anyway, back to my original question, does anyone know what the thread size is for the unit I have?

Edited August 29, 2021 by blackrose

[dmr]

I think these are available with both a metric and an imperial thread so you need to find out which one you have, and  surprisingly they are not BSP, so no tapers, they seal on a copper washer, but then again I think I have seen taper fittings going into these so maybe somebody here knows more than me. I half remember either a UNF or metric thread?????

[dmr]

Thinking more, no tapers, all parallel threads, some fittings seat on a copper washer whilst others engage with a nipple and seat arrangement at the bottom of the hole (lack of technical terms due to cider drinking 😀)

[MtB]

5 minutes ago, dmr said:

Thinking more, no tapers, all parallel threads, some fittings seat on a copper washer whilst others engage with a nipple and seat arrangement at the bottom of the hole (lack of technical terms due to cider drinking 😀)

 

I too, might be able to say something costructive, but for the cider.... 

 

Ill have a go anyway. Them filters are generic stock items in the world of oily boilers. They have a 1/4"bsp parallel thread. 

 

What was the question again? Oooh look, a squirrel....

[dmr]

22 minutes ago, MtB said:

 

I too, might be able to say something costructive, but for the cider.... 

 

Ill have a go anyway. Them filters are generic stock items in the world of oily boilers. They have a 1/4"bsp parallel thread. 

 

What was the question again? Oooh look, a squirrel....

 

Nah, I reckon they are 1/2" unf or 18mm, or somethink like that, 18 sounds big, maybe m12, I suspect the www has the answer, is cider metric or imperial 😀

I believe some cheap filter heads are prone to cracking, a difficult fault to track down,  so if you have space its worth keeping a spare on the bote.

 

Its one of the few pipe things where its UNF rather than BSP.

 

I need to clarify, BSP is British Standard Pipe and NOT Blue Sign Pandemic (from Matty)

[blackrose]

Thanks, so it's these I need then?

 

https://www.asap-supplies.com/products/ag-male-compression-coupling-1-4-bsp-to-5mm-compression-1-23716

 

As the threads aren't tapered am I ok to use some PTFE tape on the threads or is that no good with diesel? The 2 blanked off ports on the unit have copper washers but the ports in using just have red plastic bungs without washers so I guess I'll need a couple more. Why aren't they supplied with the correct amount of sealing washers if they're needed?

[David Mack]

7 hours ago, MtB said:

 

Ill have a go anyway. Them filters are generic stock items in the world of oily boilers. They have a 1/4"bsp parallel thread.

I had one of the small ones on an oily boiler at home. It had a tapered thread fitting screwed in. The alloy head split.

[Tony Brooks]

5 hours ago, blackrose said:

Thanks, so it's these I need then?

 

https://www.asap-supplies.com/products/ag-male-compression-coupling-1-4-bsp-to-5mm-compression-1-23716

 

As the threads aren't tapered am I ok to use some PTFE tape on the threads or is that no good with diesel? The 2 blanked off ports on the unit have copper washers but the ports in using just have red plastic bungs without washers so I guess I'll need a couple more. Why aren't they supplied with the correct amount of sealing washers if they're needed?

 

Because they are not needed when installed with the correct pipe size and fitting. The fitting is a hollow hexagon setscrew with a taper on the inner end. When fitted, this taper get compressed onto the pipe to form a fuel tight seal. However, I have not heard of fittings for a 5mm pipe. It is a parallel thread, so you will have to use a suitable adaptor and soft washer. I think that I would use a Dowty washer from choice, but if not a copper one.

 

Sorry, I don't know what thread or size you need, but any decent fuel injection specialist should be able to help.

[BEngo]

The filter heads are available for either UNF or BSP Fittiings.  You need to check which. The UNF one is 1/2in  × 20tpi. These are easily cross threaded.  The BSP ones are either 1/4 or 3/8.

 

  ASAP do (or did do)  the UNF ones for various pipe sizes, though 5mm would be an uncommon size.  There are also ebay suppliers. I Think BES do BSP ones.  Seal the threads with Heldite, or the blue stuff from Screwfix.

 

 

There is enough metal on a 3/8 BSP fitting to turn the thread off and cut a new 20 tpi UNF thread.😊

 

The filter head will also accept hollow nuts and separate pipe-end nipples, but you would have to get the nipple silver soldered or  brazed onto the pipe  to pass BSS.  Again,  5mm would be an odd size for solder nipples.

 

N

[Ex Brummie]

The spill return on my Perkins 4108 uses a rubber 'o' ring on the pipe which is about 3/16" and which is then compressed by a hollow bolt. It only requires a minimum pressure to seal it. 

As the feed to your Webasto is  not gravity, using a large filter may give you problems in bleeding it as the pump does not have a high capacity.

[dmr]

There are two common types, one takes the standard 296 filter, the other takes a spin on replacement (496). They are mostly 1/2 inch UNF but some are m14.

ASAP and SSdiesels sell them.

You can get blanking plugs and 1/2" to compression fittings, both seal on a copper washer.

The 1/2 inch to compression fitting is not common but I think ASAP sell them.

 

some old ones might be BSP but I can't find any on the web sites of the common suppliers.

[blackrose]

1 hour ago, dmr said:

There are two common types, one takes the standard 296 filter, the other takes a spin on replacement (496). They are mostly 1/2 inch UNF but some are m14.

ASAP and SSdiesels sell them.

You can get blanking plugs and 1/2" to compression fittings, both seal on a copper washer.

The 1/2 inch to compression fitting is not common but I think ASAP sell them.

 

some old ones might be BSP but I can't find any on the web sites of the common suppliers.

 

I've just measured the inside of one of the female ports as about 10.95mm or 0.43" so would that be 1/2" UNF allowing for the thread height to take it up to 0.5"?

 

I'll call ASAP tomorrow and see what they say.

Edited August 30, 2021 by blackrose

[BEngo]

Core diameter of 1/2 20 UNF is 0.439 in so it looks like that is wot you 'ave.

 

Both 1/4 and 3/8 BSP parallel would be significantly larger.

N

[Tracy D'arth]

5mm pipe or 3/16"?  Very close to each other.