PBO August CAV filter picture page 15

[CalicoJack]

Under the title "Where are the holes when you need 'em?" is a photograph of a CAV filter taken from above complaining that the fuel could not flow because of the lack of holes, but I'm confused; not difficult as many people will confirm. Surely fuel entering the system will not enter through the hole in the middle, but will drop onto the large flat area on top of the fuel element, and then will flow to the outside of the filer and drop down between the wall of the canister and the filter element. Following that it will be filtered and drawn through the filter element to eventually reach the centre of the filter where it will be drawn through the centre hole and on out of the filter head.

Hope that this makes sense, my point being that you don't need any other holes.

Nigel

 

[vyv_cox]

All the ones on the ASAP website have holes. Here is their CAV replacement type. http://www.asap-supplies.com/search/fuel+filter/fuel-filter-element-199296-for-cav-fuel-filter

 

[rob2]

In a CAV filter, the filter is the body of the filter and the fuel flows in through the (missing) holes in the top of the filter, flowing down into the bowl clamped onto the bottom. It then goes up the central hole to the outlet port. Without holes in both top and bottom plates, the filter is totally blocked.

Rob.

 

[CalicoJack]

Interesting. I have just fitted Fram filters and they looked like the one in the PBO picture, and they worked well.

 

[prv]

All the ones on the ASAP website have holes.

The Volvo-labelled ones don't though:

I'm fairly sure I've seen other brands with a similar arrangement.

Pete

 

[Steve_N]

As prv says, no holes in the Volvo ones and they work just fine.

 

[vyv_cox]

It's not entirely clear in the PBO photo whether the dark annular object around the periphery of the filter is a passage, as in prv's photo, or a seal, but it looks more like a passage to me. However, the writer of the letter could get no fuel into the bowl with the filter photographed, whereas when he changed to one with holes it filled immediately.

 

[prv]

I assume this difference reflects the different arrangement of filter medium inside the can. The ones with holes on top, do they have a similarly open bottom? I assume they do, so the fuel passes vertically from top to bottom.

The ones like the Volvo example pictured above have a solid bottom, with only a hole in the middle. So the fuel will go in through the slot around the outside at the top, and pass radially from outside in.

Pete