This is a bit of a follow up to post 31658 where there was discussion about whether to use 2 (one CAV+original) or 1CAV filter in the Landcruiser diesels. I was also interested in Peter2's comment about running the fuel flow opposite to that recommended by the manufacturer.
I contacted a
well known diesel servicing company (that cannot be mentioned on this site by name) and they forwarded an interesting and helpful response that is reprinted below, with their permission.
The CAV type filter system is called and agglomerator. This means that the
fuel passes THROUGH the filter media FIRST. Any micro droplets of water
agglomerate as they pass through the filtering media to larger ones and then
combine to a larger droplet which then falls to the bottom of the bowl. This
type of filtering is, from what I can remember is about 99% efficient at
trapping water particles.
IF the filter is plumbed up for REVERSE flow then the micro droplets of
water have a higher chance of continuing up through the filter media and on
their way to the pump and injectors. This is classified as about 95% or less
efficient in water trapping.
The Toyota factory manual suggests 'for mining use only' that the 2 filters
be left in place from the factory on the 75/78/79 series. It is suggested
for road use to remove the steel pre filter canister (the one with the paper
element in it only) to reduce fuel flow restrictions at road use (revs). If
this is not done the fuel flow can be reduced leading to higher than normal
fuel pump temperatures. Case in point is to look at the 100 series. Same engine
but different application (road use) and only ONE filter.
We suggest remove the paper element from the primary filter and leave the
canister empty and just run the ONE spin on fuel filter.
For the adaptor you will be looking at $140.80.