UncleBob said..

grich62 said..
don,t want to start a fight but were do people get the idea that the cav filter should be hooked up reverse flow,this is incorrect.if you look under the casting the two in arrows enter to the out side of the filter,this allows any water and debris to run down the out side of the filter as the paper is treated to risist water entry,the fuel travels through the paper and in to the center of housing were it is ported by a gallery to the out arrow.if you hook your lines up to 2 ins or 2 out the filter will not function correctly

Hi, for a small diesel engine in a marine environment, the reversing of the connections in the filter directs the possibly contaminated fuel to the bowl first, (we all know that sailboats use so little diesel that it stands a greater chance of contamination) which allows any junk and water to separate out prior to going through the filter, thus enhancing filter life and efficiency. These engines draw so little fuel through the filter that the possibility of damaging the filter by reversing the flow is so small that it is not a consideration. This is a workaround that some have adopted , not a mandatory install and if one doesn't understand the reasoning than simply install as directed for a higher flow use such as a road going vehicle. No problem.

You might have to pull a filter and have a good look at the flow because the fuel enters on the out side of the filter element and all water and heavy solids drop to the bowl, the fuel then passes through the element and exits the filter. By sending the fuel in the outlet it will travel to the inside of the filter and then through the element and only then can the water go to the bowl ,water can then travel to your primary filter which on most small engines is not very big ,it wont take long to pass water in to the fuel pump ,heavy debris will stay traped in the filter blocking the element prematurely .I have been diesel fitting for 43 years on marine and heavy equipment and sat through days of filter training on several brandsand can assure you that what you are saying is incorect. If you want to use the cav as water collection there use to be a shorter bolt or a out side non filter housing available that deleted the element The only way you will enhance the life of a filter is keep your fuel and tank clean,filter life depends on how much it cleans out the fuel.

UncleBob said..

grich62 said..

UncleBob said..

grich62 said..
don,t want to start a fight but were do people get the idea that the cav filter should be hooked up reverse flow,this is incorrect.if you look under the casting the two in arrows enter to the out side of the filter,this allows any water and debris to run down the out side of the filter as the paper is treated to risist water entry,the fuel travels through the paper and in to the center of housing were it is ported by a gallery to the out arrow.if you hook your lines up to 2 ins or 2 out the filter will not function correctly

Hi, for a small diesel engine in a marine environment, the reversing of the connections in the filter directs the possibly contaminated fuel to the bowl first, (we all know that sailboats use so little diesel that it stands a greater chance of contamination) which allows any junk and water to separate out prior to going through the filter, thus enhancing filter life and efficiency. These engines draw so little fuel through the filter that the possibility of damaging the filter by reversing the flow is so small that it is not a consideration. This is a workaround that some have adopted , not a mandatory install and if one doesn't understand the reasoning than simply install as directed for a higher flow use such as a road going vehicle. No problem.

You might have to pull a filter and have a good look at the flow because the fuel enters on the out side of the filter element and all water and heavy solids drop to the bowl, the fuel then passes through the element and exits the filter. By sending the fuel in the outlet it will travel to the inside of the filter and then through the element and only then can the water go to the bowl ,water can then travel to your primary filter which on most small engines is not very big ,it wont take long to pass water in to the fuel pump ,heavy debris will stay traped in the filter blocking the element prematurely .I have been diesel fitting for 43 years on marine and heavy equipment and sat through days of filter training on several brandsand can assure you that what you are saying is incorect. If you want to use the cav as water collection there use to be a shorter bolt or a out side non filter housing available that deleted the element The only way you will enhance the life of a filter is keep your fuel and tank clean,filter life depends on how much it cleans out the fuel.

Hey, the last time I looked fuel floats on water, debris tends to sink and the fuel goes through the filter, but hey I know FA unlike those that have sat through days of filter training.

i think if you got a boat with that much debris and water coming out of a tank you have major problems ,as i said i do not want to pick a fight sorry if i have offended you ,but most paper wound filters are built the same as cav and the design offers a lot of surface area for fuel cleaning , so its not just cavs you would have to turn around.I dont no what you mean about fuel floates on water as it will sink ever way its hooked up.

UncleBob said..
If you look at the element you will see that it is radially wound and that everything enters the top of the filter and transits through the element to the glass bowl beneath, any debris is trapped on the top of the element,and the filtered fuel returns through the centre column to the secondary filter. By reversing the flow, the fuel and everything that may be with it enters the bowl first, allowing water and any debris to settle then travels through the filter to the secondary. The radially wound filter performs equally well whichever direction of flow, but is better without a layer of crud on the top.
I made the decision to install a sedimenter prior to the filter for each tank on my boat, the best decision I have made in a while , which catches any water and debris before the primary filter. The main reason is that my tanks have (or at least had) asphaltenes that tended to clog the fuel lines, usually at the most inopportune times, this has eliminated the problem.
By reversing the flow the filter is somewhat mimicking a sedimenter.

is your eng electronic injected fuel asphaltenes is normaly associated with high fuel temps ,i can see your reasoning about the fuel flow i think it comes down to what you call debris ,any thing with large debris staying on top of the filter to me is going to head me to a fuel tank clean out as the fuel lines are going to block,when i talk debris i mean small stuff ie dirt and stuff, i also prefer all bigger items to stay in the top as it makes it easier to identify ie rust scale, ruber hose or diesel bug .i have even found small rocks in filters.if its in the bowl its easy to drop and lose because of were the filters are located,one of the big problems i have on cav filters are the fuel drains are always broken or seized