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89GQ
18th October 2010, 12:15 PM
Hey all, Whats the story with microns in the filters? Is it the more microns better filtration, Is 5 better than 10 microns etc. Cheers

patch697
18th October 2010, 12:26 PM
The more microns the finer the filtration........... & thats the story...................lolol

Maxhead
18th October 2010, 05:47 PM
The more microns the finer the filtration........... & thats the story...................lolol

You sure Paul?

I thought the less microns the better the filtration.
ex. 5micron filter will filter particles 5micron small where the 10 micron will only filter particles down to 10 micron and let anything smaller through....if that makes sense

patch697
18th October 2010, 08:48 PM
You sure Paul?

I thought the less microns the better the filtration.
ex. 5micron filter will filter particles 5micron small where the 10 micron will only filter particles down to 10 micron and let anything smaller through....if that makes sense

Yeah you may be right on that one Sorry 89GQ ...........What Kris said...........

89GQ
18th October 2010, 10:26 PM
Cheers lads, Just trying to work it out, Went past a injector/diesel shop today and the guy said ille be getting restricted delivery of fuel due to my cav filter after the original one????Cant see it myself! Iv'e run it since new! I know the cav is 5 microns (i been told) dont know what the original is rated at.

89GQ
18th October 2010, 10:40 PM
Going to try a photohttp://i737.photobucket.com/albums/xx11/jeffs51/beths093.jpg I thought it was low preasure before the Injector pump and high after it. Confused,but its allways ran well.

89GQ
19th October 2010, 07:27 PM
Was my photo too big????????

Woof
19th October 2010, 07:34 PM
Was my photo too big????????

No mate it is fine.

Finly Owner
19th October 2010, 09:15 PM
I think what his concern is , is that more filtering slows fuel flow. Diesel is slighty thick and hence takes longer to strain through finer filter. Yes low pressure before pump and higher on output is right. Maybe run a ten micron next time and see if you notice a difference. It may be only noticable on your idle.

89GQ
19th October 2010, 11:11 PM
Will find out if the cav can be a 10, Anyhow next job is injectors and pump, Thats why i went past diesel place,Was weird he said all the reduced flow etc. etc. but when he started it he asked why do you want to renew any of it, It starts as good as new , have you done youre IP and injectors,I said thats why ime here its on 300 thousand and never been touched! so he went quiet and said 2-3 thousand new injectors and reco pump and G-plugs. What to do leave it??I think i will do it! Maybe not their though.

Finly Owner
19th October 2010, 11:30 PM
Reco injectors i believe should se you back approx $70 each exchange. ($420/set of six) pump I think was $1500 for overhaul when I checkked but won't swear on that one.

The trick is to ask do they presseure test the injectors at their workshop. Also check to see if the rebuild room is sealed to dust etc. (If you can)
Otherwise they may be getting someone else to do the work and they are the middleman, hence the mark up.

89GQ
20th October 2010, 08:05 PM
Reco injectors i believe should se you back approx $70 each exchange. ($420/set of six) pump I think was $1500 for overhaul when I checkked but won't swear on that one.

The trick is to ask do they presseure test the injectors at their workshop. Also check to see if the rebuild room is sealed to dust etc. (If you can)
Otherwise they may be getting someone else to do the work and they are the middleman, hence the mark up.Cheers,They did have the sealed off room with the big machine in it! Thing was no cars in the carpark or workshop,Will go to a few others and check it out,at 300 thousand k's its gotta be done.

Finly Owner
20th October 2010, 08:54 PM
mmmmm...wonder why there's no work lined up???????????????????????????

89GQ
20th October 2010, 09:20 PM
mmmmm...wonder why there's no work lined up???????????????????????????My thoughts exactly!!!!! That machine in the dustless room is that where they test injectors/Pumps ???

Finly Owner
20th October 2010, 09:34 PM
yeah, deisel technicians used to do on open benches years ago, until it was found that being subjected to deisel vapours for prolonged periods, caused cancer. So i believe now they test injectors in a specially designed cabinets that control the vapours. And the rest of the process and testing of pumps is all done in dust free enviroment to keep internals 100% free of micro debri.

We have the best deisel repairers close to us. Merces-Benz workshop uses them.

Chaz
22nd October 2010, 12:56 PM
Hi 89GQ,

The finer the filter the better in all cases, but it does increase the load on the IP to pull fuel up from the tank. I think from memory that most of the generic filters like CAV, Lucas, Racor and Delphi were in the 5 to 7 micron range and genuine Nissan filters were in the 3 to 5 micron range. Some of the generic manufacturers do make special filters in the 2 to 3 micron range also, but not commonly used unless specified.

The problem with what you have done, by fitting another filter in series with your Nissan filter is that you have in affect doubled the resistance for the IP to pull fuel up from the tank. This can impede fuel delivery under extreme loads and can even shorten IP life. I think the best thing to do is remove the CAV filter element and fit a sedimenter to the housing head, but it should be fitted before the genuine Nissan filter. This will reduce any chance of water or large particles entering the genuine filter and you’ll be able to see any impurities through the glass bowl.

http://www.chaz.yellowfoot.org/images/sedimentbowl.jpg

If you really want to run two filters in series or a sedimenter, you would do well to fit an auxiliary lift pump to help the IP by supplying fuel at low pressure instead of using vacuum to draw the fuel up from the tank. This is a proven method and by pressurising the fuel line, there is less chance of air entering the system, as well as reducing EGTs as a result of slightly advancing fuel timing. The only issue here is that you must use a pump specific to the job so that if the pump fails, the IP can still pull fuel through it.

http://www.chaz.yellowfoot.org/images/PumpMounting1.jpg

These pumps have a check valve in the inlet which makes them flow through and fuel can't drain back to the tank, so they remain primed. This also makes priming the fuel system after a filter change a very easy job.

Finly Owner
22nd October 2010, 10:25 PM
great post Chaz