Replacing Raycor Filter with Cat

[Dick Simonis]

I know this topic was discussed at length some time ago and I'm almost reluctant to bring it up again but, my heretofore perfectly performing Racor has again developed an air leak as well as a slight fuel drip.

Since I will be in Idaho Falls a few more days I'm thinking about running over to the Cat dealer and have them replace the Racor with a Cat filter.  A couple of questions thought:

1)  Without the strainer assy to visually see air, how does one know if there is an air leak in the suction side?
2)  Right now I have an automatic water purge which works quite nicely but how do you handle an water with a Cat filter?
3)  Is the primary filter the same as the secondary with just a different element?

Thanks for any feedback.

Dick

[Edward Buker]

Dick,

I was not a big fan of this subject either given all that has been discussed. As far as your questions, there is no sight glass in the new system to see air in the fuel flow.

1. The old Racor design pre filter screen is problem prone due to aged plastic and orings, so most of the time you are seeing leaks from the unit itself, which on balance is not a great trade off, so that is not an over riding reason to hang onto it. If you had an air leak somewhere in the fuel system a sight glass would then be installed to diagnose it and moved to isolate the leak source.
2. When you get a replacement pre filter look for one that has a plastic sight bowl or a means to drain at the bottom of the prefilter. You can then drain any visible water accumulation off if you are concerned about water accumulation.  These designs are not problem prone given it is a screw on assembly not relying on friction fit of several orings like the old Racor design. You can discuss this possibility with Cat. The new fuel is much cleaner and less prone to having water issues from storage but you never know for sure.
3. The primary filter is usually separating water and filtering larger particles to keep them from
plugging the 2 micron Cat final filter media. Usually the rating size of the primary is somewhere between 10 and 30 microns and any of those ratings should do the job. Too small a particle rating would be unwise given the system may become too restrictive to fuel flow. The rating of the Racor 30 micron filter is 98% removal at 30 microns so it is also filtering much smaller size particles at varying efficiencies.

This unit is a good buy and has an integrated pump. You would have to check to make sure it is 12V and may already have integrated the water probe and drain feature. This unit is not prone to any of the issues that the old Racor design had and has a changeable pump.

http://www.nwrvsupply.com/product/790R30.html

There is a Racor unit with a manual pump also. Cat may offer a prefilter unit with a pump also. I am still an advocate of having a way to purge air out of the filters before cranking the engine. You can discuss that issue with the Cat dealer and sort out your own degree of comfort on this. Hope this helps.

Later Ed

[Dick Simonis]

Thanks Ed, it turns out my original concern was not valid.  When I saw a small puddle of diesel fuel on the ground under the service bay is jumped to the conclusion it was a leak.  Turns out it was probably just the water purge doing it's thing.  Guess all the previous conversations pushed my paranoia button.  A lot of driving and sitting with high humidity (rain) combined with quite high and very low temps coupled a fairly low fuel level caused condensation in the tank is my guess.

[Edward Buker]

Dick,

Glad all is well. Should run like a Cat....:-)

Later Ed

[Dave Atherton]

Good morning, this subject Racor has been run around the block how many times. There are some who feel they want to have Racor reguardless of who says what and is always the same answers,
Few that seem for the ongoing problem now is just down to that. Than we have people asking questions Racor versus Caterpillar ( reason want to see the air bubbles in the site glass ) well
If caterpillar seem to think that having a site glass so owner could see air bubbles they would
Have installed a television camera at that point and a monitor in the cab. Not trying to be smart
But at some point being I started this subject because of low power problem and pin pointed
The water/ fuel filter was the Root cause of problem. Than the Name Racor comes into the problem.
Dave with his background suggested putting fuel system back to the way Caterpillar built and
tested the engine. Very simple change and trouble free and air free for $ 135.00 to $ 153.00.
We need to stop beating this subject up and just do what you want. Dave again background with
Caterpillar and bringing out problems from failure seems to be a contest at present and again
time to put this to bed. Dave is more than willing to assist membership with caterpillar problems
and known air with the fuel system is a very big and costly as I pointed out. Let take a few
minutes an think about what Dave is bring to group. Dave Atherton Retired Cat Mechanic