I've been watching this one from afar as I know to some it is an emotional topic. I'm not a filter expert I went to several filter Mfr sites and learned what they had to say on the topic plus called their tech lines and spoke to them for their .02.


In my daily job I have to compile observations from field issues to help our Engineers root out causes of a problem from evidence collected. Here are some of my thoughts please read and keep to a technical discussion of what has been presented I have no agenda just trying to separate trees from forest.


What I think is happening here is GM undersized their filters, plus has given no mechanism to determine when a filter is blocked. Rather than go through something I posted last year I'll direct you to story somewhat related to similar experience I had in the Navy towards the bottom of the thread http://dieselplace.com/forum/forum_posts.asp?TID=2590&KW .


I have since learned where I described the 6.5 system in that post there is no lift pump in the DMax but the main point of premature blockage I think still holds merit. There are photos of filters in cutaway here and over on Diesel Page I'm not sure which threads exactly that show complete failure of filter media.


Now another thread here http://dieselplace.com/forum/forum_posts.asp?TID=4057


My suspicion that Inj fails are induced by plugged filts failing, in post above they find media in the injector similar to my Navy story. At 2 micron only those with catostrophic failure of media would you find material plugging the injector itself. What about a partial failure long term would it allow "dirty fuel" direct to the injectors. "Holes" in the filter in neighborhood of 2 micron would be nearly invisible but you would be still flowing "dirty fuel" to the injectors.


I've read the posts and fuel sample results post CAT & MEGA filter install both result in good and clean the fuel as was GM's intent.


Actually I think if GM had installed either of these as the main filt there would have been fewer problems. What they were counting on was clean supply of fuel, we have no control of what comes out of the pump unless you are treating it yourself, recircing/settling through own stationary tank before filling your truck.


Baldwin/Racor/Wix never intended a 2 micron filter to be a raw fuel filter http://www.parker.com/racor/pdf/Section01.pdf 2 micron is for fuel to be of known good fuel quality. Personal experience and numerious reports we know pump fuel is anything but good fuel.


Ideal systems would have 3 levels of filtration coarse, med, fine in Racor 30 mic, 20/10 mic, and 2 mic final, size cost and real estate for mounting make this impractal for a pick up truck. Baldwins fuel manager and the Vormax come closest to doing a all in one set up. But substantial in size really & a bit expensive(but cheap insurance) for over the road trucks with much more real estate to install them.


So what about DMAX, CAT & MEGA are both successful in quality fuel delivery, pre OEM or Post OEM, your call; but Racor says that even though their filts are for press or vac side install they work best on suction side pre-pump. I would suspect same of CAT & MEGA, in my view if we are trying to protect the total fuel system including the 1st element of the IP pre pump would be the best.


I'm inclined to agree with Racor & others that 2 mic as a primary is too fine, that a larger rated filt to sift the "big chunks" 10/20 feeding the 2 mic is they way to go. That we have been successful with the MEGA & CAT is due t

Sound very reasonable. It would be nice to swap out the stock filter for a true 2mic. Then put in 1 single large 5-10 mic before the stock filter. I belive a lift pump would also be helpfull for all the extra filter resestance,plumbing and also the power adders. Is there a 2 mic that can be put in place of the stock unit?

Tim,
Conversations with Greg at Lube Specialists today
yielded additional info on the new Racor Pre OEM, GM
system that is a topic of today. Per Greg, the filter
is to be mounted into the same holes in the frame that
his kit provides for. Apparently a WIF sensor will be
present. Filtration will be 10 Micron. Greg mentioned
the WIF, etc, are all parts available for addition to
his Racor system or any Racor system, and will research
the system, and make upgrades available. Am
interested in hooking up the WIF in the pre as well
personally. As you know I am also interested in your
guage solution. Seems that indications of reduced flow
would allow both indication of potential catastropic
failure due to a bad fuel load, and also allow for
optimum indication of the need to change your filters.
P.S. Total Power arrives on Thursday. No additional
trucking cost. Will advise on price, will pick up
Friday.

If all that is needed to cure these injector problems, is a proper filtration system, why did GM redesign the LB7 into the LLY? I am sure emissions played a large part, but just making the OEM filter 1" longer is a real cop out in my opinion.

"Instead of correcting the CAUSE of the injector problems, we'll just make them easier to change"http://www.dieselplace.com/forum/smileys/Confused.gifEdited by: Pick

Pick I agree a longer single filter isn't the cure, my suspicion/theory is that the longer/ bigger filter allows you to live with it better, but that eventually it will fall victim to OEM design of single filter only at 2 micron, if not changed before fully blocked it will also fail.


I don't have the set up to prove it, a instrumented flow bench and supply of dirty fuel to be evaluated for final result, but I think dual filtration med/coarse into fine is the fix. Dual filtration plus instrumentation in my view.


You can pick up bad fuel anywhere anytime. I had a loss of power on a "new" filter <5 K on the recently changed filt., running empty no problems but towing 5800 lb trailer I could only do 45 mph flat run and struggled to make 25 mph up a hill, dropping trailer power was back; 2 weeks later same drive and trailer then loaded with 5 K of tractor I was able to run to 75mph.


Only difference was changed fuel filter, now I have (2) a Racor 10 mic pre lift pump filt, and the 5 mic OEM post pump filt. also have switches that set alarm when filt needs changing. This is on my 6.5 to my knowledge no 2 micron filt. for the OEM bowl, or I'd be running 2 mic there like DMax for a final.


Evidently according to Silat's post above there is some additional thoughts along these lines at least in area of dual filts.


As far as GM knowing best well maybe, one only needs to look at 6.5 PMD fails and all the work by members here and at TDP, to get it to be reasonable to live with(GM hasn't sanctioned the fix but you can't argue with results), and the overheat problems that led to the 130 gpm waterpump with dual thermostats that wasn't fixed by GM until almost the end of the 6.5s production run.


Edited by: Turbine Doc

I'm a firm believer in heavy to fine filtering. It's insanely logical.

Doesn't mean the other way around doesn't work but what's the point in filtering 5 microns after you just filtered 2 microns? Yes the OEM will be able to filter a whole lot better with cleaner fuel coming into it. That's why pre-OEM does work reasonably well.

Both methods work. No one has proved to me that a lift pump is required. I run two filters, the second being a large 2m Racor and have no problems at all with the way my truck runs. Getting ready to change to my third Post OEM cartridge this spring.

OK now your saying the OEM filter is 2 microns ? I like the idea of double filtration, one pre OEM then the OEM one. I like the idea of 2 or 5 at the OEM position and a 10 at the pre. my confusing question is... "what size micron is the OEM filter?" the more I read it seems I get more confused. can you guys help the rookie diesel owner out? Thank You, AkDually61

I just talked to Racor engineering about the new kit. They said the OEM filter is 2 micron, the kit has a 10 micron designed to be a pre-filter.

The OEM is and always has been a 2 micron filter. But there are 2 micron filters and then there are 2 micron filters!
It boils down to the efficiency level of the filter, the capture ratio. In real world testing the OEM filter captures roughly 50% of the +2 micron component. So, yes, you can say it is a 2 micron filter, just not a very effective one. Conversely the CAT and Baldwin 2 micron filters capture 99.8% of the +2 micron particulates..
And yes, the OEM 2 micron no doubt meets ASTM specifications for multi-pass hydraulic oil at the 2 micron beta 200 level. However, in the real world of diesel fuel, single pass performance, quite another matter.
George Morrison

I think it's 2 MICRONS "NOMINAL" and not "ABSOLUTE" is where we have the issues and confusion. It's only 50% effective at 2 microns if I have that right.

George,

What are your feelings on the Racor 2 micron. Several will use the new factory setup, but add the 2 micron filter, rather than the 10 micron.

Turbine Doc, I agree with you. That's why I chose a Stanadyne system with a 30mic 1st stage and 2mic 2nd stage.


I don't think a lift pump is mandatory, or our trucks wouldn't be running, but I do think they help on a few levels.


1. pressurize the system to eliminate possible sources of air from the QD fittings.


2. Fully wet the filter media for more efficiency. Why have a huge CAT or Baldwin filter and only use 1/2" of it at a time? We already know a suction side filter is not full of fuel.


3. Helps the IP maintain fuel rail pressure on a high demand system, especially with two levels of filtration. Just ask the packager of the Nicktane kit why he's running a lift pump.

Steve,


the only reason i've added a pump to mine is to support the TTS Extreme's fuel requirements. i actually have the pump wired to a switched relay in the cab and run w/ it off most of the time as its a bit noisy...http://www.dieselplace.com/forum/smileys/Confused.gif

Thats a Holley for you. The one on my Bronco sounds like a weed wacker is below my feet.http://www.dieselplace.com/forum/smileys/Approve.gif.

Turbine Doc, I agree with you. That's why I chose a Stanadyne system with a 30mic 1st stage and 2mic 2nd stage.


I don't think a lift pump is mandatory, or our trucks wouldn't be running, but I do think they help on a few levels.


1. pressurize the system to eliminate possible sources of air from the QD fittings.


2. Fully wet the filter media for more efficiency. Why have a huge CAT or Baldwin filter and only use 1/2" of it at a time? We already know a suction side filter is not full of fuel.


3. Helps the IP maintain fuel rail pressure on a high demand system, especially with two levels of filtration. Just ask the packager of the Nicktane kit why he's running a lift pump.





Are you saying that Nick is running with a lift pump?


What info do you have for the Stanadyne Filter set up....were you mounted it and how much was it.


Thanks for the info.