Any ideas out there on the lowest recommended micron rating for 300DT engines? How tolerant are the injectors and what is the rating of the stock main Mercedes fuel filter - and is that a nominal or absolute rating? If it is 10 mic nominal, then I would assume the injectors could tolerate something between 20-40 microns (human hair being 74 microns).

Thanks

I don't think there are options for the stock filter but If I was going with an external fuel filter, I would go with a 2 or 5 micron "just cuz". I think the factory filter is 10U nom.

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Ron Schroeder
'85 300 Turbo Diesel 2 tank WVO
'83 300 Turbo Diesel 2 tank WVO
Some former WVO vehicles since ~1980:
'83 Mercedes 240D
'80 Audi 4000D
'83 ISUZU Pup
'70 SAAB 99 with Kubota diesel
'76 Honda Civic with Kubota diesel
'86 Golf
Several diesel generators
All with 2 tank WVO conversion
LI NY

The VW TDI guys install a kit using a 2 micron Caterpillar spin-on filter.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Yes, this is what I want to know, how does one reasonably filter svo/wvo to be able to use 2 micron fuel filters without either paying several hundred dollars for waste filtering or going through 2 micron filters every week. Currently I go through a 10 micron fuel filter every 2-3,000 miles, with a 5/1 micron polyester gravity filter bag setup. I would bet that the injectors can easily handle 10-20 micron fuel, but others obviously do not think so.

WHY? Have there been injector/pump failures?

I just finished putting a 2 Nominal Micron filter on my 300D over the weekend. I do not have the CAT number but the NAPA number is 3528 and 1 filter was $15.99. I also bought 3 Baldwin filters on Ebay for about $11.35 each that are for the same application (BF7633). I wanted to use the stock filter housing. There are several problems with this: 1- the filter threads are 1"-14 and the filter bolt is M14x1.5, 2- the CAT filter is a lot fatter, 3- the CAT filter is a lot longer and there is a casting that protrudes under the stock filter and 3- those now hard plastic hoses on the fuel system are not going to want to bend into new positions and require raplacement with rubber hose.
I made a bracket/plate to move the filter out further so that there would be clearance under the longer filter.
I made a threaded adapter that is 1"-14 threads on the outside diameter and M14-1.5 on the inside dameter.
I had to do some grinding on the stock filter housing to gain clearance fot the top of the fatter filter.
Here showing the parts:

I do not have a complete set of pics as I did not intend to post this information. But you guys seem interested so I did.
RACOR has filters with 1 Micron filter elements but the Filter Housings are expensive. There are 2 micron filters out there that would be a better fit (not as fat) but are expensive (around $30) and none I could find so far match the Mercedes filter bolt thread size.
My Volvo diesel car engine is made by VW and the filter bolt is M16X1.5 and in my searches I did see 2 micron filters with these threads; this is probably what the TDI people are using.
Added 06-13-08: The CAT filter number is 1R-0750 and in their advertasment they claim it is a 2 micron absolute filter. I got one a few days ago and the outside diameter of the cat filter is smaller and may fit on the housing with out having to grind the casting webs on the Mercedes filter housing.

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84 300D, 82 Volvo 244Gl Diesel

Part of how I did my search for filters was to go to Ebay and search "diesel fuel filters" and "water separators". But most sellers will not have the Micron rating of the filter listed and many who do have the wrong Micron rating for the filter element they are selling. WIX filter is the only company with a filter interchange that almost always gives you the Micron rating of their filters. I would find a filter on Ebay and use that part number in the WIX interchange to look up the Micron rating. Here is the WIX filter look-up interchange.
http://www.wixfilters.com/filterlookup/index.asp
You will get the Micron rating for the filter that WIX makes.
Also a Nominal Micron Rating of 2 means that the filter will filter 50% of the 2 Micron and larger particles on the first pass.
Some time the Micron Rating is expressed in a Beta Ratio like: (this side is the Micron size of the particles tested) 2/20=10/75 (this is a number that represents a formula used to calculate the (efficiency) percent of the particles filtered on 1 pass through the filter and you need a Beta Ratio chart to find out).
In this case on the first pass through the filter 90% of 2 Micron or larger particles are filterd out and 98.7% of the 20 Micron or larger particles are filtered out on the first pass through the filter.
Also; A 2 Micron Absolute filter would be written 2=200, meaning it filters 99.5% of the 2 Micron and larger particles are filtered in the first pass through the filter.

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84 300D, 82 Volvo 244Gl Diesel

The factory seconday filter has a Nominal Micron Rating of 10 Microns as do a lot of other diesel engines. CAT and companies that make diesels with Common Rail Systems now want finer filtration and seem to be using Nominal Mircon rating 2 Micron filters.
As far parts of the fuel injection system at risk of damage it is the Fuel Injection Pump itself not the Fuel Injectors that would most likely suffer damage. Not to mention that the Fuel Injectors are easy to remove an do not cost too much to repair compared to removing and repairing the Fuel Injection Pump.
I wanted finer filtration so I adapted that filter in my earlier post. Next I want to replace the plastic primary filter with a small water separator with a 5 or 10 micron filter but I have not foud anything at a resonable cost yet.
A person could install something like a RACOR water Separator with a 1 Micron filter element in place of the plastic primary filter and just leave the old stock 10 Mocron secondary spin on filter in place and you would be done.

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84 300D, 82 Volvo 244Gl Diesel

On larger marine diesels that have more than one filter we usualy run like a 10 and a 2 inline.

Unless you are running some crap fuel I really don't see the need for anything more than the stock canister. Marine engines usualy run crap fuel so they need it.

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1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

Have you looked at Stanadyne FM100?
I believe it costs around $50 or $60 for the block and 1 filter. Filters are approx $12 in various micron ratings. A water separator bowl is avaliable as well. Trouble is I only know of 1 source: reliableindustries.com.

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'83 300D Turrrbo 295K miles

Thanks; I have seen one on Ebay and years ago when I worked as a mechanic I would see them on forklifts and tractors that used Roosamaster (Stanadyne) Fuel Injection Pumps CAV also makes one that looks so similar it appears the filters will interchange. The price you gave is resonable as you would pay more for a comparable sized RACOR.

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84 300D, 82 Volvo 244Gl Diesel

Hey D-911,

I was thinking of a similar setup last year but never gotten around to implement it because I couldn't find a M16x1.5 banjo bolt to hold the Baldwin Filter that I want to use. The Baldwin BF7591-D according to the Baldwin rep is rated between 1 or 2 microns and it is a fuel/water separator in which includes a drain. It fits perfectly on the base with no grinding at all, but needs a M16x1.5 banjo bolt instead of the standard M14x1.5 banjo. My intention was to "clock" the base with so the filter can clear the power steering. If I can find this banjo bolt or get a drill press to make it, it should work out very well.

I got the idea of using this filter from researching other filters that I can use on my GreaseCar kit.

Attached Thumbnails

       

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1983 123.133 California
- GreaseCar Veg System

replacement stanadyne elements are available almost everywhere- GM diesel vans in the 90-95 range, and also bobcats use them. expect to shell out about $28/ ea for a gm van element. they are less$$ online, as is almost anything these days.

Diesel911-
I really like the stock filter mod- you making any more of those adapters???

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1984 123.193 372,xxx miles, room for Seven.

1999 Dodge Durango Cummins 4BTAA 47RE 5k lb 4x4 getting 25+mpgs, room for Seven.

Added: If someone decides to use the Baldwin filter BF7591-D be sure to use only the Baldwin made filter. When I cross referanced it to a WIX filter the WIX verson was 10 Microns not 1-2 like the Baldwin version.
The center bolt on my 82 244GL Volvo Diesel is I believe the size you need M16x 1.5 and since the engine is made by VW it may be VW Rabbits use the same central bolt. If they will be long enough is unknown.
I went to this site and ran my Volvo and a 82 VW Rabbig 1.6L diesel through the site and the bouth use the same filter with a M16x 1.5 central bolt. I might be that you could get the whole filter housing from a junk yard. Go to this site and rung the number through the interchange I believe you will find that the VW/Volvo filter have about the same OD as the Mercedes filter; meaning that the VW filter housing would work with the water separator you want to use (if the bolt is long enough). Or make a short m16 adapter (as I made the 1"-14 adapter) with inside threads of M14.
http://www.wixfilters.com/filterlookup/index.asp

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84 300D, 82 Volvo 244Gl Diesel

That looks like a slick modification. Does the Baldwin have a internal water separator? Keep us posted!

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

The Baldwin BF7591-D has a drain at the bottom. As it has turned out it is not so slick as I thought. The VW and Volvo type filter head do not have a bolt that goes all the way through to the filter. The threaded part that attaches to the filter is part of the housing.
It looks like it may be possible to use a VW Rabbit Diesel Filter Housing but I need to pull one at the junk yard to be sure. However this housing has nothing to hook up the fuel return lines too but that should not be too hard to do. I would require that you change the plastic fuel lines to rubber hose (1/4" fits). I had to do this on my modification for the CAT filter both because the plastic lines were not long enoungh and also because one cracked (old and hard) when I moved them around. I heated them with a butane lighter to melt the ends by the Banjo fittings to pull the plastic lines off.

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84 300D, 82 Volvo 244Gl Diesel