Why are diesel filters so big?

[jongies3]

Is there any particular reason a diesel filter is so large? This is my 7.3 filter and I never understood why they need to be so big. Cummins and 6.7 Powerstroke filters are about the same size length wise but this one's a few inches wider. The ones on Class 8 truck engines are massive, but so are the engines themselves. My 7.3's about the same size as a 460 big block gasser and it has a smaller filter. Does it have something to do with holding 15qts of oil that it needs a bigger filter? I'm just curious is all, can't find any explanations online so I figured I'd ask here. Sometimes 7.3 filters can be really hard to take off! I've worked on a lot of trucks, and never had so much trouble getting a sucked up tight filter off any vehicle quite like a 7.3 filter. Thrown my back out on these things more times than I care to count!

 

[Kamele0N]

If there will be no picture I would think that we are talking about diesel fuel filters

Probably because your f250 is producing so much soot byproducts in combustion cycle

 

[DemoFly]

Diesels burn crude. Larger filters because of the soot.

 

[Popsy]

Reading the title, I thought you were talking about diesel fuel filter, which are big compared to equivalent gasoline filters

Regarding oil filters, I second previous posts, probably because of soot/by-products of combustion.
Actually considering the two Fiat in my sig (one 1,75L gasoline, one 1,9L disel), they have similar oil filters, but the factory OCI are twice longer on the gasoline engine.

I don't know if it's true, but weren't "old" diesel oil supposed to agglomerate soot and insolubles in bigger particles, so they can be caught by the filter? Hence the bigger filter? But I'm not sure it really makes sense (in term of wear) agglomerating particles instead of keeping them dissolved until oil is changed.

 

[demarpaint]

Soot and typically diesel engines have a larger sump than a gasser.

 

[53' Stude]

Larger filters cause of the psi from oil pump and probably since trucks that are diesel hold 4 gallln plus. Also Diesel engine oil filters are made bit better I found.

 

[bullwinkle]

Need to trap more crud (soot, sludge, & dirt) from a pretty big (for an LD application) 15 quart sump. The one on my (non-turbo) 7.3 IDI in my sig is a lot smaller, maybe 1/2 to 2/3 the size, & it still holds 10 quarts.

 

[Chris142]

Lots of contaminants compared to a gasser.

 

[Branson304]

I always assumed it was because diesel engines contaminate their oil at a much quicker rate than gas engines, so there is more filter media to catch all the junk.

 

[The motor guy]

One word..... FLOW! The bigger the surface area the more oil can pass thru and get filtered without restriction. You think that is big I see used oil filters at the boat yard that are the size of a gallon milk jug.

 

[901Memphis]

It's contamination holding capacity period

 

[MolaKule]

Originally Posted By: 901Memphis
It's contamination holding capacity period

 

[SirTanon]

See this:

... do you think that it's ALL going out through the exhaust valves/pipe? Nope, lots of it gets in the oil. The filter has to catch and hold it.

 

[CDX825]

Your 7.3 has piston cooling jets plus the oil feeds the injectors as well. That plus all the bearings is a lot of oil flow. With the added soot load the diesel makes a small filter would load up and become restrictive fast.

 

[alunsy21]

Look up the Donaldson big blue for the 7.3 PSD application. It is HUGE. Something like 12" long.

Part number DBL7405

 

[DoubleWasp]

Contaminant loading and flow. My 6.7 flows a ridiculous amount of oil for an engine of its size. If you look at the outlet opening for either Cummins or Powerstroke, they are huge.

Keep in mind that our engines have 50 psi bypass valves. The filters have to hold ridiculous flow under all circumstances.

 

[ZeeOSix]

Originally Posted By: DoubleWasp
Contaminant loading and flow.


+1

 

[artificialist]

In VW engines, it is due to containment loading. I sometimes would encounter OEM filters on the MKIV and B5 1.8T that would say "25,000km gasoline, 15,000km diesel." The 1.9 TDI had equal or slightly larger oil capacities to the 1.8T

 

[txgp17]

As was previously mentioned.....
Diesels require more oil flow. Bigger bearings, piston cooling jets. Plus the 7.3 has a HEUI injection system, meaning it has a secondary high pressure oil pump that uses engine oil as a hydraulic fluid to drive individual injectors.

The oil for the injection system needs to be a bit cleaner than you would expect for the engine components. So the 7.3 filter not only has to handle more flow but it needs to clean the oil a little better than the average engine oil filter wood. To meet both of these requirements the amount of filtering media must be increased to reduce the amount of restriction as the oil passes through the filtering media.

Also note that the oil change interval for a 7.3 is relatively short for most diesel engines.

 

[mobilaltima]

on my 7.3 Stroke, I always punch a hole in the bottom of the filter and let it drain for at least 15 mins, then I use one of those 1/2 drive square bar filter wrenches with the strap to take it off, never had a problem. Long live the 7.3!!