What are the +/- 's of oversized filters?

MarkC · Sep 14, 2003

The application is question is the Jeep 4.0.
Can any of you kind 'experts' give me the good, the bad, and the ugly?
Also,cross- ref part #'s would be great, especially for Napa Gold, Purolator,etc.(the more common brands).

Thanks.

Ken2 · Sep 14, 2003

Plus--
1) The belief that bigger is better.
2) Larger oil capacity might be an advantage...more time for cooling, etc.
3) The assumption that a bigger can holds filter media with more filtration capacity.
4) The belief that a bigger can and maybe more filter media will allow easier oil flow.

Minus--
1) No one knows exactly why the engine designer picked the particular filter they did pick for that engine out of the dozens that would physically fit. What were the criteria for filtration, hot flow, cold flow, bypass valve setting, filter dirt capacity, etc? Is the bigger filter indeed a suitable replacement?
2) No one is sure that the media in a bigger filter actually filters more or flows better. The number of holes of the correct size in the media do the filtering and flowing, not the square inches of the filter.

Ken

[ September 15, 2003, 01:10 PM: Message edited by: Ken2 ]

jason07-1zzfe · Sep 15, 2003

quote:

Originally posted by Ken2:
2) No one is sure that the media in a bigger filter actually filters more or flows better. The number of holes of the correct size in the media do the filtering and flowing, not the square inches of the filter.

I am and it does. Unless it uses a different media of course. Which if it is the same brand, why would it be?

timzak · Sep 15, 2003

Good response, Ken2. I use an oversized filter on two of my cars simply to get a little extra oil capacity, which will keep the oil a little cooler and reduce average contaminants per QT of oil. If I end up with more sq inches of filter, that's an added benefit.

FYI, Wix has good info on their website regarding bypass psi ratings, etc. It helped me find equivalently-rated oversized filters.

Patman · Sep 15, 2003

I always use oversize filters on the GM cars that I own, which makes finding larger filters very easy since GM engines have the bypass valve in the engine, so the filters used in these applications do not need one.

So I know that I'm safe going with a larger filter since the bypass does not change. If anything, the larger filter might cause the engine's bypass setup to operate less frequently, if the larger filter allows for better flow (which I'm assuming in most cases it definitely will)

labman · Sep 15, 2003

I have to agree with much of Ken's post. I have cut open the popular PF 47 and larger PF 52. As far as I could see, they were same inside except the larger PF 52 did have more of what looked like the same filter media. I admit that I could not see pore size or spacing, but the media did seem to be the same. If you have room, and it doesn't increase the chances of being punctured, etc., I don't see any reason not to use the larger PF 52. I think the manufacturers are just down sizing filters to cut costs leaving smaller margins of error.

A few years ago I was maintaining 3 different GM 4 cylinder engines, a 77 Chevy LUV, a 90 Beretta with the Tech 4, and a 92 Grand Am with the HO Quad 4. The specified filters were PF 1177, PF 52, and PF 47. The newer, larger, more highly stressed engine, the less filter area by actual measurement. Since I have trouble finding the PF 1177's I have used and checked several other similarly priced filters. None of the others, including the well regarded Purolators and Hastings, had as much filter area, although the size of the can was the same. Fram came in a very poor last. I am using ST's now.

sbc350gearhead · Sep 15, 2003

As long as the bypass valves are identical, the only downside I see for using an OS filter, is that unless it is mounted on the bottom of the engine, it will take longer to pressurize during startup.

unDummy · Sep 15, 2003

No problem with pressure buildup here.
As far as I can tell, if there is a working ADBV, the pressure on the gauge builds up just as quickly with the large filter.

Mitch · Sep 15, 2003

On my '03 Jeep and my previous 3 Jeeps I used the oversize oil filter. The standard oil filter is a 1085 from NAPA and PH 16 from Fram. I now use 1515 from NAPA and I could use(but won't) PH8A from Fram.I looked in the filter book and the relief valve is the same for both filters.Since the 4.0 has the filter on the side of the block I don't think there is any more potential for the filter to bleed off with a long filter vs. a short filter.I know on all of the Jeeps I have had there is not a clearance problem.

FreedomOil · Sep 15, 2003

The Puralator filter# for and over sized filter for your Jeep 4.0L is L30001
Same filter for a Ford Truck.
I run the same filter on my Mini-Stock Racecar. 22RE Toyota. That extra oil sure helps alot!
A good Over-sized one for a Ford Truck is a Baldwin #B251 -- Holds 2X the Oil. I have a Bronco with Remote filter setup and Dual Filters. Now holds 7.5 to 8 qts instead of 5! and a heck of a lot easier to get to!! hahaha

Chris 2421 · Sep 15, 2003

I have 2 Jeeps and a '02 Dodge truck.All call for the short filter.I use the equivalant of the Fram PH8A,which is the larger filter.I use the SuperTech ST8A from Wally Mart.

I worked for a few Chrysler dealers over the past 20 years.The reason for the small filter is that it's the standard filter on 95% of all vehicles that Chrysler produces.

Gary Allan · Sep 15, 2003

The larger PH8A equivalent works on MOST 4.0's AMC/DC inline sixes. The base/thread are identical (as we all here clearly appear to know) ..the thing with the 4.0 is that in various years and various installation it just can't fit it. Some years, in the YJ for example, it would hit the motor mount. Some years in the XJ it had a right angle adaptor that caused it to hit something else when the engine rocked slightly..

If you've got the room ...go for it!

Mobil2 · Sep 30, 2003

Great reply Ken2. I think you really nailed it with most people thinking Bigger Is Better. There is some logic to this, but then why is there a trend by manu's moving to smaller filters? There's gotta be a reason for this.

For my Acura, I'm worried about moving from a 7317 to a slightly larger 3593A. Both are common Honda filter sizes and they share the same thread size, by-pass PSI and gasket diameters. But if this 3593A filter that is only 13% larger is better, why didn't Honda go with this in the first place

Ken2 · Sep 30, 2003

quote:

Originally posted by Mobil2:
Great reply Ken2. I think you really nailed it with most people thinking Bigger Is Better. There is some logic to this, but then why is there a trend by manu's moving to smaller filters? There's gotta be a reason for this.
...

Any way to save a nickel in costs? The thing is that we really don't know.

Ken

Mobil2 · Oct 1, 2003

Since we're basically working with educated guesses here, do you think it'd be safe to say:
"Using an oversize filter in the summer months would be better because flow is more important, while in the winter months the stock size filter would be better as pressure is more important?"

I'm a bit of a newbie here, but given all variables are the same (except filter/media size), this seems logical... no?

[ October 01, 2003, 02:19 PM: Message edited by: Mobil2 ]

labman · Oct 1, 2003

NO. In the winter we want pressure from filtered oil on the far side of the filter. A PF 52 has more filter area than a PF 47*, and likely the same media and etc. Therefore more cold, thick oil should pass through the larger filter and on to the bearings and other parts we want to preserve. I think an oversize filter is even more important in the winter. I think the manufacturers oil recommendations are going to thinner oils, 5w30, 5W-20, as they specify smaller filters.

*I have cut them apart and measured filter area. I have also cut apart PF 1177 and other low cost equivalent filters and the Ac had up to 3 times as much filter area. More area, more flow unless the media is different.

MarkC · Oct 1, 2003

Labman, If more filter area means more flow, then a Pureone with 400sq.in of filtering media should flow more than, say a Napa Gold with 337, right?
yet, the Pureone flows 3 gpm while the Napa Gold flows 7-9 gpm. These numbers are for the equivalent size: Napa Gold 1085 and PureOne PL14670.
The bypass settings are different; 8-11 psid for Napa and 12-15 for PureOne. And of course the media is different.
So, what do you think?

jsharp · Oct 1, 2003

quote:

Originally posted by MarkC:
Labman, If more filter area means more flow, then a Pureone with 400sq.in of filtering media should flow more than, say a Napa Gold with 337, right?
yet, the Pureone flows 3 gpm while the Napa Gold flows 7-9 gpm. These numbers are for the equivalent size: Napa Gold 1085 and PureOne PL14670.
The bypass settings are different; 8-11 psid for Napa and 12-15 for PureOne. And of course the media is different.
So, what do you think?

It shouldn't flow necessarily flow more if the media is different. But more surface area will = increased flow if it's the only difference.

If you're looking at full sized Ford filters you might also look at the Motorcraft FL-1A. I'm sure the flow rate is adequate for your application judging by what engines it's specified for by Ford...

MarkC · Oct 1, 2003

Thanks. i'm just looking for great filtering while also keeping good flow. I don't even know what's considered 'good' for flow. Maybe 3gpm is fine.

labman · Oct 1, 2003

quote:

Originally posted by MarkC:
Labman, If more filter area means more flow, then a Pureone with 400sq.in of filtering media should flow more than, say a Napa Gold with 337, right?
yet, the Pureone flows 3 gpm while the Napa Gold flows 7-9 gpm. These numbers are for the equivalent size: Napa Gold 1085 and PureOne PL14670.
The bypass settings are different; 8-11 psid for Napa and 12-15 for PureOne. And of course the media is different.
So, what do you think?

I specifically said if the media is the same. Maybe I should have been more explicit about flow through the media, not around it. Set the bypass low enough and anything can flow well.