Oil filter capacity and oversizing thoughts...

[KCJeep]

I've seen a lot of comments (especially on places like Jeep Forum) like "Use the FL-1A instead, it holds a whole quart of oil!" as well as similar. Well I didn't think that was right but I didn't really know how much they did hold. Here's what I found out.

Over time I've discovered full oil changes in my Jeep with the spec filter (PH16 equivalent) versus an oversize (PH8A equivalent). The difference to full? A mere 1/4 quart... that's a measly 8 ounces gained with the oversize PH8A/FL-1A type filter.

But here's the real eye opener for me. This week doing another experiment, I removed a PH8A and spun on a PH3600 replacement. I had just driven the Jeep, so I know the PH8A was full when I removed it. I then spun on the dry PH3600 and started it up. It was down on oil of course so I topped off a bit. I drove for a few days checking the top off and it was still perfect.

The total capacity of the full PH8A plus the new PH3600 plus the oil that drained down from the top of the engine when I removed the filter turned out to be... a simple 1/2 quart, just 16 ounces to fill two filters, one of which was oversized, and the top of the engine to boot!

That tells me these filters don't hold near as much oil as you'd think by looking at them...and those of us who like to oversize for the "extra oil capacity" are fooling ourselves with wishful thinking. You'd still get more media, theoretically better flow...but...are we really gaining anything?

 

[Mr Nice]

Its the extra media I want, not the additional oil.

 

[SteveSRT8]

This has always been a "feel good" type of mod.

I run service fans to 300-500k miles with the tiny little factory filter.

 

[heynow]

Originally Posted By: SteveSRT8


I run service fans to 300-500k miles with the tiny little factory filter.


Service fans?

 

[Jim Allen]

Originally Posted By: SteveSRT8
This has always been a "feel good" type of mod.

I run service fans to 300-500k miles with the tiny little factory filter.


Very true, with a very few exceptions.

 

[ZeeOSix]

Originally Posted By: KCJeep
That tells me these filters don't hold near as much oil as you'd think by looking at them...and those of us who like to oversize for the "extra oil capacity" are fooling ourselves with wishful thinking.


That's because these squirrely guys are just looking at the outside size of the can and don't realize how much volume the stuff inside the can takes up.

Best way to know exactly how much a filter holds is to fill a new one up with oil until it's completely full. I've found a medium sized filter only holds about 8~10 ounces.

 

[LScowboy]

my current thinking on this is that, due to the unreliability of many anti-drainback valves, that filter oversizing is best for vehicles with filters in the 5, 6, or 7 o'clock positions, since they would tend to stay full, regardless of the ADBV working.

conversely, on a vehicle with an upside-down filter at 12 o'clock, such as the old Mazda RX-7 - I would use the smallest volume filter I could get, as it would be most likely to drain back.

by the way, one thing I can say about the often-bashed OCOD, is I have never removed one that was not full of oil, so perhaps they excel in what may be the most important feature of them all!

 

[LScowboy]

if you are going to oversize, I say crack open a 40 of Colt 45 while you install this 40oz.

a MANLY filter for your V-8, oh yeah!

 

[ZeeOSix]

Originally Posted By: LScowboy
my current thinking on this is that, due to the unreliability of many anti-drainback valves, that filter oversizing is best for vehicles with filters in the 5, 6, or 7 o'clock positions, since they would tend to stay full, regardless of the ADBV working.


Best thing to do is use a filter with a silicone ADBV if the base is down at all. I use a PureOne (oversized, PL20195) on my Tacoma (filter vertical,base down) and never have start-up noises.

 

[LeakySeals]

Engines from different manufacturers with the same oil capacity use different sized filters. Why? There must be a reason other than cost.

 

[MrQuackers]

If I can get the filter for the same price and get an extra 10% oil capacity, several extra square inches of media and it is easier to remove to boot, yep I'll buy that option.

 

[Donald]

I would guess 99% of the filter removed during an OCI are no where close to being filled with contaminants.

However its been proven that chicks really like guys with oversize filters.

 

[BlueOvalFitter]

Originally Posted By: KCJeep
I've seen a lot of comments (especially on places like Jeep Forum) like "Use the FL-1A instead, it holds a whole quart of oil!" as well as similar. Well I didn't think that was right but I didn't really know how much they did hold. Here's what I found out.

Over time I've discovered full oil changes in my Jeep with the spec filter (PH16 equivalent) versus an oversize (PH8A equivalent). The difference to full? A mere 1/4 quart... that's a measly 8 ounces gained with the oversize PH8A/FL-1A type filter.

But here's the real eye opener for me. This week doing another experiment, I removed a PH8A and spun on a PH3600 replacement. I had just driven the Jeep, so I know the PH8A was full when I removed it. I then spun on the dry PH3600 and started it up. It was down on oil of course so I topped off a bit. I drove for a few days checking the top off and it was still perfect.

The total capacity of the full PH8A plus the new PH3600 plus the oil that drained down from the top of the engine when I removed the filter turned out to be... a simple 1/2 quart, just 16 ounces to fill two filters, one of which was oversized, and the top of the engine to boot!

That tells me these filters don't hold near as much oil as you'd think by looking at them...and those of us who like to oversize for the "extra oil capacity" are fooling ourselves with wishful thinking. You'd still get more media, theoretically better flow...but...are we really gaining anything?

It's just Un'Umurcin' to not go larger!

 

[MrRPM]

Originally Posted By: Donald

However its been proven that chicks really like guys with oversize filters.


exactly.


KCJEEP nice post and observation

 

[KCJeep]

I am left with the conclusion the only real reason to oversize would be to obtain more media or just personal convenience (the Motorcraft FL-1A is $3.99 most places whereas the smaller "spec" Mopar is usually over 6 bucks for example).

 

[MrRPM]

so KC, I have seen in your other posts that you like 1 filter 1 OCI because leaving the filter on for 2 oil changes leaves too much left over oil for the next fill. Its like topping off with used oil.
But if filters hold such a small amount of oil and if your not doing long ocis then is it really a big deal? How much oil do you think my jeep would need if I left my 8A sized filter on for my next change? more then 5 qts?

 

[rrounds]

On the Honda S2000 it came with the largest oil filter that Honda put on their cars. So if you go just a little bit larger you get just a little bit more oil and you won't know if you are getting a larger filter unless you take it apart.

I went with a much larger oil filter and I now use 6 qt's of oil when I change the oil and filter instead of 5.1 qt's with the stock oil filter for the S2000. Just because the can is the same size or even larger than the stock filter you don't know how big or small the filter is inside of the can, till you take it apart.

Here are some pic's of the stock Honda S2000 filter, a Wix filter for the S2000 and the Baldwin filter that I use on my S2000. I find it interesting how the Wix and Honda can's are the same size but the filter inside are different sizes.

http://s949.photobucket.com/user/rrounds/library/Oil Filters?sort=2&page=1

ROD

 

[LScowboy]

I am not a big fan of going with a considerably larger gasket diameter like you did with the Baldwin in this case, that is rather "iffy" territory in the filter upsizing world!

but if you insist, here is a Wix that will fit as well as your Baldwin and just as big

 

[KCJeep]

Originally Posted By: MrRPM
so KC, I have seen in your other posts that you like 1 filter 1 OCI because leaving the filter on for 2 oil changes leaves too much left over oil for the next fill. Its like topping off with used oil.
But if filters hold such a small amount of oil and if your not doing long ocis then is it really a big deal? How much oil do you think my jeep would need if I left my 8A sized filter on for my next change? more then 5 qts?


Yes I used to leave filters on quite a bit. But even now I figure leaving the filter on is leaving at least half a quart of old oil in my engine, between what the filter holds, what the filter holds in the top of the engine, and the old oil you can't get out anyway when you change it. In my Jeep this total is about a half quart based on what I learned in this experiment.

That didn't used to bother me till I got a UOA back that surprised me, and I suspected the old oil hadn't helped as I had much more shear than expected and a lower TBN than I thought I should have. So leaving an extra half quart in the crank isn't helping anything IMO, although I can only control about half of that.

 

[rrounds]

Originally Posted By: LScowboy
I am not a big fan of going with a considerably larger gasket diameter like you did with the Baldwin in this case, that is rather "iffy" territory in the filter upsizing world!

but if you insist, here is a Wix that will fit as well as your Baldwin and just as big

The gasket is not that much bigger than the stock one, about 1/10" bigger. I have over two million miles with Baldwin filters and never had one fail or leak and that is why I use them on my cars and toys. I have over 65k miles with this filter on my S2000 and my UOA's show my oil is cleaner with this filter at 8k miles than the oil was with the Honda filter at 4000 miles.

ROD