ok to use over-szied filter?

[stchman]

Originally Posted By: Bgallagher
Been using PF52 in place of my PF47 for years now. No difference in flow rate etc. just longer. Probably all in my head but I feel like it runs a little quieter with the longer filter versus the shorter.


It's not probably all in your head, it IS all in your head.

 

[ZeeOSix]

Originally Posted By: dnewton3
Regarding your last point, I agree overall, but I'll point out this ...

The pump relief is typically a linear progression spring device not unlike the valve in the filter. I've not known any pump relief to be an "on/off" switch with a high/low setting. They will bleed off pressure as it builds, in a variable response to the overage. Like the filter bypass valve, it will first crack open, then bleed more as the pressure increases. It's not like the pump relief opens and then 100% of the pressure is bled to the sump, while the engine gets zero. Rather, it only bleeds off the excess pressure , keeping the engine satisfied.


Agreed ... if I somehow gave the impression it was on "on or off" valve it wasn't meant that way.

Originally Posted By: dnewton3
So, in my example above, when the filter media is totally blocked at it's bypass open, the pump will supply enough pressure and volume regardless, even if it is in relief to some degree.


True ... however, if the opening in the filter's bypass valve was somewhat restrictive and had to take 100% of the flow from the oil pump, it may cause the oil pump to hit pressure bypass sooner (especially with viscous oil and/or high revs), and thereby decrease the total volume of oil delivered to the engine. That's because if the oil pump hits pressure relief sooner due to higher down steam resistance, then the flow volume has to also decrease due to the laws of fluid flow in a pressurized source of flow - which is what's going on when the oil pump has been limited to a constant, max pressure.

Originally Posted By: dnewton3
I would agree that there is some portion of unknown risk whereas the filter bypass hole may not be large enough for a total-meltdown stupidly ignored condition (filter NEVER changed, totally blinded media, and full revs at cold start with 15w-40 in a gasser in Alaska in winter ....). But then again, how many BITOGers get into that condition anyway?


Reminds me of an indecent I say many years ago. Some drunk guy came out of a bar and fired up his old pick-up truck on a cold winter evening when it was about 0 degrees F outside. A few seconds after the engine started he basically revved the engine to near red line for 5+ minutes straight. He probably thought he could get heat in the cabin faster that way.

 

[dnewton3]

I agree with you overall, as I typically do. We're only debating the very small minutia in a topic that is grossly overblown in the first place.

As a side note, I'll tell a story on myself ...
I used to do a very similar thing in high-school (well, not the being drunk thing, but the cold high revs). This is back in the 1980s with carb'd Ford Escorts.

I had to park outside, and in winter, I wanted a nice warm car to drive to pick up my friends on the way to school. I would start the car, let it idle perhaps only 10-15 seconds, and then back out. As soon as I hit the road, I'd run it in first gear (manual trans) up to about 5,000 rpm through the neighborhood, to put as much heat into the block and coolant as I could, as soon as I could. I would do the same thing on the way home. I'd do it going to work, and coming home. I did it all the time in winter. Only after the temp came fully up would I shift into higher gears. Never gave it a thought whatsoever! Did it all the way through high school. In fact, I was brutal on that engine, even when fully warmed. I was a teenager with little care and a lot of privilege. I'm a bit embarrassed now to admit I was not very respectful of the gifts I had when I was young. But never did the engine ever fail or shows signs of distress. It just took it and soldiered on.

Today's equipment, lubes, filters are all "better" designed and made than ever before. They are way more capable than those of yesteryear. They are WAY more capable than the average person will need, and given the excessive over-maintain mentality of the typical BITOGer, their vehicles should last to "Infinity and beyond" (cue Buzz Lightyear).

And so, knowing how I abused stuff previously, and seeing more than a decade of more than 10,000 UOAs, and practicing my craft of statistical process analysis, I can say with a large degree of certainty that a slightly larger filter used in normal applications is a fools errand. I will never hurt, but it won't help either, because there is a HUGE amount of reserve capacity (defined as safety margin in the various products) so that you're not going to usurp the average components in the first place.

I only caution folks (repeatedly) about the fact that the risk of warranty denial/deferral is very real, and since the reward is only imagined, it's not a practical thing to do.

 

[ZeeOSix]

Originally Posted By: dnewton3
As a side note, I'll tell a story on myself ...
I used to do a very similar thing in high-school (well, not the being drunk thing, but the cold high revs). This is back in the 1980s with carb'd Ford Escorts.

I had to park outside, and in winter, I wanted a nice warm car to drive to pick up my friends on the way to school. I would start the car, let it idle perhaps only 10-15 seconds, and then back out. As soon as I hit the road, I'd run it in first gear (manual trans) up to about 5,000 rpm through the neighborhood, to put as much heat into the block and coolant as I could, as soon as I could. I would do the same thing on the way home. I'd do it going to work, and coming home. I did it all the time in winter. Only after the temp came fully up would I shift into higher gears. Never gave it a thought whatsoever! Did it all the way through high school. In fact, I was brutal on that engine, even when fully warmed. I was a teenager with little care and a lot of privilege. I'm a bit embarrassed now to admit I was not very respectful of the gifts I had when I was young. But never did the engine ever fail or shows signs of distress. It just took it and soldiered on.


That's a good story for sure. Would have been interesting to cut open the oil filter after use like that to see what was going on.

I recall when I was young and stupid about oil (back in the 70s with my 1st car), I'd leave 20W-50 in the engine over the winter. On very cold mornings the engine would barely turn over and make some crazy noises for the first minute or two of operation. Of course, the motor never blew-up, but I'm sure it wasn't doing it any good. It was probably damaged to some degree but of course engines can run quite a long time (and seem to run normal) with some pretty extensive wear damage.