Longer than stock oil filters

[Patman]

I thought this would be a good topic to bring up. What do you guys think about using
filters that are longer than stock? For the LT1 engine, they specify the PF25 filter (AC),
but the PF35 and PF1218 filters also fit and are about an inch longer. Many LT1 guys,
including myself, have used these filters.

My theory is that the longer filter not only traps more dirt, but also probably goes into
bypass mode a bit less often, allowing more oil to be filtered when cold, and more oil to
be filtered at higher rpms.

Thoughts?

 

[richard612]

I like the idea.

There is another filter that works for PF25/35 applications. I think it's the PF932 and it is about 10"(!) long.

For the Vortec V6, the PF52 can be used in place of the PF47.

Be careful with the interchanging, however. There are two filters which are identical externally (one is equiv to Fram PH3614) but one has an internal bypass and the other relies on the engine's own bypass (maybe be the aforementioned PF47 - not sure). Put the non-bypass filter on a non-bypass engine and risk a filter explosion.

RM

 

[Patman]

That's a good point! I have been lucky, the three cars I have used longer filters on in the past all had bypass valves in the block anyways (98 LS1 Formula, 97 Grand Prix GTP, and this car)

BTW, for those with LS1 powered cars, the PF58 is the longer filter. That stock PF44 filter is tiny! Especially on a Vette with it's 7 qt capacity!

 

[MolaKule]

I always thought increasing the filter length to be a good idea, assuming BP
considerations.

1. The more surface to trap particles, the cleaner the oil.
2. The larger the filter, the more heat rejection by the oil.
3. Greater amount of oil in engine tends to dilute sludge and other contaminates.
4. More water trapping.

 

[VaderSS]

I've been told that the PF35 will not fit the Impala LT1 application, how does it compare to the PF52?

 

[BlackFormula]

This is a topic that tends to come up quite a bit on the LS1/F-Body boards.

I run the stock specified size, but I run the Ultraguard version (UPF44). It is a small filter for such a big engine and 5.5 qt capacity. But my main concern has always been that the longer filter hangs down below the oil pan. If I used the longer filter, it would be the lowest point underneath my car. I would hate to hit the filter and dent or actually tear the thing off. It probably wouldn't ever happen, but it still concerns me. I scrape the plastic front air dam on my car a little too often as it is (darn raised entranceways

).

I question whether the risk/reward of the longer filter is really worth it in my application. I don't abuse the car, so I don't guess my filter goes into bypass very often

. I'm running Mobil-1 with about 4k intervals, so the oil isn't in there for an extremely long time. Can I really gain anything quantitative, that would be worth the risk, by switching to the longer filter?

 

[Patman]

When I ran the longer filter on my LS1 Formula, I had no problems with it's length, it wasn't the lowest point on the car at all, and only sits a tiny bit below the pan. I ran longer filters the entire 2.5 years I had that car, and my car was lowered too. If something large enough hit your underbelly, it would take out the oil pan first, long before it knocked off the filter.

 

[Patman]

quote:

---

Originally posted by VaderSS:
I've been told that the PF35 will not fit the Impala LT1 application, how does it compare to the PF52?

---

The PF52 won't fit the LT1, that is the long filter for the 3.8 GM engines. Or did you mean PF25? The PF35 is about an inch longer than the PF25, and should easily fit the Impala, there is tons of room on my LT1 for a longer filter, and aren't the LT1s identical on your car, other than the different cam and iron heads?

 

[widman]

You need to know a lot more than the length. There are different pressures for valves, some have solid tubes to prevent drain-back. Longer is not always more area. I've cut apart 13 filters that are all supposed to be the same as the PH-8A. The filter area varied from 900 sq cm to 3600 sq cm. One brand uses the same filter in almost all filters with a different size can, gasket, thread, and only varies the size of the spring that holds it tight inside the can.

 

[Patman]

That is a good point! In my cases, I always knew that the longer filters I was using had the same bypass valve pressure on them. Plus the GM engines also have the bypass in the block too, which is a good back up in case the one in the filter didn't work for some reason.

 

[VaderSS]

For B/D/Y Body (Caprice/Impala/Roadmaster,Fleetwood,Corvette) GM LT-1 Applications the correct filter is the PF/SPF/UPF-52. For F Body (Camaro, Trans Am) LT-1 apps it is the PF/SPF-25. You can go to the ACdelco.com site to verify.

You are correct in the -52 able to be used in Buick V-6 apps(where there is clearance). I had one on my Olds Ciera S 3.3 Buick V6. It would touch the subframe rail before being screwed on.

F/Y-body LT-1s have aluminum heads.

B/D body LT-1s have iron heads and a a cam designed for more low end power, also have a smaller throttle body and MAF.

Y-Body LT-1s and factory replacement LT-1s have 4 bolt main bearings.

[ June 16, 2002, 10:48 PM: Message edited by: VaderSS ]

 

[Bill Harper]

As far as the B-body, the 94-96 cars with LT1 or L99 had the exhaust packaged very tightly--the catalytic converter on the left side, especially--which resulted in the use of the PF52 filter rather than the PF25 or PF35 as was used on the Camaro with LT1 or the 91-93 B-body .

94-96 B-body owners CAN change the cooler/adapter base to the earlier version (from the L05 engine) and run the PF35/PF35L/1218 or even the 932, IF the exhaust has been modified to create room in that area. I'm not certain this is true in every case of the various "long tube" headers that are available for the car--probably not--but if you run export pipes with stock manifolds or shortie headers (stock flange in other words) this is doable.