Oil filter design & engineering

lal Naja · #1 (**permalink**) 08-20-2010, 10:09 PM

We all know that oil will leak past threads unless you've got some type of sealent on the threads like teflon tape, teflon paste or similar.

In a typical canister oil filter. The filter attaches to the engine, or remote filter mount with a threaded nipple, for example a 3/4" diameter x 18 threads. And we know that bigger the thread, the bigger the leak. So does it leak when under pressure?

If you look at this part of the filter it is made from a stamped steel plate with perimeter holes and a female thread. And other bits & pieces like anti drain back, pressure relief, etc.

When the filter canister is screwed on to the engine/remote it seales itself around the outer perimeter with the rectangular cross-section 'O'-ring rubber seal. When the filter is screwed on, a chamber is created, where pressurised oil from the engine oil pump enters the filter, is forced through the element and out through the center of the nipple back to the engine.

So I was curious to know how much oil would leak past the nipple threads as we know threads leak so easily! So is it just the virtually equal pressure on both sides of the thread that make It leak free?

What are your thoughts?

Arthur

coosawjack · #2 (**permalink**) 08-21-2010, 02:30 AM

Only a small percentage of oil goes through the filter on any "pass" depending on viscosity and temperature so a small leak there will make no difference!!

The filter has a pressure "bypass" built into it for the purpose of letting most of the oil bypass the element......

If all the oil had to go through the filter element you wouldn't have enough flow to lubricate the engine and the pressure due to the restriction of the element would be sky high!!

mkassab · #3 (**permalink**) 08-21-2010, 05:24 AM

Arthur.... you're thinking too much! Coosawjack is spot on! It's more important to high quality oil filters, e.g., WIX, Canton, etc.

Mark

Bob In Ct · #4 (**permalink**) 08-21-2010, 05:53 AM

Quote:

Originally Posted by coosawjack

Only a small percentage of oil goes through the filter on any "pass" depending on viscosity and temperature so a small leak there will make no difference!!

The filter has a pressure "bypass" built into it for the purpose of letting most of the oil bypass the element......

If all the oil had to go through the filter element you wouldn't have enough flow to lubricate the engine and the pressure due to the restriction of the element would be sky high!!

Can you point me to a place or source to backup your statement? I thought modern filters were "full flow" (unless they became clogged).

Bob

coosawjack · #5 (**permalink**) 08-21-2010, 07:20 AM

Quote:

Originally Posted by Bob In Ct

Can you point me to a place or source to backup your statement? I thought modern filters were "full flow" (unless they became clogged).

Bob

This will give you some insight.......modern filters are a balance between "Full Flow" and "Bypass"......

http://en.wikipedia.org/wiki/Oil_filter

Bob In Ct · #6 (**permalink**) 08-21-2010, 07:57 AM

I think the article and I are in agreement.

Bob

coosawjack · #7 (**permalink**) 08-21-2010, 08:58 AM

Contact www.bobstheoilguy.com and inquire but I have a hard time believing you can put 50 weight oil through any descent modern filter medium at any temperature without a bunch of it being bypassed either by the "Filter Bypass" or the oil pump "Pressure Relief Valve??

Either way most of the oil does not go through the filter in a single pass.

At any rate you DO NOT need any thread sealant on the filter's threads!!

Bob In Ct · #8 (**permalink**) 08-21-2010, 09:04 AM

I'm running 5W-30 Redline and I think most, if not all, of it is getting filtered (through a Moroso 27 micron racing filter) each time through.

And I agree no thread sealant is necessary.

Bob

FUNFER2 · #9 (**permalink**) 08-21-2010, 09:58 AM

Quote:

Originally Posted by Bob In Ct

I'm running 5W-30 Redline and I think most, if not all, of it is getting filtered (through a Moroso 27 micron racing filter) each time through.

And I agree no thread sealant is necessary.

Bob

Bob and others.

Be careful about choosing "racing filters" for a driver. The larger micron, 23 & up (Moroso 27) are for racing applications, where you're more concerned about high flow rate. Most race engine are torn down often compared to street cars, so they don't care as much about fine filtering the oil.

The small microns are for street drivers and do a better job of filtering.

lal Naja · #10 (**permalink**) 08-21-2010, 10:55 AM

Great replies, thanks. When I built my engine I followed the advice in a book about building a performance engine. One of the tips was to install a dual remote filter system and to remove the engine stock bipass/pressure relief valve. So now I need to make sure that the cannister filters I use have a relief/bipass built in.

Arthur

madmaxx · #11 (**permalink**) 08-21-2010, 11:18 AM

the motorcraft fl-1hp has a higher setting on the bypass 18 psig instead of 11 psig so it forces more oil through the filter

FUNFER2 · #12 (**permalink**) 08-21-2010, 11:28 AM

What's the intended purpose of your car ?

What type of canister filter do you have, normal or a true canister like this one ?

mkassab · #13 (**permalink**) 08-21-2010, 12:11 PM

Quote:

Originally Posted by FUNFER2

What's the intended purpose of your car ?

What type of canister filter do you have, normal or a true canister like this one ?

I use two of these.... a pre/course filter, followed by the Canton fine filter. Both are Canton high flow, no bypass filters, then into a oil thermostat, oil cooler and accusump pre oiler... I know, over the top. Here's my build link for more details http://www.uniquecobra.com/forums/forumdisplay.php?f=68
Mark

FUNFER2 · #14 (**permalink**) 08-21-2010, 12:38 PM

I find this great as I also have the Canton products to use with my new motor. I'll get back to you later, as I'm leaving to race our sprint car tonight. I may have some questions.

lal Naja · #15 (**permalink**) 08-21-2010, 01:12 PM

Quote:

Originally Posted by FUNFER2

What's the intended purpose of your car ?

What type of canister filter do you have, normal or a true canister like this one ?

The intended purpose of the car is first of all the build. I have done pretty much 100% of the mechanical, electrical work including whatever designing that takes. I will also be doing all the body work and paint. It will be street driven as often as possible. Some times it will see road tracks for some extra-fun driving. You can see some photos in my two albums on my profile page.

The cannister filters are just the typical disposable filters that production cars use. I will always try to use the best quality of these.

Arthur

zrayr · #16 (**permalink**) 08-21-2010, 08:12 PM

Quote:

Originally Posted by Bob In Ct

Can you point me to a place or source to backup your statement? I thought modern filters were "full flow" (unless they became clogged).

Bob

you are correct. Modern filters are full flow (all oil filtered) unless clogged.

Z.

coosawjack · #17 (**permalink**) 08-22-2010, 02:42 AM

More than you will ever need to know here!!

http://www.google.com/cse?cx=0182999...ubbthreads.php

I still believe the "full flow" filter bypasses a lot of oil through the internal bypass valve!!!

mkassab · #18 (**permalink**) 08-22-2010, 04:41 AM

Quote:

Originally Posted by lal Naja

....The cannister filters are just the typical disposable filters that production cars use. I will always try to use the best quality of these.

Arthur

Arthur.... Canton cartridge oil filters are not the "typical" filter. Much higer quality and you can buy them @180 micron for the 1st filter and 8 micron for the 2nd filter. ... here's their link http://www.cantonracingproducts.com/...&category=2500

Mark