3/4 turn method for oil filters

[pa38112]

Actually, the 3/4 turn method is far more accurate than a torque setting (not that it is super critical in this application). 3/4 turn will always compress the gasket the pre-determined amount. The filters have 16 threads per inch, so 16 turns will produce 1" of travel. Therefore one turn will produce 1/16" of travel. 3/4 turn will compress the gasket 0.046875". You cant say the same for a torque setting. - Prove it to yourself by doing both. Mark the filter and then set it with a torque wrench. Measure the rotation you achieved. Also use a inside caliper to measure the gap between the filter face and the filter housing face. Do this over a few oil changes.

For high precision "Torque" settings the angular method is always the preferred method. A torque wrench is used to ensure all parts are pulled-in together and then a angular rotation is set using a torque angle gauge: https://www.amazon.com/OTC-4554-Driv...780774&sr=8-12

[BillL]

All cannister oil filters are tested(developed) to a standard test procedure. Today it may be some ISO test, but the 3/4 turn was based on the SAE hydraulic pulse test to ensure it would not fail internally, or come loose. Included is a 1/2 turn and even a 1/4 turn test to be sure it is not on the edge of acceptability. The pulses and pressures are much higher and any engine produces, diesel or gasoline.

There has to be a historical reason for safety wire, but not sure why torque is involved, it was not part of the past test procedure.

If a Toyota filter "came loose" it was never tight.

[deek]

Originally Posted by pa38112

Actually, the 3/4 turn method is far more accurate than a torque setting (not that it is super critical in this application).

For high precision "Torque" settings the angular method is always the preferred method. A torque wrench is used to ensure all parts are pulled-in together and then a angular rotation is set using a torque angle gauge: https://www.amazon.com/OTC-4554-Driv...780774&sr=8-12

^^^ Exactly right ^^^

[rocketbob]

Originally Posted by pa38112

For high precision "Torque" settings the angular method is always the preferred method. A torque wrench is used to ensure all parts are pulled-in together and then a angular rotation is set using a torque angle gauge: https://www.amazon.com/OTC-4554-Driv...780774&sr=8-12

Last year I overhauled one of the heads on my 911 which uses one-time-use stretch bolts that are torqued to an initial NM torque then torqued to an angle. I tried one of these tools and they are a bit of a pain so I got a highfalutin Snap On digital torque wrench that does angular torque. Just for kicks I marked the bolts with a protractor and sharpie and found that method to be nearly as good as the angle reading on my torque wrench.

[gasman]

Originally Posted by BillL

All cannister oil filters are tested(developed) to a standard test procedure. Today it may be some ISO test, but the 3/4 turn was based on the SAE hydraulic pulse test to ensure it would not fail internally, or come loose. Included is a 1/2 turn and even a 1/4 turn test to be sure it is not on the edge of acceptability. The pulses and pressures are much higher and any engine produces, diesel or gasoline.

There has to be a historical reason for safety wire, but not sure why torque is involved, it was not part of the past test procedure.

If a Toyota filter "came loose" it was never tight.

Rav oil filters are cartridge filters. They do not seal the same as spin on filters.

The Rav filter failed because it was not tight.

[Snowflake]

Originally Posted by PCHunt

However, most standard torque wrenches and their required sockets or crowfoot extensions don't fit easily on the oil filters installed on most RV aircraft.

This. The oil filter *just* fits between the engine and the firewall on my RV-6 when it's first placed into position (before spinning on). I can't only just get a closed-end wrench onto it when it hits the rubber. No way I could get a torque wrench in there.

And since all the filters i've seen say 3/4 turn after bottoming on the rubber, there's no real need for a torque wrench. I've never seen a safety wire on an oil filter that was under any tension when it came time to remove it, either, and yet I still safety it because "it's always been done that way."

Unfortunately the closest safety wire point on my twice-overhauled-and-due-for-a-third Lycoming finally wore to the point where it broke off the last time I did an oil change, so I had to safety the filter to another nearby hard point.

[snopercod]

Originally Posted by cajunwings

You can?t go wrong with the official guidance, 18 to 20 ft lbs is the torque for the Champion brand.

I strongly disagree. A few oil changes ago, I torqued a Tempest EZ-Spin filter per their instructions and, at the next oil change, it was frozen solid. The can wouldn't budge no matter what I tried. Ultimately the can was completely destroyed by using 1. An Anti-Splat wrench; 2. A standard oil filter wrench; 3. A screwdriver driven through the can; and 4. An oil filter wrench with spikes on the tips. Even after I chiseled the can off from the base, a set of 24" Channel-Loks wouldn't budge the base. Don't be this guy:



I actually had to use a BIG hammer and chisel to pound on the circumference of the base to break it lose. I will NEVER torque to manufacturer's specs agaion. Now I use the 3/4 turn method with no problems. A couple flights ago I used the hand tight plus 1/2 turn method and I'm still alive to tell about it.

[erich weaver]

Originally Posted by snopercod

I actually had to use a BIG hammer and chisel to pound on the circumference of the base to break it lose. I will NEVER torque to manufacturer's specs agaion. Now I use the 3/4 turn method with no problems. A couple flights ago I used the hand tight plus 1/2 turn method and I'm still alive to tell about it.

Just changed my oil today and had a similar but not quite so bad experience. Had to put a 3 foot cheater bar on my ratchet to budge the Tempest oil filter that was installed to specs- no lube and 16 ft lbs of torque. Fortunately my oil filter is located up high where use of the extension is possible

Erich

[Scott Hersha]

3/4 turn always works. I have that ‘special’ oil filter wrench. It torques the can tighter than 3/4, every time. I don’t use it. 3/4 turn doesn’t over torque the filter, and doesn’t leak. That’s the measure - doesn’t leak. Second measure - you can get it off during the next oil filter change. This is a relatively liberal spec, dealing with a compressible gasket subject to relatively low pressure - usually less than 100psi. With a fairly coarse thread, safety wire will hold the torque pretty close, even if you don’t get the safety wire installed really tightly.