Cracking oil filters

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Frank

Pre-takeoff checklist
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Frank
I follow a few aviation forums and on one Jabiru Engine group two pilots reported that they had engine problems that led to emergency landings as a result of cracks in oil filters. In both cases stress risers led to cracks in five or fewer hours of flight after changing the filter. The oil then sprayed on the exhaust, causing dense smoke. I do not have any reason to believe their filters are less robust than others. Apparently the cracks were in one case a result of a dent and in the other scratches left by a filter wrench. I have not heard similar reports from more common GA engines, perhaps because filters have to meet some specs. Nonetheless, it makes sense to use tools that will not leave small cracks or scratches in your filters. Since changing your oil can be preventive maintenance, this might be a caution for a lot of us.
 
Standard aviation filters have hex shaped stamping a welded on, so even IF it cracked due to the wrench leaving a mark no leak would occur.

It has been a while since I played with a Jab, is it the same or are people using a wrench that bites into the can?
 
Apparently they do not have hex heads. I know my automotive filters do not have hex heads, so I have wrenches for the outside of the can. A newby could easily decide to use that tool on his airplane with unfortunate results.
 
BTW- I just looked at filters on aircraft spruce and the rotax filters seem not to have the welded on nut.
 
Skylane81E said:
Standard aviation filters have hex shaped stamping a welded on, so even IF it cracked due to the wrench leaving a mark no leak would occur.

It has been a while since I played with a Jab, is it the same or are people using a wrench that bites into the can?
Click to expand...

I guess it has been long enough since I bent a wrench that I forgot about the hex heads, if indeed I had ever noticed. OTOH, it may just be that I never changed oil on one. I overhauled an opposed engine (Franklin), but somehow never changed the oil. It reminds me of my time as an Aviation Machinists Mate in the Naval Air Reserve. We were training to maintain engines on C-118s (DC-6s), but only had the engines at NAF Andrews. When we went for ACDUTRA at Keflavik, I could fix the engines just fine. Another mechanic asked me to secure the engine controls. When I got to the top of the ladder at the door, I discovered that I had no idea how to open the door to get into the aircraft. Sometimes you don't know what it is you don't know until it becomes an issue.
 
I never install an oil filter with a wrench or any tool. Hand tight is all that's needed. Turn it down until its snug then a 1 1/2 turn more. You will need an oil filter wrench to remove.
Make sure you oil the seal or you may need a lot more then a oil filter wrench to remove, oh and also make sure the old seal is not still in place. I have seen this happen more then I care to remember.
 
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1600vw said:
I never install an oil filter with a wrench or any tool. Hand tight is all that's needed. Turn it down until its snug then a 1 1/2 turn more. You will need an oil filter wrench to remove.
Make sure you oil the seal or you may need a lot more then a oil filter wrench to remove, oh and also make sure the old seal is not still in place. I have seen this happen more then I care to remember.
Click to expand...
Champion specs say 16-18 ft lbs of torque, and Tempest sets its oil filter torque wrenches to 17 ft lbs in the box.
 
1600vw said:
I never install an oil filter with a wrench or any tool. Hand tight is all that's needed. Turn it down until its snug then a 1 1/2 turn more. You will need an oil filter wrench to remove.
Make sure you oil the seal or you may need a lot more then a oil filter wrench to remove, oh and also make sure the old seal is not still in place. I have seen this happen more then I care to remember.
Click to expand...

I use DC-4 on the rubber seal. Oil actually gets sticky and makes removal difficult.

Dan
 
Frank said:
Apparently they do not have hex heads. I know my automotive filters do not have hex heads, so I have wrenches for the outside of the can. A newby could easily decide to use that tool on his airplane with unfortunate results.
Click to expand...

That's why I buy K&N filters for my autos and motorcycle. They have a 17 mm nut that's welded on.
 
some pictures of standard Champion Aircraft oil filters and their tools
 

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Rotax says turn 3/4 after gasket contact. Can do it by hand. No nut on it.
My understanding is that turning a given amount of degrees after contact is more accurate than a torque setting as many factors can influence the torque setting but a give number of degrees (270° in Rotax situation) is more definitive in getting a consistent, predictable setting.

Here's a discussion about bolts. I assume they'd apply to any threaded connection, but any scientist are welcome to chime in.

http://www.boltscience.com/pages/tighten.htm
 
I remember having a conversation about oil filters 3 or so years ago
We normally used NAPA Gold 1394 (no nut) in Lightnings and there were two reasons for that - 1) it fit better 2) the other brand (I forget what it was, but it did have the nut) did have a couple that cracked around that nut.
But again, three years at least, details are foggy. Lightnings still use NAPA Gold 1394's
 
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