Plastic Oil Fill Neck Torque?

[Frank Smidler]

I had to replace the metal oil fill neck on my O-360-A1A because it was too short for easy filling and checking. The new fill neck is the plastic type. I only hand tightened it before safety wiring. After 4 or 5 hours it came loose. The safety wire was not tight enough to keep it from turning maybe 10 to 15 degrees. I don't like it coming loosening every time I check the oil. I have tried to not tighten the dip stick too tight and this seems to help.

So how did others tighten the plastic fill neck? I am cautious because I don't want to strip it. Will re-safety wire without slack be enough? Did anyone put thread lock on before installing?

Thanks

[Ironflight]

Hi Frank,

Not an expert here by any means, but I found mine was a touch loose a few times as well. I finally did tightened it down just a touch more than before (but was also afraid of stripping it), and then did a GOOD safety wiring job such that it was tight. That was probably 300 hours ago, and it has stayed tight ever since. Getting in there to safety it is mildly challenging, but it is worth it to do it tight.

Paul

[hgerhardt]

The problem seems to be that the gasket shrinks after a new install and requires a re-torque or two before it takes a set. I retorqued mine twice before it finally stayed tight. And yeah, I was worried about stripping the plastic too.

Heinrich Gerhardt
RV-6

[osxuser]

You can torque it gently with a wrench, but gently... The other trick is to NOT tighten your dipstick very tight when you check your oil. A gentle snug on the o-ring is enough.

[MNAv8or]

Everyone is right. The gasket will take a set over the first couple of flights. Just retighten and re-safety and do not allow any slack in the safety wire.

A little trick with safety wire. If you have safety wire pliers, once you have twisted the wire to the correct twists per inch. Do not disengage the pliers. Instead, while you keep twisting the pliers, move the pliers in a cone shape (with the tip of the cone is the safety twist up by the filler neck and the edge of the cone shape is the butt of the safety wire pliers). This will pull the safety wire nice and tight. Its hard to explain how to do. I tried to do the best I can.

Osxuser: I have told so many pilots that they just need to snug the dipstick and not tighten it. But for some reason they think that if they don't get it super tight, the oil is going to leak out. What they don't think about is thermal expansion. You tighten the dipstick as tight as you can get it on a COLD engine. Then you go fly for an hour, guess what happens?! O yeah, the dipstick sinches down due to heat expansion and then the engine cools down locking it in. When I used to rent airpalnes, I would go out to preflight in the winter time and man o man that would set me off. I couldn't get the dipstick loose without having a set of pliers in the flight bag. To many people have the mind set, "a little is good, a lot must be better"

[JonJay]

Originally Posted by MNAv8or

Everyone is right. The gasket will take a set over the first couple of flights. Just retighten and re-safety and do not allow any slack in the safety wire.

A little trick with safety wire. If you have safety wire pliers, once you have twisted the wire to the correct twists per inch. Do not disengage the pliers. Instead, while you keep twisting the pliers, move the pliers in a cone shape (with the tip of the cone is the safety twist up by the filler neck and the edge of the cone shape is the butt of the safety wire pliers). This will pull the safety wire nice and tight. Its hard to explain how to do. I tried to do the best I can.

That was a great explanation of something that is really hard to explain! It is kind of a half twist, circular motion and really locks the safety wire tight. I was shown how by my 84 year old aviation mentor, God rest his sole.

[rvmills]

Originally Posted by JonJay

That was a great explanation of something that is really hard to explain! It is kind of a half twist, circular motion and really locks the safety wire tight. I was shown how by my 84 year old aviation mentor, God rest his sole.

Concur, that was a very good way to describe it. Like Jon, I was taught it by an old salt...great A&P. Still trying to perfect it, but I think of it as sort of a half barrel roll with the back of my twister hand, then reverse the grip and finish the roll...up, over, and back under. But the plier butt-end scribing a cone is a good visual! I call it the "Walt cinch" for the guy that taught me.

Just to keep the thread on track...gotta go check that filler tube safety wire...you guys got me thinkin'! Good points!

Cheers,
Bob

[Sam Buchanan]

Originally Posted by rvmills

Concur, that was a very good way to describe it. Like Jon, I was taught it by an old salt...great A&P. Still trying to perfect it, but I think of it as sort of a half barrel roll with the back of my twister hand, then reverse the grip and finish the roll...up, over, and back under. But the plier butt-end scribing a cone is a good visual! I call it the "Walt cinch" for the guy that taught me.

Just to keep the thread on track...gotta go check that filler tube safety wire...you guys got me thinkin'! Good points!

Cheers,
Bob

Excellent tip, and one I hadn't heard. Sounds like the "barrel roll" is creating a spring-like coil in the wire that maintains tension.

I've also had to resafety the dipstick tube a couple of times.....and it is loose again (seems to always happen in the winter). Hmmm.......weather is lousy today, might go to the 'drome, pull the cowl and really fix it this time.