Primer Lines

[NHPacerPilot]

I'm getting tired of the copper tubing breaking off at the nut and ferrel at the cylinder fitting of my primer lines. They are standard 1/8 copper. It is getting to be a pain in my back side and there just has to be another way. I really don't know what I'm doing wrong but all the other fittings are flare fitting and they are fine. Just the ones at the cylinders seem to break off. Not a hard fix but just a pain. Any ideas? Is there an approved alterante tubing for primer lines. Mine go to all 4 cylinders.

[Frogdad]

You might try adding a loop in the line to reduce vibration. See left portion of photo.

[tferraro]

Are you saying yourr fittings are flared with a ferrell and nut? If so that that is not the standard copper tube primer fitting. The typical fitting is a brass fitting with a compression ball on the copper line and a brass nut. I've had these in my Pacer, 160hp 0-320 for years and have never had one crack or break. Also have them in our Tiger with 0-360 - never had one break???

[Steve Pierce]

I have seen them break at the nut on the primer nozzle from time to time. I use these AN800-2 solder on cones and no more problems. http://www.aircraftspruce.com/pdf/20...l/Cat11099.pdf

[P.o.P.]

Are you REPLACING tubing or cutting shorter?

The tubing should be SOFT.

If it isn't you may want to replace or anneal.

[NHPacerPilot]

Naw it is the standard brass nut with the compression ring/ball that I call a ferrerll fitting. I never thought about the loop so I'm going to try that and order the solder connections. Thanks for the advice. This is the value of this site. Sometimes you never think of the simple fix but others have. Thank-you all.

[Steve Pierce]

P.o.P. has a good point. Copper is bad about work hardening and cracking.

[NHPacerPilot]

Thanks Steve et al. I think I'll get some new copper and rework them. Do they make a fitting that accepts a 37 degree flare for the cylinders. The 74225 (63D2140 nipple is the only one I can find. Seems they should make a flare fitting for this and that would eliminate my problem altogether. But if not I'll do the AN-800-2 solder. Thanks. Saw the pics from WAD on SC.org too bad the weather between me and there was bad on Sunday my only day off that week! Looks like it was a great time.

[Steve Pierce]

Never seen a flare fitting or tool for the 1/8" tubing.

Yea, sorry I missed it too. This work thing is a drag sometimes.

[NHPacerPilot]

I think I figured it out. The above photo from frogdad showed the primer lines secured with an small adel clamp. Mine are not secured anywhere except with the clamps to the intake tubes so I suspect some pretty good vibration going on. I'm going to use the loops as did frogdad and secure the lines better. Now I just have to spring for a flaring tool for the ends that go into the t-block and they ain't cheap! Thanks for your help and I'll let you know how it works out.