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Lycoming Fuel Pump Fittings

rapid_ascent

Well Known Member
I?m still learning about FWF related items. I know for NPT threads some type of thread sealant is required. I have some questions about the use of thread sealant on the engine fuel pump fittings which have an o-ring. I plan on using the fittings that Van?s sells. Is sealant required? Also, how tight is the nut torqued? Is there a reference that covers attachment to these fuel pumps?

It all looks pretty simple, but on the other hand it?s pretty important that these parts are installed correctly.

Thanks in advance for any guidance.
 
Ray ---no sealant on the fitting. O'ring is pressed into a recess int he pump to make the seal. Lock nut torqued to maintain retention.

Tom
 
Fittings

The nuts can be obtained with holes for safety wire. If a 90 degree fitting is used orient the fitting so the hose does not try to turn the fitting.
You should find the proper torqueing method for the nut.
These fittings are very critical and have caused accidents in the past.
 
The Parker reference is has some good numbers, but the reference values are in the Continental Titan Installation Manual engine torque table B-1 for my IO-370. It is 75-110 in-lbs.

The Parker value is 100 in-lbs +/- 10% or 90 - 110 in-lbs.

For Lycoming Engines the reference is in SSP-1776-B, in table Vi which lists 8-9 ft-lbs or 92-108 in-lbs.

So 100 in-lbs it is.

Sorry for being such an engineer type, but I?ll certainly feel better on such a critical item in my mind.
 
For Lycoming Engines the reference is in SSP-1776-B, in table Vi which lists 8-9 ft-lbs or 92-108 in-lbs.

So 100 in-lbs it is.

Sorry for being such an engineer type, but I?ll certainly feel better on such a critical item in my mind.

I would have thought that the straight thread on the Lycoming fuel pump outlet fitting (the one with an o-ring) would be a 9/16-18 and therefore the correct torque according to Lycoming SSP-1776 Table V1 would be 23 - 24 ft lbs.

The inlet fitting would presumably be the same.

Does anyone else have any input on this.
 
This is in the Van's manual section 5. See the pic attached
 

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