Carburetor mounting to Lycoming O-360-A1A

[flyenforfun]

Question, does anyone know what the correct carburetor mounting hardware is and torque for mounting the carburetor to a lycoming O-360-A1A is?

[flyingriki]

See Service Instruction 1484C for Lycoming Torque.

ECi Assembly Hardware Manual has their torque, nuts and washers on page 18. #s 1, 2 and 5:

Item Part No. Qty. Description Torque Values
1 AE9887-5 4 Nut, Hex, Lock, 5/16-18 UNC 204 in.-lbs.
2 AE51412-5 4 Washer, Plain, 5/16 ID N/A
3 AE100104 4 Washer, Belleville, Safety Serrated N/A
4 AE100111 4 Bolt, Int. Wrenching, UNC 5/16-18x1.00 Long 70-80 in.-lbs.
5 AE51413-5 4 Washer, Internal Star, 5/16 ID N/A

[az_gila]

Originally Posted by flyingriki

See Service Instruction 1484C for Lycoming Torque.

ECi Assembly Hardware Manual has their torque, nuts and washers on page 18. #s 1, 2 and 5:

Item Part No. Qty. Description Torque Values
1 AE9887-5 4 Nut, Hex, Lock, 5/16-18 UNC 204 in.-lbs.
2 AE51412-5 4 Washer, Plain, 5/16 ID N/A
3 AE100104 4 Washer, Belleville, Safety Serrated N/A
4 AE100111 4 Bolt, Int. Wrenching, UNC 5/16-18x1.00 Long 70-80 in.-lbs.
5 AE51413-5 4 Washer, Internal Star, 5/16 ID N/A

You have too many lines in there for the carb. mounting.

It should be -

1 AE9887-5 4 Nut, Hex, Lock, 5/16-18 UNC 204 in.-lbs.
2 AE51412-5 4 Washer, Plain, 5/16 ID
5 AE51413-5 4 Washer, Internal Star, 5/16 ID

Some of the earlier Lycoming manuals specify a palnut as a locknut and no internal lock washer.

[flyenforfun]

So I also received back some word directly from Lycoming. They specify the parts as follows:
STD-35 Washer
STD-475 Internal Tooth Lock Washer
STD-1411 Nut

Now when I look up that nut it is just a plain nut, not a lock nut. Is the ECi part actually a lock nut? I don't completely trust those type of lock washers.

[jrs14855]

The star type lock washers work just fine as long as you don't reuse them.
Example: mounting the carb, for some reason you need to remove the carb, throw the lock washers away.