Oil Drain Tube Thread Size

dmaxweb

Well-known member
The hole in the rear bearing cap is 1/8-27 NPT. The tubes sold by the vendors are 3/8-32 UNF..
Should they be the same?
 
Ford used two different sizes of these tubes. The one the vendors have is the later version meant to cure a problem with clogging, etc. You may have to search for a used one or drill and tap the cap for the larger tube.
 
Berts has both sizes of drain tubes...

https://modelastore.com/index.php?route=product/search&search=drain tube&category_id=0

NOTE: Most main caps I see have a SMALL tack weld so it will not fall off.

You have to be sure when gas welding or brazing not to melt the babbit in the main cap.

Maybe an engine builder will comment on whether Mig or Tig is better.

I checked with Steve and the 3/8" tube has 3/8-32 thread not pipe thread.

Ora at Schwalms recommended red loctite.
 
The hole in the rear bearing cap is 1/8-27 NPT. The tubes sold by the vendors are 3/8-32 UNF..
Should they be the same?

I checked with Steve and the 3/8" tube has 3/8-32 thread not pipe thread.

Ora at Schwalms recommended red loctite.


Steve is correct. Just for clarity, the early A-6325-AR Cap's hole was threaded 5/16-32.


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