Fitting size

captndave737

Well-Known Member
Joined
Feb 14, 2006
What is the thread size for the oil feed line in the top of the turbo? I lost mine somewhere. I think it's a 1/8" NPT but I want to find out for sure and not screw it up.
 
Almost all journal bearing, 3-bolt Buick turbos, have female 1/8" NPT threads. Some of the larger, "Big Boy" turbos use 3/8" NPT. The stock setup uses a brass 90* 1/8" NPT male to reverse tapered thread adapter for the stock hard feed line.
The exact reverse tapered thread size escapes me ATM. If you are using an aftermarket oil filtration kit, most of them utilize a -4an braided feed line, so any -4an male to 1/8" NPT male adapter will work. Don't forget the PTFE pipe sealant paste or tape on the 1/8" NPT threads only.

-Patrick-
 
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