I got the vortech oil return line system from someone on ebay because I'm putting together a supercharger kit. I am really confused about the nut fitting that actually goes onto the oil pan. Isn't it supposed to be 3/8"? Did this guy send the wrong part? Please look at the pictures and you'll see what I'm saying. I have a 3/8" drill bit in the pictures for reference.

 

what I'm trying to say is the diameter of the part that goes into the oil pan is much larger than 3/8"

 

dont use a drill on it cause youll get lots of metal shavings inside the pan. It is supposed to be a 3/8NPT fitting. The best way is to use a hammer and punch to make the hole. Well really the best way is to remove it and get the fitting welded, but if you cant remove the pan then thats what you have to do. Just be very careful when punching that hole. Work really slowly because if its just a tiny bit too big youll have leaks forever.

Oh and to answer your question that measurement is 3/8ths ID (inside diameter). The drill bit you have is measured as 3/8ths OD (outside diameter). If you needed to drill the hole you dont want to try and drill it the same exact size as the fitting anyways. You want to drill it slightly smaller so the threads will cut in the metal and seal it. Use a magnetic pickup tool after the hole is made to stick in there and pick up any shavings inside the pan. They can be found at the parts store for like one or two dollars...

 

You are the first one who is actually starting to help me. Thanks. I knew the hole has to be punched and I've gone through that section of the vortech manual several times already. I have a 3/8" NPT tap and it is just way too small there is no way it will fit inside of the 9/16" punched hole (Diameter of the hole punched into the pan according to vortech). If you think of it this way, the 3/8" tap is equal to 6/16". How can a 6/16" tap possibly thread into a (larger) 9/16" hole? Is that pictured NPT fitting I have wrong?

 

Go over my install here.

http://members.tccoa.com/392bird/sup...gerinstall.htm

That should answer all your questions.

 

Its a 3/8 pipe thread which is larger then a 3/8 drill bit!!!

 

There's nothing wrong with drilling the pan; i've done it quite a few times on some of my kits, but you do have to have the pan off to clean out the metal shavings & of course using silicone to help seal is a good idea.

I would recommend welding it though.

 

Okay I think im good thanks for all your help. I have a tap that is literally the exact diameter of a 3/8" drill bit and it says '3/8 NPT' on it. That is where all the confusion was probably coming from. Thanks again

 

btw nice car man.

 

Keep in mind it's a good idea to use a nut on the other side of that fitting after it's threaded in; just threading into the pan doesn't provide a great hold.