The threads are NPT and they're in the turbo center section so heat is a bit of an issue. Idahno what happen to the picture the first time around. Thanks, Kurt
Is it a new fitting or an old one re-used? I ask because I am running into the same problems with new parts store fittings. Some are tight, and some bottom out and never get tight....cheap crap, that is inconsistant from part to part...
it doesn't look like you have enuff material to go one size up , and i doubt JB Weld would stand the heat. Helicoils are available in NPT...i'd look into that
Are you sure it has tapered threads? Like for 1/4" NPT there's a tapered version which you drill with a 7/16" drill, and then tap. But there's also a straight version that uses a 29/64" drill before tapping. I think the straight version uses an o-ring or copper washer maybe. Maybe you're supposed to be using a straight fitting with a copper washer? That would actually make sense having a copper washer make the seal on something like that because most sealants probably can't take the heat.
I'm pretty sure it's NPT because I believe the brass fitting is a stock part, and it's NPT. The silver-color fitting is just an extension. I'll take it apart and eyeball the threads and try a new fitting, too. Thanks, Kurt
Rustybolts hit the nail on the head, even if it is a taper pipe if the hex adaptor that you are using goes all the way in put a copper crush ring under it and tighten it up. Will probably work great. Rex
Try different fittings if the threads in the hold appear ok. They are not all identical. I had a 1/4" npt hole with a plug in it, that leaked. I tried a coulple plugs I had laying around and they didn't fit tightly in the hole. I bought 6 new plugs and 2 of the 6 were large enough to fit correctly.
Be careful, the straight pipe threads are the same pitch and the tapered fittings screw right in. The copper crush washer (like on a banjo fitting) sounds like the best fix and would take the heat.
It's hard to tell in the picture, but where the fitting screws into the housing, is the housing machined nice and flat on the face of that boss? If it is, a copper washer would probably do the trick, but it may have originally been a straight thread fitting. If it's faced off and there are concentric rings machined into the surface, then it's even more likely it originally used a copper washer (or aluminum washer, nylon washer, etc.). At work we have a lot of large pumps with oil filtration systems attached to them. It is kind of typical for oil lines coming out of the base of some of the newer cast iron pumps to have straight threads and make the seal using o-rings, nylon seals, copper crush rings, aluminum crush rings, etc. The original fitting could also have been a banjo type fitting using a copper or aluminum crush washer.
use a little pipe dope and wrap the threads with cotton string. theflon tape SUCKS in almost everything. wrap string on clockwise looking at the front of the fitting.that will tightenthe string as the fitting is screwed in. string=benfodden for our german friends. jim
I believe it's 1/8" NPT. I cleaned a bunch of Teflon tape bits out of the female threads and tightened it up with a lot of fresh tape and it's holding so far. The hardware store didn't have a crush washer, I'll try one when I get one. Thanks, Kurt
thats correct. it maybe a BSP or British Straight Pipe. it will thread up just like any other tapered thread but youll never get it to tighten out until you bottom it on the shoulder of your fitting. one cheap trick to try if you cant get it to stop leaking is to peen it on the top of the hole. take a ball pein hammer and set it in the hole ball end down on the hole. then with another hammer wrap the face of the ball pein a couple of times not a whole lot mind you. what youre doing is distorting the top threads of the hole so that they will fit tight on the threads. it makes them somewhat harder to start, but not impossible to put a fitting in. just an idea anyways.
what kind of turbo is it? if it's a garrett GT series then you will find that it is probably 7/16" - 24 thread,, close to an npt thread, but it isn't. It's an odd pipe thread and fairly specific to Garrett turbos.
The Jalopy Journal
