If you can’t buy it....MAKE IT!!

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Righty Tighty

Righty Tighty

Blame it on the dog
FABO Gold Member
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If you can’t buy it, make it! Needed an adapter to go from 1/8-27NPT to 7/16-20 standard. Pretty much doesn’t exist, and my lathe is down, so I improvised.

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....and then break it upon the initial test fit.
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Unfortunately I went too far below the hex head and that weakened the part.

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Why do you need such an oddball fitting?
 
When I chased the threads on the block the first time I rebuilt it, I mistakenly used a 7/16 standard tap for the oil pressure sender, instead of 1/8-27 pipe thread. So as a result I took the taper out.
 
Straight thread, you'd best be considering a copper crush washer or an oring to seal it... after smoothing the block area.
 
Better get a oil drain plug gasket under there. Teflon on the threads may not be enough. IMHO. LOL......2 minutes too late!
 
Yup. With no taper, see post #4. He's dead right.
 
Y’all ain’t gonna like this, but I ran it for a while with a 1/8-27 adapter, permatex thread sealant, and JB Weld. No leaks. However, for obvious reasons I wasn’t comfortable with that, so now I have an opportunity to do it a little better and I’m hoping to do that.
 
Can you tap the hole for 1/4NPT or is the casting too thin?
 
CFD244 said:
Good call 67dart273, but it looks like the engine is still in the car so I'd be super worried about getting filings in the oil gallery. IMHO.
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Put a magnet next to the bit while your drilling. After its drilled/tapped you can prime the oil pump and let the oil pressure flush out the hole.
If you want I can make you up a fitting on my lathe. I would use a piece of hex stock. No charge.
 
CFD244 said:
Good call 67dart273, but it looks like the engine is still in the car so I'd be super worried about getting filings in the oil gallery. IMHO.
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Considering he already ran the wrong tap through the hole I’m inclined to believe there’s already bits of foreign metal floating around in there.
 
Just idle the motor while you tap it. I bet you won't get any chips in the hole.

Look into a British straight pipe thread. Might need less material removal than jumping to the next npt.
 
Jesus Chrysler said:
Considering he already ran the wrong tap through the hole I’m inclined to believe there’s already bits of foreign metal floating around in there.
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It was tapped when it was a bare block, then cleaned. I didn’t realize the mistake until the engine was assembled.
 
I don't think there's enough meat on the back side of that hole to go up to 1/4" NPT, though that was a great idea. I think the direction you're going is probably the best "at this point". Just remember to seal your new fitting "somehow".
 
I agree, although tapping to 1/4 NPT was certainly considered. I also am not comfortable doing anything to the threads while the engine is assembled since there’s no way to catch the chips. Yes, I could “flush” them out, but there’d be no way of being 100% certain I got all of them.


MoparMike1974 said:
If you want I can make you up a fitting on my lathe. I would use a piece of hex stock. No charge.
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That’s a terrific offer! I might take you up on that. Sending a pm.
 
And Rusty I was thinking of using Loctite bearing retainer. Have you ever used that for high temp applications?
 
It was recommended to me as a possible solution, I think because it fills gaps larger than regular Loctite.
 
Yup stud and bearing mount. I wouldnt think twice about using it in this case.
 
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