Team Chevelle banner
  • Hey everyone! Enter your ride HERE to be a part September's Ride of the Month Challenge!
61 - 80 of 101 Posts

·
Gold Founding Member
Joined
·
10,983 Posts
Unlikely to work in this particular case.

You're suggesting that he cram male straight threads, intended to be sealed with an O-ring (O-Ring Boss style, ORB) against a tapered O-ring pocket machined into the casting, into female tapered pipe thread with no O-ring pocket.

Incompatible threads, incompatible sealing methods.

At least, I expect the OP has pipe thread at the inlet, and both outlets.
 
  • Like
Reactions: 71malibuu

·
Registered
Joined
·
494 Posts
Looks like a reduce coupling to go from the -6 to the -8 looks like hose. On a side note I’m surprised that more people don’t use 1/2 in or 5/8 aluminum soft roll for fuel line.
 

·
Registered
1969 El Camino SS396
Joined
·
987 Posts
I've used regular white teflon tape for 40 years or more. Make sure you wrap it the right direction and put 3-4 wraps on the fitting. Also, the tape should only be on the threads, not across the open end of the fitting. No leaks with a carb or EFI.
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #65 ·
Well the Gasoila sealant seems to have done the trick, I'll post a pic of the fitting too
Light Product Blue Bicycle fork Automotive tire
Finger Thumb Nail Gas Automotive tire
 

·
Gold Founding Member
Joined
·
10,983 Posts
Well the Gasoila sealant seems to have done the trick, I'll post a pic of the fitting too View attachment 721132 View attachment 721133
The inlet fitting appears to be a tapered pipe thread fitting, screwed into a tapered pipe-thread hole. There's male threads visible, because male pipe thread should never screw into the hole so deep that the threads disappear.

The outlet fitting in your hand appears to be straight thread, screwed into what is almost certainly another tapered pipe-thread hole. Incompatible threads, possibility of damage to the female threads.

Good luck.
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #68 ·
So I need a tapered AN fitting? I mean tapered on the threaded side not the AN side, same type fitting on the other hole
 

·
Gold Founding Member
Joined
·
10,983 Posts
So I need a tapered AN fitting? I mean tapered on the threaded side not the AN side, same type fitting on the other hole
Almost certainly.

I'd expect the inlet and the outlet holes in the casting to be threaded the same. It's not impossible that they aren't, but I think it's extremely unlikely.
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #70 ·
I have a couple pics but I don't think it's possible to tell from the pics? it's a fairly new Summit reg., I'll give them a call to see what they say and order what's needed, don't want the car going Up In Smoke...or Flames
Automotive tire Bicycle part Motor vehicle Engineering Gas
Camera lens Camera accessory Digital camera Film camera Carbon
Camera accessory Cameras & optics Gas Automotive tire Auto part
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #71 ·
I just noticed the small threaded hole to the R of where the outlet fitting goes, should that be capped? never even noticed it before
 

·
Registered
Joined
·
3,095 Posts
Do you have the part number? I just did a quick look at Summit’s site at all the Summit brand regulators of that style, and all of them list a 3/8 NPT fitting for both inlet and outlet.

I have a couple pics but I don't think it's possible to tell from the pics? it's a fairly new Summit reg., I'll give them a call to see what they say and order what's needed, don't want the car going Up In Smoke...or Flames View attachment 721240 View attachment 721241 View attachment 721242
 

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #73 ·
It would be over with the car in a receipt folder, I'll take a look for it tomorrow, I have 2 other regs there that I'll take a look at, can you tell with a caliper in the threads?
 

·
Registered
Joined
·
3,095 Posts
If you measure the threads, an NPT thread will be tapered and the female side will be larger at the opening and smaller on the inside.

It would be over with the car in a receipt folder, I'll take a look for it tomorrow, I have 2 other regs there that I'll take a look at, can you tell with a caliper in the threads?
 
  • Like
Reactions: shovelrick

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #76 ·
Well I guess I'll be calling the local speed shop Gear Head Perf. mon. to see if they have the correct fittings in stock, no wonder it kept leaking before, I'm not waiting for the Gasoila sealant to leak then say it DID NOT seal good
 

·
Registered
1965 El camino. Originally roman red with a 283 and rear air ride suspension
Joined
·
18 Posts

·
Premium Member
1968 Malibu sport coupe, 489 ci. 590 hp 600 tq, RV T-400 Freakshow 3200 stall, 3.73 12 bolt posi
Joined
·
9,134 Posts
Discussion Starter · #78 ·
Yellow tape does say gasoline, I might have the wrong fitting in my case
 

·
Gold Founding Member
Joined
·
10,983 Posts
I just noticed the small threaded hole to the R of where the outlet fitting goes, should that be capped? never even noticed it before
First Guess: A vent that allows the diaphragm to move without restriction. Needs to be open. CHECK YOUR PAPERWORK for confirmation.
Didn’t know this
The taper rate for all NPT threads is 1 inch of diameter in 16 inches of length
An experienced eye can see the taper in tapered pipe thread. Newbies generally can't...at first.

Not all pipe thread is tapered, but I can't remember the last time I worked with non-tapered pipe thread--it exists, but it's not common. So again, you've gotta use male tapered pipe thread with female tapered pipe thread, male straight pipe thread with female straight pipe thread, and then there's metric pipe thread, and British pipe thread, and fourteen other variations. Enough to make a guy crazy.
 

·
Gold Founding Member
Joined
·
10,983 Posts
I just did a quick look at Summit’s site at all the Summit brand regulators of that style, and all of them list a 3/8 NPT fitting for both inlet and outlet.
That is what I'd expect. HOWEVER, I can't be certain by looking at his photos.

I am moderately sure that the rough casting has a taper leading into the hole--for ease of machining the threads on fast-paced automated thread-cutting equipment. I think the female threads are tapered, but that could just be the angle the photo is taken at.

MAYBE that taper leading into the hole is for an O-ring seal. I don't really think so, and it would mean that the threads have to be straight, not tapered. And, it might be that what I'm seeing is damage from using the wrong fitting.

Best to find out directly from Summit, based on his actual part number.
 
61 - 80 of 101 Posts
Top