Customs Figuring out the Fuel connection

Hey all. Been looking for weeks for a solution to a fuel connection issue that I don't think exists. Many of my searches bring me here so I figured I'd jump in and ask.

The issue I am having is with an older Carter fuel filter. I'm switching my fuel line from rubber to all hard line (it transitions soon after the fuel pump). Anyways my current hard line is 5/16 then at the transition it's 3/8 rubber. My carb fuel inlet is a 5/8-20 (female) but the adapter I have turns that into a 5/8-18 inverted flare.

The carter threads are 3/8-24 (female) on both ends. I had planned to have a fuel cutoff petcock in the middle of all this but I'll be lucky if I can even get the filter to work. It seems in my search that 3/8-24 is more of a brake line fitting so yes, that adds to the cluster.

Anyways, any input from this board would be very appreciated.

 

I think the threads in your filter body are pipe thread, which means you have a lot of flexibility in adapting it your hard lines. Just need the correct fittings for pipe to inverted flare in the correct size.

Ray

 

Thank you Ray. I know that when I chase the threads a 3/8-24 is a perfect fit but my threading set shows that size under fine thread so it's very confusing. I've been to parts houses and have googled for at least two weeks now and I see many NPT threaded adapters but nothing that gets me from point A to B. What I did find at the last parts house was a 3/8-24 to 1/4 inverted flare. I'm to the point where I want to take the 3/8 NPT petcock that I have, bring it to a machine shop and see if they can lathe it down to the threads I need on each end.

 

I would bet a substantial amount of cash that your Carter threads are not 3/8-24, but 1/8 npt which is about .030 larger but very close in thread pitch. Think about it, how would a bolt size thread seal?

 

Yup, it's pipe thread, you can get adapters to IFF (flare) in 1/4, 5/16 or 3/8.

 

Ok, this helps a ton because this whole time I've been working under wrong assumptions. Last question I hope. If my fuel line is 5/16 will that connection be 5/16 inverted flare? Since my line need to make a turn forward I've found a 90 degree 1/8 NPT to 5/16 IFF but checking first.

 

Around here if you need fittings that are right go to the hydraulic repair guys. They have a big selection and actually have to make things that don't leak , unlike the parts house.

 

5/16 inverted flare to 1/8" pipe thread fitting is what I would expect to find on a filter like that...either straight, or 90 degree, or maybe 45 degree.

 

1/8 pipe thread is 27 threads per inch. $5 says that is wat the fiter is.

 

Ok guys, here's another stupid question but choffman brought up a point that I hadn't thought of. It seems that now that the general consensus is that it's 1/8 on the filter, I have one other area of concern. The inlet on my carb is 5/8-20 (m) and the flip side of that is 5/8-18 iff. The next connection from that point is 5/8-18 (m) to 1/4 npt which works out fine however, the two 5/8-18 connections are not NPT therefore would I not have an issue with leaks since that's not NPT nor am I running a flare nut into that connection?

 

I don't know offhand where to find the 5/16 flare fitting new...but the carburetor does take a special fitting, it is not pipe thread. here's the 3/8" fitting

http://www.summitracing.com/parts/edl-8090

probably need to find an old used one off a Carter AFB?

 

The 8090 is what the carb has now, that's the 5/8-20 to 5/8-18 iff that's currently mounted. I went to the quadrajetparts website and found the 5/8-18 male to 1/4 npt but I'm not sure I can use these two connections the way I had hoped.

5/8-18 iff to 5/18 male is the thing that's getting me confused.

 

probably not.

here you go...

http://www.ebay.com/itm/Rochester-C...let-Fitting-5-16-Inverted-Flare-/171012397297

 

I may have to rethink all this because this Rochester adapter is for if I were running a line direct to the inlet. I have a fuel filter and a petcock between all this. It seems that there's no real way to bridge the gap between 1/8 npt and 5/8-20 unless you forego the filter/petcock. The only inlets I can find are the ones that turn the inlet into iff, nothing that lets you adapt to npt.

 

Just run your filter ( not sure why you need a petcock on the fuel line) a bit away from the carb. Run a length of hard line from the carb to the filter, then filter to the fuel pump. I might have pic of how I did a 61 Olds set-up somewhere, it CAN look nice and neat.

 

If you can, I would like to see your setup.

 

This guy is right on the money. You are like a dog chasing it's tail, from what you've written.

 

Places like that do not exist here but I wish they did. People always say to go to a speedometer shop, brake shop or hydraulic repair. My town has no such places. We have mechanic shops and speedy oil change places. Maybe a transmission shop here or there. I've not seen a speciality repair shop in well over a decade. Sometimes I feel that these places stopped existing in the 80's.

 

How about some pics and a location, thanks, Rick

 

Absolutely, I'll get some pics tonight. My location is Birmingham, AL.

 

If not pipe thread it could be rubber o ring, does it have a relief around the outward I.d. For an o ring to seat in?....as far as fittings go do you have a "Parker" store near you?


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Hose Power USA

Hydraulic Equipment-Repairing

3950 Pinson Valley Pkwy, Birmingham, AL 35217

(205) 949-1671

These people should be near you. They should have some fittings.

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now you know why we usually just run a modern inline filter, connected with a short length of rubber hose...

but you shoudl be able to do it with the old filter, if you do like he suggested and run hard line from the pump to the filter, and from the filter to the carb.

if you have an old AFB like from the 60s, they often had a larger fitting, 7/8" threads, at the front of the carb instead of the side. It's easy to find an adapter from that to NPT.

 

http://www.bragusa.com

Also, these guys are on industrial in Birmingham, and they're listed as having a Parker store.

 

I have the same setup on my 265 ci with a WCFB I got my fittings at the Parker store.

 

Seems there should be a place there that helps the farmers. Those other guys looked it up for you from somewhere .

 

I'm going to ring up these two sources this week and see if I can visit the store. Do you guys typically bend your own fuel lines or do you bring them somewhere with a mocked up version using wire?

 

bend them myself.

 

I don't know why the others have had problems, but I've never had any with using Dorman, or other auto parts store IFF fittings. or pipe thread to IFF adapters. I do buy them in bulk now, from Discount Hydraulics, but they seem the same quality.

 

usually if you can't find the fitting at a real auto parts store (not one of the pep boys type chain stores), then you're probably doing it wrong.