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-   -   -6 AN fuel rail bungs (https://www.rx7club.com/race-car-tech-103/6-fuel-rail-bungs-833696/)

SCCAITS 04-17-09 12:29 PM

-6 AN fuel rail bungs
 
During my complete ground up rebuild I am plumbing the car in all -6AN braided hose. The rear was done before from the cell to hard lines, I'm addressing the front during the rebuild.

I'll be running braided hose under the car and the inlet to a CM canister 1 micron fuel filter, out a Y block with parallel lines to each rail and returning to an Aeromotive regulator before going back to the cell.

I have cut the fuel rails, S5 NA streetport motor, and have a question on the bungs.

Do you see an issue with TIG welding 7/16" washers on the end of each rail and then TIG welding the steel -6AN bungs to the washers? It's not a "smooth flow" so to speak as the washer will create a wall, but shouldn't be an issue, right?

Let's not change my setup too much, I have alreay bought all the parts :rolleyes:


http://img301.imageshack.us/img301/2...ct0159o.th.jpg

http://img301.imageshack.us/img301/3...ct0160d.th.jpg

http://img301.imageshack.us/img301/8549/pict0163.th.jpg

moremazda 04-17-09 08:46 PM

That looks like a pretty good way to take advantage of those S5 rails.

TrentO 04-19-09 09:11 AM

Funny, my S5 rails were almost a perfect fit to the AN-6 steel bungs. I Mig welded them on, leak tested, repaired a small leak and they've been fine for a few years at 400 rwhp. I would have TIG welded them but my Mig skills were much better at that point. With the amount of aluminum welding I've done lately with the TIG I'd probably try it this time. Given what I've seen in some aftermarket rails I really wouldn't be worried about the flat step. Weld the bungs to the washers then the washer to the rails as it should be easier to get to the bungs before the washers are attached to the rails.

-Trent

SCCAITS 04-21-09 12:03 AM


Originally Posted by TrentO (Post 9139847)
leak tested

Any easy way to do this? The TIG welding I had done by some guy and it looks decent, but I don't want to find out after I put the motor in there is a pin hole.

The only thing I could think of was bolt them up and hook up the fuel lines...is that my only option?

Marek 04-23-09 08:02 PM

Plug the ports and hook it up to an air compressor. Or just make sure you run the fuel pump for a while to test for leaks before you put everything together.

TrentO 04-24-09 09:11 AM

leak testing
 
I took some AN-6 hose, put a fitting on one end and jammed a air compressor fitting in the other end. pushed some rubber plugs I had laying around in the fuel injector holes, taped them in there with duct tape. I put another chunk of hose with a fitting on one end and a bolt jammed in and clamped in the other. Using an in-line pressure regulator I pulled the rail up to 40 psi and put soapy water over the whole rail. I had a small leak and it bubbled up quite quick. A little cleaning, some welding and re-test and no leaks. Be cautious with this approach as 40 psi doesn't sound like much, but it will shoot a little rubber plug pretty far.

-Trent


Originally Posted by SCCAITS (Post 9144531)
Any easy way to do this? The TIG welding I had done by some guy and it looks decent, but I don't want to find out after I put the motor in there is a pin hole.

The only thing I could think of was bolt them up and hook up the fuel lines...is that my only option?


SCCAITS 04-24-09 11:40 AM

Thanks guys, I'll give that a try.

wackaloo13 04-27-09 09:41 PM

i converted my s5 rails with out a problem, i just chopped off the ends and brazed on the new ones after cleanign things up

SCCAITS 05-03-09 08:05 AM

This has turned into a nightmare project. I am having a guy with a welding degree TIG the bungs as I only know how to MIG. We have spent at least 6 hours over multiple days and evenings so far on the fuel rails. Finally got one done and to hold, the other one is so jacked up that we decided to scrap it and start over. I've got to get another donor rail first.

We pressure tested at 70 PSI and used some leak detection spray (thicker than soapy water and better). Used the air compressor method with a cap on one end and hose on the other. The injector ports were plugged with some rubber caps and held in with a bench vise.

Trying to get leak proof at 70 PSI is proving difficult.

Gene 05-03-09 10:10 AM

Just get your hands on some S4 rails, you can screw AN fittings straight into them and you're done. Here's Ted's article on the matter with pictures and part sizes included:

http://fc3spro.com/TECH/MODS/FUEL/fpr.htm

SCCAITS 05-03-09 10:35 AM


Originally Posted by Gene (Post 9177510)
Just get your hands on some S4 rails, you can screw AN fittings straight into them and you're done. Here's Ted's article on the matter with pictures and part sizes included:

http://fc3spro.com/TECH/MODS/FUEL/fpr.htm

True if I had an S4, but I am almost positive S4 rails won't fit on an S5. The primary rail is done already. I just bought another S5 secondary on eBay this AM. I have (2) S4 secondary rails and will double check but am almost sure they don't line up with the S5. I have read that the primary won't fit either.

I'd much rather screw on fittings for both rails if it could work.


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