Hi All,
I'm new to the forum, but not to F-Bodies. I am in the final stretch of a build of a 2002 Z28, with a freshly stroked forged LS6 block at 11.0:1, Patriot Stage 2 heads, a Lunati 60511 cam, hydraulic roller lifters, etc...

As part of the build, I chose a Performance Products Typhoon intake (96mm) and aluminum high flow fuel rail on 60lb Siemens fuel injectors. Today, my roommate and I filled all the fluids, buttoned up all the ends and prepared to start... ONLY TO HAVE FUEL SPRAY FROM THE TOPS OF THE INJECTORS UPON THE KEY TURN!

Fortunately my roommate was on leak detection duty, but he didn't have to look close, it was pouring out of the tops of the injectors! Of course we suspected o-rings, so we took the rails off and inspected. These brand new Siemens injectors had rings that freely spun on both ends So we headed down to O'Reilly's with injectors and o-rings in hand, picked up a set of 8 new pairs of o-rings that fit significantly more snugly and headed back for install.

We replaced all the o-rings and set them in the fuel rails and each had a very satisfying seat. We were able to rotate the injectors by hand in the fuel rail, but with more effort than the original ring set. We set everything back in the intake and tightened the rail supports, went to pressurize and fuel still sprayed, but only from a couple on one end (I think driver's) near the front. That's an improvement, but something about this job makes me feel like I'd like no injectors to leak

A little more about the fuel system, I installed a 255lph pump in the original fuel canister with the factory regulator and a new fuel filter. The fuel rails are the ones that come with the Typhoon intake with a front braided line crossover. No leaks at any of the fittings, just from the fuel tops.

So we quit for the night, hoping someone out here might save us from ourselves. Has anyone here had issues with these fuel rails like this? What else should we be considering? I'd really like to hear this fresh new 383 LS6, thanks in advance for any information you can provide!

Oh, and I apologize for the REALLY long post...

 

BTW, here are some pictures from the progress... The Altezzas are long gone for smoked factory taillights

 

Sounds like the rails were made wrong.

I had the same issue a couple years ago, brand new rails that leaked.
I called the place I got them, they had me take some measurements and verified that the holes were 1mm to large.

They sent me new ones free of charge and did not even ask for the old ones back.

 

You know, I haven't been able to sleep because I was thinking in the back of my mind this could be the case... thanks for the quick response! Due to time constraints, I'm ordering a new fuel rail with expedited shipping right now with the hopes that I'll get it sometime next week early. If I can confirm the old rails are bad, I'll see about getting a new set from Performance Products. Fortunately I've got a B4C that could use a nice upgrade

In the mean time, I noticed a lot of kits advertise that they come with viton o-rings. Are these the o-rings that I'm thinking of, rings for the fuel injectors specifically for fitting them to these rails? Or are they o rings for the fittings? Because I don't remember them coming with the Performance Products rails...

 

Well, got the injector issue under control, LS2 o-rings on top and some beefy LS1 rings on the bottom. New problem, the fittings are blowing out on the rail after we prime the pump twice before start up! We were using the recommended permatex thread sealant, but we did all the fittings twice and each time the second priming of the pump started leaks! We've quit for now, ordered a fuel pressure gauge, the adapting fitting and some form-a-gasket that indicates it's resistant to fuel. Someday, someone will hear this motor crank...

 

Define blowing out...

Common teflon tape is fuel safe and will seal the threads fine. Did you apply it properly? Torque the fittings properly? Overtorque? Alum threads are easy to strip out

 

Tomorrow is Monday, call the manufacturer, with them leaking from so many different places something isnt right about them.

 

By blowing out, I mean leaks develop at the fittings' threads and small streams of fuel are spraying. So the fittings aren't literally leaving the rails, but leaks are developing around the 360 degrees of each fitting. It should be mentioned that it's not immediately all the fittings, on the last attempt, the last one on the rail developed the first leak, then the fittings on the front of the rails. NPT fittings are leaking on that end, AN fitting ends are not. Now I'm ashamed to say I didn't get a torque spec in the instructions, though I did find it odd that they said "tighten, but don't overtighten", sure seems like a torque should be listed for that kind of warning. Is there in fact a torque spec for these fittings into the aluminum rails? If so, what is it? The fittings are 3/8NPT and 6AN...

I've been told to fear teflon tape on the ends, but in my darkest hours, I've thought about trying it. Instead, I picked up some Permatex Form-a-Gasket yesterday, formula 2 (not 3, but it appears the properties are the same, just 3 says aviation and 2 is in the automotive sealant section.) It says it's resistant to oil and fuel, good from -65DGF to 400DGF and remains non-hardening yet requires a set time. That sounds like my best option. I've also got a fuel pressure gauge and adapter fitting on 2 day shipping from Jegs for troubleshooting, hoping to try again this week about Wednesday.

I'll be calling the manufacturer on these rails though. I'm hoping the Scorpion rails I ordered arrive soon so I can try all this on those rails.

 

"I chose a Performance Products".... Try a search. seems others have had this "stuff" leak.
AIRC, some had to weld the fittings in to get them to stop leaking...
Exactly Y we use ONLY rails w/ o'ring fittings.

There are different "NPT" threads.
Npt for plumbers.
Nptf for fuel.
I doubt Ho Chi Min knows the difference....

 

Yes, there are NPT ant NPS threads that both fit but one wont seal the other perfectly

Use common teflon tape, remember to wrap it in the correct direction. If it still leaks, you may need to seek other venues

Teflon tape is the devil to people who dont know how to use it

 

Ouch. Well, thanks for the information here, I certainly won't be dealing with that again.

I picked up some Permatex Aviation Form-a-Gasket for my next attempt, but if that fails, would Teflon tape be an improvement as far as pressure handling?

 

Update, I didn't try the professional products fuel rail with form-a-gasket, but I did try the scorpion fuel rail with AN fittings and Viton o-rings... no problems! So if anyone wanted to know, the issue was the NPT fittings not sealing in my application. Thanks for all of you who threw in information!