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Fuel Rail Woes - Help!
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TOPIC: Fuel Rail Woes - Help!

Fuel Rail Woes - Help! 11 years, 4 months ago #14870

Dave Hauk and I maintain 3 late 944 cars race cars and we are having unbelievable problems with leaking fuel rails. It seems that no sooner than we put one on it leaks. We currently have 7 leaking rails piled up! We have tried silver soldering, brazing, TIG welding and a combination of TIG and MIG and have still not achieved a reliable repair. The only source of refurbished ones I have found is through Paragon and costs $231. We'll spend that if we have to but we would really be interested in any alternatives you may have found, be it repair or replacement, that will let us make use of all these rails we have.
Steve Marlow
944 Spec #47x
NASA Certified Instructor
NASA AZ Licensing Director
2012 AZ Region 944 Spec Champion

Re: Fuel Rail Woes - Help! 11 years, 4 months ago #14871

  • Big Dog
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Bummer. I have no answers for you, Dave and Steve. However, if I may, I would like to expand this thread to include what causes our rails to crack and leak.

We had a 924 suffer an engine fire after the final race of the season from a cracked rail. It was the early fitment of the fuel lines (coming into the engine compartment at the drivers side) but it was a late (lines going into the front and rear) fuel rail, as I recall.

This is an all too common problem and, in my mind, is the most dangerous failure that our cars have.
1. Where are they cracking and are most at the same location?
2. Is there another rail (VW, etc.) that might fit?
3. Is there a shop that KNOWS how to fix them so they do not crack?

In order to start some discussion from Erick, Tim and others with much more experience that I, is there some common issue that contributes to the cracking? Because the rail is at the top of the engine, does it suffer from more motion and vibration due to its distance from the motor mounts? Do early have more issues than late? Does the location of the hard lines have anything to do with the problem? Do the fuel lines add pressure to the rail mounting points by being pushed down by the hood (especially if they are too long)?

What other questions/issues are there to consider and are there solutions to try such as adding more material at the mounting points to spread the load over a larger surface or mounting/routing the fuel lines some other way, supporting the fuel lines somehow, etc, etc.

Great minds (those of others ) can find solutions so get on it gentlemen!
Jim Foxx

Re: Fuel Rail Woes - Help! 11 years, 4 months ago #14872

  • dmdirks
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Check your balance shaft timing. Incorrectly timed balance shafts is the most common cause of failure of fuel rails and oil suction tubes.
David Dirks
www.944MotorWerks.com
2010 944-Spec National Champion
Rocky Mountain Region

Re: Fuel Rail Woes - Help! 11 years, 4 months ago #14873

First as David says Check Balance shaft timing. Also we have in the race shop a few extra good rails . Greg 18582796404
TYLER PALMER 2010 NATIONAL CHAMPIONSHIP RUNNER UP 2011 NATIONAL 944 SPEC CHAMPION 2011 SO CAL REGIONAL CHAMPION 2012 NATIONAL 944 SPEC CHAMPION 2012 SO CAL REGIONAL CHAMPION 2013 NATIONAL 944 SPEC CHAMPION

Re: Fuel Rail Woes - Help! 11 years, 4 months ago #14876

I went through 5 fuel rails in one season before my engine builder realized that he was mis-timing the balance shafts (he had the markings confused, and was doing it exactly wrong every time). After fixing that, I've never had another failure in 100's of hours of racing.

I agree with the others above. If you've been through that many, there is an underlying problem - probably balance shafts, maybe motor mounts.
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re: Fuel Rail Woes - Help! 11 years, 4 months ago #14878

Thanks for the info on the balance shafts everyone, we will definitely make that a point of emphasis going forward. We are still be interested in suggestions on methods of repair and/or refurbishing services that would allow us to do something with all of the leaking rails that we have sitting in the garage.
Steve Marlow
944 Spec #47x
NASA Certified Instructor
NASA AZ Licensing Director
2012 AZ Region 944 Spec Champion
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