How many of you replace your CIS fuel lines?

[Jameel]

I've got my CIS apart for cleaning and testing. A lifelong Porsche mechanic took a look at my lines and said to leave them alone. I'm talking here about the rubber supply and return lines on the CIS itself, not the hard lines from the FD, which are steel on my 1983 SC.

My lines are soft and pliable, not hard or cracking. I know they are 34 years old now, but doesn't condition have merit too? I'm not averse to spending the money, but I don't have a bank roll to just throw at this.

The question is, if you can visually and "feel" inspect the lines, and the surfaces look good, rubber still pliable, and they don't leak, is there a magic number of years where you would just replace them regardless if they looked perfect or not?

[T77911S]

leave them.
I would spend the money on replacing injector sleeves, Orings, the rubber boots on the runners, other vacuum lines and if you feel the need, rebuild the WUR and FD. also look at replacing injectors.
that would be my "blanket" CIS rebuild.
I did the reseal on my 77 when I got it along with a new WUR. no injectors or FD.

[mickey356]

Why not replace 34 year old hoses if you have unfettered access to them?
I mean I get that they seem ok but it seems silly to short cut it if you can swap them....unless of course you drop your engine fairly often and will have the same access in the near future.

[schoward]

Leave them. If you want to replace that wur to FD line, it's about $80 and can be done in 10 minutes even with engine in the car (need a $5 angled 10mm wrench for the tight clearance). But even that one I wouldn't mess with unless visually not right.

[fanaudical]

When I rebuilt my 2.7, I replaced every CIS line on the engine from fuel accumulator to return (in addition to replacing injector sleeves, o-rings, etc). I made the mistake of not replacing the lines through the tunnel or from the pump to the accumulator (but did replace the rubber lines near the tank and the fuel pump).

My lines were in bad shape and some had gotten "crinkly". I didn't replace the lines through the tunnel because they "seemed fine" - but now I just keep wondering if I should have done it....

[David]

You may be OK but I personally think the risk is too high. The area I've seen fail most often is in front of the tunnel behind the fuel tank. So if the lines there are soft and pliable you may be OK but remember fires can easily total a car.

[Jameel]

Thanks for the thoughts everyone. I am replacing my tunnel and front lines.

[911tracker85]

I just had Len Cummings build all new lines for my 78 SC/930 conversion project.

this will be a bare tub-up rebuild so not leaving any old stuff in place to be an issue or disaster down the road.

YMMV

[3rd_gear_Ted]

One of the tangible factors for a 3.6 conversion is to allow the modernization and refurbishment of the other stuff on a 35 year old car. The FIRE risks mitigated by completely replacing ALL the fuel lines and replacing the wire harness along with how that makes you feel is different for each of us.
(The above is an alternate explanation for being poor, paranoid and knowing ***** happens)

[Dodge Man]

Do not forget the tank to tunnel lines. I had to replace mine. I was able to Dremel cut the OEM sleeves to reuse fittings and just use compressed air sleeves on new pressure hose(suction line). Saved weeks of time from Germany and some $$$ too. Engine lines have pressure and have to be replaced if in doubt. A CAR-B-QUE is not the way you want to part with your 911.