Replacing Engine Fuel Lines – ’88 911

[dkirk]

As far as I knew, all the engine bay fuel lines on my 911 were original equipment. With the danger of 30+ year-old rubber lines leaking and causing an engine fire, I thought it prudent to upgrade. One of our forum contributors, Paul Mason, offers a kit consisting of all necessary fuel lines, made of aircraft quality components. Commonly known as Aeroquip lines (brand name), these consist of a Teflon inner tube surrounded by a stainless-steel braided jacket. Over this, Paul fits a black shrink tube for additional protection. The ends are all black-anodized AN-6 threaded fittings with spherical seating surfaces.



Four adaptors are included in the kit, necessary to adapt Metric to English threads where necessary. The complete kit along with written instructions, appears as follows:



The cost was $400 and well-worth the price, especially when comparing to the OEM cost of replacement lines from Porsche which still utilize the low-tech rubber line material.

Removal and installation of fuel lines is not a project for the faint-hearted – the combination of tight quarters, working blind or in a mirror, and the posture one assumes while doing this job (kneeling and bent over the engine) makes for a time-consuming and somewhat unpleasant ordeal. I totaled close to 30 hours for the job, but 2 hours were spent rebuilding, cleaning, and lubricating the rear blower motor while it was removed. Had the engine been out of the car, this job would have only taken probably 3 – 4 hours at most. Doing it again, I’m sure I could knock off 10 hours as one learns tricks that speed up the process.

The most time-intensive part was removing the metal, 90 degree-bend fuel line that runs over the top of the engine. I found that using a hand-held grinder with cut-off wheel (Dremel Moto-Tool) and cutting off the “T” fitting, allowed for easy extraction of this tube. The grinder again proved its worth in removing the OEM metal crimp that holds the rubber tube to the metal return line. The location of the fuel regulator and damper make for use of a mirror mandatory when positioning wrenches on fuel fittings and finding the fasteners that secure the mounting brackets.

Reassembly with the new parts went much faster and was more enjoyable. Happy to report that I didn’t forget to tighten any fittings, thus no leaks on the initial test. A new fuel filter was also installed at this time, as recommended in the instructions.

Now that the bruises and cuts on my arms and hands have healed and muscle soreness has subsided, I’m happy that this upgrade has been completed. The only downside is that you can’t see the majority of these beautiful parts – only line really visible is the outlet from the fuel filter:



There is a lot of value in this very nicely prepared kit and I highly recommend it for the peace of mind that it offers in preventing engine fires. Paul may be contacted at mason_paul@yahoo.com .

[Discseven]

Nice load Dave. Been thinking as you have concerning aged fuel lines.

"Unpleasant ordeal"... that's funny (from the armchair I'm occupying at the moment. Doing this type of hunched-over engine work... 1 hour is unpleasant. That said, am with you on bypassing an engine BBQ being of supreme value.)

Would appreciate you saying exactly where Paul's kit begins and ends in the fuel system.

.

[Bert87]

Where is the tiny j hose that goes on the fuel pressure regulator?

[Mason_paul]

Hi everyone! Dave, thanks so much for the write up, it’s much appreciated.

The J-hose under the regulator is included. In fact, this kit simply replaces every rubber fuel line in your engine compartment.

Since Dave bought his I’ve upgraded the line between the regulator and the damper; it is now all metric fittings with no adapters necessary. Increases clearance in a very tight invisible space, while also eliminating two more joints.

I also have kits for SC’s, 964s, most of the middies, tunnel lines for SC’s and 3.2’s (they’re identical), and engine flex lines for SC’s / middies.

Paul

[dkirk]

Karl - Paul's kit replaces all the fuel lines in the engine compartment. Starts with the fuel outlet from the filter and ends at the return line from regulator back to the metal fuel line that returns fuel to the tank.

Bert87 - I forgot to include the "J" regulator hose in the group shot. Here is the hose in question attached to the regulator:



While the hose may appear kinked, it is not as the metal outer jacket prevents it from collapsing.

[patkeefe]

Glad to see someone else is fabricating lines for the air-cooleds. I had mine done in the past by Len Cummings, who has since retired, I believe. Mine were all mostly custom, except for the tunnel lines. That looks like nice work, Paul.

[Mason_paul]

Thanks Patrick! I like seeing these cars on the road

[ramonesfreak]

Paul, I’ll be ordering a kit from you this winter for my 1983 SC. Feel free to PM me your contact info

Nice thread. I hate those tough positions this engine requires. My back can’t take it anymore but this is a job I’ll be doing over the winter and this kit will inspire me to do it finally

[Mason_paul]

PM sent! It’s always the right time to prevent an engine fire

Thanks!

[Ok here we go]

Great looking kit! I've been contemplating the fuel line job lately but have yet to pull the trigger. Have you considered including in the kit the piece of line that runs from the tank to the fuel pump?

[Mason_paul]

Thanks!

Yes, with the tunnel kits I include a short length of hose for that little bit.

Paul

[Peter Zimmermann]

Interesting write-up by the OP. However, I did not read that he removed the intake manifold, which my shop found necessary to make the job a far more pleasant task. BTW I; when the manifold is removed worn manifold gaskets can be replaced, which my shop discovered can change the CO% by as much as 1%! BTW II; it's also a good time to replace the aging cylinder head temp sensor.

[dkirk]

Peter - You're correct, I didn't remove the intake manifolds. Most time spent on an individual OEM component was the metal fuel line that is placed atop the cooling air shroud and beneath the intake system. This has to be cut to be removed and I found that the hand grinder with cut-off wheel makes quick work of this. As shown in the photo, I first cut the rubber lines that feed the fuel rails then cut the metal line right at the "T", which is easily accessible. After removing the fastener at the regulator end, the line is easily withdrawn by moving it towards the firewall and rotating it as you go. Hate to admit it, but I wasted lots of time trying to remove this without cutting it up.

I did a top-end overhaul on my engine in 2011 so really didn't need to replace anything other than fuel lines. Wish I had done the line replacement when engine was out of the car - would have been a cake-walk.

[plasgar]

Dave- Thanks for this writeup, I have the kit and want to know what torque settings you used for the new fittings? After having this on for a year do you have any further recommendations for anyone getting ready to start the install?

Gary

[yelcab1]

Hint: Remove the intake manifold on 4-5-6 side. Get ready to scrape that intake manifold gaskets off the heads. 30 years of frozen gunk.

[plasgar]

Yelcab1. Thanks, I just completed that for both sides!

[Mason_paul]

I just checked Bentley...they list a torque of 9 ft-lbs for the fuel pressure test port cap, which is the same size as most of the fittings.

That’s where I’d consider starting. Go to 9 ft-lbs and make sure it feels ok, then jumper the DME as described in the instructions to leak check and tighten additionally as needed.

I don’t have crows-feet sockets, so I couldn’t use a torque wrench when installing mine. I just used box wrenches and was careful and conscientious about it.

[tschall]

I just did the Mason lines on my '86 M491 cab. The engine was out for a rebuild, so the install was so easy even a cave man could do it. I also ordered the tunnel fuel lines. They would NOT install. From the engine bay, it is necessary to hand bend an "S" into the line to make the compound curve to get into the tunnel "compartment" which holds each line. I was told directly, this "compartment" is only there on M491's, and 930's. All I can say that after two men working over 7 hours each, it was abandoned. I should say in all honesty the two men were very experienced Porsche mechanics. Bottom line, Mason very nice for engine (bought from our host), tunnel lines would not work for my car. Your experience may vary... Well made product!

[Mason_paul]

Wow. That’s some intake manifold goodness there. Beautiful.

I’m sorry to hear about your tunnel lines mishap. Send me a PM if you like, I’d be happy to offer a refund if you want. I’ve now had one 3.2 and one SC that just wouldn’t work. The rest have been successful.

[dwelle]

can't imagine doing this with the intake manifold on!

i just used paul's lines on the 3.2 in my '76. i took the opportunity to remove/clean/replace anything that needed it. my injectors really needed to be serviced anyway. great kit and very well built. transformed my idle and low end throttle response.

fwiw, even removing the intake i don't think i was into this for 30 hours, and i spent at least 4-5 just cleaning the throttle body and manifold...