Fuel Pump+/-Lines: "While Your in there"...

[Geneman]

Question for the brain trust: 88 3.2 G50 86 K miles light track use.

gas tank is out for hollow thru body SB install ..

fittings to F pump and pump itself look pretty crappy. ..see pics. i am doing new lines at the engine as prev maint. as discussed many times on this board (Len Cummings hosese/setup) ..but wonder about this stuf in front


Should I go ahead and do the front lines , fuel pump and the line all the way thru body at same time? is that a big job?


(does it go thru or mount under tub?)

thanks very much for your advice!

frank

[KNS]

Certainly not a bad idea to do the lines in the tunnel, part of it being a "big" job is dropping the tank. I think you can get the lines through without dropping the engine, if that's the case I would definitely do them. Do a search on "fuel lines through tunnel". Was that car driven in the rust belt in its prior life..?

[Geneman]

thanks kurt very helpful it has been a pennsylvania/nj car its whole life.. almost never driven in winter. however winte stored at the jersey beach house ...mighty corrosive air..thats probably it. i will do the long hoses if its possible.. cheers frank

[80-911SC]

there was a post a bit back that they replaced the fuel lines with braided and feed them thru the tunnel to the back ..

[pete3799]

I'm debating the same thing. I've got my front suspension out for a rebuild and my pump and hoses look just like that. In fact the hose clamp holding the fuel pump was rusted off

[frankc]

If you would like to see pictures of the fuel lines from both ends of the tunnel, I posted some here: Should I replace theses brake and fuel lines?

[steely]

Originally Posted by pete3799

I'm debating the same thing. I've got my front suspension out for a rebuild and my pump and hoses look just like that. In fact the hose clamp holding the fuel pump was rusted off

I did my front susp last year and now I wish I had done the tunnel lines.

For the OP, the tank being out is a plus. You still have to get over the front cross-member but I have read where it can be done. The trans mount should be removed to get to the rear of the tunnel, and the drivers floor board and pedal assy as well if I recall correctly.

Two links a I saved:
How hard is it to change the fuel lines?

Fuel lines in Tunnel?

[BoxsterGT]

Hi Frank,

The condition of the fittings between the black Polyamid tube and the rubber hose is what will determine the need to replace or not. The factory tubes thru the tunnel almost never have a problem, its the rubber hose & the fittings that fail.

I am afraid the return hose fitting to the tank looks quite rusty in your first photo above. It looks like the crimp sleeve is pretty weak. Of course, the return runs a lower pressure and likely will not be the first one to fail.

Any chance you could show us a photo of the pressure hose & its connection to the black Poly tube?

If the fittings on the pressure hose from the pump to the tunnel are as bad, then you should replace them both.

If you had the motor & trans out I would recommend using flared SS tube thru the tunnel as JeremyD and Shaun 84 Targa have done. That gives you the advantage of removable fittings.

However thats a lot more work. The factory Black Polyamid lines are really the most practical way to go, and our host has them in stock.

I only wish the fitting to the rubber hose was not a permanent one-time only connection. (See the first photo from frankc's link above.)

I plan to work on that revision sometime in the near future. Poly tube w threads to accept a removable fuel hose at each end.

Good success with the job ahead.

Len

[Geneman]

Thanks Len and everyone else all fantastic comments and resources/threads. the job at the rear sounds quite ugly even with the engine etc out!

Len i will post more pics . That is great advice if thru tiunnel stuf is fine i will just do the ends.

question on another strategy: in looking thru this another way to go would be to put a fuel cell in now ..and simply run new SS lines to the engine. ...running the lines thru firewall and inside of car to rear ...completely bypassing the tunnel tubes. can these also be run under the car? i am pretty sure i have seen this fuel line routing ..either ..inside or outside car on both early and late model race cars..

btw : my project is pretty much race car conversion anyway. .. but still vaguely streetable

i cannot find any threads on fuel cell installation that also describe running new fuel hoses outside the tunnel...i guess they mostly use the tunnel ones again .. please let me know if you know of any things like this

len i am sending you $ today for the rail hose setup

thanks frank

[BoxsterGT]

I started looking into making up replacement Black Polyamid fuel tubes that run thru the tunnel.

I would not make them with permanent hose attachments, just threaded Male fittings at each end.

They should be an easy pull thru (even w the motor & trans in place as they are somewhat flexible) and will accept whatever hose is desired that has M16 Female fittings at either end.

It will take (6) weeks to get stock out of Germany. Just have to gather the funds, as it is pay first, then wait, and wait, and wait.

I would hope the cost would be much less than the other options available.

Frank- this is only my opinion, but I would not run fuel hose inside the passenger compartment. I think the safest place is within the tunnel. If anything, I would run seamless SS tube w flare fittings at each end. You can then fit any hose combination you like front and back.

I personally like the Fuel Safe cells made specifically for our Porsches. Everything fits w/o hassle.

Just my 02 cents.

Len

[BoxsterGT]

Here's what the factory Polyamid lines that go thru the tunnel look like.................



(Thanks to the fellow Pelican who originally posted this photo.)

The permanent hose attachments at the front are what bother me.

PS- Does anyone have a measurement of the actual length up to the 90deg bend in each of these lines?

Len

[RWebb]

I have seen some recent posts to the effect that the lines in the tunnel differ in materials by model years. Apparently, some are plastic and have a higher failure rate.

dunno how low the rate is or when the changes occur... or if I saw that here or on Early911 bbs...

BUT I for sure do not like seeing rust on those critical safety components of yours...

[Geneman]

thanks len just to be clear see pics from frankc thread.

do i have the layout correct? also if i understand correctly, the fittings going into the black pamid tube going into and thru tunnel are one time only thius i cannot just replace the small bit between, this fitting and pump/tank .

i will get a pic of mine to evaluate condition

thanks again and for your patience

frank

[BoxsterGT]

Yes frankc has it correct on the ID of his hoses. Also, his fittings don't look too bad. Compare them with yours as a first step. See how much rust flakes off the crimp sleeves.

The fittings that go directly into the Poly tube are one-way only. You must cut them off, thus making the tube shorter. Then to insert the fitting again you must secure it & force the fitting into the tube, almost impossible to do in the tunnel.

It takes a lot of mechanical effort to insert this fitting. I have not done these before as even out on the workbench it takes special tools/fixtures. Looks like its now time for me to buy what I need along w the fittings required.

The white nylon tube used in the 1970's is the type that cracked & failed. Most 914's & 911's of that era have this fuel line thru the tunnel and it is a failure waiting to happen. JeremyD went through this recently, and he opted to run seamless SS tube thru the tunnel. He used fittings & Hose I supplied and I believe it worked out well for his beautiful Mexico Blue 911.

I don't know of any failures with the Black Polyamid tube used in the later models. The rubber hose & rusted fittings are the real issue with these models.

Thats my next goal, to make an inexpensive "Fuel Line in the Tunnel Fix".

Hope this helps.

Len

[RWebb]

I know some of the lines in the tunnel were steel (up to 1973 at least??); AFAIK P AG went to polyamide at some point

you need to replace the rotted wire terminal covers also

I did 4 searches at the Early 911S bbs - covering both forums (General & Technical):

polyamid ---> no hits

fuel line tunnel - produced 5 hits in General; 21 in Technical - most deal with the rubber hoses or how to find stuff that looks stock and concoursey enuff for der cognoscenti

But I did find one interesting tidbit - apparently, the ends of the steel lines sometimes rust where the hoses are attached. People should check carefully for this whenever changing the fuel hoses; and I guess that means about every 10 years.

[Brown747]

I just did the job of replacing the tunnel lines in my 78...really not a bad job but I will say that I had the engine, shift rod and shifter, and the interior out of the car before starting. The 2 lines, pressure and return were available from our host. I also removed the fuel pump and bracket and removed the T fitting where the brake lines come together just in front of the tunnel lines at the front. You can work around the brake lines but since I am going through the brakes and changing the fluid it made sense to open it up to drain and get myself a little more room. This job would be easier if you had a helper but I was able to do it alone.

I started by disconnecting the lines at the front of the car, pressure line has the banjo fitting that goes on the pump and the return line into the tank, and at the rear of the tunnel where the lines attach that run up to the accumulator and the engine.

Next push out the grommets that go around the tunnel lines at the front and rear of the tunnel (4) I found it easiest to push them with a long screwdriver into the tunnel then retrieve from inside the car.

I replaced one line at a time starting by securing a piece of stout string to the fitting at the back and pulling the line out of the tunnel from the front. Pull a liberal amount of string out at the front then cut it off the old line ensuring that there is enough string remaining at the back to get a grip on when it is time to pull the new line.

Tape over the end of the fitting on the new line so as not to pick up any debris and secure the string. I also lubed the line with some spray silicone. If you have an assistant have them start pulling on the string at the rear while guiding the new line in from the front. Inside the tunnel is another tunnel that runs down the left side that these lines need to run through. It starts maybe six inches back from the front so go inside and check that the line enters that smaller tunnel. The string should help in following the correct path and you can also see where it needs to go by looking in though the shifter hole. Without an assistant I pushed the line in from the front a couple of inches then went inside to take a look to make sure it was going to start down the inner tunnel.
The line will exit the inner tunnel then out through the wall at the end of the tunnel.

Repeat procedure for the remaining line. Clean up or replace the rubber grommets (also available from host) then lube with some silicone spray and reinstall at the front and back. Push them in from the outside. Tighten all fittings and thats it!

HTH Thor

[BoxsterGT]

Really nice report. This should be on a sticky for all of to read before attempting this job.

Len

[Brown747]

Thx Len!


Thor

[BoxsterGT]

Made up my first set of Polyamid Tunnel Lines a while back, but could only buy M16 Male fittings, and SCs & Carreras use M14. Only the 3.6 motors use the larger M16 sizes throughout.

Since then, I have taken fittings that are available, machined & brazed them together to make a M14 fitting. Of couse, they also must be re-plated, so the cost of each fitting is much more than if I could bring them in from Germany.

For now, I am offering the Poly Tunnel Tubes at $50ea for the M16 and $60ea for the M14 Tunnel Tubes.




Of course, new front & rear Hoses are now needed and this is what I have made up to complete the system.............










These can be installed with the motor & trans still in the car, only the tranny mount need be removed to gain access. I even have a small tool I am working on to assist in pulling the replacement lines through the tunnel.

Please email me for full details & pricing.

Cheers,

Len at Autosportengineering dot com

[dshepp806]

MAN! I'm up with the "small tool"....keep us posted!

BEST!

Doyle