Anyone Run A 10MM Return Fuel Line In a '74 or '75 CIS?

SalParadise · 03-01-2018, 03:43 PM

Anyone run a 10mm fuel return line in a '74 or '75 CIS?

I am asking because they no longer make the 8mm - and I have the 10mm that I purchased here from Pelican. It is part #911 356 062 07. It is a black line, so obviously I will have to make the inlet and outlet hole larger with a new grommet.

Was just wondering if anyone has run this 10mm line (vs. the smaller 8mm) as the return and has had/ or did not have any trouble in doing so.

I was going to have Len make up a 8mm line but he's been pretty busy with a move and has fixtures in different places.

If I can make this one work it will be great as I already have it.

inaminit · 03-01-2018, 04:54 PM

Sal- Why don't you use this new line for the supply? Get a stepdrill and a bit extension to enlarge the holes, and get 2 of Len's grommets. Lastly-fish this through the tunnel so that it is tight to the driver's side upper corner of the tunnel. I just finished doing this today.

SalParadise · 03-02-2018, 04:04 AM

Then what would I use for the return?

I am replacing the supply as well - just want to see if there is room for this one where the return goes. I don't want to ram it through if there is no space.

No matter what anyone says about the black polymid lines - my old ones look mint from the outside, but they are breaking up like candy canes - they are pretty stiff.

What's it look like in there to run this one?

inaminit · 03-02-2018, 04:39 AM

Sal-There is ample room in the tunnel. I did this with engine/trans and fuel tank out. You will have to drill the front and rear firewalls to allow the larger end fittings. Buy 4 grommets from Len to fill the oversize holes.
Unbolt the handbrake and shifter so you can get your fingers into the tunnel. I used an old clutch cable for a fishing tool, and guided it with my fingers as I slid it from rear to the front. There are hoops and tabs in the drivers side upper corner space to hold the fuel lines-run the fishing tool through these.
Insert new fuel lines through the front holes and tape to the fishing tool under the dash, after taping the open ends. Pull these through.
Almost done! Proceed to grommet frustrationl! Push the grommets in place. For me-I could not get them into the oversize holes and finally had to grind them down a bit.
Good luck with it!

SalParadise · 03-02-2018, 04:55 AM

Quote:

Originally Posted by inaminit

Sal-There is ample room in the tunnel. I did this with engine/trans and fuel tank out. You will have to drill the front and rear firewalls to allow the larger end fittings. Buy 4 grommets from Len to fill the oversize holes.
Unbolt the handbrake and shifter so you can get your fingers into the tunnel. I used an old clutch cable for a fishing tool, and guided it with my fingers as I slid it from rear to the front. There are hoops and tabs in the drivers side upper corner space to hold the fuel lines-run the fishing tool through these.
Insert new fuel lines through the front holes and tape to the fishing tool under the dash, after taping the open ends. Pull these through.
Almost done! Proceed to grommet frustrationl! Push the grommets in place. For me-I could not get them into the oversize holes and finally had to grind them down a bit.
Good luck with it!

Thanks a lot for the advice and taking the time to respond. I have been building this up for years in my head and now it's time to do it - so I psyched myself out. Were your old lines still in? Len was saying something like using weed-eater line through the old lines then trough the new, tie both ends and feed it through?

Also, how are you going from the 10mm return line to the CIS return on the fuel distributor? Did Len make this line for you? He's been really busy it seems and has stuff all over like I said - I just want to get this done as it's been on my shoulders for awhile.

boyt911sc · boyt911sc's Garage

Sal,

There is plenty of room to install a larger size diameter fuel lines in the tunnel. Like what Dean suggested, tack the fuel lines on 1-2-3 engine side of the tunnel. I used a strong nylon string to remove and install these fuel lines. An assistant at the other end of the car makes the removal/installation easier.

Make sure you have the correct fittings that are compatible with the other fuel lines in the engine or worse, locate adaptor/s unless your 10-mm return fuel line has the same fitting size as the 8-mm lines. There are several metal strips inside the tunnel that hold the fuel lines in place. Locate them and pry them loose before pulling the fuel line/s.

Keep us posted. Thanks.

Tony

SalParadise · 03-02-2018, 07:42 AM

Quote:

Originally Posted by boyt911sc

Sal,

There is plenty of room to install a larger size diameter fuel lines in the tunnel. Like what Dean suggested, tack the fuel lines on 1-2-3 engine side of the tunnel. I used a strong nylon string to remove and install these fuel lines. An assistant at the other end of the car makes the removal/installation easier.

Make sure you have the correct fittings that are compatible with the other fuel lines in the engine or worse, locate adaptor/s unless your 10-mm return fuel line has the same fitting size as the 8-mm lines. There are several metal strips inside the tunnel that hold the fuel lines in place. Locate them and pry them loose before pulling the fuel line/s.

Keep us posted. Thanks.

Tony

Thanks Tony I will. Thanks for the heads-up about the strips. I had no idea they were there.

I will need an adapter of some sort to run from the 10mm line end (seen in the photo above) to the fuel distributor.

I honestly do not know what is out there for me to patch in. I have looked at all year cars and do not see that connector line from this fitting to the return side in the engine compartment.

eastbay · 07:58 AM

I believe JeremyD use some pretty large SS lines in his 74 3.6 project, thread is floating around here somewhere

here it is:
http://forums.pelicanparts.com/porsche-911-technical-forum/529220-well-here-she.html

post 648

he used 3/8, close enough to 10mm

SalParadise · 03-02-2018, 07:57 AM

Quote:

Originally Posted by eastbay

I believe JeremyD use some pretty large SS lines in his 74 3.6 project, thread is floating around here somewhere

Thanks I'll check. I had this tremendous worry that the Germans left no margin for error (ie like threading a needle) with the old 8mm line and that it was going to be a major headache.

I would just like to add that with all you guys who haven't changed these lines might want to think about it - as my lines were not leaking and looked great - but when any kind of twist or flex was applied to these things (black polymide) they were snapping clean in areas like a candy stick.

Also I don't know how in the heck I would have ever attempted to do this without the engine and tank out - it's even really tight as it is.

75 911s · 75 911s's Garage

Sal, was the candy cane comment exaggerated or are they literally that brittle?

BoxsterGT · 03-02-2018, 09:12 AM

Hi Sal,

I have adapters in most thread sizes. The 8mm tube usually takes M14 x 1.5, the 10mm tube usually takes M16 x 1.5.

I would like to see this original black tube that is breaking up. I will pay you to send it to me or swap for something you need.

I wonder if this is really Polyamide or a black version of the 74 White Nylon tube that has a history of being brittle and breaking up into pieces.

Len

SalParadise · 09:40 AM

Yes, it's that brittle. It's the return 8mm line that is very brittle after it comes out from the rear wall to the engine compartment.

I was under there yesterday and was poking around and seeing (and trying to convince myself) I did not need to replace the lines and then figuring that I needed to replace the 8mm where it connects in the engine compartment where it has a small ding.

When I was moving it away to unscrew the loop and the body clips it rests in it literally snapped in several places with very little effort. I was shocked to see it snap like that - as I was not even moving it very far - and every in-engine CIS black line I have in my collection somewhat bends (or at least just dimples or kinks) or moves away in its shape.

I will post pictures and send it to Len if he wants - I have no use for it obviously.

For reference it's a '75 S made in October, 1974.

Len - I sent you some photos of these lines via email a couple days ago.

SalParadise · 03-02-2018, 12:56 PM

Here at the photos. Here is the tail end of the 8mm black line that comes out of the tunnel and attaches to the engine return fixture. It's the stock line that goes from the screw point all the way to the tunnel to the tank. From the last broken spot you see is where the plastic body clip is, and then there are two or three other white plastic body clips and into the tunnel.

As you can see, they snapped off in almost equal sections. I suspect that when I move the rest of the line to the tunnel that it will all go this way.

Pretty scary for me, and that's why I'm doing everything at this point.

BoxsterGT · 03-02-2018, 12:58 PM

Sal-

Got the pics but none showing the broken 8mm line. Yes, please send what you can of this line, I will gladly pay the postage.

I will bet $$ that the 8mm tube is a black version of the white nylon tube in the 74 models that is known for failures.

Every 74 911 out there should have their original tunnel lines replaced.

Please let me know about any adapters needed.

Len

SalParadise · 03-02-2018, 04:21 PM

Len, no problem I can send you the broken pieces. I suspect it is a black nylon.

So what I need is a line/adapter from that new 10mm line (shown above). The line and/or adapter will go from this 10mm new line with that fitting above to the CIS bracket part that goes on the engine (shown in the photo with the broken line).

Brian911T · Brian911T's Garage

Sal I just did this on my '75 using the edger cord method and step drill bit to enlarge the hole. Even if the line breaks while your pull it through it should stay on the edger cord.
Removing the pedal cluster will be needed to make it easier at the front bulkhead. Here is a link to my build thread post 25

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/980963-930-targa-engine-drop-upgrade-project-2.html

Matt Monson · 03-02-2018, 07:32 PM

Not lookung forward to this on my 74. I may get the tank pulled tomorrow.

inaminit · 03-03-2018, 04:29 AM

Brian-that dewalt right angle attachment is perfect for this job!
Also, I forgot to mention earlier-when you go to insert the front grommet-leave the front section of the tunnel line out of the bend over tab, so that the line is free to wiggle. Then the grommet can be inserted into the hole perpendicular to the firewall-much easier! Then put the line under the tab and bend it tight.

BoxsterGT · 03-03-2018, 04:33 AM

Sal-

I have 8x10 Hose adapters.......

and 8x10 Tube adapters (They are NOT the same).

I also have M8 Tube x M14 Male and M10 tube x M16 Male, but would have to make an M10 x M14 Male adapter to connect this together.

Sal - Happy to discuss this if you email me. Cannot send photos by pm.

Len at Autosportengineering dot com

75 911s · 75 911s's Garage

Am I to understand that 74 MY 911 Porsches had a specific problem with the fuel lines that you've identified Len?

Sal's is a MY 75 (built in 74 though) Perhaps the 75 cars use the same?

Disconcerting for obvious reasons. :-)