bullfighter

Given its age, it's time to replace the fuel lines on my 1993 964 C2. There are no leaks, but to my knowledge they're all original and likely to have deteriorated somewhat.

Questions for those who know:
1. Does this require that the engine be removed?
2. Are OEM (Porsche) fuel lines available?
3. Are the fuel lines susceptible to damage from ethanol-blend gasoline, or have they been constructed with modern fuels in mind?

Thanks all! I plan on keeping the car for the long term, so would like to do this properly.

Peteinjp

The long lines that run front to rear are often left unreplaced due to the relative difficulty. Lindsay Motorsport sells an crimp adapter that you can use not eh hard lines to convert them to an AN line so you do not have to replace the whole line (assuming the metal tube is in god condition.)

https://www.lindseyracing.com/LR/Por...A-COMPFIT.html

I have not used these as I had my lines reconditioned by Ninemeister but this is what I would do if not:

https://www.pelicanparts.com/More_In....htm?pn=MAS-K2

P

bass 1

I replaced all of the engine bay fuel lines with the Paul Mason kit due to some light bubbling and loose crimps on the originals.

Generally, there seems to be positive praise for the OEM Choline lines (still available new, but pricey), I liked the PTFE lined Paul Mason kit more.
No need to remove the engine to replace them, but removing the intake runners is needed.

Haven't looked into the longer lines running to and from the front yet... visually, they do not show the same bubbling as my engine compartment lines did.

bullfighter

So the long lines are just left in place? I'll have to check the condition of the metal tubes.

Peteinjp

That's the idea. I have the fittings but have not installed them yet. When I looked at it before I thought that shortening the metal line and running a longer hose might be the ticket if I could not get the fitting on with the line in place. Taking the long line out looks like quite a job- well taking them out is probably not so bad because you can just bend as needed- but putting in a new one... it looks real tight with the right side trailing arm in place.

Here's some real experience:

http://forums.pelicanparts.com/porsc...intenance.html

Pete

Ubipa

I’m still amazed why more people don’t convert to the 993 fuel setup. Is there a specific reason that I’m overlooking? There’s so many more fittings in the 964 lines and the fpr is not readily available.

From my perspective it would make sense to replace the hard supply line from the pump and switch to the 993 fuel rail setup with fpr and 993 stacks.

revolve40

Paul Mason kit here as well. Can be done in situ, but need to remove intake bits - pretty easy to do and you can take advantage of the extra space to replace things / clean.

cobalt

There are conversion FPR's available. They use the simple bosch regulator the 993 uses and allows you to swap them out for different pressures. This is just for example there are many manufacturers. https://adaptmotorsport.com/products...-7-3-0-3-2-3-6 New 964 regulators are now available and not that expemnsive. I agree the 993 setup is better and less complicated but some like originality. Also the 993 rails are connected by a single hose which is also susceptible but made with 10% rated line. As I see it after 30 years and running many of those on 10% ethanol my lines held up quite well.

The new factory lines aren't rated for today's ultra high ethanol content and we have seen tests of as much as 18% ethanol in some stations by me. I believe they are only rated like the 993 lines for 10% max. I swapped mine out for new although my factory lines of nearly 30 years were no different than the new lines as far as flex went. No signs of the internal polyamide lining becoming brittle. The outside rubber is just protection and not the line itself. I have seen some that are so fragile it is scary but 90% of the time if you don't mess with them they will last. Although it is cheap insurance to replace them.

You don't need the 993 stacks to use 993 lines on the 964 although I swapped mine out and they do raise the injector 4mm which is nice for better atomization and valve cooling.

Ken D

Those are the high-pressure feed and return lines. The metal portions are likely fine. However, those lines do have rubber sections, e.g. where the feed line transitions to rubber in the engine compartment.

Several years ago I replaced all the 'top of engine' fuel lines, as I found a few had deteriorated. At the time, I left the long lines alone. Sure enough, two years ago, the HP feed line experienced a pinhole leak in the rubber section behind the airbox, spraying a jet of fuel over the engine. I just happened to catch it at the right time, and replaced both feed and return lines. You don't need to remove the engine to replace these, but it's a squeeze.

As others have said, spend the time to remove the manifold, it'll make the job that much easier. With unobstructed access to the topside, you can check your FPR, oil pressure sender o-rings and breather cover gasket.

All lines should still be available from Porsche.

cobalt

Also If you pull your injectors replace the rubber o rings as they shrink and I have seen them leak and spray gas. Porsche also changed the lines IIRC in 92 could be 91 changing the routing and eliminating some of the tight radii.

I also carry a fire extinguisher in these cars. Always best to be safe.

racoguy

I did a full replacement recently on mine, details in my thread.
Removing the lines completely is the best way to go, buy hose and ferrules from Cohpro in the Uk and replace it all.
My hoses looked absolutely fine but hard as a rock and in twisting them to get them off just snapped in half.
I just cut all the factory ferrules off, removed the hose and copied the lengths. Swaged back on the factory pipes I had re zinc plated for a 100% OEM solution.

Metal Guru

Ethanol content is limited to 10% so as to not degrade the materials in the fuel system.

cobalt

Sadly we are finding by me as high as 18% in some fuels so be careful what grade fuel you buy. They do vary.

-nick

The circled corner of the metal pipes can corrode and it’s really tough to spot (inside radius of the corner is practically invisible). I’ve noticed it on a few 964s including mine. I replaced both lines with genuine parts a few years ago. Engine was out, and they were still a pain in the …

Replacing all these with flexible -an lines isn’t a bad idea at all. I would way over-engineer extra supporting brackets for flexible lines to avoid any potentials for chafing/etc.

Peteinjp

Very nice example:

https://rennlist.com/forums/964-foru...l#post10624869