tempest411

Hello,

I was able to remove the rubber portion of the fuel lines from the hard lines in the engine bay of my '87 924S without damaging the hard lines at all. I have new lines made up by Travis at Rennbay, but they are intended to be secured via compression fittings. I'm wondering if I can just secure the new rubber lines to the existing hard lines with Oetiker clamps, which I have used in the past, though not on fuel injection lines. Another thought would be to pick up one of these 'inexpensive' on-the-car hose crimpers and just replicate the factory setup. Either of these ways would eliminate the need to cut the lines and bend them up a but to make room for the crimp fittings, allowing for a cleaner installation. I should mention that I have the power brake booster and master cylinder out...Your thoughts?

Thank you for your comments!

Rick

V2Rocket

Do the pipes you removed the rubber from have barbs?
If so you probably would be fine.

But the Rennbay kit is so easy and quick I wouldn't chance it if there aren't pre-existing barbs.

tempest411

Yes, there are barbs on the ends of the factory hard line. Removing the crimped ferrules really wasn't as difficult as I thought it would be. On the 924S, and 85/1 series 944 the real issue is access. But as old as these cars are, replacing the power brake booster and master cylinder is a good idea anyway for preventative maintenance. I was going to install one of those firewall reinforcement thingies as well, but decided it would be too much of a pita to make it work.

V2Rocket

removing the booster?

I've done a few of these kits on early models and never needed to do that. The hoses are long enough that you can cut the tube off well below the booster and stuff.
Though a 924S might be different?

thomasmryan

Pi R squared on a 1/4" line at 100 psi is about 5 pounds. If it's a barbed end, it should be fine with the proper sized hose/line.

Tiger03447

Oetiker clamps can't exert pressure on a line that a F.I. clamp will. They are good clamps, but for fuel fittings under pressure, I would use a screw-through bolt type clamp, especially on a fuel delivery line. For the return line, not so much. I would use them on vacuum and water lines though. Just my thoughts, probably overkill, but if it's back by the tank, out of sight is out of mind..if there are no leaks...

tempest411

In a pinch I could've done that, but I took the booster and MC out anyway for the reason mentioned, and since they are out I want to make use of the original connection points.

I have discovered that they do use Oetiker clamps on EFI systems. Specifically, they are common on the in-tank fuel pump units on most cars these days, and they use them on EFI motorcycles. I'm still doing more research...

V2Rocket

Fuel pressure should be no problem for oetikers.
Oetikers are used in all PEX plumbing which sees about 60psi give or take in residential plumbing...on hard plastic tube, not even nice soft rubber with good bite.

curtisr

These.

Fuel injection system clamps feature solid, rolled edge bands with a special nut and bolt tightening design and are designed to provide uniform sealing pressure required on fuel injection system hoses. Available in attractive packaging and bulk at Automotive stores everywhere.

tempest411

Honestly, I have more confidence in Oetiker clamps. I've seen the above pictured clamps distort pretty easily where the screw is. I'd like to think there are better quality ones out there than the ones I tried years ago from my local auto parts store, however.

curtisr

Understood. However, this type gives one more control over the amount of tightness (?) one can apply, they are reusable and I love the rounded edges.

Tiger03447

The ones sold in most auto stores are small diameter. You'll have to go to Amazon to get larger ones. Try to get the stainless ones since they are subjected to all kinds of crap under the car. They'll cost about 1.00 apiece. If you want a trip down memory lane, the Japanese wire type clamps used on radiator fittings were terrible for distortion and would fall apart at a moments notice. They were good ONCE. Spencer is correct..They do use the Oetiker clamps on the fuel pumps for in-tank pumps. Less problem to worry about since the pump is immersed, and way, way harder to get to if you have to change it. I'll use the Oetikers on the vacuum lines and water lines or a worm gear clamp on those, but I'll stick with the pictured clamps on the fuel system, at least on my car..Thanks and good luck...keep us posted on how they work out for you..hopefully no problems either way..like I said..I'm probably overbuilt in this dept.
Stay safe, healthy and warm ...

Dan Martinic

Since we're talking about clamps... recently, I thought I'd be cool and get some "constant-tension" spring-type hose clamps. Well, the ones I got from Amazon (China) are garbage! They've been leaking on all kinds of small vac connections I tried them on--never mind coolant. And here I thought these were supposed to be something good ie. keep tension as hose shrinks and all that.

I got ones similar to this; maybe I just got really bad ones

tempest411

I think it was just the particular clamps you got. I had those all over my Audi's cooling system and never had a problem.