Injector return line sizes

[tyb525]

What sizes are the injector return lines on an '81 1.6 NA? My car currently has semi-clear Tygon lines but no size markings on them. I'd like to replace them with some "Fuel and Lubricant Yellow Tygon PVC Tubing" from Mcmaster-Carr.

Does anyone know what I.D. the small return lines are (injector to injector)? I think the line from the last injector to the pump is also the same diameter? I've search several forums and can't seem to find a solid answer.

[vibraphone321]

I asked the same question a few weeks ago and got some mixed responses. I found these ads on ebay and it led me to believe that they are 3.5mm. I am currently using some black vinyl line from Lowes and it appears to be working well enough. Check this url for the ads I am talking about and see what you think.

http://www.ebay.com/sch/i.html?_trksid= ... &_from=R40

One post that was helpful was talking about using another small piece of hose to go over the lines to act as a hose clamp. This is a good idea because the original equipment had a braiding on it that held the lines in place.

[caddywompus]

1/8" ID or 3.2mm. I carry this in Viton for folks wanting multi fuel (biodiesel/SVO/ULSD, etc) compatibility:
https://www.greaseworks.com/store/index ... uct_id=214

[Fatmobile]

I like clear lines between the injectors, for troubleshooting.
"What can clear lines between the injectors help you troubleshoot?", you say?

A couple weeks ago I had a car that was pushing foam out the injection pump,
usually makes you think the mainshaft seal is toast and allowing air to be pulled in past it.
An injector was shoving air into the little return line. Clear lines made it easy to find which one.

1/8" urethane from motorcycle shops, I've been getting it at Honda,
It's hard/impossible to slide over injector barbs at first so slide it on as far as you can
after it heats up it slides right on.
Then seals good but slides off and on easily for working on injectors.

[tyb525]

I ended up get 1/8" ID, 1/4 OD Tygon PVC from McMaster-Carr. I use clear for the same reason. Sure they won't last as long as the "real" stuff, but it's so inexpensive and easy to change, and makes it easy to track down bubbles.