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-   -   can I use pvc pipe as an oil return? (https://www.miataturbo.net/media-53/can-i-use-pvc-pipe-oil-return-54279/)

aug 12-11-2010 04:58 PM

can I use pvc pipe as an oil return?
 
What do you think? :idea:

http://lh5.ggpht.com/_HPBeu8WGPLg/TQ...ff%2520005.jpg



:facepalm:

thirdgen 12-11-2010 05:10 PM

You said pcv pipe and I thought you meant like use the PCV valve port as an oil return. I think you mean, PVC. Why is there such a long piece on there?

aug 12-11-2010 05:18 PM

Thanks for the fix.. The oil return is routed through the fender well

thirdgen 12-11-2010 05:23 PM

I've never seen that. What's the reasoning? As for using PVC, I wouldn't do it. I wouldn't even use any kind of extension pipe for that. Just use the AN fitting directly to the oil pan. The braided line will flex and absorb vibration, but an extension pipe between the pan and fitting won't. The fitting on the pan will be more of a permanent thing, but the braided line will easily removed if necessary. Ya dig?

fooger03 12-11-2010 05:43 PM

I believe PVC may be too heat sensitive for this use, it can soften at temperatures as low as 65* C, depending on composition.

You are asking a LOT of that plastic where it joins the oil pan. There is an insignificant quantity of thickness available at the oil pan for the polyvinyl-chloride to thread into. I fear that at operating temperature, the PVC will soften significantly enough that even a small amount of leverage at the outboard end of that pipe will be enough to destroy the 2-3mm of threads holding the pipe to your oil pan - I would argue that the vibration of the engine might be enough to destroy the connection over time, but any unforseen tugging or pulling on your oil return line may be enough to cause acute damage.

I would prefer to see a short metal fitting tapped into the oil pan which immediately connects to a non-ridgid section. Then you can do whatever you like.

As a possible alternative to your proposed setup, consider installing a short metal fitting to your oil pan which is connected to a short length of rubber tubing. The short rubber tubing is then connected to a length of PVC plumbing. The entire mess (metal fitting, rubber hose, pvc pipe) is held together with hose clamps. The PVC pipe can actually touch the metal fitting inside of the rubber hose.

We have solved both problems with the above method:
1. PVC Softening at the very thin threaded area.
2. Eliminated the high torque area inherent in your design, and replaced it with a flexible section.

You may still experience PVC softening, but because it will have to soften to a much higher degree to cause a significant effect, the amount of risk is reduced.

thirdgen 12-11-2010 06:08 PM

I don't get the whole PVC idea, to be honest and tell it in a way that I can best tell it...It's a stupid idea. You're asking for nothing but trouble. It's so stupid, that if you run it that way, you will eventually end up making future threads about how you don't understand why your PVC pipe is causing so much problems. Just thread the fitting directly into the oil pan, and run a braided line from the pan to the turbo. Done.

chriscar 12-11-2010 09:08 PM

My question is WHY? Why not just use a longer return line?

C

aug 12-11-2010 09:18 PM

Holy moley, I should have responded to this thread earlier! I got this from M.net-- the link is actually on the bottom of my thread.

Sorry! I found it humorous, but am writing a paper-- I'm not a good multitasker.

Please forgive the troll.



Chris you should know my car is already turboed!

curly 12-11-2010 11:36 PM

Doesn't that constitute a horizontal drain that might not drain all the way? I suppose it's not too bad since it's on the bottom, but still.

Bottom line is he tapped the wrong spot, didn't he? Should be further back behind the AC compressor. Oh well.

WonTon 12-11-2010 11:43 PM

that looks about where mine is....


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