What is the "ideal" way to do the oil drain line?
#1
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I have seen how it is done with a drill and tap. It seems to me that is a compromise given that the pan is so hard to remove that nobody wants to do it just to add the oil drain. But my engine is on a stand and the pan is already off.
Welding a bung might be nice but I can't weld aluminum.
Why is the usual location so far forward? Is there interference from something otherwise? Obviously where a straight shot down from the turbo ends up will vary depending on the manifold design, but with my non-exotic cast manifold, a straight down oil return will end up right around the rearmost part of the shallow end of the oil pan. The FM instructions (for example) show the drain all the way at the front of the pan. What am I missing here?
This bulkhead fitting seems like a good alternative to a tapped hole and the usual brass fitting.
Welding a bung might be nice but I can't weld aluminum.
Why is the usual location so far forward? Is there interference from something otherwise? Obviously where a straight shot down from the turbo ends up will vary depending on the manifold design, but with my non-exotic cast manifold, a straight down oil return will end up right around the rearmost part of the shallow end of the oil pan. The FM instructions (for example) show the drain all the way at the front of the pan. What am I missing here?
This bulkhead fitting seems like a good alternative to a tapped hole and the usual brass fitting.
#3
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there is a baffle plate running along the side of the pan wich you will hit if you drill further back even drilling at the front you have to watch the oil pickup pipe if you drill in too far if your engines out take your sump to an engineer they will gladly weld a alloy fitting on for you
here is why
here is why
#7
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Hmm. Thanks for the pics. The pickup tube might make it very difficult to put a drain directly below the turbo. (Though I suppose a bung could be welded such that there was no internal clearance needed.)
What about mounting the drain in the deep part of the pan, on the side of the sump? Seems like it would result in a shorter drain line with less angle.
What about mounting the drain in the deep part of the pan, on the side of the sump? Seems like it would result in a shorter drain line with less angle.
#9
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You're overthinking it man. Just put it up front like everyone else, you're not going to get any more flow by ensuring it's exactly straight up and down.
Here's mine (seems I've been posting this pic a lot lately!), it's not dead-on 180* but it does not want for flow!
![Name: img018.jpg
Views: 6322
Size: 74.9 KB](https://www.miataturbo.net/attachments/diy-turbo-discussion-14/206811d1501254202-what-ideal-way-do-oil-drain-line-img018.jpg)
Edit - Besides, think about it, your feed line is likely 1/3rd the size of the drain, and is probably restricted in some way.
Here's mine (seems I've been posting this pic a lot lately!), it's not dead-on 180* but it does not want for flow!
![Name: img018.jpg
Views: 6322
Size: 74.9 KB](https://www.miataturbo.net/attachments/diy-turbo-discussion-14/206811d1501254202-what-ideal-way-do-oil-drain-line-img018.jpg)
Edit - Besides, think about it, your feed line is likely 1/3rd the size of the drain, and is probably restricted in some way.
Last edited by kotomile; 04-12-2009 at 10:55 PM.
#11
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This bulkhead fitting seems like a good alternative to a tapped hole and the usual brass fitting.
Since the pan is off, a welded fitting is your best option. If the aluminum isn't cleaned really, really well, there's a high risk of porosity that could cause an oil run. So clean it really, really well and take it to a good shop.
Assuming it doesn't have a negative impact on packaging or access to turbo fasteners, etc., the shortest run possible is generally a good way to go. Moving it slightly forward of the turbo so the hose doesn't block tool access to the drain fittings and stuff might be a good idea.
#12
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Re: overthinking it, yes, probably. But I would prefer the neatest solution and I have the time to do it right. I need to make sure the engine mount won't be in the way though, your pic makes that clear.
Re: failure modes with the nut inside - I would safety wire it if I did it. Right now I am leaning towards having a bung welded. I need to find a good welder anyway, since my cast manifold has a crack in it. But I'm sure it will cost me more than $30. Skilled labor is not cheap in these parts...
Re: failure modes with the nut inside - I would safety wire it if I did it. Right now I am leaning towards having a bung welded. I need to find a good welder anyway, since my cast manifold has a crack in it. But I'm sure it will cost me more than $30. Skilled labor is not cheap in these parts...
#19
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Kday, buy a 60 degree fitting. I did the 45 but most people have interference issues with the steering rack. Mine BARELY clears. It's a -10AN fitting. I also used nylon braided line so I don't cut myself every time I look at it. If you're using a BEGi manifold, you should only need a foot (I took 2ft of -10AN and ended up using 8") since you aren't going down to the front of the motor.