Topic: Custom oil tank help

[wannabridin]

Hey guys, I'm working on designing a custom oil tank to fit behind the "triangle" in the frame.  It will be made out of aluminum and our own "little horse" will be making it.

My question is about the bungs.  Bungking.com has 1/8, 1/4 and 3/8 inch NPT bungs available and I wanted to know what y'all thought I should get??  If it's too big I feel the pump won't be able to push against that large of fluid head.

I was planning on using one of their vented fill caps, and then two 1/8" for the sight tube.  Now for the engine drain and engine return line, I think the 1/4" would be best?  Thoughts??

Also, I wanted to just use the engine drain plug as my only oil drain location.  Is there a problem with doing oil changes thru just this and allowing the oil to drain back from the tank and cooler this way??  Thanks guys!!

[kerryb]

From my limited knowledge of hydraulics, I recall that "hydraulic head" pressure is related only to the height of the column, not the size of the tube.  This should then allow you to base the bung and hose size on the desired flow, which is a question I cannot answer.  On the question of oil tank drain...I would want a separate drain on the tank to save the time of waiting for the oil to drain through the engine.

just my 2 cents.

[wannabridin]

True, it does tank awhile for it to drain through the engine...

Does anyone know the ID of the stock hose??  Oh wait, I have some outside!  I'll look

[754]

 You will probably be using 1/4 or 3/8 NPT.
 I used to build a lot of fitting kits for H-D tanks, probably at least 500 sets or more.

 Here is a cool trick;
 for an oil drain use a npt bung or weld in a hose barb.. then run a short hose from it to a low part of the frame. Weld a pin on the frame that has a bulged end.. a bit like the head of a finishing nail..(hose should be a light press fit, on small portion) then slip a hose clamp over the hose then sip over pin and tighten..
 Now to drain tank, put a pan under the pin, loosen clamp, pull hose off, and drain oil.. leaves no mess on your frame..

 If you want really nice fittings, I can make them, some filler caps look like crap..

[wannabridin]

i was going to use this as my filler cap:  http://www.bungking.com/osc/product_info.php?cPath=70&products_id=121&osCsid=db3a100fbf8bf8307ebe27ce1d4fda9d

i dont think it looks too bad at all!  also, i had an idea for the drain using a valve and barbed end.  just have the line hug the frame down to the underside and when i'm ready to drain, just flip the valve. 

[Silverback]

If you are using a vented cap, would you omit the vent to the rear of the crankcase? I'm in the process of making a tank. Is your welder a member here?

[wannabridin]

ya, i'm going to give my stuff to Little_horse.  he's got a whole list of stuff i need to get up to him so he can get crackin! 

you know, i don't know about the crank case vent.  that's a good question!  if i don't need to use it, i can always just put a plug on it...  thoughts?

[MCRider]

ya, i'm going to give my stuff to Little_horse.  he's got a whole list of stuff i need to get up to him so he can get crackin!  

you know, i don't know about the crank case vent.  that's a good question!  if i don't need to use it, i can always just put a plug on it...  thoughts?

As another here has taught me, (Mystic or Ecosse I think) the vent on the rear of the crankcase is actually the end of the drain from the condensor on the top of the oil tank. In other words, the "flow" is not from the cases to the tank, but from the tank to the cases. If you had the cases apart you would see that nipple on the rear of the crankcases enters the cases and stops right above the little sheetmetal plate that funnels oil into the final drive shaft to lube the chain.

In other words, the chain oiler gets its oil from the condensor on the oil tank. I know, news to me too!  having just put my cases back together again, I was able to confirm this relationship.

So, if you don't care about the automatic chain oiler, and many of us don't, you can plug that nipple off. It does not vent the case, at lesat not primarily. That happens with the tube coming out of the cam cover. Crankcase pressure easily travels up the cam chain tunnel and out the top.

[wannabridin]

thanks Ron!!  very good information indeed.  i did notice these things with the cases apart, just wanted to confirm everything first!  looks like a plug will be used for the rear vent, as i don't care about my chain oiler!

[Silverback]

Not sure where I read it, but somebody had mentioned they had oil burping out of their vented oil cap. They did not run the oil tank vent back to the case. I think it depends on the design of the tank (size/configuration) and efficiency of the vented cap. I can certainly see how one of those cylindrical oil tanks might be prone to oil burping while the oil is being sloshed around, but if your tank is large enough and the vent is on the top, I'll venture to say that it should work fine. Another option is a catch can.

[wannabridin]

my tank will also function as a psuedo fender on the backside of the triangle.  i'm going to make it at least as big as the stocker, and i've even thought of having a baffle put in about halfway with holes in it to try to keep the oil from splashing around as much. 

i'll put one bung up top, as high as i can, for the "from engine" (fill) feed, and then one on the bottom (not the very bottom) as a "to engine" (return) feed.  then i'll throw the oil cap directly on top where it's easiest to access from under the seat.  in addition, i'm going to run an oil sight on either the side of "front" of the tank.  i'll use some red line to match the fuel lines.  this is mainly for the coolness, but it has some function as well.   

[coma13]

did the custom tank ever get finished? i'm interested in making one myself.