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Ideas On Slimmest Possible Oil Return From Back Of Head...

bubba

By bubba,
in Engines & Forced Induction

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bubba Grand Master

bubba

Posted
Posted

My motor had an oil return from the back of the head but when we put it in my car it didn't fit (was in a commodore) so we put a blank there (the fitting for the return was so huge it was preventing us from tilting the motor back to get the gearbox in and out).

Now this hasn't presented an issue until a track day a few weeks ago where the sustained high revs started pushing a heap of oil into the catch can.

I'm trying to find the slimmest possible way of putting a decent sized oil return back on.. something along the lines of drilling/tapping the blank fitting in there at the moment and screwing in a banjo fitting of some sorts..

Any suggestions? and how big (ID) would the return have to be?

Sydneykid Grand Master

Sydneykid

Posted
Posted

The problem is it's a gravity return, no pressure to move the oil though the pipe/hose. Plus, at high rpm, there is a lot of oil to move. So the biggest possible fitting and hose is the go.

Cheers

Gary

bubba Grand Master

bubba

Posted
  • Author
Posted

Thanks Gary :(

Yeah I figured it was gravity return and that's why the old fitting was so large.. wonder if I can find/make something that is wide but not deep..

Maybe two small banjo fittings.. guess I'm going to have to peruse mucho catalogues and see if there is anything to suit.

If I drill/tap the existing bung I have in there, I would need to be doing so as low as possible yes?

bubba Grand Master

bubba

Posted
  • Author
Posted (edited)

Yeah that's pretty much what it used to have but that fitting sticks a good couple of inches out the back of the head, there is probably *just* enough room to have it there but it has to be taken out everytime the engine goes in or out.

I'm trying to come up with a way to do the same thing but with something that only protudes say 20mm out of the head.

Edited by bubba
r33_racer Grand Master

r33_racer

Posted
Posted

I machined up and fabricated one that fits the ID of the whole welsh plug hole with an ally pipe coming off it that goes down towards the inlet side, the ID of the return pipe is 3/4" and has a -12 fitting on the end. The whole block sticks out 39mm from the back of the head. In our r33, there is no problem with clearance when taking the motor in and out. The same fitting was used in a r32 4 door and the firewall had to be moved back for it to clear, but it wasnt much.

But both these are used in dry sump setups. But I would imagine you would want the return as big as possible as gary stated.

As said you can always move the firewall back a little!

bubba Grand Master

bubba

Posted
  • Author
Posted
just tap it in, give it the old tap tap taparoo.

Whats the problem you oil fitting you to good for your home???

ok im tired, im going to bed now...

lol wut?

get some sleep and try again :P

infamous_t Veteran

infamous_t

Posted
Posted
just tap it in, give it the old tap tap taparoo.

Whats the problem you oil fitting you to good for your home???

ok im tired, im going to bed now...

lol, don't worry, I got it, Happy Gilmore ftw!

Duncan Grand Master

Duncan

Posted
Posted

I've got the same fitting as Al, also with 3/4" return and I don't have too much oil in the head problems. Mine is tapped into the head beside the welshplug though because a the engine doesnt sit flat in the engine bay and b you cant tap into a brass welsh plug so you have to machine a replacement for that as well. this is in a 32 (gtr). I have massaged the firewall for tilting clearance but did not need to just to fit it :thumbsup:

bubba Grand Master

bubba

Posted
  • Author
Posted

Cheers guys.

My head has had the welsh plug removed and thread tapped in, there is currently 1" BSP plug/bung/blank/whatever in there. Been talking to my mechanic and we're just going to put the old 90deg fitting that he was using back in.

Any dramas with T'ing into the turbo oil return?

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