turbo oil feed size

[crazyclark31]

Hey question for the turbo guys out there.

What size would you consider the minimum oilfeed for a thrust bering turbo?
Reason is my second turbo is starting to get fair amount of play in shaft and has started to smoke abit. Both turbos were checked out by reputable turbo shops and were in good condition. The latest one (tdo5h) was pretty much as new.

Am running valvoline diesil extra oil,serviced every 5kms.
turbo is only running 10psi.
When origionally got oil feed guy at local enzed shop said to -3 was plenty big enough so got that. but after looking round on here seems eveyone uses -4 lines and fittings.

Feed is taken off a tee at the oil pressure sender.
Thanks
Mike

[Crash bandicoot]

the oil pressure sender may provide the pressure but not the flow rate required, i think you'll find if the block was never a factory turbo block or came from the early 1990 or before(when turbo technology left something to be desired) that the oil feed bores for the likes of the sender unit are dismally small . no where near enough volume of oil to keep a 700 degree C bearing from seizing or wearing out.

what you want to look for is a 1/4 inch or 8 ml(about) bung on the pressure side of the block that is tapped into the oil galleries that feed the head.

then the return line you want to plump back into the sump below the oil level line(the reason for this you ask) as when you feed oil to a 700 degree bearing it tends to boil it and turn it into what looks like head on a pint of beer. (that is why most oil return lines on turbos are 25 ml diameter(most that is)

by returning it into the sump below oil level line it will be forced to return to liquid form.

[crazyclark31]

Yep all the return side of it is sweet as.Is 25mm hyrdrolic hose to a 25mm pipe welded to the sump.
So if i took the feed from the spot at the left engine mount this wopuld ok? Can i stick with the -3an(?) hose/fittings of should i go up a size?

[Crash bandicoot]

get a pressure gauge and fit it to the place you choose to ensure it is. you haven't said what motor but from the motor's i have worked with(yota's nissans and holdens mainly) there will be allowances for these lines if the model of engine you use came with a turbo option from factory.

google is your friend.

[darinz]

Take your oil from the factory fitting inside the LH engine mount. That has more than adequate flow and pressure.
Don't all turbo's run an oil restrictor at the turbo anyway so the oil feed can be quite small?

[crazyclark31]

yeh whoops its a td42. The hole on oil feed side of turbo is bout 2mm.
have done the google thing but every time come across topic they always go off on some tangent

Am going to rebuild turbo(tdo5h) as think best option.Is there any kit in particular i should be looking for?
Would their be any other issues that could be contributing to premature failure?Ie fuel setting,air flow to/from turbo

Lastly am i good to keep current feed size or should i go bigger?

[Crash bandicoot]

well, ya need to investigate as obviously the current feed isnt supplying enough lubrication to the turbo.

[crazyclark31]

yeh got that. Was meaning if i take feed from side of block is the current -3an line big enough or should i go with a bigger line?
which brings me back to origanial question of is a -3 line big enough to suppy oil to a turbo.
Can't see the point in changing size if were i'm taking oil from is the problem.Hence the questions.

Again thanks for any advice

Mike

[coxsy]

Take your oil from the factory fitting inside the LH engine mount. That has more than adequate flow and pressure.
Don't all turbo's run an oil restrictor at the turbo anyway so the oil feed can be quite small?