Turbo snowmobile oiling system insight

[kingcat162]

So I just recently had to change my turbo oil pump because it got to hot and the housing warped and ended up leaking - heat issue is rectified now with temp sensor extension on straight pipe - on the outlet fitting it had a carb slow jet threaded into the backside of the fitting as a limiter - I took it out - my logic behind taking it out is : in the morning when you gotta piss really bad and while your pissin if u try and pinch it off the pressure gets a little high - right - I'm hoping less oil consumption now in the open loop oiling system - does anyone else have any exp or R&D with doing this?

 

[SUMMIT TREE]

Ok. First of all lets get things straight.
- what is the problem?
- what is the desired outcome?

Im assuming some things here.
You have a small oil pump, pumping oil from a reservoir to the center section of the turbo to lubricate the bearings, then said oil drains back to the reservoir?

where was this “jet” exactly?

 

[SUMMIT TREE]

Im not familiar with that particular pump, but Im guessing perhaps its a little gear pump maybe (cheap to make fairly reliable). If so its probably a positive pump, meaning you cant just choke off the outlet to control flow.
does the oil just flow thru the turbo back to reservoir in a continuous loop?
im thinking like a typical Turbo say on a diesel truck, the turbo is supplied with a flood of oil that just freely pours thru the center and back to the oil pan. Or does it just keep a journal filled at all times with no means for drain back?

 

[kingcat162]

It's an open loop system fed back to resevoir then to the pump and back again - the slow jet was in the backside of the outlet fitting - I'm hoping to take out the slow jet (restrictor) out of the fitting and straight flow it - and maybe the centre section will be less pressurized - the centre section always leaks after a full rebuild and then the bearings start howling after 1300kms

 

[TROLLCAT]

What size is the pilot jet ?

 

[tripster]

Removing the jet completely may not keep enough oil in the housing for proper bearing lubrication. Might want to try a larger jet instead.

 

[TROLLCAT]

Removing the jet completely may not keep enough oil in the housing for proper bearing lubrication. Might want to try a larger jet instead.

Thats me is thinkin to

 

[SUMMIT TREE]

The “simple” way to check this would be to install a low pressure gauge on the inlet to the turbo. Even if you have to “monkey fluck” something as a temporary test set up. Say a 0-5 psi press gauge. I assume the pump is constant? Alway same speed same output?
With it set up I would shoot for an orifice to achieve around maybe 1 psi? Maybe not even that much

my next though is, how about no orifice?
route the drain line in a “u” fashion to the equivalent height that would achieve the bearings being partly flooded but not so much to flood the seal area. This will achieve constant supply of oil, free to flow at will, without starving the bearings at any point. And without pressuring the housing to the point of pushing oil out the shaft seals.

Restricting pump flow with orifices is not a good way to control them.
pressurizing a turbo center section by restricting the oil outlet isn’t very good either.

i wonder how it would fair with a constant flood? Some systems are not full flow, they just fill the center section and it stays in there. Then a line just keeps it full, but not pressurized. Basically on demand, if it consumed some oil it would be replaced to keep it full, but its not flowing thru.
MNT TEK turbo is like that.

just thinking outloud here.

 

[Dragonalain]

I’m pretty sure the jet is supposed to be on the inlet side of the oil. A turbo flooded with oil won’t light up as easy as there’s drag from the excessive oil. I’ve been restricting that same pump for 6 years before it ch!t the bed.

 

[kingcat162]

this one has the gears turning in my melon the system isn't vented at all - I'm thinking I should Jimmy a gauge on there - restricting the flow with the slow jet on the outlet would build pressure in the system I'm thinking - like squeezing the garden hose at the tip and spraying across the yard - I'm running synthetic 2 stroke oil in the system because if it blows by the seals at least it's just a bit of extra 2 stroke oil burning and not 15w40

 

[ABMax24]

What turbo are you running?

Those pumps aren't gear pumps, they're a pump made by Facet and called a "solid state" pump, but just have a magnetic piston in them that is driven back and forth when energized with a couple check valves to allow flow in only one direction. Some of these are capable of putting out in excess of 15 psi, and could be the cause of your oil bypassing the seals of the turbo if the output is restricted, Garrett recommends a large and free flowing drain back to the oil sump, any back pressure on the oil drain will cause oil leakage past the seals. If they are ceramic ball bearings (like a garrett 2860RS) they just need a small amount of oil for lubrication and cooling, unlike standard journal bearing turbos that need constant oil pressure to operate. Again this points me to a ceramic ball bearing turbo, because that pump would not keep journal bearings happy for very long at all.

All that being said the Garrett turbos are designed for 40-45psi of inlet oil pressure at max engine RPM and have a small 1mm orifice in them to restrict the oil flow to the bearings, using a low pressure supply will reduce flow to the bearings, if you believe oil starvation is an issue then pull this fitting and drill it out to 1.5mm to allow more oil to the bearings. FWIW though I've got a very similar system to yours, my turbo has over 5000km on it and is still going strong, I have no reason to believe mine is starved of oil.

On a terminology note this is a closed loop system, not an open loop, an open loop would be like the mountain tek turbos where 2-stroke oil is pulled from the engine oil pump, sent to the turbo, then returned to the engine. 2-stroke engines as a whole use open-loop lubrication, more commonly known as a total loss lubrication system, this system recycles the oil and is closed loop.

Finally, that system needs a vent; if you get any moisture, low vapour pressure volatiles, etc into that system the pressure has no where to go once heated up and evaporated. Well it has one place to go, and that's through the seals on the turbo and you already know how that's working out. Put a vent on the top of the reservoir, or like Boost-It used, a cap with a vent, theirs had a ball check in it so the oil couldn't flow out with the sled overturned, something else to consider.

 

[kingcat162]

What turbo are you running?

Those pumps aren't gear pumps, they're a pump made by Facet and called a "solid state" pump, but just have a magnetic piston in them that is driven back and forth when energized with a couple check valves to allow flow in only one direction. Some of these are capable of putting out in excess of 15 psi, and could be the cause of your oil bypassing the seals of the turbo if the output is restricted, Garrett recommends a large and free flowing drain back to the oil sump, any back pressure on the oil drain will cause oil leakage past the seals. If they are ceramic ball bearings (like a garrett 2860RS) they just need a small amount of oil for lubrication and cooling, unlike standard journal bearing turbos that need constant oil pressure to operate. Again this points me to a ceramic ball bearing turbo, because that pump would not keep journal bearings happy for very long at all.

All that being said the Garrett turbos are designed for 40-45psi of inlet oil pressure at max engine RPM and have a small 1mm orifice in them to restrict the oil flow to the bearings, using a low pressure supply will reduce flow to the bearings, if you believe oil starvation is an issue then pull this fitting and drill it out to 1.5mm to allow more oil to the bearings. FWIW though I've got a very similar system to yours, my turbo has over 5000km on it and is still going strong, I have no reason to believe mine is starved of oil.

On a terminology note this is a closed loop system, not an open loop, an open loop would be like the mountain tek turbos where 2-stroke oil is pulled from the engine oil pump, sent to the turbo, then returned to the engine. 2-stroke engines as a whole use open-loop lubrication, more commonly known as a total loss lubrication system, this system recycles the oil and is closed loop.

Finally, that system needs a vent; if you get any moisture, low vapour pressure volatiles, etc into that system the pressure has no where to go once heated up and evaporated. Well it has one place to go, and that's through the seals on the turbo and you already know how that's working out. Put a vent on the top of the reservoir, or like Boost-It used, a cap with a vent, theirs had a ball check in it so the oil couldn't flow out with the sled overturned, something else to consider.

Yes your correct a closed loop system with no vent - I took out the restrictor - the return line to the reservoir is larger than the line feeding the turbo - I'm thinking take the slow jet out and run her for a few 100 kms and then check the intake hose off the turbo for oil - I now need to figure out how to aquire a ball valve breather cap for my resevoir - maybe a fab/machine shop? - garret 2860rs ceramic bearings is what it is yup

 

[ABMax24]

Yes your correct a closed loop system with no vent - I took out the restrictor - the return line to the reservoir is larger than the line feeding the turbo - I'm thinking take the slow jet out and run her for a few 100 kms and then check the intake hose off the turbo for oil - I now need to figure out how to aquire a ball valve breather cap for my resevoir - maybe a fab/machine shop? - garret 2860rs ceramic bearings is what it is yup

I'm not sure where Boost-It sourced those caps, they look commercially made and just have a 1/4" hose barb on them to tie the vent line to.

By pulling that restrictor and venting the tank I think all your problems should disappear.

 

[kingcat162]

I'm not sure where Boost-It sourced those caps, they look commercially made and just have a 1/4" hose barb on them to tie the vent line to.

By pulling that restrictor and venting the tank I think all your problems should disappear.

I could drill the cap and put a Barb fitting if I find a ball valve breather that's goes in rubber line - just another thing to add to the list of things that had to be re-engineered on this sled - I also feel like my centre section issues should be over also after this

 

[kingcat162]

Hoping this works for me