Mcx nytro burning oil, can see it smoking out the exhaust. I have a few questions.

Tuesday · Feb 4, 2013

I tired a few things. First off i bumped the starter and sure enough the shaft and gear are spinning.(shear pin not broken)

Then i used a magnet and you can pull the 5 star section piece right out. The shaft would only come a small ways out. With the shaft partially pulled out the shaft will spin freely but when you push the shaft back in towards the motor you can feel the shaft lock up on what I assume is the shear pin.

I put in the m5 long bolts and tried to back off the pump but its on very tight and I did not want to mess up the threads so I never did get the pump all the way off.

Breather hose of mcx return line is free and clear. All oil lines are free. Oil was basically brand new.

Could use some thoughts and suggestions.

Again you can smell oil when driving around but it only appears to burn out the exhaust with a short run (with load) then shut it off.

Thanks.

Tuesday · Feb 4, 2013

Sent an email to Erik see if he has some insight.

Spoke with Chad at CR racing, he mentioned sometimes the lines can get frozen and will see oil push pass the seals. That is not the problem with mine just an FYI.

His thoughts where possible the turbo is failing, pull the turbo and have a look for oil puddles and look into the charge tube.

Guess I am going to be dropping the skid and looking at some internals.

Any other suggestions?

Sleds R Fun · Feb 4, 2013

Charge tube

I know your smokin fron the exhaust but while u have it apart check half moon shells along left side of motor, the charge tube pushes them in! Valve seals?

08nytromtxa · Feb 4, 2013

oil

how many miles on sled since first smoked on the cold start? if the oil was cold it would push past seals and fill your exhaust pipe. therefore would take quite awhile to burn out all that oil.. seen it lots on my powderlites when it had the hindle exhaust pipe on.

Tuesday · Feb 4, 2013

Artic Cat said:
I know your smokin fron the exhaust but while u have it apart check half moon shells along left side of motor, the charge tube pushes them in! Valve seals?

Just changed the half moons last winter.

Tuesday · Feb 4, 2013

08nytromtxa said:
how many miles on sled since first smoked on the cold start? if the oil was cold it would push past seals and fill your exhaust pipe. therefore would take quite awhile to burn out all that oil.. seen it lots on my powderlites when it had the hindle exhaust pipe on.

I am beginning to wonder about this myself. The night I pulled if off the deck it wasnt that cold out maybe -15c idled for about 5-7 min while a screwed around getting it off the deck and into the heated shop.

Prob only put on about less then 5 km since this oil burning started.

Put everything back together and put it on stand and ran it for awhile, no oil smoke during or after so maybe it had to burn out. Never sees load on stand so I will give it a test in the day light tomorrow and give it a good burn.

If it continues to smoke after running I will pull the turbo and charge tube apart and have a look

Thanks for the ideas.

relentless rider · Feb 5, 2013

Check your crankcase breather Holes, take it off and blow through it .I've had mine get full of water and freeze .

Tuesday · Feb 5, 2013

relentless rider said:
Check your crankcase breather Holes, take it off and blow through it .I've had mine get full of water and freeze .

Its been in a heated shop for 10 days, i would guess its thawed by now but i will double check the hoses again.

Tuesday · Feb 5, 2013

Went for a 30 min rip, when i would slow down and turn every so often i could smell hot oil. Never could see and drips or oil smoke.

Put it back the shop and no oil fumes out the exhaust. Maybe it was a fluke and had to burn off the oil?

Will keep riding it and see what happens i guess.

Sleds R Fun · Feb 6, 2013

Smoke

Did you roll the machine or anything on last sled trip!

Tuesday · Feb 6, 2013

Artic Cat said:
Did you roll the machine or anything on last sled trip!

Not once. First time i have noticed this.

Octanee · Feb 6, 2013

well, i think i've read the thread, and it appears you have NOT checked your turbo...?

if so, that would be the place to look, you havent pulled your charge tube off?, i'd bet any money that your oil seal for the turbo, probably exhaust side is done for, its seeping oil out and the exhaust heat/turbo is burning it, thus why it takes a bit for this to occur is because the turbo needs to warm up.... or could be oil from compressor side being spat out into your intake and engine is burning the oil from that?

also everything warms up it expands too, so it may not leak so much cold.... but the heat of the turbo its self could cook the oil

but from experience on reading truck forums and other turbo sleds.... im putting my money on your turbo!, so pop your exhaust side off of the turbo, and take a good look, feel your shaft for play, any play up and down to a certain extent could cause a oil leak, but also a seal, so i'd imagine you could see the turbine/propellors ( what ever they are called

) probably wet with some oil if that is the cause,.... it is clear its coming out of your exhaust (or atleast from the video it appears to be) but the compressor side you probably wont see any oil on them, it should be coating your charge tube if its that side/the problem

Tuesday · Feb 7, 2013

Octanee said:
well, i think i've read the thread, and it appears you have NOT checked your turbo...?

if so, that would be the place to look, you havent pulled your charge tube off?, i'd bet any money that your oil seal for the turbo, probably exhaust side is done for, its seeping oil out and the exhaust heat/turbo is burning it, thus why it takes a bit for this to occur is because the turbo needs to warm up.... or could be oil from compressor side being spat out into your intake and engine is burning the oil from that?

also everything warms up it expands too, so it may not leak so much cold.... but the heat of the turbo its self could cook the oil

but from experience on reading truck forums and other turbo sleds.... im putting my money on your turbo!, so pop your exhaust side off of the turbo, and take a good look, feel your shaft for play, any play up and down to a certain extent could cause a oil leak, but also a seal, so i'd imagine you could see the turbine/propellors ( what ever they are called ) probably wet with some oil if that is the cause,.... it is clear its coming out of your exhaust (or atleast from the video it appears to be) but the compressor side you probably wont see any oil on them, it should be coating your charge tube if its that side/the problem

This has been my thought all along but I have been doing some testing to rule out other easier possibilities. I will drop the skid, pull the turbo and see what the internals look like.

Later

kimoaj · Feb 7, 2013

A turbo can have some freeplay up and down on the turbine wheel, its normal.
However ofcourse there are limits, at work we use a micrometer with a special tip to measure the freeplay of the turbine wheel.

Axial freeplay (in and out) is worse, if you have any axial play at all the bearings are shot.
(this goes for the turbos on the marine diesels I work on at work, however I do think the basics are the same).

Octanee · Feb 7, 2013

kimoaj said:
A turbo can have some freeplay up and down on the turbine wheel, its normal.
However ofcourse there are limits, at work we use a micrometer with a special tip to measure the freeplay of the turbine wheel.

Axial freeplay (in and out) is worse, if you have any axial play at all the bearings are shot.
(this goes for the turbos on the marine diesels I work on at work, however I do think the basics are the same).

all i know is if your turbine can scrape the housing on the compressor or exhaust, thats too much wear/play, or atleast im pretty sure...., but in my books its too much

boostedballz · Feb 8, 2013

There are no oil seals in a Mitsubishi turbo. They are different than a ball bearing set up. It uses a bushing style set up that moves on oil clearence. This is why you will sometimes get oil in the exhaust if the sled sits vertical for a few moments (eg stuck climbing a steep hill). Advantages to this system is you have essentially infinite bearing life unless debris gets in to the oil damaging the surfaces. Disadvantages are they are extremely sensitive to proper venting any pressure build up will cause oil to push out of the bearing cartridge and in to the intake and exhaust housings. Half a tablespoon of oil in the exhaust can smoke for a suprisingly long time. To me this sounds like a venting issue whether it be temporary (frozen vent line) or still existing (pinched vent line). In a case of a sheer pin or damaged turbo cartridge you would be getting mass amounts of smoke much more than the amount described. It is rare to see a cartridge fail and usually occurs shortly after an engine failure when debris gets in to the oil system. We sell maybe 5-6 cartridges a year given the 4-5000 kits on the snow many of which have big miles on them it is a very low failure rate.

LL
McXpress North America

Tuesday · Feb 9, 2013

boostedballz said:
There are no oil seals in a Mitsubishi turbo. They are different than a ball bearing set up. It uses a bushing style set up that moves on oil clearence. This is why you will sometimes get oil in the exhaust if the sled sits vertical for a few moments (eg stuck climbing a steep hill). Advantages to this system is you have essentially infinite bearing life unless debris gets in to the oil damaging the surfaces. Disadvantages are they are extremely sensitive to proper venting any pressure build up will cause oil to push out of the bearing cartridge and in to the intake and exhaust housings. Half a tablespoon of oil in the exhaust can smoke for a suprisingly long time. To me this sounds like a venting issue whether it be temporary (frozen vent line) or still existing (pinched vent line). In a case of a sheer pin or damaged turbo cartridge you would be getting mass amounts of smoke much more than the amount described. It is rare to see a cartridge fail and usually occurs shortly after an engine failure when debris gets in to the oil system. We sell maybe 5-6 cartridges a year given the 4-5000 kits on the snow many of which have big miles on them it is a very low failure rate.

LL
McXpress North America

Thanks this is very helpful. Shear pin is fine, and smoke seems to be getting less all the time. I need to do some more riding to see if its gone.

judger101 · Nov 27, 2013

I know this thread is old, but I had a similar problem last season. I believe it was due to a frozen breather vent line. i was also blowing oil out the turbo.

Tuesday · Nov 28, 2013

Eventually mine cleared up and has never done it since.

I think the one oil return line was getting pressure from the fuel tank and causing increased pressure back to turbo. After disassemble and reassemble problem went away.

GL

Mcx nytro burning oil, can see it smoking out the exhaust. I have a few questions.

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