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I did some testing tonite. Decided it was time to see the 'real' temp of the oil. I used a calibrated digital thermometer and came up with some interesting readings.

I gave my FST a beating on some deep wet snow. When I stopped and let the machine idle to cool down the temp was 162. While riding it never got above 163. When I shut it down the temp raised to 169. I checked my oil and it was above the Full mark. I stuck the temp probe in the filler/check neck and low and behold the temp increased to 205. Kinda surprised me. What even surprised me more was the fact that in order bring the level down to the 'ADD' mark I sucked out over 12 ounces. Hard to believe there is that much fuel getting into the oil. I was sure I pumped out all the oil at the last change and I only added 3 quarts with the filter. Anyhow now it's back to the 'ADD' mark.
I took out for a second hard run and I had the same results, except the level was where I had left it , at the 'ADD' mark. We'll see after a few hundred more miles where I'm at.
I'm really getting more confused as the time goes on with this German whiz bang motor. Sorry for the incorrect date on the pics, they were taken on Jan. 4, 2007.

NOTE: The test I did with the oil temp was on a '06 FST Classic with all the updates and stock thermostat. The outside temperature was at 31*F. when testing was done on mostly deep heavy snow at near wide open runs.

The oil temp was checked while engine was idling after the run, and continued to check temp after engine was shut off. The highest temp that was seen was 205*F. which remained there for at least 5 minutes after engine was shut down. These engines really hold the heat for a long time.

It really baffles me that there is any fuel that that should be entering into the lubricating system unless it is getting in there from the fuel delivery system in excessive amounts during start up. What am I missing here?

I may change out the thermostat to the a 180* Car Quest unit and then do some more testing or maybe I'll just ride the bitch and let 'er buck.

[attachment=279927:DecJan__06_009.jpg]
[attachment=279928:DecJan__06_013.jpg]
 

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Great testing real-steel. It is good to see actual numbers!

I am curious to know if the FS models are affected with the same problem, or this is just an issue with our FSTs? If it is just an FST issue, I am guessing that the majority of the fuel in our oil is arriving during high boost, cold motor conditions before the combustion chamber/cylinders are fully heated. With the high cylinder and fuel pressures that we get with our engines, this is just a thought.

In the end, I think I may just "drop" that 180 degree thermostat in anyway. I don't really want to do that much work, but it may be the only option that we have. I have had all of the updates done as well, but I know that my FST isn't operating any warmer with that insert in the cooler (at least on the MFD reading).

The other thing that I was thinking of was ditching the factory "liquid" cooler that Polaris gave us and going to a remote automotive style of stand alone oil cooler. This may give a better control of oil temperature than what we have now.

P.S. Good job on the topic title (listing the FST). I guess this is just a habit we need to get into!
 

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I posted this on the other FST thread talking about this:

Huge factor on diluted oil is cold start enrichening and how long it takes to get to operating temp. The colder the engine, the more clearance between pistons, rings, and cyl wall. With a ton of fuel dumping, it will wash the cyl walls down and get passed rings into crankcase.

Oil should get to min of 160°-180° before WOT blasts are performed. Some 'burn off' will happen to oil around 180°, but 210° is much better. Oil works fine in the 250° range believe it or not.

If these engine's don't have a oil temp thermostat and route it thru an oil to air or snow cooler, this can be an issue. Oil should bypass an oil to air or snow cooler until at 180° or higher. If the cooler uses engine coolant, than it is fine, since coolant temp will rise faster than oil and bring oil up to temp faster.

I read earlier today about cold start issues - therefore I believe these two will be related if issue is 'too rich' at start up.

Do these engines have a crankcase breather system ? If not or restricted - this can trap all moisture that's trying to burn off also.
 

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Do these things really need that much cooling capacity?

It seems like they have alot of cooling capacity - I thought I had read on this board that someone had actually removed some of the cooling capacity from this engine.

:dunno:
 

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Do these things really need that much cooling capacity?

It seems like they have alot of cooling capacity - I thought I had read on this board that someone had actually removed some of the cooling capacity from this engine.

:dunno:[/b]
I have been looking into removing the front radiator on mine, but haven't done so yet. My dealer called both SLP and the Polaris race department and was told to not do this no matter what. I say WTF as the engine doesn't get warm enough anyway. I was told that the SLP radiator removal kit for the 900/700 (big block) RMK will not fit the FST. I may just go this route on my own. If I do, I'll post pics of the work and the results.
 

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I have had all of the updates done as well, but I know that my FST isn't operating any warmer with that insert in the cooler (at least on the MFD reading).
P.S. Good job on the topic title (listing the FST). I guess this is just a habit we need to get into![/b]
The oil cooler insert (update) will not have any effect on the MFD reading. The MFD reading is coolant temp. The insert raises oil temp in the oil resevoir.
 

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I posted this on the other FST thread talking about this:

Huge factor on diluted oil is cold start enrichening and how long it takes to get to operating temp. The colder the engine, the more clearance between pistons, rings, and cyl wall. With a ton of fuel dumping, it will wash the cyl walls down and get passed rings into crankcase.[/b]
100% correct.

Oil should get to min of 160°-180° before WOT blasts are performed. Some 'burn off' will happen to oil around 180°, but 210° is much better. Oil works fine in the 250° range believe it or not.[/b]
Good info!

If these engine's don't have a oil temp thermostat and route it thru an oil to air or snow cooler, this can be an issue. Oil should bypass an oil to air or snow cooler until at 180° or higher. If the cooler uses engine coolant, than it is fine, since coolant temp will rise faster than oil and bring oil up to temp faster.[/b]
The oil is going over 200 deg. as real-steel posted, so I think the sleeve is working.

Do these engines have a crankcase breather system ? If not or restricted - this can trap all moisture that's trying to burn off also.[/b]
Yes, part# 2520541 Separator, Oil/Air (Called ventilation cyclone in service manual) It is used to return unburned fuel vapors present in the oil storage tank to the air intake system as well as oil mist back to the engine sump.
 

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The oil is going over 200 deg. as real-steel posted, so I think the sleeve is working.[/b]
I read it was only doing this when shut-off ? Not enough time. It will raise for a little since there is no circulation, and then begin to cool off quick.
If you boil water in two exact same pots with same amt of water and you boil one for 1 minute and the other for 2 hrs - which will have less water ?


We need the oil temp to come up to this temp as fast as possible, which is hard when running easy with no oil temp thermostat.

I have worked on this issue with many a performance motor since they usually have a light tension ring pack, large ring gaps, and loose tolerance forged pistons. Add to this, the very cool water temp (100°-120°) for max power. Many have oil coolers fed by unrestricted cold water supplies. These things dilute the oil something fierce.

Fuel calibration is #1 issue with gas diluted oil.
#2 issue is tied between low tension rings/large ring gaps/loose piston clearance + low oil temps.
#3 deal with water condensation - not getting oil to water boiling point (212°) will keep moisture in oil. 180° reduces this but 212° get's rid of it quick.

Time at proper operating temp (coolant and oil) is what we are looking for.

===========================

If we start our engines and shut them off before temps come up enough, or for only a little time when at proper temp, we have not done anything but add more water and fuel to our crankcase. That's why Grandma's car usally has oil issues.
 

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100% correct.

Good info!
The oil is going over 200 deg. as real-steel posted, so I think the sleeve is working.
Yes, part# 2520541 Separator, Oil/Air (Called ventilation cyclone in service manual) It is used to return unburned fuel vapors present in the oil storage tank to the air intake system as well as oil mist back to the engine sump.[/b]
Snowbeeler, you covered it pretty well.

as real-steel posted, the sleeve in the oil cooler is working to raise the oil temperature up to an appropriate range in my opinion. 200F is good for removing any fuel in the oil.

On MY07 sleds I have observed that in certain conditions they still run significantly below the 154F area where the factory thermostat opens up. When running at 20-30 mph on smooth trails, at 25F, the engine coolant temp. was between 130 to 140F. It seems that even with the coolant flow restrictor that is in the radiator/oil cooler loop for all FST's, the radiator system can pull out all the heat that it is producing.

Opening up the black cleanout lid near the hood hinge, and putting some duct tape or cardboard to partially block the air flow to the radiator, could help fix this 'low-load overcooling' problem. You could duct tape the 'grill' in the front nosepan also. It is possible that some of this overcooling is caused by bleed past the thermostat when closed, but the front heat exchanger is the first place where this bleed would go, and the front heat exchanger does not seem to warm up at all until the engine temp. gets to around 150F.

I am sure that some of the thermostats are sticking or opening at the wrong temperature, but I think that most are consistent around 150-155F opening.

==========

Regarding a crankcase breather:

Our sleds have a engine oil sump pump in the crankcase that pumps oil out of the engine, thrut the oil cooler and into the reservoir. It pumps much faster than the engine oil pressure pump, so it sucking in some air and all crankcase blowby. That is the reason for the cyclone separator referred to, to remove the air and crankcase blowby(which contains some fuel vapor) from the foamy oil skimmed from the top of the reservoir, so relatively liquid oil without foam can be fed from the bottom of the oil reservoir to the engine oil pressure pump.
 

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Sounds like a dry sump system.

So.........The oil + crankcase blowby is routed thru the oil cooler before it goes in the sperator / resevoir that then goes directly to oil pump and engine ?

I'm assuming that there is a breather system attached to the top of this seperator ?

Sorry for all the questions - Iknow a good deal about this stuff but do not have one of these FST's myself. Just trying to help.
 

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I read it was only doing this when shut-off ? Not enough time. It will raise for a little since there is no circulation, and then begin to cool off quick.
If you boil water in two exact same pots with same amt of water and you boil one for 1 minute and the other for 2 hrs - which will have less water ?
We need the oil temp to come up to this temp as fast as possible, which is hard when running easy with no oil temp thermostat.

I have worked on this issue with many a performance motor since they usually have a light tension ring pack, large ring gaps, and loose tolerance forged pistons. Add to this, the very cool water temp (100°-120°) for max power. Many have oil coolers fed by unrestricted cold water supplies. These things dilute the oil something fierce.

Fuel calibration is #1 issue with gas diluted oil.
#2 issue is tied between low tension rings/large ring gaps/loose piston clearance + low oil temps.
#3 deal with water condensation - not getting oil to water boiling point (212°) will keep moisture in oil. 180° reduces this but 212° get's rid of it quick.

Time at proper operating temp (coolant and oil) is what we are looking for.

===========================

If we start our engines and shut them off before temps come up enough, or for only a little time when at proper temp, we have not done anything but add more water and fuel to our crankcase. That's why Grandma's car usally has oil issues.[/b]
CFM, you are making some very good points and supplying good info :beerchug: I had asked Real-steel to be more specific on when he checked the oil temp and he did reply it was after a hard run and still running.
 

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Sounds like a dry sump system.

So.........The oil + crankcase blowby is routed thru the oil cooler before it goes in the sperator / resevoir that then goes directly to oil pump and engine ?

I'm assuming that there is a breather system attached to the top of this seperator ?

Sorry for all the questions - Iknow a good deal about this stuff but do not have one of these FST's myself. Just trying to help.[/b]
It is most certainly a dry sump system.

If you go to Polaris online parts and look at Snow, 2007, FST IQ CRUISER.

open the Oil Cooling System and you will see it laid out. About the only siginficant thing missing is that the liquid from the bottom of the cyclone separator goes down to the sump, not the pressure pump. The air from the cyclone goes to the air intake box above the clutch guard.
 

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Sounds like a dry sump system.

So.........The oil + crankcase blowby is routed thru the oil cooler before it goes in the sperator / resevoir that then goes directly to oil pump and engine ?

I'm assuming that there is a breather system attached to the top of this seperator ?

Sorry for all the questions - Iknow a good deal about this stuff but do not have one of these FST's myself. Just trying to help.[/b]
Yes, dry sump. Here is the overview out of shop manual.

[attachment=280077:Lube_Overview1.jpg]
 

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Thanks for the diagram - saves my other hundred questions. LOL.

Damn!
They put the oil/vapors thru the oil cooler before it can be vented. Well, well, well isn't that a kick in the ass. We are cooling off the oil/vapors befor we vent it !!!! Schit ! Plus, we are giving more time to reintroduce the vapors/consensation/etc back into the oil. Double poop. LOL.

Okay - what we need to do is measure the oil temp in the oil storage tank after these hard runs or long running time.

Why the heck isn't the oil cooler mounted in the presssurized side ?
 

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Reread 1st few posts. He was measuring temp at oil container.

Okay 206 degrees is fine. Still don't like the vapors and such going thru cooler to, but let's move on.

Excursion - you mentioned times in which coolant temp got pretty low while cruising. This could be important with fuel trim. At what coolant temp is fuel enrichment no longer ? Many 4 cycles will be around 160 degrees. Some are at 175-180 degrees. If these things are running around still in the fuel enrichment mode (cool coolant temp) this could add to the situation.

Anyway, for now, if the vent really is venting properly to the air intake system and the oil fill bottle is getting to 180°+ for extended periods of time, I would blame it on too rich programming where too much unburnt fuel is making it's way back into the crankcase. Couple this with the cold start problem (programming) you guys seem to be having is probably the biggest factor of this.
 

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Discussion Starter · #16 ·
Reread 1st few posts. He was measuring temp at oil container.

Okay 206 degrees is fine. Still don't like the vapors and such going thru cooler to, but let's move on.

Excursion - you mentioned times in which coolant temp got pretty low while cruising. This could be important with fuel trim. At what coolant temp is fuel enrichment no longer ? Many 4 cycles will be around 160 degrees. Some are at 175-180 degrees. If these things are running around still in the fuel enrichment mode (cool coolant temp) this could add to the situation.

Anyway, for now, if the vent really is venting properly to the air intake system and the oil fill bottle is getting to 180°+ for extended periods of time, I would blame it on too rich programming where too much unburnt fuel is making it's way back into the crankcase.[/b]
Bingo..........Too much fuel enrichment
 

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WoW!
You guys really know your chit!!

So we gonna get another map and lean this sucker out like it's supposed to be or what? 12 oz of gas into the oil after short runs sounds like a hell of a lot of gas to me. I just can't understand why Polaris won't lean it out .... surely they can figure this stuff out?
 

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At what coolant temp is fuel enrichment no longer ? Many 4 cycles will be around 160 degrees. Some are at 175-180 degrees. If these things are running around still in the fuel enrichment mode (cool coolant temp) this could add to the situation.[/b]
I am pretty sure the sled goes "closed loop" above 128 deg. "Closed loop" is when fuel delivery is not richened.
 

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I'd find out about that. You know what assuming does. LOL !!!

If that's true than we - okay, you - are dealing with the typical cold start fugg up. Happens all the time with many manufacturers, as I said before.

If you can find the -10 degree (or whatever) temps the issues are at - how long is the coolant at -10 after engine get's fired up. That's the deal - hard to blame the manufacturer unless that same issue is there for years after.

Has anyone witness any injector flowing fuel when engine is started below freezing ? Below 0 ? It is unfrickin believable how much fuel comes out of those suckers even when programmed correctly !

=============================

One way to find out - try the resistor thing I talked about earlier when it get's this cold. Super easy to do if the coolant temp sensor plug is easily accessible.
 

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I am pretty sure the sled goes "closed loop" above 128 deg. "Closed loop" is when fuel delivery is not richened.[/b]
In other words, if we could "piggyback" the temp sensor to show no lower than 128 degrees we would 'disarm' the fuel enrichment circuit. Now the $10 question is if the cold engine starting would be adversely effected.
 
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