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Never mind re: oil capacity. I just changed the oil and filter and measured what came out and added a few ounces for the filter...Now I know...

Regards,

FarmGeezer
The manual calls for about 2 quarts but your method works well. :)

I have noticed some shops just fill to the dip stick hole. I thank that is a bit over full but not if that is an issue for the 325 engine.
 

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Castrol 5w50 is what I just put in. If not that I would use rotella 5w40
Tone I was wondering if you had logic for going with the 5W-50 Castrol?

I have 5W-40 Rotella in the running 2002 Magnum 325 but two shops and the web talk about lack of cam lube at idle.
The project 2002 Magnum 325 (guy blew an oil line driving to shop two miles from his farm) we just got Saturday I expect has a spun rod bearing, etc. He started it for 3 seconds and the idle was great and no knocking but he said if shifted into gear it would start knocking and die.

Since it is a shop project for the 16 year old son (and daughter to a degree) I hope we can get it running on the cheap just for the experience if the crank is still smooth but odds are low I am sure. If that does not hold up then we will come back with new crankshaft , etc. It would cost us the price of the gasket set and inserts. I was thinking of Castrol 20W-50 but did not know about the 5W-50 option. It might be good to help cam lobes too.

Anyone know if the Polaris 325 engine with rod caps like most cars have inserts are sold in sizes other than like standard, .010, .020 undersize inserts.

Anyone know if there is a source of for like .001, .002 undersize rod bearings. 50 years ago this was common when rebuilding old motors under the shade tree. I know they were not high RPM high performance engines. :)
 

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I sure as hell would NOT run 20W-50!
 

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20W-50 Motor not good below 20F

I sure as hell would NOT run 20W-50!
True you would not want to run it when it was below 20F degrees outside. After warmed up and running 5W50 and 20w50 should offer about the same features.

The .002 gap between the rod bearing inserts and crank needs to be filled with motor oil to have a good film strength.
 

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It's the "warm up part" that's the problem with oil 4x heavier than spec'ed......that's the problem. Run it if you like, just stating I sure as hell would not.
 

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New news to at least one. :)

I have been buried in my 2002 Polaris shop manual and I thought 0W-40 was current.

You are correct you do not want too thick of oil on start up. Per specs from the maker 20W-50 should not be used if the air temps are going to be below 20F on start up to insure good lube at start up.

Polaris 2W-50 means owners do not have to think about air temps in most of the world. My age and physical limitations do not encourage me to be riding an ATV when the temps are below 20F. :)

Now I do understand 500 owners have a real concern where when hot max oil PSI is typically 20 PSI where as the Magnum with the 325 like we have in each standard oil pressure hot and full speed is 71-99 PSI.

It seem like the cams get eaten in a lot of Polaris engines due to low PSI. I am going to plumb in oil gauges one day so I can see the idle PSI difference between hot 5W-50 and 20W-50 synthetic motor oil. In my case with the 325's we need min of 20 PSI at idle so prevent cam damage per Polaris.

The 500 version only needs 12 PSI to prevent cam damage per 2002 Polaris shop manual that we use.

Again it was last night when I first heard of 2W-50 motor oil and like others thought it was a typo. :)

Have you pulled physical oil PSI reading from your engine and if so what do you see at idle and WOT?
 

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5W-50 is really close to 2W-50 too. :)

Sticking with the manual specs is a safe bet. Until yesterday I thought 0W-40 was what Polaris motor oil was so I put in the 5-40 Rotella since I have been using it for all the gas and diesel stuff we change oil in around the place. When I get some manual oil pressure gauge taps added to our oil lines I want to see if what the idle PSI is for 5W-50 and 20W-50. In theory hot both should be 50 weight oil but testing will tell the tale. :)

Is your 400HO engine oil pressure specs low and more like the 500HO? I think the 99 PSI max in the 325 engine is the reason the cooler lines fail so often. At 300F and up to 99 PSI is very demanding of rubber hoses. I am going to look at how hatzie plumbed his 500HO to add oil pressure gauge. I am thinking of picking up one or two of the HF $25 manual oil pressure test kits. I may plumb one into the 1983 John Deere 310B since it just has the light.

Engine Oil Pressure Test Kit
 

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5W-50 is really close to 2W-50 too. :)

Sticking with the manual specs is a safe bet. Until yesterday I thought 0W-40 was what Polaris motor oil was so I put in the 5-40 Rotella since I have been using it for all the gas and diesel stuff we change oil in around the place. When I get some manual oil pressure gauge taps added to our oil lines I want to see if what the idle PSI is for 5W-50 and 20W-50. In theory hot both should be 50 weight oil but testing will tell the tale. :)

Is your 400HO engine oil pressure specs low and more like the 500HO? I think the 99 PSI max in the 325 engine is the reason the cooler lines fail so often. At 300F and up to 99 PSI is very demanding of rubber hoses. I am going to look at how hatzie plumbed his 500HO to add oil pressure gauge. I am thinking of picking up one or two of the HF $25 manual oil pressure test kits. I may plumb one into the 1983 John Deere 310B since it just has the light.

Engine Oil Pressure Test Kit
Just checked my service manual, oil pressure @5500 rpm is 20 psi, 12psi minimum.
 

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I run Rotella Full Synthetic and it works great. Royal Purple is too expensive but I know hey are an excellent lubricant.
 

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OK the 400/500HO's have the same oil pressure specs as in our 2002 Polaris shop manual.

One guy with a near by ATV/Harley shop said they are replacing the oil pumps with an after market pump when these engines loose the lobes off their cams due to this design weakness. I was told it was the exhaust valve lobe that stared for oil the worse but do not know enough to understand the logic behind that.

All I know from two ATV shops that do a lot of cam replacements is if you let these engines idle down to where oil PSI drops below 12 PSI that in time you WILL drop a lobe off your cam. For those having shops to fix these engines ask about the replacement oil pump options and removing the one way valve that can stick and reduce oil flow to the cam. For what I remember from a couple weeks ago the the one way valve is not needed with the new oil pump.

I am not finding any after market oil pump options for the 500 so I will ask the shop owner for more details the next time I see him.
 
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