Motor Oil Ratings

Discussion in 'Softail Models' started by Billbo, May 9, 2011.

  1. Billbo

    Billbo Junior Member

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    Hello to all - this is NOT another usual OIL question. I have an 2001 Heritage, the owners manual says to use diesel oil with api ratings CF,CF-4,CG-4,CH-4. That was back in '01. Now days the oils have ratings such as SH,SJ,SL. My question, which S_ ratings are EQUAL to the OLD C_ ratings? I have looked on the internet and api site to try to figure it out - so the best thing for me to do is ask that question right here on the Forum.

    Thanks all
    Bill
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Bill,

    I think the OM is offering that as an option if a VTwin 20w-50 engine oil can not be found, and intends that use to be short term. Are you considering using a diesel engine oil RATHER than a premium full synthetic VTwin engine oil?

    Back to your question though, I think you will find the "C" ratings on the manufacturer's websites for their various products. Here is Mobil's for their Delvac 1300 as an example:

    Mobil USA | Heavy-Duty Engine Oils | Mobil Delvac 1300 Super

    TQ
     
  3. dbinbc

    dbinbc Active Member

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    I can't help with the ratings question but the reason the MC suggests Diesel engine oil as an alternative is that it is made to withstand the higher heat levels that diesel engines produce (or at least use to a few years ago), and the higher mechanical demands put on the oil. Oils formulated for cars don't have to withstand the high temps. Our air cooled bike engines can get pretty hot.
     
  4. Billbo

    Billbo Junior Member

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    thanks TQ and db ..... I have a 2001 w/45K miles and I have been advised by HD (and this forum) to stay with dino oils instead of full syn. now - HD360 costs me $8 a qt. That is why I am looking for another dino oil less than $8 that meets the owners manual for the C_ oil rating requirements. IF I have to pay 8 dollars for HD360, then, like Jack said, I may as well be using M1 full syn. BTW I did buy Valvoline VR1 racing oil 20W50 for $4.69 a qt. --- another reason for not buying the HD360. Just would like to know IF the new dino oils meet the C_ ratings of yesteryear.

    Bill

    Bill
     
  5. propflux01

    propflux01 Active Member

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    the "C" ratings your referring to are not "old" ratings per se. They are Commercial ratings. Still very well in use today. The current "C" rating is "CJ-4", mainly used in 2007 up diesels. The former, "C-4" ("C4 Plus", and "AH-4") was implemented in 1994. Generally, SAE "S": ratings cannot be used in place of "C" ratings, but the "C" ratings can be used ( in certain vehicles) in place of "S" ratings. The main difference in the two are the additives in "C" rated oils often exceed those allowed in Passenger car oils ("S") oils, causing issues with Catalyst. As for passenger car oil not able to withstand heat of diesel oils, that is not correct. Both can withstand heat the same, as both usually have the same or very similar flash points in equal grades. Again, its the additive compatibility that makes the difference
     
  6. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Really? Who gave you that advice?

    I personally think that there are NO disadvantages to switching to a premium FULL synthetic VTwin 20W-50 engine oil for your 2001. I also think that your 5 speed OEM tranny will do VERY well with a FULL synthetic GL-5 rated 75W-140 gear lube even though a GL-1 will suffice. And the primary should have a fit-for-purpose wet clutch/chaincase lube like HD Formula + or Spectro Primary.

    But it is your bike, so you decide.

    TQ
     
  7. jethro706

    jethro706 Member

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    the "s" is for spark combustion as in spark plug as in gasoline engines. the "c" is for compression combustion as in a diesel engine. if you check out the 20W50 mobil vtwin oil, it will have rating for the diesel engine oil. as with the air cooled engines, diesels are concern with great amounts of heat also. that is besides the lubrication aspect of the oil. I plug the mobil oil due to this what I use. you have to decide which brand to use. not starting an oil war.

    most oil websites, you can figure out if the additive packages meet your needs. you to check out all the data sheet information you can find. they don't always list the same way.
     
  8. glider

    glider Veteran Member

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  9. Billbo

    Billbo Junior Member

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    Thanks TQ - I do run synthetic on my trans and formula + in the primary. Im OK with the dino oil in the engine - just not HD360 at $8 a quart!

    Thanks propflux - if you go to an autoparts store and look at all their oils - most all of them have something like SN or SJ or S-something but NO C anything. Thats why I asked the question - how do I cross reference?

    - Thanks also - I read the C is for compression ignition and the S is for spark ignition. My HD manual says to use CF,CF-4,CG-4, CH-4 - so what S number equals any of these C numbers??

    Thanks again to all that responded - I really have lots of faith in this group and the information and advice you all give.

    BILL

    I would like to add here - that I believe the M1 VTWIN oil does reference a C_ designation. I just might HAVE to use M1. :) I also think it is the only synthetic that refers to a C_ rating.

    Bill
     
    Last edited by a moderator: May 10, 2011