Welcome Guest - Sign Up today
Welcome Guest - Sign Up today
Store Links Mobile - Shop Now

Announcement

Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

what motor oil should I use

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • what motor oil should I use

    My 1996 4.3 l mercruiser calls for an SG grade oil. After searching the web it seems that designation has been superseded to SM. No problem there. What viscosity though? 20/50 ? Conventional or full synthetic? I don't know what's in there now. Can I go to a full synthetic safely? I live in Northern California where temps can go as low as 25-30 degrees. I'm planning on using the boat in the colder months more this year. Whats a good choice given those conditions. The boat is only used in freshwater lakes.
    1996 Glastron 185GS fish and ski
    4.3LX Gen+ (190 hp 2 barrel carb)
    Alpha 1 Gen 2 S/N 0F 845543

  • #2
    20W-50 is too heavy for that engine. I use Shell Rotella 15W-40 in in my '97 Mercruiser 5.7 EFI. The diesel oils have more of the antiwear compound that is needed for the distributor gears, etc.

    Comment


    • #3
      Not a big fan of taking an older motor to high detergent diesel oils if they were not used in it before. Plenty safe to use a automotive 10-30 or 5-30, depending on local temperature ranges.

      I have seen a couple older motors that DELO was introduced and the motor basically failed after a short period of time.

      There is always a lot of differing opinions around here on oil. You're probably safe using pretty much anything quality in a normal viscosity range for your climate, even a DELO.. Personally I don't use a synthetic, I don't get enough hours in a year to justify the longer life of synthetics, and there is really no downside to a 50 hour annual oil change using standard non-synthetic oils.
      17 Foot '90 Bluewater
      Alpha 1 3.0 Merc - repowered in 2016
      now - 4.3L Vortec - Alpha 1 GenII
      Honda BF100L kicker
      Engine custom - Transom 0D65328 - Drive 0D648864
      If you ain't fishin, then yer working too much.

      Comment


      • #4
        manual calls for 20W-40 or 20W-50
        1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

        Past Boats
        1970 Wooster Hellion - Merc 9.8
        2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
        1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

        What’s behind you doesn’t matter.Enzo Ferrari

        Comment


        • #5
          If you only boat in warm weather then no need for a multi grade, straight 40W is good
          94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
          95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
          07 SeaDoo GTX
          Raw Water Pump Maintenance
          Merc Adults Only
          G-Dad always said "First Liar doesn't stand a chance"

          Comment


          • #6
            The can of worms has been opened,
            And certainly not for the first time. I agree that a good quality oil is prudent, at a viscosity appropriate to expected low and high temperatures. This motor has a total of maybe 1500 hours on it since new. In my truck I use 5W/30 as recommended by the manufacturer. It has 160K on the clock. The manufacturer recommended weight oil for this 4.3 is 20W/50 as set for a new motor built in 1996. Motor oil additives have changed and improved during those years. I'd say I'm having trouble appreciating the increased level of maintenance required on a boat motor. I just don't understand why it's that much different. I'm over thinking this but the conversation is interesting. I'm going to check with a trusted marine mechanic and just see what he says. As always, the input of this group is quite valuable to me.
            Thanks,
            Jcris
            1996 Glastron 185GS fish and ski
            4.3LX Gen+ (190 hp 2 barrel carb)
            Alpha 1 Gen 2 S/N 0F 845543

            Comment


            • #7
              5W-30 and 10W-30 oils are too thin to properly cushion the bearings in a marine engine. As to why a marine engine needs higher maintenance than an engine in automotive use. Well they are operating under different conditions. Marine engines are under much higher loads and rpms, they generally are run at much cooler temperatures, 150 - 160 degrees vs 195+ for auto. Additives in auto oils do not exactly match the requirements of marine engines either. But since many marine engines have some parts in common with auto/truck engines... they are perceived to be the same as an auto/truck engine.

              Comment


              • #8
                The other issue is that while the engine water temp can be lower than in auto use, oil temps can be higher when running on plane due to the constant 3500-4000 rpm use. Some engine marinizers use engine oil coolers which help a lot to keep oil temps from getting too high. Most typical sterndrive powerplants do not have engine oil coolers, so using a heavier viscosity oil becomes necessary for good protection from wear. This is why Merc recommended straight weights, 20/40 and 20/50 until they came out with their own 25/40 oil. Volvo used to recommend a syn straight 30 and then changed it to a syn 10/40. I would not use any low vis automotive grade oils in a stendrive marine engine that does not have an oil cooler.
                Last edited by Lou C; October 31st, 2017, 07:47 AM.
                1988 Four Winns 200 Horizon
                4.3 OMC Cobra

                98 Jeep Grand Cherokee 4.0 Selectrac
                07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                "While air doesn't freeze....rust never sleeps"

                Comment


                • #9
                  Hmmm,
                  I spoke to the mechanic who did the last oil change when I purchased the boat. He used 10W/40 conventional automotive motor oil. Which is what I bought and was preparing to use. Then I realized this motor has no conventional drain plug. At least not of the type used on every car I've ever worked on. It apparently needs to be changed by pumping it out through the dip stick tube. So now I'll need to rethink what oil to use and buy a pump for the crankcase. I hadn't thoroughly considered the cooler water operating temps and greater oil temps of a marine motor. At this point I'm going to look more closely at the 25W/40 as a better choice. I'm also curious if an automotive oil filter is appropriate?
                  Thanks gentlemen, your experience is invaluable
                  Jcris
                  Last edited by Jcris; October 3rd, 2017, 05:05 PM.
                  1996 Glastron 185GS fish and ski
                  4.3LX Gen+ (190 hp 2 barrel carb)
                  Alpha 1 Gen 2 S/N 0F 845543

                  Comment


                  • #10
                    Any good oil filter, myself I use Baldwin, I refuse to use Brand F

                    Comment


                    • #11
                      Wix filters, Napa filters, Purolator filters, AC Delco filter, just not Fram or Penzoil (may as well use a piece of cardboard and some toilet paper)

                      http://www.austincc.edu/wkibbe/oilfilterstudy.htm
                      1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

                      Past Boats
                      1970 Wooster Hellion - Merc 9.8
                      2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
                      1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                      What’s behind you doesn’t matter.Enzo Ferrari

                      Comment


                      • #12
                        Originally posted by Jcris View Post
                        Hmmm,
                        I spoke to the mechanic who did the last oil change when I purchased the boat. He used 10W/40 conventional automotive motor oil. Which is what I bought and was preparing to use. Then I realized this motor has no conventional drain plug. At least not of the type used on every car I've ever worked on. It apparently needs to be changed by pumping it out through the dip stick tube. So now I'll need to rethink what oil to use and buy a pump for the crankcase. I hadn't thoroughly considered the cooler water operating temps and greater oil temps of a marine motor. At this point I'm going to look more closely at the 25W/40 as a better choice. I'm also curious if an automotive oil filter is appropriate?
                        Thanks gentlemen, your experience is invaluable
                        Jcris
                        Personally I like the 10-40 oil choice. The lighter cool temperature viscosity is now all the major motor manufacturers recommend since it ensure early oil delivery when you start your motor, they have mostly gone to 5-30. It will also suction out a lot easier than 25-40 using a vacuum unit.

                        I keep an eye out for the 1/2 price NAPA oil filter sales and buy a case of their NAPA Gold filters, made by WIX. The good stuff.
                        17 Foot '90 Bluewater
                        Alpha 1 3.0 Merc - repowered in 2016
                        now - 4.3L Vortec - Alpha 1 GenII
                        Honda BF100L kicker
                        Engine custom - Transom 0D65328 - Drive 0D648864
                        If you ain't fishin, then yer working too much.

                        Comment


                        • #13
                          Originally posted by Rick Stephens View Post
                          Not a big fan of taking an older motor to high detergent diesel oils if they were not used in it before. Plenty safe to use a automotive 10-30 or 5-30, depending on local temperature ranges.

                          I have seen a couple older motors that DELO was introduced and the motor basically failed after a short period of time.

                          There is always a lot of differing opinions around here on oil. You're probably safe using pretty much anything quality in a normal viscosity range for your climate, even a DELO.. Personally I don't use a synthetic, I don't get enough hours in a year to justify the longer life of synthetics, and there is really no downside to a 50 hour annual oil change using standard non-synthetic oils.
                          The oil manufacturers are continually reducing the ZDDP (zinc dialkyl diphosphate) additive in the motor oils due to several reasons - It depletes the catalyst in a catalytic converter as well as modern automobile engines no longer have distributors and use roller cam followers. The older engines with distributors and traditional style lifters need additional ZDDP to prevent accelerated wear to the distributor gears and the camshaft lobes and that's where the diesel oils are suited for that as they have a higher concentration of ZDDP vs. gasoline engine oils. Hard to believe an engine fell apart using Delo oil - I've been using Rotella oil in all my older engines with distributors based on recommendation from a GM Powertrain engineer for years without any issues.

                          Finer micron oil filters are not necessarily better for your engine either - 10+ years ago, AC Delco had an oil filter called "Ultraguard" that had a much finer filter media vs. the standard blue "Duraguard" filters. What was discovered in testing was that the filter media restricted flow and the filter went into bypass mode much sooner and the result was that much less of the oil was filtered. They dropped the Ultraguard filters very quickly after learning this.

                          That said, I don't think you can go wrong using the Mercruiser 25W-40 oil either.
                          Last edited by khe; October 4th, 2017, 09:33 AM.

                          Comment


                          • #14
                            Great info!
                            Excellent link Scott. There is a Tough Guard Fram on the motor now. It seems better choices are out there. After reading through that link I'm inclined to give the Mobil 1 filter a try. I have to say it just slays me how much the public is "duped" by advertising. I use to wrench on classic BMW's and when it came to basic maintenance parts I always spent the extra cash on quality (OEM) parts. IMO, packaging on most parts is designed to make the consumer "think" their getting something better. I'm embarrassed to admit that I wasn't nearly so focused when it came to my daily driver. Sure I'd maintain systems at proper intervals but mostly I'd look for a good deal. I figured if I did the maintenance regularly that I would be safe. Competition to remain profitable has undermined a lot of what is available, in all areas. Not just automotive parts.
                            Very interesting post khe
                            1996 Glastron 185GS fish and ski
                            4.3LX Gen+ (190 hp 2 barrel carb)
                            Alpha 1 Gen 2 S/N 0F 845543

                            Comment


                            • #15
                              Sign up today
                              To understand the difference between auto and marine use, think of it this way. Marine engine do not have ability to use different gear ratios in the transmission to make the load easier on the engine. They can never coast or loaf down the road at 1700 rpm like the Chrysler Hemi in my Jeep can. Imagine if your truck had only 2 gears and your highway rpms were between 3600 and 4000 rpm all the time. Now while 4 stroke outboards are designed to run that fast constantly, I do not believe the old school Chevy small blocks were. So I have said and still will say, that Merc and Volvo did not recommend conventional lower vis oils in their engines, yet people feel the need to question what engineers have recommended and specified and will try anything just not to buy the 'approved' oil. Everyone wants to experiment and that's understandable but I would also say this: if you do that, then do an oil analysis to see, if that oil really stayed in grade. If so then fine, if not then well you learned that the engineers know more than we do!

                              ​PS I have done 2 oil analyses on my old '88 4.3, one with Chevron Delo 400 straight 40 and one with the Merc/Quicksilver 25/40. They both held up well but the Merc oil held its grade better believe it or not.

                              ​Another data point. People think that the NMMA spec for corrosion resistance for the marine engine oils is a bunch of BS. Well all I can tell you all this:
                              ​Last summer my engine blew both head gaskets and I had salt water in a cylinder, probably for about a week before I figured out what the cause of my reluctance to start problem. I blew out the water, fogged it several times and drained the block and manifolds not knowing yet where the water was coming from. Did more tests when I got the boat back home and confirmed it was not a leaky manifold but blown HGs. When I took it apart, there was no rust at all on the cyl walls, cam, lifters, rocker arms, etc. And this engine has been used in salt water at least 15 years. The only rust I found was a tiny bit of it on one of the pushrods, surface rust and some on the combustion chambers of the heads. The motor oil looked milky but I have to think, it being salt water, that the additional corrosion resistance in NMMA certified oils do help.

                              One last point:
                              ​1 check the amount of ZDDP in the lastest formulation of Delo and Rotella, its not much more than the gas only motor oils, it used to be but that was changed.
                              ​2 all the worry about ZDDP may be irrelevant, unless you have a Chevy small block older than 1987. Why, well the roller cams and lifters were adopted in that time frame, my old '88 has a roller cam. The concern over wear applies to flat tappet cams, not roller lifters. I can say that when I pulled out all the lifters, the cam lobes had very little wear as did the lifters, they looked almost new. So if you have a roller lifter cam you do not need to worry about the ZDDP issue, at all.
                              Last edited by Lou C; October 4th, 2017, 11:11 AM.
                              1988 Four Winns 200 Horizon
                              4.3 OMC Cobra

                              98 Jeep Grand Cherokee 4.0 Selectrac
                              07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

                              "While air doesn't freeze....rust never sleeps"

                              Comment

                              Working...
                              X