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KA24DE Oil Starvation (KA SR Debate)

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  • KA24DE Oil Starvation (KA SR Debate)

    I recently did my first track day at VIR, and ended up developing some nasty rod knock by my 5th lap =[. Im guessing its from oil starvation under hard corners, but I'm on street tires, so I am a little concerned.

    What have you guys that run a KA around the track been doing? How about you SR guys? Any Pros/Cons on KA vs SR when it comes to being a track slut and oiling?

    Currently I have a supercharged KA, but wouldn't mind going SR if it meant having a reliable track car....

    For oiling, my setup is stock with the exception of a skullworks relocation kit.

  • #2
    I did a lapping day that included a 100+mph banked 1/2 oval and didn't have any oil starvation with roughly 2.5 hrs track time in that weekend....motor was a fresh rebuilt 10.7:1 KA with ACL bearings, no oiling mods running Rotella 15w40

    I know because i got to tear the motor down immediately after the event due to over heating that led to detonation death of the cylinder head and the bearings were score free and happy as clams,

    how fresh was the motor?
    do you have alot of dyno hours on it, was this the S/C dev. motor?
    were you monitoring knock?
    was it a stock motor or did it have a rebuild with aftermarket bearings?

    Both oiling systems in KA/SR use essentially the same oiling system, I don't know that one has an inherent advantage over the other, if anything id think the SR's valvetrain oiling system would require more volume and therefor be more likely to evacuate the pan, AFAIK they both have ball valves that close off the piston oil squirters at lower pressures...
    Last edited by Tower240sx; 03-15-2011, 10:58 AM.
    I am SKULLWORKS

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    • #3
      Rod knock after 5 laps seems rather excessive to me.

      I may be on a mostly stock KA (new cams and valve seals last summer), but the bottom end is stock and tired with 150k, once had a bunch of gas run through it with a leaky injector o-ring, and was leaking coolant / semi overheating at VIR last July and it still runs fine with no knock two HPDE weekends and 5k street miles later.

      I'm also on street tires still, but I do however run into fuel starvation issues all the time at VIR through turns 1-2, and at summit through turns 7 and 9. I can't help but wonder if going lean exiting one of the turns might have had an effect on the motor.

      Were you monitoring air fuel or fuel pressure to be sure it wasn't caused by a lean condition?
      '95 240sx

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      • #4
        agree with the others... doubt it is due to a wet sump/oil slosh issue. KA and SR have similar wet sump systems. The SR might have more enlarged lower pan options but am not sure.

        did your dummy light ever flash?

        how was your oil level before going out? heavily topped off or just around the middle?
        even still, i find it hard to believe that your oil pickup could become uncovered with G forces alone.

        did the motor have significant blowby? perhaps the oil was pooling somewhere due to high rpms (in the head, being blown by to your catch can, or into the intake?) to cause low oil. I know some nissan motors have issues with sustained high rpm and oil pooling in the head. hence the addition of restrictors and enlarging oil drains back into the pan.

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        • #5
          Originally posted by Tower240sx View Post
          I did a lapping day that included a 100+mph banked 1/2 oval and didn't have any oil starvation with roughly 2.5 hrs track time in that weekend....motor was a fresh rebuilt 10.7:1 KA with ACL bearings, no oiling mods running Rotella 15w40

          I know because i got to tear the motor down immediately after the event due to over heating that led to detonation death of the cylinder head and the bearings were score free and happy as clams,

          how fresh was the motor?
          do you have alot of dyno hours on it, was this the S/C dev. motor?
          were you monitoring knock?
          was it a stock motor or did it have a rebuild with aftermarket bearings?

          Both oiling systems in KA/SR use essentially the same oiling system, I don't know that one has an inherent advantage over the other, if anything id think the SR's valvetrain oiling system would require more volume and therefor be more likely to evacuate the pan, AFAIK they both have ball valves that close off the piston oil squirters at lower pressures...
          I appreciate all the info guys!

          As far as some questions you all had:

          1) the engine was a stock s14 engine with 170k
          2) I have an AEM wideband and was monitoring the afrs without seeing anything out of the ordinary.
          3) my dummy light is not there, so I can't tell you on that one.
          4) it happened on the back straight while at 6200 rpms and just a little over 100mph
          5) the guy I had just passed said he saw a large black smoke cloud come out and I noticed my tack needle jumping around at that point also.


          It's very possible it was just a tired motor with a going oil pump I guess. I ran it for a week in my car with no issues, and my SC setup is only boosting 2psi right now in an effort to keep iats low.

          I'm going to rebuild my previous engine that detonated on the dyno and throw it back in the car.

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          • #6
            I do know that a few KA-T guys have killed their motors tracking/drifting. I think that for anyone who is serious about keeping it together you would be well served by upgrading the oil pan and adding an Accusump.

            Xcessive Motorsports sells an upper pan that allows you to run a Greddy or Moroso trapdoor pan for an SR20 to the KA. I have considered just modding the factory pump to include better windage, trap doors and increased capacity.

            http://www.xcessivemanufacturing.com...pid=145&step=4
            http://www.crank-scrapers.com/Datsun-Nissan.html
            Trap-Door Example:

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            • #7
              I have a rebuilt .040 over KA24DE that I run mostly autocross, with a few DE's and PDX's mixed in. I installed one of those crank scrapers when I put it together. I haven't had any issues but it may be like deer whistles....., The fact that you haven't hit a deer doesn't mean it works I bought an oil pressure guage about 2 years ago and it's still in the package. I've met a couple of IT racers and one ChumpCar driver that's stuck rods through the block but they were all hi-mileage motors. I suspect the worn oil pumps can't keep up with the increased clearance of the worn bearings. Real trouble-shooting would require a separate pressure guage at some downstream point in the oil path to determine pressure-drop.

              I do know that I can get oil slosh even with the crank scraper in place. The motor takes 4.5 quarts of oil when changing the filter. A couple of times I was lazy and put 5 quarts in. When braking hard and turning at autox I've had oil flood the OEM separator near the front of the block and suck oil into the intake. Nothing like driving back through a cloud of smoke from your own car!
              Don Johnson (really!)
              Just so you know.

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              • #8
                Haha, I know what you mean.

                I have been autocrossing the car for the past two seasons, but just recently decided to try the PDX (HPDE) event locally. It was a ton of fun even though my car spun a bearing.

                That's why I am asking about the route I should go with here. I would like to focus more on the PDX events and HPDE events rather than AutoX. I'm not really worried about class, I just want to have a reliable fun car I can take out to the track and make it home safely in.

                That's why I have been considering the SR. I like the trap door style pans available. I had seen the SR adapter from excessive. I may have to give that a try.

                Accusump was next on my list if I were to manage to spin a bearing again even with a fresh pump.

                Thanks again for all the useful discussion. Hard to find on most other nissan forums =[

                Comment


                • #9
                  I know the 240sxMotoring time attack car only had a few extra baffles added to its KA, but wasn't extra capacity. I was debating adding a few trapdoors and extending capacity myself, although I never had oil issues so I didn't bother. I generally make sure the oil level is at max, though.

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                  • #10
                    Thanks for reminding me...I forgot to mention, I had just put 5 quarts of 10w-30 Mobil Syn in it 3 days prior to the event. Checked it when I got there, and it was just a hair above the hashing on the dip stick.

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                    • #11
                      Originally posted by Jordan.Best View Post
                      Accusump was next on my list if I were to manage to spin a bearing again even with a fresh pump.
                      Doing it wrong, you are.

                      You will spend more money rebuilding the motor than you would an Accusump, not to mention the added frustration and downtime. I know money is tight and a total Accusump system isn't cheap, but it isn't dry sump territory.

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                      • #12
                        you can get an adjustable oil pressure switch that will trigger at any pressure you want... very handy for RR and drifting!
                        "the kid" -- "wrenching and racing" -- "will race for food!" -- '90 Nissan 240sx ITA #5
                        Kessler Engineering in Berlin, CT - dyno, engines, cages, etc.
                        Driving Impressions Racing safety equipment, motorsports shop and more!
                        Check out our ITA road race build!

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                        • #13
                          Originally posted by BlackFire240sx View Post
                          you can get an adjustable oil pressure switch that will trigger at any pressure you want... very handy for RR and drifting!
                          Didn't even know these existed! Awesome.

                          Def had oil psi gauges in all my cars, but an adjustable switch would be nice to give a split second heads up when that needle starts to head south.

                          Lights pwn analog gauges, especially when you have a large bank of them. Lights immediately get my attention where as a needle on a gauge requires me to figure out whats going on for that split second. Flashing red oil light = turn off key. Much better equation.

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                          • #14
                            Even better is a bright light and a flashing LCD screen telling you what the problem is like "OIL P LOW ! ! !"


                            I need to sell my Defi gauge setup that has lights and audible warning levels that are programmable. Definitely a must have.



                            As for the original question, I'd definitely run a baffled and extended oil pan on any Nissan motor I was tracking. The solutions are too cheap and easy to install to NOT run one. I never get any complaining from my stock SR out on track with a GReddy pan. I run it just a hair over full for a little added insurance as well.
                            '18 Chevrolet Volt - Electric fun hatch for DD duty!


                            DefSport Koni Sleeve and Spring Perch Buy!!!
                            http://www.nissanroadracing.com/showthread.php?t=5902

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                            • #15
                              Originally posted by Riggle View Post
                              Didn't even know these existed! Awesome.

                              Def had oil psi gauges in all my cars, but an adjustable switch would be nice to give a split second heads up when that needle starts to head south.

                              Lights pwn analog gauges, especially when you have a large bank of them. Lights immediately get my attention where as a needle on a gauge requires me to figure out whats going on for that split second. Flashing red oil light = turn off key. Much better equation.
                              longacre makes two kinds.. one adjustable one fixed at 20 psi warning. i have the fixed one installed and wired to my factory dummy light on the dash. works well. the adjustable one looks bulkier and needs to be adjusted on the sender.

                              either option is super cheap insurance though.

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