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Build-up on Valves I1 and I8 only??

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  • Build-up on Valves I1 and I8 only??

    Hi guys,

    Itís been a while, finally getting back into building up an engine and transmission for the 240. Iím swapping the Ferrea valvetrain from a previous (detonated) engine, so I decided to clean and lap the valves. Upon inspection, I noticed that valves I1 and I8 had significant build-up, while the others were very clean. This engine had less than 5,000 miles over about 2 years with multiple oil changes (way more than any car would need) due to other things breaking etc.

    The intake runners are clean, so I donít think itís a matter of oil getting into I8 from the vent line thatís back near cyl 4 on the intake manifold. Furthermore, that wouldnít explain I1. I havenít mixed up the valves. The only ďoff the wallĒ theory I could come up with was something funky going on with the turbo manifold, not flowing well from the ďtwo endsĒ, with airflow from E8 having to almost turn 180 degrees to follow that runner, while the runner toward cyl 1 is quite long relative to the others. Could there be some issue by where the runners from cyls 2 and 3 have super efficient airflow vs 1 & 4 which is causing some odd issue with sweeping cyls 1 & 4 due to the tortuosity at cyl 4 (I8) and the extra long runner to cyl 1 (I1)?

    Have you guys seen this before? For reference the head was on a motor with bad detonation on cyl 2, some compression loss on cyl 3 - but normal on 1 and 4 (why arenít I2 and I7 in the same condition as I1 and I8)? The turbo manifold is an early Full Race prototype. You can see the det damage on I3-I4 (cyl 2) in the pics.

    Any insight is appreciated.

    Thanks guys,



















    In Zipties We Trust....

  • #2
    I can see a little damage on I5 and I6 as well. looks to me like those cylinders are running more lean, whereas less airflow on cyls 1 & 4 so they run richer. overall they average out and the O2 sensor says things are happy, but it looks to me like you need to do a little balancing act on them to make it better.

    What ECU do you have? IS it one that you can richen cyls 2&3 a little bit, or lean out 1&4 a touch?
    Originally posted by SoSideways
    I don't care what color they are as long as they are LONG AND HARD.
    '04 G35 Sedan 6MT- The DD
    '96 240SX- The Track Toy

    Comment


    • #3
      Hey Matt,

      I think youíre right, the engine that this head came off definitely had big detonation on cyl 2 (and ~40psi compression), and Iím thinking that 3 may have been a little lean, I canít quite recall.

      That said, when I built the new motor, I used a different head which was decked, and block bored for 87mm pistons (i.e. everything was fresh) and the same setup on a fresh long block resulted in slight det across all 4 cylinders. Probably most pronounced on cyls 1&2. Pics below. AFRís were in the low 12ís and the tune was done on a dyno - but once I moved back out here to the East Coast where gas is really bad, it may have just caused a larger issue after the fact while driving and not having 2 eyes on the wideband.

      What I canít figure out though, is why i2 and i7, which are obviously in the same cyls as i1 and i8 are super clean.

      Iím running an AEM V1 EMS so yeah I could probably modify injector by injector - havenít tried that in the past. Iím hoping to update my build thread whenever I can catch up on life, finish the build, etc. But yeah this valve thing is a head scratcher...








      In Zipties We Trust....

      Comment


      • #4
        1. what kind of injectors do you have? do they have a specific type of spray pattern that your aware of?
        2. have they been flow tested? if not, label them with a sharpie or something and get them tested.
        3. was the cylinder head or intake manifold ported?
        4. what kind of intake manifold are you using?
        5. is the injector placed in the center of the runner and pointing towards the center of the cylinder port?

        Comment


        • #5
          Originally posted by clotuning View Post
          1. what kind of injectors do you have? do they have a specific type of spray pattern that your aware of?
          HKS 740ccís. Unsure on pattern.

          2. have they been flow tested? if not, label them with a sharpie or something and get them tested.
          I actually sent them out to get cleaned and tested, with a buddies DSM injectors. Because mine were side feed they couldnít handle them and sent them back untouched. Any suggestions on quality places that will do a good job? There is nothing in Eastern Canada - somewhere within Canada would be ideal to avoid customs - but any suggestions would be helpful.

          3. was the cylinder head or intake manifold ported?
          The cylinder head was ported by Head Games. Unsure on the intake manifold, I have pictures of it below. I am getting another to compare later, and will post those pics below for comparison when I get them.

          4. what kind of intake manifold are you using?
          Stock notch top S14 with S15 TB

          5. is the injector placed in the center of the runner and pointing towards the center of the cylinder port?
          They are placed in the center of the runners, just before the intake port. As you can see, they arenít all pointed perfectly, but basically yes.

          The other thing that I noticed on this head is that the exhaust ports on #2 and #4 are wet - I assume that is because of leaky valve seals. That raises as many questions as answers, as the valves from (wet) #2 were super clean, and if this is the cause of the build up on (wet) i8, how does that explain the build up on (dry) i1?


          IM:












          Intake:












          Exhaust:












          Chamber:







          In Zipties We Trust....

          Comment


          • #6
            Some of the damage on the head from #2 looks to be mechanical?????

            how is the ECU triggering spark for each cylinder? I assume using OEM crank/cam position?

            I have a friend here in town that was using a crank trigger and it turned out the trigger wheel was just a little bit off on a couple cylinders, causing them to fire earlier and cause ugly problems. a new trigger wheel solved the problems later, but the immediate fix was to go into the ECU and retard the timing a couple degrees on those cylinders. He still also had a rich/lean problem between cylinders that was only shown by sticking a WBO2 and EGT in the header on each cylinder.
            Again, individual cylinder tuning saved the day.

            This was on a NA single cam KA, but the theory still applies.

            Looking at the head photos above, the intake ports are symmetrical, but not perfect mirror images. IN THEORY, I could see why the injector is spraying mostly on I1 and not much on I2, etc..

            Also given how much oil is in the exhaust ports, it could be that the stem seals on I1 and I8 were not 100% and that's oil sludge you're seeing, not fuel buildup sludge. (that makes more sense to me as well since the deposits look 'coated and cooked on' instead of 'sprayed on' if that makes sense?

            Now.. keep in mind this is all from an armchair quarterback that's never ACTUALLY tuned an engine or done any post-blowup inspections. An experienced engine builder and tuner should be able to look at that evidence and come up with some accurate conclusions on what happened.
            Originally posted by SoSideways
            I don't care what color they are as long as they are LONG AND HARD.
            '04 G35 Sedan 6MT- The DD
            '96 240SX- The Track Toy

            Comment


            • #7
              Me personally, I don't trust injectors unless they come from a company that only deals with injectors and nothing more. Alot of company's are okay with going as high as 10% difference in flow rate and being okay with sending them like that. That's why I asked what brand and if they got tested.

              Just to avoid future possible issues I would definitely switch over to top feed and grab a set of reputable injectors. I don't know any company that sells tested side feed injectors when I searched years ago on my first build. When I used to tune a lot of cars, whenever there was a detonation issue I would send them to get their injectors tested and 90% of the time it was one injectors performing way less than the others. I always sent people to https://www.southbayfuelinjectors.com because they we're local to me. His acceptable matching flow rates were much tighter, I don't remember the exact number. It was something low like 3%

              Like Matt said the port does kinda look like it would flow more air n fuel through the inboard side of the port.

              That looks like a hand port job, can you confirm the company flow tested each port? Hand ports are hard to get matching airflow meaning that can be a reason why you detonated in that specific cylinder (more air than the other and not enough fuel)

              Did you install Aftermarket valve seals? I had that problem when installing super tech valve seals. But I chose to never try the OEM ones because it wasn't a significant oil leak and I wouldn't get blue smoke (color of oil burning)

              Comment


              • #8
                Originally posted by Matt93SE View Post
                Some of the damage on the head from #2 looks to be mechanical?????

                how is the ECU triggering spark for each cylinder? I assume using OEM crank/cam position?

                I have a friend here in town that was using a crank trigger and it turned out the trigger wheel was just a little bit off on a couple cylinders, causing them to fire earlier and cause ugly problems. a new trigger wheel solved the problems later, but the immediate fix was to go into the ECU and retard the timing a couple degrees on those cylinders. He still also had a rich/lean problem between cylinders that was only shown by sticking a WBO2 and EGT in the header on each cylinder.
                Again, individual cylinder tuning saved the day.

                This was on a NA single cam KA, but the theory still applies.

                Looking at the head photos above, the intake ports are symmetrical, but not perfect mirror images. IN THEORY, I could see why the injector is spraying mostly on I1 and not much on I2, etc..

                Also given how much oil is in the exhaust ports, it could be that the stem seals on I1 and I8 were not 100% and that's oil sludge you're seeing, not fuel buildup sludge. (that makes more sense to me as well since the deposits look 'coated and cooked on' instead of 'sprayed on' if that makes sense?

                Now.. keep in mind this is all from an armchair quarterback that's never ACTUALLY tuned an engine or done any post-blowup inspections. An experienced engine builder and tuner should be able to look at that evidence and come up with some accurate conclusions on what happened.
                Yeah I don’t really know about the mechanical vs tiny explosions bit lol. The turbo was fine, and produced 400whp+ on the new engine, so I don’t think anything major made it’s way through there (didn’t have a melted plug or anything). The (forged) piston was in pretty bad condition but I don’t know how much clearance there is between the piston dish and those quench areas, maybe it was enough to contact raised sections originally from the detonation, again I don’t know how possible that is.

                The bad seal thing actually makes a lot of sense. However with cyls 2 & 4 being wet, but cyls 1 & 4 having the build-up it just doesn’t all correlate. Maybe I should just clean them up and move on.
                Last edited by Solo_S14; 03-22-2018, 07:56 AM.
                In Zipties We Trust....

                Comment


                • #9
                  Originally posted by clotuning View Post
                  Me personally, I don't trust injectors unless they come from a company that only deals with injectors and nothing more. Alot of company's are okay with going as high as 10% difference in flow rate and being okay with sending them like that. That's why I asked what brand and if they got tested.

                  Just to avoid future possible issues I would definitely switch over to top feed and grab a set of reputable injectors. I don't know any company that sells tested side feed injectors when I searched years ago on my first build. When I used to tune a lot of cars, whenever there was a detonation issue I would send them to get their injectors tested and 90% of the time it was one injectors performing way less than the others. I always sent people to https://www.southbayfuelinjectors.com because they we're local to me. His acceptable matching flow rates were much tighter, I don't remember the exact number. It was something low like 3%

                  Like Matt said the port does kinda look like it would flow more air n fuel through the inboard side of the port.

                  That looks like a hand port job, can you confirm the company flow tested each port? Hand ports are hard to get matching airflow meaning that can be a reason why you detonated in that specific cylinder (more air than the other and not enough fuel)

                  Did you install Aftermarket valve seals? I had that problem when installing super tech valve seals. But I chose to never try the OEM ones because it wasn't a significant oil leak and I wouldn't get blue smoke (color of oil burning)
                  The work on that engine was done before I bought the car, so I am not sure. I do think that they used stock seals, as they were all “black with brown” rather than the super tech seals which I think have one side blue and the other side black?

                  The 2nd engine (actually 3rd after I broke a stock SR) that I built myself used a “fresh” (but stock) head that I decked, and a fresh 87mm bottom end. There was slight detonation on all cylinders on the “new” head - pictures in post #3 above.

                  Since I believe that I was getting valve float with that head, I decided to go back to the old head and steal the ferrea valve train to fix that issue. So basically, these dirty ferrea valves will be cleaned up and put into a new head with new stock seals this week.

                  So the porting on that head will be eliminated (going back to stock head) and seals will be refreshed. Hoping that evens things out a little - will send my injectors out again - at the moment I don’t think that a new setup is in the budget but good to consider for future.

                  For reference, here are the dyno charts for the original engine (purchased with car) on the ported head with ferrea valve train, and 86.5mm 8.5:1 pistons on 94 octane. A “high power” run (solid line) at 380whp/370tq, and then a “final” run (dashed line) at 340whp/330tq.

                  Then below, the engine that I built with 87mm 9:1 pistons, stock head, and turning the boost back from ~20 to ~16psi. There was a run on 94 octane and high boost at ~410whp (final pic). I then went down to 91 octane before moving back to the East Coast (best fuel we can get, and usually very low quality actually) - turned the boost back to try to get within a better efficiency range on the GT2871R, and believe it or not gapping down plugs resulted in more torque, and torque much earlier (lighter line ~500RPM earlier vs solid line) and overall what I consider a better result vs the high power runs on the same engine, at 380whp/360tq (light line). The solid line 400whp/350tq was a variation of the 94 octane run that had peaked at ~410 in the final picture.

                  Honestly, turning that 380/360 back to 340/320 or something and being able to beat on this thing without worry is really where I want to get with this refresh.

                  Original Engine:




                  This Engine (pre-refresh, and on stock head):



                  In Zipties We Trust....

                  Comment


                  • #10
                    Originally posted by Solo_S14 View Post
                    Yeah I donít really know about the mechanical vs tiny explosions bit lol. The turbo was fine, and produced 400whp+ on the new engine, so I donít think anything major made itís way through there (didnít have a melted plug or anything). The (forged) piston was in pretty bad condition but I donít know how much clearance there is between the piston dish and those quench areas, maybe it was enough to contact raised sections originally from the detonation, again I donít know how possible that is.

                    The bad seal thing actually makes a lot of sense. However with cyls 2 & 4 being wet, but cyls 1 & 4 having the build-up it just doesnít all correlate. Maybe I should just clean them up and move on.
                    Throwing muddy theories on the wall- see what sticks.

                    Maybe cyls 2&4 have bad seals on exhaust side, or damaged pistons/rings causing oil blow-by...
                    valves I1 and I8 have leaky seals on intake side, but they're slower and any oil gets burned up in the combustion cycle so there's no nasty stuff on the way out??
                    Originally posted by SoSideways
                    I don't care what color they are as long as they are LONG AND HARD.
                    '04 G35 Sedan 6MT- The DD
                    '96 240SX- The Track Toy

                    Comment


                    • #11
                      You know, it didnít register when I was taking the pics this AM, that the ďwetĒ ports were exhaust side, and the valves were intake side (Doh!). Makes sense, for whatever reason a number of the seals are leaking, including i1, i8, and the exhaust seals on Cyl 2 and Cyl4. Who knew that actually paying attention would aid in noticing things from time to time .
                      In Zipties We Trust....

                      Comment


                      • #12
                        Originally posted by SoSideways
                        I don't care what color they are as long as they are LONG AND HARD.
                        '04 G35 Sedan 6MT- The DD
                        '96 240SX- The Track Toy

                        Comment


                        • #13
                          I'm betting you have redrilled injectors right? Poor spray pattern is the culprit.

                          Some FOD definitely went through CYL 2. I'd make sure the piston rings are fine - that can sometimes cause cracks as the FOD is hammered into the head quench pads.
                          '18 Chevrolet Volt - Electric fun hatch for DD duty!


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

                          Comment


                          • #14
                            Originally posted by Def View Post
                            I'm betting you have redrilled injectors right? Poor spray pattern is the culprit.

                            Some FOD definitely went through CYL 2. I'd make sure the piston rings are fine - that can sometimes cause cracks as the FOD is hammered into the head quench pads.

                            The injectors were bought with the car, but Iím 99% sure they were taken out of the box and put into the fuel rail. HKS 740cc.

                            That head with the deep damage on cyl 2 is from my old engine ~2009. Youíre right, the rings are in pretty bad shape. But the only debris that caused the damage in cyl 2 were bits of cyl 2

                            Went back and found the pistons:






                            Separately (from the newer engine), have you guys ever seen chipping (not breaking) of piston rings, without any other damage? The bottom of my top compression rings on cyls 3 and 4 have these chips. No damage to piston ring lands etc, and no damage on the bores. Since itís the bottom of the top ring, I also assume itís not detonation based. For a minute I was thinking installation damage, but then figured it was odd that it would be at the same orientation on both 3 & 4, but not on 1 & 2. The chips are in the same place on both rings (pointing toward the back of the engine at time of install).





                            In Zipties We Trust....

                            Comment


                            • #15
                              Valve seals leaking or guides are loose. There are FSM specs on (installation) height for both for the spring seats.

                              That and some FOB (Throttle plate screw maybe??)

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