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Thread: My gearbox revision thread

  1. #21
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    Hi, goldnsx.
    If you are doing CL service, you may find this info useful.
    These are the parts that will be replaced during my CL service although I know you don't like replacing the parts that amy be re-used for some time.

    OEM CL set
    Flywheel bolt x 8
    Release bearing: probably too late but HUK is the cheapest, about GBP42 at the time of writing
    Release bearing guide: this is a MUST unless there is no markings or rust
    Release fork: this is a MUST
    Release fork hunger
    Hunger spring
    Hunger bolt x 2

    Please invest in good quality grease. Honda OEM Urea grease is expensive but very good especially for CL task.

    When removing the flywheel, I normally replace the crank end seal at the triangle cover plate if not done for years.

    For the mainshaft clearance, you already have 2 x shim from the previous service so just temporarily install the thinner one (I think you have 0.65mm) and carry out the final inspection method for 0.14 – 0.21mm clearance target.
    Then, calculate the total shim thickness required aiming around 0.17mm. That's what I normally do unless freshly building the gbox from new parts.


    By the way, I don't know how old your friction disc is but the torsion spring looked rusty but not too bad at all for the mileage covered.
    Quite often, they are much more rusty and even broken off resulting in not being able to disengage the CL.
    On the other hand, the mating surface at the pressure plate, mid plate and flywheel looked to be partially contaminated by oil/grease and also some blue markings…


    When you removed the gbox off the engine, did you find any oxidation on the fixing bolts?
    If the gbox was removed in the past and care was not taken on re-assembly, some of the mating thread on the eng side could be damaged and you won’t be able to apply enough torque when re-installing the gbox this time.
    You may want going through all of the mating thread on the eng side by tightening the bolt with just the finger to see any changes in friction before re-assembly.
    I normally apply dash of silicone spray to prevent future oxidation.

    Also, having 2 x much longer fixing bolt with bolt head cut off and tapered can be useful as they can be used as the gbox case alignment guide when re-installing the gbox especially if you are doing this task on the floor….


    Kaz

  2. #22
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    Hi Kaz

    Thanks for your valuable reply.

    Release bearing
    So I'm going to change all the parts around the release bearing: fork, guide, hunger, spring...

    Mainshaft
    I'm going to install two new bearings on the mainshaft and put it in the gearbox. Cleaning the contact surface of the two case halfes thoroughly. 45 Nm. With only one shim (standard 1.00) I'm going to measure the clearance. As I expect it to be higher than the targeted 0.14-0.21 mm, so the resulting clearance will be determined. Also, as I don't have the Honda tool I won't be not able to use that much force like the tool would allow, so I'm aiming for the lower half of the deviation (0.14-0.17). I've done some combinations of pairs of shims which allows me to order just 4 additional shims and still being able to get any clearance from 1.00 to 1.40 mm (for example) with 0.05 steps in between. For 1.05 I'd be using 0.50 and 0.55 for example (easier to install too).
    I know that I have to do it again as soon as the new parts (new hub and gear for 5th) are installed but I don't think the clearance will be way off then. I just try to avoid to place a second order with weeks to wait again...

    Oxidation on the fixing bolts
    I didn't see any oxidation. The screws came out by hand without headaches. For breaking them loose most of them were pretty stiff but not overtorqued. I'm going to use less torque on them I guess (well, the one stated in the SM) and use a calibrated torque wrench for sure. I always use ceramic paste as an adhesive. You just have to make sure that you don't torque it too much as the resistance of the threads is lower with ceramic paste, so the resulting torque is maybe 10% higher than intended. Worked good in the past but will check for oxidation again.
    The threads of one screw at the rear engine mount were damaged by a complete idiot who must have used air tools in the past. The threads can be repaired I think and I'm going to test if the threads can take 105 Nm or better reduce the torque a little bit.

    In this time-consuming project I'll tend to replace more parts than actually needed. For example, the 2nd gear synchro was perfectly good, no need to replace it until I ruined the new part. If you can change a part within an hour I'll have a slightly different approach.
    Last edited by goldnsx; 02-01-2017 at 05:00 PM.

  3. #23

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    Quote Originally Posted by Kaz-kzukNA1 View Post
    Hi,
    If you are doing CL service, you may find this info useful.
    These are the parts that will be replaced during my CL service although I know you don't like replacing the parts that amy be re-used for some time.

    OEM CL set
    Flywheel bolt x 8
    Release bearing: probably too late but HUK is the cheapest, about GBP42 at the time of writing
    Release bearing guide: this is a MUST unless there is no markings or rust
    Release fork: this is a MUST
    Release fork hunger
    Hunger spring
    Hunger bolt x 2

    Please invest in good quality grease. Honda OEM Urea grease is expensive but very good especially for CL task.

    When removing the flywheel, I normally replace the crank end seal at the triangle cover plate if not done for years.

    Kaz
    Hi Kaz.
    I am due to replace my slipping clutch assy and have bought the complete OEM clutch kit and separate clutch release bearing, along with new driveshaft oil seals and the crankshaft oil seal behind the flywheel you mentioned.

    You suggest replacing both the release fork and guide as a MUST do job, but as they are very costly items, about £650, can you please explain your reasoning behind needing to do this as the Honda dealer doing the clutch job would not be able to get these items at short notice once the gearbox is removed.

    The hunger spring is presumably the hanger spring, and lastly can I buy a small quantity of the Honda Urea grease before I take it into the dealers so as to ensure they only use that type of grease when doing the job.

    http://www.lingshondaparts.com/honda...8&block_05=hcr

    Thanks in advance.
    Pride.

    1992 My beloved Red/Black manual NA1.😎
    1992 Chevy Lumina apv Rockford Fosgate sound system demo van.🙉
    2003 Hartge Mini Cooper S (2 x UK & 1 x European sound quality finals winner) 🏆 

    "The NSX's greatest victory was to WIN the 1995 Le Mans 24hr GT2 Class"
    ..............and guess what, it was a RED one but of course.  

  4. #24
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    Quote Originally Posted by Pride View Post
    You suggest replacing both the release fork and guide as a MUST do job, but as they are very costly items, about £650, can you please explain your reasoning behind needing to do this as the Honda dealer doing the clutch job would not be able to get these items at short notice once the gearbox is removed.
    I've taken a picture of the release fork and will post it later but I've seen that there's pretty much material shaved off after 190k km and using the clutch quite often. So Kaz' suggestion completely makes sense to me. Maybe not in a car with low miles (<100k km?).

    They should have the UREA high temp grease I think. If you mention it you'll see their reaction.

  5. #25
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    Hi, Pride.

    Release fork wear is easy to tell if you compare the new and old one side by side.
    The fork edge where it pulls the release bearing and slides over will show significant wear by the time when you need the CL service.
    Remember, this happens when you press on the CL pedal as well as when releasing.

    The pivot point 'saddle' where the fork sits in the hanger also shows big wear marking.

    If someone didn't use good quality grease inside the pocket where the CL slave cyl plunger sits, you will see rough markings inside the pocket.

    All these affects the pedal feeling and the wear at the fork edge and the saddle will increase the CL pedal effort.
    When NSX left the factory, the CL pedal was like feather light and smooth.

    Release bearing guide is where the release bearing slides over when the CL pedal is pressed and released.
    NSX CL uses much higher friction co-efficient materials that over the years, CL dust, debris, etc are trapped in the grease and depending on the quality and amount of the grease used, release bearing could no longer slide smoothly over the guide resulting in noise, vibration or even sticky feeling through the pedal.

    In UK, unless you track your NSX regularly, you should be able to cover lots and lots of mileage with the same CL (I can go more than 100K miles in UK but only about 30 – 35K miles in Japan using the same driving style before I start thinking about CL service through the pedal feeling) so I don't see the point of guessing how long the existing release guide can survive.
    If you see any rust or marking, you must smooth it out before re-using.

    They are not that expensive if ordered from Japan. Try one of the NSXCB vendors to get the parts from Japan. Honda Japan is closed for the new year holiday but they will be back in the office from 4th.


    I only use Honda Urea grease UM264 (41211-PY5-305). It's dark grey sticky grease. Fairly expensive for 200g….
    Outside of Japan, Honda/Acura normally uses Honda Urea grease 08798-9002.
    It's green colour, 150g and much cheaper than UM264…..
    Just make sure to pack the internal groove of the release bearing with the Urea grease before installation.
    You are going to rely on this packed grease until the next CL service.

    Kaz

  6. #26
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    I have the Honda Urea grease 08798-9002 here and going to use this one. In the US, there haven't been reports of failures due to it.

  7. #27
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    That's why you want to check the release fork:

    Click image for larger version. 

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    I've changed the diff bearings today. While the races were pretty simple to take out the 90 mm bearing on the diff was a pain to remove. We had to grind the cage off and heat the inner race up. You can't really grab below the bearing to pull it out. The good news is that all is mounted now. We heated up the 90 mm (200 degrees C) and it just fell on the diff without any problems.

    After cooling I could mount the diff in the tranny case and also fitted the mainshaft with two new bearings in the case and took some measurments of the mainshaft clearance and diff starting torque. The diff itself is at 88 Nm but I'll mount the Type R plate.

    Readings
    Mainshaft clearance
    I've calculated a shim of 1.20 mm and started with the 1.00 which was used in the past (together with a 0.65 mm). I got 0.11 mm of play. So a 0.95 mm shim would be perfect.

    Diff
    We gave the diff a long period of cooling down before measuring. The bearings have been slightly oiled. I've reused the 2.09 mm shim the diff had installed before (1.97 mm is standard) and we got readings below 2 Nm. As 0.03 mm are said to attribute 0.3-0.4 Nm (by the SM) I'm going to try a 2.18 and maybe a 2.27 (the thickest shim available).
    Last edited by goldnsx; 03-01-2017 at 07:41 PM.

  8. #28
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    Quote Originally Posted by Kaz-kzukNA1 View Post
    I'm afraid that main 5th gear needs replacing.
    As it looks like you are replacing all of the synchro related parts, not much to say but that damage is the typical sign of driver accelerating to the limit in 4th gear and then quickly shifting up to 5th.
    As you opened the gbox, you will notice that compared to the 3rd and 4th synchros (both using the same capacity), 5th one is much smaller for some reason and that is the main reason for the damage.
    ...
    Kaz
    I've found a different possible explanation for the wear on the 5th gear: long gearing, WOT in 2nd and speed limit. I was on the German Autobahn only a few times. But what I've done in the early years on normal roads quite often is shifting from 2nd at redline to 5th directly. I did this with a small delay but who knows the speed of the shafts in the gearbox by that time? Anyway, the 5th gear has to do all the synchro work, and being the smallest it wears out. Since several years I don't skip gears anymore as I've heard of the problems people/Honda had with the 6speed gearbox in the S2000.

  9. #29

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    Thanks Kaaz for your hint:

    "Also, having 2 x much longer fixing bolt with bolt head cut off and tapered can be useful as they can be used as the gbox case alignment guide when re-installing the gbox especially if you are doing this task on the floor….

    for me it is a very valuable

    I thought about it (special bolt from Germany-www.boellhoff.com/de-de/produkte-und-dienstleistungen/spezialverbindungselemente/prozesssicheres-verschrauben.php):




    ....your solution is better
    Last edited by ozon02; 05-01-2017 at 09:49 PM.

  10. #30
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    A little update. Took the flywheel off today and changed the 'KWS' (I always have to think about Porsche whenever I change one of these).

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    Still waiting for parts...

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