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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Final Touch 02

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As reported earlier, the four black plastic like slider parts were partially broken or already missing but in some way, it was helping reducing the friction as well as causing extra wear along the rail.



The biggest friction factor was not on the regulator assy.


While having the regulator out, I tested my theory on the door glass side.
It should slide freely without the regulator by simulating the in/out movement while the glass goes up and down.
While the glass was at the closed position, I started removing the tapes holding it in position with my other hand holding the bottom of the glass.
I was expecting the glass to drop freely but nothing happened.

In fact, I had to press it down towards the ground quite heavily and wiggle it in/out direction to lower the glass even a tiny bit.
No wonder why the owner couldn't open the window while the door was closed.


Even after I managed to move it down a bit, there were several places where the glass didn't slide smoothly and thus, the main cause of the slow operation was not the friction increase at the regulator assy but it was caused by the two guide rails inside the door.
Still, the rail guide at the regulator is also worn and increased the friction when the glass was around 1/3 to 1/2 from the bottom but not the wire guide at the top and bottom where many owners installed the aftermarket parts.

After speaking to Japan for many months, they advised me on the regulator rating, the possible main cause, etc and we came to the same conclusion and thus, ordered many parts for this issue but not the aftermarket one.

Based on the findings this time, I'm afraid the regulator guide is beyond the re-usable wear and since Honda won't sell it as a separated part, I need to replace the regulator assy even the motor itself was bit tired but still within the rated performance.



As in my previous blog, if you managed to fix your slow window issue by replacing the bottom wire guide with aftermarket one, eliminating the small rattle at the shaft where the two wire retracting bobbins inside the regulator motor mechanism or replacing the four black plastic like sliders at the glass holder, then you are very lucky because the wear at the front/rear rail guides and the regulator guide seemed to be still low on your NSX.




After reviewing the way the wire is tensioned, one thing we can all do for any window regulator using the similar design is to operate the window switch briefly before parking the car for long period.


When you close (or open) the window, the regulator motor continues to operate at high speed until the glass hits the front and rear stopper. The wound spring inside the regulator motor mechanism seems to help in controlling the speed but it's not electronically controlled and there is no fuzzy algorithm to slow down the regulator before hitting the end stop hard so when the glass stops in fully closed/opened position, the motor still operates for a short period and thus, the regulator wires are under massive tension.

Because of this, the slider parts moving inside the front and rear glass guide rails are also under heavy tension. Eventually, this will cause wear at the guide rails as well as deform the rail itself over the years. This is the main cause of the slow window operation. Same thing happens at the regulator assy guide and making the matter even worse. Because Honda or many manufactures use the similar design for the window operation, the motor rating, top/bottom wire guide design, etc have quite big safety margin. The specific thing with our NSX is the amount of glass height/travel that goes up/down inside the door panel when the regulator was operated. It needs 3D movement to operate that window glass shape. If you look at the small square parts acting as the slider parts, you will be amazed what they are doing during the window operation.


So, just before leaving the car or parking it for long period such as for winter storage, just apply single blip on the window switch to reduce the tension. You don't need to see the movement on the actual glass itself and you only need to operate the switch in reverse direction briefly for like 0.1sec. For example, as you normally do, close the window before you park and then blip the switch in down direction for 0.1sec.
If the parking area is secured, it may help by slightly lowering the window like 5mm.


Thank you to the friends in Japan for their time discussing this matter and special thanks goes to Mr Toyoizumi at KSP Engineering in Japan for sharing his experience and knowledge with me.
He even tried special coating on the two guide rails with great success and in endurance test mode at the moment. Always hats off to his contribution.




For now, greased the regulator rail with Urea grease until we replace the parts in the future together with the ABS upgrade.



Another quick test driving session, cooled down the body, washed the car and ready for the meeting.





The owner has already collected his NSX and provided me with great feedback on the newly installed Bilstein damper even without the alignment yet, no noise at all from the defrost panel area although I'll wait for the judgement until the winter.
I demonstarate the iPod adaptor usage and he enjoyed the music on the way back home.



Thank you for using my service and looking forward to servicing the door window area and ABS upgrade this winter.


Regards,
Kaz

Comments

  1. greenberet's Avatar
    Dear Kaz, thanks for the insight regarding the window regulators, even if it does not make for happy reading.

    It’s too bad if the fundamental problem is not the use of friction-prone guides at the cable bends and plastic axles that wear. Those issues could be fixed. If the main problem is that the one regulator rail and two window rails per door are simply not rigid enough to resist warping over time, that is more difficult to address.

    I would really look forward to hearing about Mr. Toyoizumi’s coating after his endurance tests are complete if it continues to be a great success.

    It would be nice to have window regulators that just work. Something like this looks good:



    Pulleys at all bends instead of stationary guides the cable has to be dragged over, no third rail that pushes the glass laterally during the opening/closing process, hopefully metal bushings at the bobbin, and hopefully the rails are rigid enough not to warp over time. I wonder if some car whose frameless windows have the same height and curvature as an NSX’s uses such a regulator. If mounting tabs were welded into place at the correct locations and plastic washers isolated the regulator from an NSX’s aluminum door frame, something like that could be a permanent solution to the common NSX problem of slow windows.
    Updated 06-07-2014 at 09:37 AM by greenberet
  2. L696ULO's Avatar
    Hi Greenberet

    My wife's Mark 2 TT has had both regulators changed after only 6 years and hardly any use due to the cables fraying, a common Audi fault. So almost 20 years after the NSX design other manufacturers have their problems. The only benefit is that they cost £125 each.
  3. greenberet's Avatar
    Fraying cables don't sound much better than warping rails. Maybe some car manufacturer (or supplier) managed to design a reliable regulator that could be modified to work in an NSX.