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Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

Compression Check ( my NSX )

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3 Comments
by
Kaz-kzukNA1
, 18-12-2015 at 12:32 PM (3190 Views)
As part of my annual service, I always take engine compression.
I kept doing this on my NSX every year since I bought it new in 1994 and as I changed the equipment, different altitude, etc over the years, can't do direct comparison of the absolute figures but at least, I know the condition of each cyl.




Silicone compound is doing good job in preventing any further rust on the rear bank IG coils for many years.
I have new rear set as spare as well as used complete F & R set for misfire diagnosis purpose but so far, these original ones are surviving very well.

The rubber seal at the IG coil cover is still very healthy thanks to the silicone compound so just keep re-using it until the next Eng Refresh.






No flashover markings on the IG coil tube or at the insulator body of the spark plug.
Just the usual corona arching marking with no rust so very good.
They covered about 47K miles so I think I’ll replace them at the next oil change.

Burning nicely and evenly.




I need replacing this air cleaner element/filter this time.......
I should have another delivery from Japan today or Monday......



I normally won’t show the full data of the compression check that was taken from other owner’s NSX but since this is mine, no problem showing it.

[psi]
#1: 230, #2: 237, #3: 235,
#4: 230, #5: 235, #6: 235


I’m quite sure if I place the engine on the dyno, it would show small amount of loss of output but still, really pleased with the standard compression figure over the last 21 years.






Not bad for more than 150K miles engine over 21years and I already inspected my camshaft, journals, crankshaft, metal, etc long time ago and happy with them so just keep driving.


Kaz

Updated 18-12-2015 at 01:06 PM by Kaz-kzukNA1

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My NSX

Comments

  1. solidol's Avatar
    Hi Kaz,

    I used to do compression checks every year for my s2000. It's a bit easier than on NSX too. How do you kill the fuel and spark delivery? Also if you don't mind sharing what's the reasoning behind not exposing customer's compressing test results?

    --Roman
    Updated 21-12-2015 at 05:35 PM by solidol
  2. Kaz-kzukNA1's Avatar
    Hi, Roman.
    It’s quite easy on NSX apart from the LEV and NSX-T models.
    Fairly limited space for accessing the rear bank with that air pump metal pipe in your way…..
    Also, targa model is much easier by removing the triangle brace (I know one owner managed to replace IG coils without removing this brace....) and this means that you need to somehow hold the engine cover.
    I hate removing the engine cover on targa model because it takes ages aligning it later in order to prevent fogging up of the rear hatch glass.

    For disabling the IG, since you are doing the compression check, you would remove the IG coil and spark plugs any way so not much to say.
    The ignitor module won’t be damaged by the lack of target module connected unlike some of the circuit designs.
    For other conditions that you don’t need to take the IG coils or spark plugs out, you can disable the IG by disconnecting the busbar connector on top of the trans or just disconnect the ignitor.

    For the INJ, just disconnect the INJ resistor or the busbar connector depending on the year model. The spec of the INJ changed over the years.
    The connector for the INJ resistor or the busbar is mounted at the exactly the same location.
    It’s on the bracket located at the Right side vertical section of the engine bay.
    Just disconnect it and no more INJ.


    I own the copyright of the original photos so in theory, I can use them freely but you won’t see some of the photos that contain the security related items, VIN, reg. no., etc.
    For the same reason, I treat some of the data as private matter and one of them is the compression data.
    Just my own policy since Day1 and as it’s my policy to treat everyone in the same way, I just kept doing it.

    Kaz
    Updated 19-12-2015 at 01:45 PM by Kaz-kzukNA1 (extra info)
  3. solidol's Avatar
    Thanks Kaz - really helpful.