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

Eng Refresh + LMA, Bilstein Damper, etc 23

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2 Comments
by
Kaz-kzukNA1
, 11-04-2015 at 11:02 AM (2414 Views)









Only a few photos for such long hours task but glad to be able to finish the valve clearance adjustment yesterday while the weather was good with low humidity.
Each adjustments were checked three times and finally happy with the consistency.


As I don’t want to be disturbed during this delicate process, I always switch the mobile phone off (I won’t be able to answer it anyway) but later, I found out that the owner phoned me trying to deliver the coated valve covers. He left the message but I didn't power up the mobile phone until late in the evening so inconvenient but I won’t change my procedure.


Will move onto the VTEC Spool valve and cooling system.


Time to prepare the lunch and keep working.....


Kaz
Categories
Eng Refresh Stage 1 + LMA

Comments

  1. nikey22's Avatar
    General questions about valve timing/adjustment:
    When the piston is at TDC, theoretically the valves should be closed and therefore, this would be optimum for correcting the valve lash. This happens twice during the 4-stroke cycle.
    my question has to do with the valves.
    In practice, the intake valve usually opens earlier than top dead center, and stays open a little past bottom dead center; The exhaust valve opens a little before bottom dead center, and stays open a little past top dead center.
    I think they call this lead & lag
    So doesn't that affect the adjustment?
  2. Kaz-kzukNA1's Avatar
    I think you got confused between Compression TDC and Exhaust TDC.

    When people talks about the TDC, it’s the compression stage and not the exhaust one.

    When you adjust the valve clearance, it's at the Compression TDC and hence, all inlet/exhaust valves are closed.
    Strictly speaking, if you dial the TDC at each cyl on multiple engines, you will notice some variation between them so that’s where one can apply one’s know-how during the TB service.


    You were talking about the ‘valve timing’ but the reference points are the Exhaust TDC and the Exhaust BDC so they are different from the valve clearance adjustment point (Compression TDC).


    For your reference, unlike the normal engine that has overlap (you referred this as ‘lead & lag’ above) between the Inlet and Exhaust valves, VTEC engine doesn’t have it at the Exhaust TDC below VTEC region.

    Both exhaust valves close Exhaust BTDC 7.5deg and inlet valves open at Exhaust ATDC 7.5deg and 12.5 deg. Thus, the inlet valves won’t open until both exhaust valves have closed.

    This is the reason why super charger is effective on VTEC engine including our NSX if the CG was taken into consideration for the design.
    Also, the cam profile below the VTEC region is the same between MT and AT engines so if you know how to drive Honda AT gbox, you can enjoy driving it under street driving condition.
    Several owners installed C32B 3.2L engine into their AT NSX and enjoying their AT model regularly on track.

    Kaz
    Updated 24-04-2015 at 05:12 PM by Kaz-kzukNA1 (extra info)