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

Eng Refresh Stage 1 + LMA (SoS) – 02

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Compression check before starting the Engine Refresh.

Full data has been sent to the owner.


[psi]
#1: **4, #2: **5, #3: **4, #4: **6, #5: **0, #6: **7


Apart from #1 and #4 cyl, rest of the four cyl were within the
spec but lower than the standard C30A engine.

However, all four were really close each other.


Either the cam timing is wrong or the valve clearance was
not adjusted properly and very unlikely to be valve related.


Interesting to see how it will change after the Engine Refresh.











Around this year model, it seems to show more cases of
loose locking screws at the butterfly of VVIS so I prefer
checking them with the fibre scope.

Can’t check the actual torque without opening the intake manifold
but at least, there was no gap at the base of screw head and
all butterflies were still in place.












The battery holder bracket was in the wrong orientation.

It was dangerously close to the battery terminals and
already shorted to the GND post.
It was just 2mm away from the posi terminal.


Will install it properly at the end of the service and in the mean time,
the battery will be kept on the conditioner.








Before taking the engine out, loosen the crank pulley bolt.

Never ever use the method of putting the car in gear or
locking the flywheel and applying parking brake or
even using the starter motor to loosen this bolt on
V6 90deg V-angle engine.


Always lock the crank pulley side.

FEM stress analysis showed the possible kink if
huge torque was applied across the crank shaft.







The RR wheel speed sensor was replaced in the past but
the bolt seemed to be seared off or missing and tyrap was
used instead.









Same story at the left side parking brake cable.
Bolt was seared off and tyrap was used instead.




Having lots of fun around the brake caliper and parking barke.

6point socket won’t go in to the bleeder screw and banjo bolt
without some persuasions.
I have spare banjo but not the bleeder screw so
it’s going to be interesting later.


The parking brake cable is stuck in its bracket at the
back of the caliper.
It just doesn’t want to come out.

I’m going to soak it in penetrating oil overnight.
If it still doesn’t come out, I’ll just remove it together with the bracket.











Front O2 sensor is not at the ideal position on this aftermarket header.
Due to the short collector length and position of the fitting,
the signal will be dominated by almost just one cyl.


When aftermarket header for NSX started to show up on
the market in Japan, there were lots of owners getting
CEL after installing this type of header design.

At that time, Honda engine control was very sensitive to
this kind of O2 sensor layout whereas the control on other
car manufactures were not.

Also, from the amount of black carbon build up,
I think the exhaust is/was leaking from the ball socket joint
although I didn’t feel any leakage at idle rpm.








However, it’s definitely leaking at the de-CAT pipe at
the rear bank where it meets the back box.
I can feel it with my hand even at idle rpm.


I didn’t see any sign of gasket used on all of the
connection points of the exhaust system apart from
the ball socket.

Will be interesting to see how it was sealed when
removing the pipes for engine removal.










Couldn't get the camera into the ideal angle but the position of
O2 sensor at the rear bank was not too bad compared to the front one.






However, the angle of de-CAT pipe is not good.

The ball joint was in this state/angle.......

With black carbon at the upper side of the gasket,
it seemed to be leaking there.




The owner is planning to put the CAT back in place
so hope all of these leakage and angle will be sorted.




For the record, there was CEL #1 (Front O2 sensor),
#31 (ECU-AT comm.), #40 (DBW motor) and
TCS 6-1 (AT Shift signal) were registered at the controllers.

#40 is very likely to be the result of compression check on DBW
model because I always get CEL on DBW model.

There was error code(s) at the AT unit but couldn’t make it(them)
to repeat so couldn’t read it(them) in time.

The #31 and #6-1 could be the result of weak battery in the past.
Will check them after the service as these will be reset by
disconnecting the battery.


Until the cam timing, exhaust leakages were fixed,
I’m not going to replace the front O2 sensor unless
I find other issues once the engine is out.



The connection of O2 sensor to the ECU port was correct
and front one was going to the ECU front input.



Just lots and lots of wrenching at the moment removing
all sorts of parts in preparation for the engine removal.



I need to stop working on this engine for several days next week
as my boss is returning from Japan and I must start cleaning the
house and the garden.

Especially, I must move all the parts from her room.
.....

More to follow some point later.


Kaz

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