The Naza Ria first came out in the 2004 (?), initially as Kia Carnival CBU. Decent ride & equipment specs. for a reasonable price compared to other MPV's.
See, my daughter totally agrees with my opinion. She liked the BIGGG space inside the MPV. The setback is the maintenance cost for a V6 powertrain. Changing sparkplugs is not a job for an amateur.
Pictured here is the intake manifold removed to gain access to the Bank 2 cylinders spark plugs (Cylinders 2,4,6). The Ria's V6 is not exactly positioned upright, but slants at an angle of approx. 30 deg. The reason is to facilitate a compact hood, enabling the designers to cram in the intake runners, and ancillaries such as the alternator, A/C compressor, Pwr Steering, etc.
The photo shows the intake manifold removed, cleaned and ready for re-assembly back to the runners. I always blocked off the throttle body entry to prevent accidental dust / sand entry as it is a very sensitive part.
See how much I have to stretch to reach Bank 2 Cylinder spark plugs.
New O-ring seals are used to prevent any possible leakage that may lead to misfire or delay in throttle response. The other 3 cylinders uses a spring metal gasket that is re-useable (sorry, not pictured).
This is a good look at the spark plugs (NGK PN6 -11) that has been used for 4 years ! They are with Platinum core. This particular set has been running for 38,000km.
Another look at the sorry set, which are 4 years in service. Notice the oil deposits on the threads. The owner has been using synthetic oil, which explains the penetration.
As the Ria has 3 induction coils, I increased the spark plug gap by 50%. Standard platinum gap is 1.0mm. The advantage of doing so are high spark intensity, longer flame travel, resulting in more completed combustion and increased power. The spark fire must be checked prior to doing this (refer other resources on checking spark intensity).
This is a comparison between standard spark gap (right spark plug) and with increase of 50% (leftmost spark plug).
As a favor, I checked the timing belt, under service for 4 years with 38,000km. Authorized service centers recommends replacement at 36 months, but they looked OK to me. I gave the green light to the owner to go another 10,000km before replacement.