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

Compression check after the service carried out.


The full data has been reported to the owner.

[psi]

Cyl 1: **6, Cyl 2: **7, Cyl 3: **5
Cyl 4: **9, Cyl 5: **0, Cyl 6: **1


Although the rear bank Cyl are still showing the lower figures, they are far better than the data before start of my service and the differences are well within the window.

As a reference, people will generally tell you that if the cyl deviation is more than 10%, you should consider further action but for our engine, I think it would be about 5% is the threshold as it is a very strong and accurately build engine.


If I see such deviation, I’ll first carry out the leak down check to find out whether the compression is leaking from the inlet/outlet valves or from the head gasket.

For this engine, it was not required as the deviation was not big enough.

As there was no report of over heating issue in the past from the owner, it could be a waste of time but as the owner may not have the full history of this NSX, just carried out the block leak test.

And it confirmed that there is no leakage of the exhaust into the coolant through the head gasket area.

During my TB and WP service, vacuum leak check on cooling system is a very good way to check the leakage but it can only be done while the engine is cold so you may not be able to detect the tiny-tiny leakage that can only happen when the engine is hot.


Block test shall be done after the engine has warmed up and it can detect even the tiny leakage into the cooling system.


In my view, it is important to carry out the compression check on regular interval and at least at the time of TB service.


It’s like the regular medical check up on your engine.


On my NSX, I take compression data at least once a year or every 6 months depending on how I drove it.


Even after 18yrs with 135K miles, the compression data is still very strong.



Time to finish the TB/WP/Valve service.

What a dirty TH body but this is probably the same on your NSX especially, if you drive your NSX with regular short distance trip or lots of stop and go driving conditions.


In the process of cleaning it......


This NSX is DBW model so while it doesn’t have EACV or big idle air port, there is a tiny port on the TH body that you must clean during the process.


You just need to know where to clean depending on the spec of your NSX.

PCV valve cleaned to this level and operation checked before putting it back in place.



Finally, the TH body is now clean.


Needs to reset the ECU after cleaning the TH body and being as DBW model, you will get error code during the compression check any way.

The idle rpm may change after cleaning the TH body on DBW model and if that happens, you need to follow the specific procedure to re-learn the idle process.