NSX Health Check Service

Back to the subject of marking on the cam shaft holder....

Spoke with my master (yes, he does exists) and although he didn’t have the definite answer, he also agreed that the marking looked to be something to do with the grouping.

As camshaft rotates at high rpm, it requires high accuracy to be held with true circle and level at the engine head and cam holders for the entire length of the camshaft.

For this reason, the cam holders are pre-machined to a slightly smaller diameter and then tightened to the head at the specified torque. Then, it will go through the line boring process to create true circle and level to accommodate the camshaft.

Because of this, the cam holders and the engine head have to be treated as a set and thus, you won’t find replacement parts just for the cam holder on the parts list. You must buy the engine head as a set.

Obviously, after the line boring process, the cam holders need to be removed from the head in order to install the cam shaft.

Therefore, we think that the marking was used to group the cam holders to the specific engine head or something else.

Again, it’s just a guess so could be completely wrong…

Regards,
Kaz

Quote:

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Originally Posted by Kaz-kzukNA1

Again, it’s just a guess so could be completely wrong…

Regards,
Kaz

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Thanks Kaz, coming from you I highly doubt it could be wrong. :)

Cheers,

AR

Hi, all.

Recently, I was helping another member here with his heavily modified NSX.

Originally, it was planned for 2 weeks service but at the end, it turned into 4 weeks marathon session with lots of overtime but I’m glad that I managed to work on this NSX from the safety point of view.

Because of the long delay, my apology for many owners waiting for my services and Health check but as I can only work on NSX during my spare time on a private/friend basis, I will appreciate your patience as I would like to keep the same level of service for everyone.

1. Drive shaft
Attachment 6800 Attachment 6804
During the Health Check Service, it was quite obvious that both driveshafts required overhaul especially on the right side inner joint. The boot was already split and loosing grease. They were also making some noise.
The grease inside the right side inner joint was black showing that the grease was already broken down.


Attachment 6805
When I started to work on the right side outer joint, straight away, I felt something wrong with it.
I simply couldn’t even disassemble it. After briefly cleaning the joint for inspection, this was what I found. One of the roller was cracked and deformed the internal wall of the outer joint and thus, impossible to separate the spider/roller from the housing.

The metal inside the joint is specifically hardened to cope with the high torque of our NSX so it won’t break like this under normal condition. Before the current owner bought this NSX, it was used on track many times so possibly it hit something and locked the wheel while the clutch was still engaged with high torque from the engine.

Luckily, I had spare right driveshaft so just replaced it. I’m glad to find this now.

If the damage got worse while on the motorway, you never know what will happen…

Interesting enough, while I was replacing this drive shaft, I received an email from another owner. He was on track and felt something wrong so stopped his NSX at the side of the course. While he was pushing his NSX to move it, some sort of greasy square parts fell out from the bottom. He pushed a little further and another one fell out. They were indeed, the rollers from the driveshaft.

Unfortunately, due to the geometry, the driveshaft is one of the weakest point on our NSX and requires regular maintenance especially if you have aftermarket header, lowered rideheight, wide spacer or wide tread tyres.
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If you track your NSX or use track day tyres, this is a MUST service item.

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Although it is a time consuming process, I always inspect even the internal wall of each rollers. This will require planting of hundreds of pin bearings with the new grease but you won’t be able to inspect the state of the roller unless you disassemble it.

2. Bolts seized to the bush
As our NSX is getting old, it is quite common to find some of the suspension bolts seized to the metal collar of rubber bush. There is a know-how to deal with this kind of situation but on this NSX, there were three bolts seized to the bush and later I found that one of them was actually cross-threaded and already nearly sheered off.

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By the way, this is what happens when the bolt has corroded. The new one at the top and completely corroded one at the bottom. The corrosion will fatten the diameter of the bolt and it will simply bond heavily to the metal collar of the bush.

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Because of this, it is important to remove all of the alignment bolts and nuts to apply thin coat of silicone grease just before visiting the alignment platform. If you manage to find the corrosion at its early stage, you can gently remove just the surface corrosion and re-use the bolt.


I used to test many suspension systems on NSX for R&D projects so for me, it is quite normal to deal with damaged suspension bolts and threads using helicoil, spark erosion, etc.

This NSX seemed to be used as a track day car and with the extra heat combined with the moisture/salt in the air, most of the bolts and nuts were corroded and making the service very difficult.
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Due to the previous damage and the state of other parts, it was decided to replace the rear beam.

I always feel hornored to be able to work with the owner who is allowing me with extra time and also the great support from the members on this forum and even the ex-owners.

I would like to say special thank you to one of the member here for providing me with his spare rear beam and another ex-owner for his generous offer even while he was out of UK.

3. MTF strainer
Before removing the Left side driveshaft, you must drain the MTF/ATF. Whenever I drain the MTF, I always check the MTF strainer/filter near the drain plug.
This will provide me with some sort of feedback on the state of gbox as well as how it was used in the past.

It is quite normal to see some metal powder/dust inside the strainer.

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However, on this NSX, there were several metal particles came out from there. I drove this NSX to/from the alignment place later and didn’t feel any issues on shifting so probably the damage was done in the past. Not many people (including Honda) inspects and cleans the MTF strainer at the time of MTF service.
This gbox must have been already overhauled as it has aftermarket LSD. Still, it is good to tell the owner about the findings as he may want to look into the gbox service in the long term future.

4. Header
Being as a race engineer, I’m very interested in the design and material of each component.
Quite often, with the aftermarket headers for NSX, it was designed without any thoughts for the service work on the car after the installation.

Attachment 6820
Sometimes, you find that you can't remove a certain bolt due to the layout of the header.
This is quite important point for engine area service like timing belt as you want maximum space when tilting the engine. On some of the headers, it won’t provide you with enough space around the edge of oil pan and front engine mount.

5. Alignment
Before going to the alignment place, all of the adjusters were checked as well as applied the silicone grease as mentioned above.

Attachment 6822
Once again, the caster adjuster was seized on both front sides so it was not possible to adjust them but the result came out not too bad at the end.

Attachment 6821
This NSX was heavily modified with lowered rideheight and wide spacers so factory setup was no use and thus, used the customised setup considering the owner’s driving style.

6. Main Relay

Another 'MUST' maintenance item on our NSX.

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The one on this car was from very early 1995 and the replacement new one from late 2009.

Although the owner was not feeling any issues (yet), I always strongly recommend all owners to replace it as a preventative measure.

There were several members here stranded or failed to start the engine at the most inconvenient timing.

There were several failure reported even on the later models including 2001 and 2002 ones so you are not alone.
One NSX actually failed to start up while taking my Health Check Service :eek:.

Install the new one and re-solder the old one and keep it on the car. It will be used for emergency spare for you and possibly, you may be able to rescue another owner in the future.

7. Clutch Master and Slave Cylinder
During the Health Check service, it was noticed that the master cylinder was leaking.

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The leakage was so bad that I decided to remove the carpet and give a good leaning.
You don’t want to leave the brake fluid under the carpet and on the metal floor. The leakage from the master will result in brake fluid into the cabin under the clutch pedal.

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And it is always best to replace the Master and Slave as a pair because they are always operated at the same time. Also, replace the hose at the same time.

If you are doing this as a DIY project, one tip for you.

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Unlike the brake master cylinder, it is not so difficult to get rid of the air inside the clutch master so bench bleeding won't save you a lot. Still, if you have a spare brake pipe, it will save you a little amount of fluid by carrying out the bench bleed first.

Attachment 6830
Before installing the Slave Cylinder, position it like this and bleed the hydraulic system by keeping the bleeder screw upwards. It saves your fluid and time.
Make sure to open the bleeder wide enough otherwise, you will be shooting the new piston into the air. Half turn is enough.
Unlike the brake bleeding procedure, you don’t need to worry too much about the air getting back to the system when releasing the pedal. Due to the geometry of the clutch pedal and the piston ratio of the master and slave, the clutch pedal will stay at the floor. You will need to lift it by your hand. Once there are no more air bubbles coming out of the bleeder, close the bleeder before lifting the pedal and repeat it a few times and you are done.
Remember to apply good quality high temp grease at the saddle of clutch folk where the slave piston/plunger sits otherwise it will create squeaking noise in the future.

Quote:

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Originally Posted by Kaz-kzukNA1

There were several failure reported even on the later models including 2001 and 2002 ones so you are not alone.

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Good advice.

My car was registered in April 2001 and the main relay failed in March this year at just under 9 years old.

Kaz
Thanks (again) for taking the time to document your findings and work.

Looking forward to my health check (although I'm feeling nervious about what you may find given the age and mileage!)

Keep up the great work:)