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NSX Refresh by michaelbrat

Joined
27 July 2014
Messages
343
Location
Southern California
The NSX is my dream car. I went through the Honda ranks over the past 10 years and experienced the EP3, DC5, AP1, and finally an NA1.

I bought my 91 Sebring NSX in July 2014, with 94000 miles. Since then, I've been on a mission to make the car fully functional and reliable. Mostly OEM replacements for the old or worn out bits, and some modest modifications to suit my needs.

NSX Prime is such an amazing place to share our ideas and styles with other Honda enthusiasts around the world. In my short stay, I've met some great people and have learned so much about the NSX. I would like to begin to share my own experiences and ideas with all of you, and hopefully contribute to the collective knowledge of Prime.

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A lot has happened in the past 17 months of ownership, so I will try to focus on the key moments. Here is the NSX on day one; bone stock and in need of some maintenance.



Mostly standard stuff. All fluid change, oil pan and valve cover gaskets, axel boots, spark plugs, fuel filter, engine and trunk lid struts. The front was missing the lip and some fender liners. The horns didn’t work (bad connection) and the half lip was curbed, so I had it repainted.



I wanted the steering wheel to be smaller and closer than the OE position, so swapped in a Works Bell hub, quick release, and Momo steering wheel. The turn signal operation is a bit of stretch, but I’ve since gotten used to it.



The radio was malfunctioning, so I disconnected the unit and installed a stand alone mini amp to power the speakers directly, using a bluetooth receiver to play music wirelessly from my phone. The main bits are housed in the OE subwoofer housing with some slight modification to fit everything.



Step one of the refresh was complete. We celebrated with a little NSX party.



Malibu sunrise canyon runs were a weekly norm.



Then tragedy struck on a hot Sunday in Malibu. The coolant hose closest to the front cylinder head ruptured. I happened to be GoPro filming at the time and reviewed footage of the coolant temp gauge rising. Once it maxed out, it took me a full 5 minutes to realize what had happened. By the time I stopped, the coolant tank was empty and any coolant from the rupture had evaporated.



I hoped for the best, but assumed the worse. A leakdown showed 27% leak at one cylinder, which meant a blown head gasket. The NSX sat for 6 months, cold and lonely.



$6000+ was the estimate for parts and labor to replace the head gaskets and other bits that came along with dropping the motor, and that’s only if it went smoothly. I made the decision to invest in a lift and complete the repair myself. Never having dropped a motor, it would be quite the adventure. Armed with the service manual and NSX Prime, I began.





To be continued…

Mike B
 
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I commend your DIY approach and look forward to reading about your progress. That's a sweet lift; I just put a (much less fancy) lift in my place. Looks like you are doing nicely so far. Please post the things you learn as you go, since your perspective is valuable to many of us.
 
I'm just jealous of all you guys able to have a garage with a lift.
 
Were you at NSXPO? I chatted with someone who dailies a silver coupe in LA. Really sweet car..

Anyway the Wolf and I approve. ;-)
 
I had a hose bust on a spirited drive, luckily my buddy behind me called as soon as he saw coolant. I was able to pull over before it reached the max. Awesome garage, your garage is still cleaner than my room lol. Good luck on the build, keep us informed
 
Wheres the next segment!!! Good stuff so far Mike. I remember dropping off some parts at your shop and seeing EVERYTHING disassembled, yikes!!! Was happy to hear everything went smoothly and the car was running like new again.
 
I commend your DIY approach and look forward to reading about your progress. That's a sweet lift; I just put a (much less fancy) lift in my place. Looks like you are doing nicely so far. Please post the things you learn as you go, since your perspective is valuable to many of us.

Great read Mike! Already one of my favorite build threads!

Need more posts, Michael. Beautiful car.

Impressive! Look forward to more.

I'm just jealous of all you guys able to have a garage with a lift.

Love the garage setup. I can't until someday I have a lift.

Nice thread Michael.

Wheres the next segment!!! Good stuff so far Mike. I remember dropping off some parts at your shop and seeing EVERYTHING disassembled, yikes!!! Was happy to hear everything went smoothly and the car was running like new again.

keep up the good work buds!
Glad to see another Sebring Silver NSX saved and in good care

tagged, love seeing threads like these.

Thanks guys. I’m glad to read that there are some who enjoy my ramblings ;)

Were you at NSXPO? I chatted with someone who dailies a silver coupe in LA. Really sweet car..
Anyway the Wolf and I approve. ;-)

I generally don’t daily the NSX but yes I am in the LA area. I talked with a bunch of cool people at NSXPO so maybe it was me.

I had a hose bust on a spirited drive, luckily my buddy behind me called as soon as he saw coolant. I was able to pull over before it reached the max. Awesome garage, your garage is still cleaner than my room lol. Good luck on the build, keep us informed

I’m glad you caught it so quickly. It seems to be an all but uncommon occurrence. All the reason to change out those old hoses when convenient enough.

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With the engine and subframe assembly out, I spent the next 2 months disassembling the engine down to the block and replacing worn out gaskets and hoses.



I took my time, read the manual throughly, referenced Prime threads and asked members for advice when I wasn’t feeling sure. The last thing I wanted was to make a mistake. The NSX isn’t all that complicated, but my lack of experience could easily lead to overlooking some key processes.



Pieces of NSX occupied every open surface. The heads turned out to be flat, no warpage. The valves were within spec. I began to put everything back together.



Anything worn out was replaced with original parts, with few exceptions. The lost motion valves were upgraded to the NA2 spring design and a TODA timing belt was utilized, being not much more expensive than OE and supposedly 200% better in every way.





The NSX trunk space gets quite warm on longer drives. This was an opportunity to heat wrap everything and test the different types of reflective materials. Besides all of that, it just looks damn cool.





Heat wrapped intake manifold cover and oil pan. The pan proved to be the most difficult to wrap in the exhaust pipe recess area. You can tell by how many slits were made in the tape and how many pieces were used.





Once completed, the engine and subframe assembly went back into the chassis.



This was the freshest everything had been in years and it just felt good to have the NSX back in service. I’ve since put 7000 miles on the car and it continues to run strong.





I was finally able to spend time with the NSX on twisty roads and begin to experience its splendid driving characteristics. What a car.



The below thread was updated during the engine refresh project. More information and pictures can be found at this link: http://www.nsxprime.com/forum/showthread.php/189030-Dropping-the-motor-tomorrow-Advice

Until next time.

Mike B
 
This is so cool.
 
michaelbrat said:
$6000+ was the estimate for parts and labor to replace the head gaskets and other bits that came along with dropping the motor, and that’s only if it went smoothly. I made the decision to invest in a lift and complete the repair myself.

So awesome. Great job, Michael!!! :)
 
This is so cool.

So awesome. Great job, Michael!!! :)

Awesome Mike - what a journey it's been.

Thank you guys. The journey is just getting started!

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During the engine refresh, I decided to install a Defi ZD multifunction display. If one of these was installed initially, I likely would have caught the coolant hose blowout right away.



My setup reads oil temp, oil pressure, water temp and fuel pressure. The ZD display doesn't match the 90's styling of the NSX interior, and would stick out like a sore thumb if mounted in the usual locations. After much thought, I found my perfect place to install the ZD... behind the radio display.





I won't bore you with all the details here, but if you want to read more about the Defi install, I wrote about it on this thread.

In light of the coolant hose blowout, I even went as far as to install a coolant pressure sensor, per @illwillem. He also referred me to a local hardware store where I picked up one of these for a few bucks. It's a nice little light that is a bit more elegant than the Longacre orange monster.



I went with this sensor from Longacre Racing. It worked great for the first few thousand miles. The light would come on at startup, and turn off once once the system exceeded 3psi. Then I noticed my warning light would stay on all the time. After contacting Longacre, they were nice enough to send me a new sensor.

Once I got around to swapping out the sensor, I found that it was actually clogged with sediment. The strange thing is that the sensor was mounted on the top of the hose, so it didn't just settle in that area. It seems like there was some type of reaction in the coolant that caused the sensor to collect and build up this gunk. After going back and forth with Long acre about this, they weren't able to come up with a reason, so I decided to ditch the sensor all together.





Some other refreshes included an ABS rebuild with one of @warrenw kits seen here. He did a great job putting together the oring and grease kit. My abs has been working excellent ever since.



Koyo radiator install as well. The core itself fit great into the car, but I had to trim the fan shroud in 3 places due to some contact with a drain bolt and radiator hoses. Otherwise, I would have had to warp the shroud to line up the mounting bolts. It seems a result of mounting the fan shroud about 1/2" away from the core. The OEM setup puts the shroud right up against the core, but Koyo leaves a rather large gap. I'm not sure why, but I plan to contact them to ask. I haven't heard of anyone else having this issue.









H ghost badge.



And finally, turning a Type-R horn button into a Type-S horn button; at least until I can find a reasonably priced Type-S button.



Save water, wash your NSX in the rain.



Until next time.

Mike B
 
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Some recent mods.

The standard Works Bell steering wheel hub cover is ribbed. I wrapped it in leather for a more premium feel.







My car is missing the center console mat, and it is discontinued from Honda. I used some soft velvet style material to cover the area.





A dome light rattle has been bugging me for a while. Adding some foam tape to the area fixed the vibration issue.



When last inspecting my air filter, I noticed there was oil puddled in the corrugated hose that links the airbox and throttle body. Upon further investigation, it was coming from the rear valve cover vent that feeds into the side of the hose. I'm not sure why there was so much oil and vapor from the head.

To solve the recirculation issue, I decided to put an oil catch can in the loop. It's a rather large can, and it took some time to find a good place for it. I made a bracket from an 1/8" aluminum plate which bolts to the unused heat shield holes (replaced with gold foil) behind the control box.















Radium makes a really nice machined catch can with wire mesh to collect oil out of vapor, and a dip stick to check the level. The bottom screws off to empty the can, or there is a drain plug at the bottom.





A recent addition to the Defi ZD display is fuel pressure. The NSX was hesitating at WOT below 4K RPM. I found that the fuel pressure wouldn't exceed 290kpa below 4K and would jump to 310-390kpa above 4K. After researching on Prime, it could have been a number of things starting with the fuel pump resistor. Luckily, changing the resistor fixed it right away. The fuel pressure now goes above 300kpa below 4K RPM, and the hesitation is gone :)

The fuel pressure sensor is mounted on top of the fuel filter, via a Russell banjo bolt adapter and 1/8NPT to 1/8BSPT adapter. Japan uses BSPT, while NPT is common to the US. There is a difference in thread pitch, so be sure to use the correct adapters instead of just screwing in your Japanese (Defi, Greddy, HKS) sensor into an NPT port. More info here.



Also, was chasing a leak at the thermostat housing bleed bolt. Found that the tip was corroded away; something I didn't notice when refreshing the car initially. (Old vs new pictures)





Until next time.

Mike B
 
Wow Mike! You're attention to detail is phenomenal. I have the same dome light rattle and it's annoying the living snot out of me. Yet, I always seem to forget about it until the next time I drive the car lol.

Roman turned me on the Radium catch cans. If I can convince myself their unit works well in a closed loop (does not vent to atmosphere) i'm jumping on one.
 
Wow Mike! You're attention to detail is phenomenal. I have the same dome light rattle and it's annoying the living snot out of me. Yet, I always seem to forget about it until the next time I drive the car lol.

Roman turned me on the Radium catch cans. If I can convince myself their unit works well in a closed loop (does not vent to atmosphere) i'm jumping on one.

Thanks Ryu :smile: The next time you roll by my shop, we'll fix it. It's only 2 screws!

Mine is setup closed loop to just the rear valve cover. (The front cover PCV is still clean, so it doesn't seem like anything is getting through there)
I'll let you know how it works out over time.

+1: I really appreciate the info in this thread.

:biggrin:

Mike B
 
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