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Big McLargeHuge’s 1990 JDM NSX Adventure Thread

8 February 2019
Atlanta, GA
Hey everyone, I'm Tyler and I’m pretty new to forums in general but wanted somewhere to document my journey with this car, give credit to some long-time members that have already helped me through old forum posts, blogs, FB posts, etc., and hopefully help some current and future owners if they happen to stumble on this thread in 2030. I'll keep the image sizes reasonable resolution since I hate scrolling past huge in-line pictures. (edit: this was determined to be a lie)

My new-to-me car is a 1990 Honda NSX, Chassis ID NA1-1000368, likely one of the first cars produced and came with all the classic "first model year" issues and no service records at all over the past 30 years. Picked up from an import dealer in Texas with 68,000 km/42,200 mi on the odometer and driven back the next day to my home in Atlanta, GA. The car is almost a completely stock automatic, but will be a manual soon. I plan on keeping this car for the long haul and am honored to be its steward and hopefully treat it right with an overall restoration and modernization.

(before pickup)



Here’s some background you can skip if you have better things to do. See TL;DR.

My daily is still a 2007 Scion tC, my first and only car since I was 16 and loves to eat oil, but I learned a lot from working on it and it got me into cars in general. Anyways, I’ve been obsessing over the NSX for ~1.5 years now since I drove behind one on a Fun2Drive rental car experience (highly recommend) around the Hakone turnpike in Japan back in 2018. A friend and I were in their silver BNR34, and while obviously amazing, I’m not patient enough to wait until 2024 and pay out the ass to get one. Fortunately I fell in love with the NSX styling and sound and have been looking for a JDM one ever since, especially in the classic red & black color combination.

(Fun2Drive NSX that inspired me, not my car)


JDM manual trans cars are ridiculously overpriced, and are off the table for my budget and without $60k+ to spend regardless of mileage and condition at this point. The market price for JDM manual cars is at least 50% higher than any automatic, as opposed to the 6-10% premium they bring here, and no import dealer in the US will be able to make any reasonable profit on bringing one in anymore. I spent months looking for one and turned up with nothing, and since I’m stupid and single, bought an automatic car and will convert it to a manual instead of waiting to win the Craigslist lottery.

Obviously, getting a USDM Acura would have been significantly easier, faster, less risky, and cheaper, but there’s something about the Honda version that just does it for me. The badging, RHD, reverse gear chime, etc...I wanted every time I saw or got in the car to be a special experience, and I think I did the right thing for me and my specific dream car. That being said, I would not recommend doing this unless you have way too much time on your hands and feel a similar way. Especially since imported cars rarely come with complete maintenance history, I have to assume it's behind on maintenance in most ways, and there's a lot of time and money investment into bringing it back up to my standards. There are plenty of Acuras that already have the EPS rack repaired, coolant hoses replaced, circuit boards re-capped, driveshafts rebuilt, etc., but unless I win the car lottery, all that responsibility falls on me. (spoiler: none of it was done already, unsurprisingly).

TL;DR: JDM NSX was/is my first attainable dream car, JDM manuals way overpriced, bought an auto to convert to manual, bring back up to modern standards & maintenance, and enjoy driving it.

The car has been driven less than 8000 km since 2014, is five years older than I am, and has absolutely zero records to speak of. Not even an owners manual, but I do have a leftover Japanese gas station receipt that I can frame on my wall. Fortunately, I plan on doing 95%+ of the work myself and I’m a certified YouTube mechanic, otherwise I will surely be in a debtors prison specially constructed for me. It's a combination of wanting to learn more about cars and hating paying for shop labor and parts.

Stuff to Fix, not comprehensive (UPDATED 01/31/21)
-(COMPLETED 2/8/20) Hatch & trunk gas strut replacements, bought new OEM for all 4 but could've had old ones re-charged.
-(COMPLETED 3/16/20) All critical maintenance: timing & accessory belts, water pump, crank pulley, lower timing cover update, head cover gaskets, TB cover gaskets, thermostat, coolant flush, etc. based on Kaz's parts list (http://www.nsxcb.co.uk/showthread.php?6286-NSX-Health-Check-Service/page35&p=74593#post74593). EDIT: My write-up here (https://imgur.com/a/pv9ABxv). Next time I'm dropping the engine...
-(COMPLETED 3/31/20) Turns signals don’t cancel, probably need to clean cams/contacts. EDIT: No change after cleaning, might need to replace module but not worth it at the moment.
-(COMPLETED 3/31/20) Tachometer is slow to respond or sticks, brake lamp indicator permanently on. EDIT: Gauge cluster was repaired here (https://imgur.com/a/WlvXGU5). Brake light issue continued after repair but turned out to be corrosion on brake light bulb sockets due to water intrusion.
-(COMPLETED 4/18/20) Electric door mirrors adjustment doesn’t work, needs electrical diag. EDIT: My thread here (http://www.nsxprime.com/forum/showthread.php/213444-Power-Mirror-Switch-Troubleshooting)
-(COMPLETED 4/24/20) Right door speaker is blown or the amp isn't working. EDIT: Repaired & replaced capacitors, works just fine now.
-(COMPLETED 4/24/20) Door lock occasionally acting up. EDIT: Cleaned connector contacts and seems to be working again. EDIT 2: Still intermittent issues, will replace with OEM weatherproof connectors
-(COMPLETED 4/25/20) Windows slow on up/down, needs upgraded rebuild parts & lubrication/adjustment. EDIT: Removed windows, replaced one guide, rebuilt regulators with Hugo/SoS upgrade parts.
-(COMPLETED 5/6/20) Wind noise and water leaks all around the upper door gaskets and front door sashes. EDIT: Replaced upper weatherstripping and front sashes with updated design.
-(COMPLETED 5/6/20) Lower door seal torn and missing clips, door panels missing tabs, missing vapor barriers. EDIT: repair mostly but could use new lower seal and panel mount fasteners.
-(COMPLETED 5/6/20) B-pillars, drip molding (A-pillar cover), door handles, and door belt molding need to be repainted in Berlina Black due to failed clear coat. Done.
-(COMPLETED 5/10/20) Some annoying creaking in front suspension during accel/decel, sounds like right front side. EDIT: Replaced right tie rod, problem was actually loose control arm camber adjustment bolts rubbing against control arm bushings on both front arms.
-(COMPLETED 6/21/20) EPS codes 31 and 33 appeared and speedometer started jumping around, went away after clock fuse reset. Likely VSS1 speed sensor on A/T going bad, ordered aftermarket replacement to prevent future inevitable intermittent issues. EDIT: Replaced VSS1 and will see if they come back. EDIT2: They keep coming back...intermittent MIL code 17, TCS code, and the EPS codes after driving for ~1hr or so, heat related? M/T swap with new VSS1 did not fix, only sensor left is the NC sensor. EDIT3: Replaced NC and still no good. EDIT4: Replaced VSS1 as well...no more speed sensors to replace.
-(COMPLETED 6/21/20) Replaced VTEC solenoid gaskets, oil pan gasket, and oil pressure switch O-ring
-(COMPLETED 6/21/20) Replaced fuel filter
-(COMPLETED 7/8/20) Intermittent CEL/MIL codes 1 and 2 for HI/LO O2 sensor voltage, both banks. EDIT: New Denso sensors installed w/exhaust system replacement
-(COMPLETED 8/29/20) General circuit board repairs for electrolytic capacitors & transistors: CCU, SRS, gauge cluster (done), speaker amps (done), radio head unit (done)
-(COMPLETED 9/13/20) Right inboard driveshaft boot is torn and probably no grease left in the joint. Will be rebuilt during transmission swap, hopefully is reusable.
-(COMPLETED 9/17/20) JDM cruise control limited to 110 km/hr from factory. EDIT: Have USDM cruise control brain, just need to install and see if it removes the limiter. Will replace during M/T conversion. EDIT2: USDM unit does unlock speed limiter.
-(COMPLETED 10/3/20) Need new taillight gaskets and right taillight housing is slightly warped, plus brake bulb melted the holder on the left light...
-(COMPLETED 10/3/20) Aspirator fan/temp sensor fan rattling, needs cleaning/adjustment/lube
-(COMPLETED 10/11/20) Need to replace all coolant hoses sooner rather than later, likely along with a radiator replacement of the original factory one w/coolant flush for future spirited driving
-(COMPLETED 10/20/20) Replace & re-solder main relay & fan control unit
-(COMPLETED 11/12/20) Laser wheel alignment
-(COMPLETED 01/24/21) Rebuild brake calipers, inspect or replace pistons, install stainless steel lines, new slotted rotors & better pads, refinish dust shields, flush with DOT4, powder coat calipers
-Final window adjustment & replacing door connectors with OEM waterproof
-Black trim repaint/restoration (Rear garnish, re-do A & B pillars)
-EPS rack rebuild

Goals & Mods, roughly in order (UPDATED 01/31/21):
-(COMPLETED 2/14/20) Paint repair, restoration, and extensive detailing. Write-up here (https://imgur.com/gallery/gUR6Pxg)
-(COMPLETED 7/8/20) Aftermarket headers and catback exhaust. EDIT: Ordered Pride V2 headers, exhaust, and resonated test pipes since my system is all rusted out and no GA emissions required.
-(COMPLETED 7/25/20) Rebuild the 5-speed I already purchased, already has JDM short gears installed, NSX-R 4.23:1 FD installed, several new driven gears & all new sliders/hubs. Posted in various pages here, pts. 1-6
-(COMPLETED 8/26/20) S2000 gauge cluster conversion. International shipping delays put this on hold for months.
-(COMPLETED 9/13/20) A/T to M/T conversion. Will retain A/T cams for the time being and power steering.
-(IN PROGRESS) OEM seat leather replacement, new or refinished wheel, handbrake cover, center arm rest repair or reupholstering
-New wheels & proper tires, currently on 18/19” Advan Model 7’s (very JDM) but have cheap Chinese all-seasons. Need some refinishing and too big for my liking
-Coilover suspension (Fortune Auto or KW V3’s)
-ABS upgrade to S2000 or NA2 type
-Type R style black/carbon rear wing or Modulo replica if I'm feeling spicy
-Custom WRGB LED tailights and front jiko-shiki license plate driven by Arduino
-Remove purple rear window tint, tint fronts ~35% so I don’t feel like an ant under a magnifying glass
-Center console & switchgear paint stripping & refinishing
-Double-DIN radio/center console upgrade, new speakers, subwoofer, amp, etc.
-Underbody cleaning, stripping old coating & dirt, replacing/refinishing rusted hardware & brackets
-HID or LED headlight retrofit
-Engine-out refresh with manual spec cams, harmonic balancer, gaskets, seals, plugs, updated LMAs, sensors, potentially MLS head gasket and ARP studs for future-proofing if I'm feeling dumb enough

Thanks for coming to my TED Talk, and I hope you enjoy reading and following along with me on my adventure. Feel free to ask any questions you'd like.

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Welcome, car looks super clean.

Aspirator fan is an easy fix, a bit of grease and adjustment and it will be silent.

Window repair isn't as simple as just cleaning and lubricating, they are just a bad design and you'll need to source a few parts to rectify the issues. Hugo used to sell kits to convert the "U" shaped slider into a pulley but I don't know if he still does. Also the slider feet should be replaced with aftermarket teflon feet and the bit that holds the cables into the part that attaches to the window is prone to breaking as well, and there are better aftermarket options available.

Also it's much cheaper to buy the door gaskets from Amayama in Japan than it is to order from the US, even after you factor in shipping, FYI. Same for taillight gaskets.

Unfortunately, automatic transmissions are very nearly worthless. They don't sell for more than a couple hundred bucks because nobody really wants them. You might get lucky though since yours is fairly low mileage.
Thanks MotorMouth, I'm very happy with it and I think the exterior and interior will clean up nicely as the pics are a bit misleading as you'll see in future posts.

I've been looking into the window parts for a bit and the options seem to have dwindled down to the SoS billet window retainer and retainer bushings, though I'm sure there's some other necessary parts out there somewhere. I haven't dug too deep yet since I don't fully understand the mechanism but it's on the short list.

I actually have the door gaskets, sashes, and taillight gaskets on order already from Amayama, as well as a ton of other maintenance items. I ordered some stuff from the local Acura dealership where the price difference is similar or better but would rather eat my shoe than pay a dealer double or more for a simple part. Just hope I don't have issues with customs or tax.

I understand, some auto owner should be very happy with the trans once they get it for cheap...I tried looking for past sale info but came up with nothing. Can't think of a use case for it except someone that wants a spare or theirs blew up.
Welcome Tyler, I'm going to tagscribe to this thread so I don't miss any updates!

While I'm thinking of it, what's the origin of your username?

Rock on,
Hi Tyler and welcome to NSX Prime!- that's a great list and your car looks really clean! [MENTION=33247]MotorMouth93[/MENTION] is right, the windows are a real pain to get right. The most important thing is to get the sliding tracks perfectly, surgically clean before re-greasing. That means you have to remove them from the door- also not fun. The old grease dries out and cakes onto the aluminum, which causes all sorts of issues. Invest in the Honda urea grease- it is the only stuff that actually works over the designed time horizon for the rails. Properly cleaned and greased windows will work well for about 5-7 years before they need to be re-done. Budget at least half a day to get the glass alignment right and remember that the numbers in the service manual are for brand new rubber seals. YMMV

IMHO, your first item of the list should be the gauge cluster. If you have the brake light issue, that means the capacitors are already leaking acid onto your circuit board. This is a critical issue, as you could lose the car from a fire. The cluster isn't that hard to remove- you should send it to Brian K, who should be able to fix it.

I'm in the midst of a similar project to yours. I'll be honest, It's a pretty heavy lift and will cost a lot more than you probably are budgeting. The hard part I found is sourcing a lot of the AT-MT conversion parts. You would think there are hundreds of wrecked manual NSXs out there and MT parts (clutch pedal, shift linkage etc) would be plentiful and cheap, but the reality is (at least in the US) there are just a few NSX salvage yards who are hoarding all the parts and making you pay the "NSX Tax". I had to pay $200 for that aluminum bracket under the shifter. $200 for a piece of aluminum. Any other car and that part is 20 bucks. Capitalism, I suppose. I found ATR-Parts in Austria to be very helpful in this regard. Christian's prices are reasonable and as an NSX owner/racer himself, he understands the NSX love and goes above and beyond to take care of you. Definitely reach out to him when you are ready.

The tail lights do warp over time. Depending on how badly, replacing the gaskets might not fix the moisture issues in the lenses. Basically, the clear lenses bend away from the black housing. I fixed this on my first NSX using clear silicone sealant, which I think is still holding up 10 years later with the new owner. For about $900 however, you can always just order new lenses from Japan.

Frank at Strutwise is a great resource for rebuilding the gas struts. You get to keep the OEM quality units that way.

As for the AT, it's kind of a crap shoot. I've been in the community for a long time and I've seen AT units go for almost $4k, but then I've also seen them sit for years without selling. In terms of demand, the AT is out of production and many of the boxes are starting to fail, as no one ever does the overhaul required around 100k to 150k miles. Many of those AT owners will not want to go to the trouble to convert to MT, so there is a market for used AT transmissions. You basically need to wait until someone needs one. Until then, they're probably worthless. I got laughed at on FB when I listed my working AT for sale, but I'm in no hurry to sell and I know someday someone will need one lol. Also, most of the folks who were criticizing are the some ones who want to convince you it's only worth $500 so they can buy it cheap, hoard it, and then sell it at 10X later. Watch yourself out there- I've noticed the NSX world has attracted a lot more vultures in the last 5-ish years than in times past. They don't care about you, the NSX or the community. They just want to make money off of you. As you collect parts for your conversion, you will encounter them.

Congrats on your purchase and feel free to drop me a line if you ever have questions.

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Welcome Tyler, I'm going to tagscribe to this thread so I don't miss any updates!

While I'm thinking of it, what's the origin of your username?

Rock on,

Thanks Brian, your transmission will be put to good use ;).

Username is from a Mystery Science Theater 3000 episode on the movie Space Mutiny. Used in some other misc. internet videos and I just like the sound of it, lol.
Thank you for the tips Paul, you might hear from me soon if/when I get stuck during the trans swap..

I figured the window would be a PITA, fortunately I have the urea grease already.

Duly noted on the cluster, I will prioritize it. I was planning on pulling it within a month or two anyways during the trans swap but I might take an afternoon to do it earlier. I like the idea of replacing the caps myself and have done some electronics DIY before, but if anything else is damaged I'm sure Brian would be better at it.

I agree on the expense and difficulty in sourcing swap parts, that was my biggest hangup to buying an A/T car...I've spend a few months compiling sources and reaching out, and fortunately have all of the misc parts I need lined up to ship over. The part you're talking about, the shift wires, intermediate shaft, master clutch hose, etc. really inflate the price of the job but still significantly cheaper for me to do this than buy a JDM manual car. Not so for a USDM manual but that's how it goes.

I'll try the silicone, should be able to fill in the gap between the lens and black housing. Might need to do it on the leaking 3rd brake light too.

Thanks for the strut reference, I shelled out for OEM strut replacements already but maybe I can get the old ones redone.

And thanks for the insight on the A/T, I might hold on to it a bit longer than planned then..since the market is so small it seems like it's really up to the seller to set the going rate, but like you said I really can't see them being worth any less than maybe a stock 5-speed. They're rare, someone will need one, and it's a major drivetrain component.

In other news, while I'm waiting for the rest of the TB/WP maintenance parts to arrive, I've started a full detail/polishing of the car. I'll write a full post soon, but I picked a great weekend in Georgia to do this...
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Currently writing up a big post on detailing the exterior, and Honda has blessed me with the money light in the meantime.


Seems to be an intermittent problem that's come on 2-3 times during normal driving and goes away when restarting the car. Never seen it until this week, never during my ~1000 miles driving back home.

With my paper clip scanner I get two short blinks, long pause, and one short blink, repeat. I haven't reset the clock fuse yet to reset the codes, but I assume this means both MIL codes 1 and 2 for the bank 1 and 2 O2 sensors hi/lo voltage? I will certainly check the wiring and connections out first, and test the sensors with a multimeter, but IMO wouldn't be a bad idea to slap a new $50 pair of Denso's on and hope it goes away. Again, no record of them ever being touched in 30 years. Added to the list of parts for the major service coming up shortly...

EDIT 3/3/20: Seems to have evolved into a permanent code 42 for heater circuit directly after my recent TB/WP DIY service. Still need to find the time to replace the sensors, though I might have to make sure the connectors on the front/rear head covers are okay as well now since they were messed with during the service.

EDIT 3/12/20: Code 42 was due to the rear bank connector not being seated properly...wasn't me ;). Was a bit tough to fix since I didn't hear a "click" when the connector mated up, but it ain't moving anymore and the code is gone. O2 sensor replacement planned for this weekend.
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Hey everyone, been very busy between traveling for work and completing a 3-day slog for the timing belt, water pump, valve adjustment, etc., this past weekend but here's my little write-up of detailing the car.

I put most of the details on the Imgur album below if you're interested in the step-by-step process, but I'll put some of the highlights here :smile:. Big boy pictures included since detailing's about the little things.


"After" picture first.

Tools & products used:
-Griot's 6" DA polisher older model, great for beginners but I think I'm outgrowing it after about 2 years and multiple cars. Fairly small throw and okay power isn't enough to cut through heavier defects, and it gets hung up on any sort of body line
-Adam's Swirl Killer Mini 3": great for anyone IMO, very good power, and a big time saver for intricate areas. Only negative is Adam's hates left-handed people so they put the trigger on the "wrong" side >:[-Adam's clay bars & Optimum No-Rinse clay lube solution
-Menzerna 400 heavy cut diminishing compound
-Carpro Essence polish
-Various Lake Country & Hex Logic foam pads, 3" and 5.5"
-Meguiar's microfiber pads, 3" and 6"
-Carpro Ceriglass, felt pads, Carpro Flyby coating for glass polishing
-Carpro Cquartz UK ceramic coating, Reload top coat. Promise I'm not a shill for Carpro
-Gunk engine degreaser-Dr. Colorchip touch-up paint, fine line artist's pen
-Carpro Eraser, ~50% IPA mix, Mother's foam mix, pressure washer, gloves, respirator, tons of microfiber towels, etc, etc.

Total time to complete everything was approx. 40 hours give or take a few.

Foamed, washed, and decontaminated.

Leaking door seals, I have all new seals and front sash assemblies but need to find the time to install along with the new upper windshield rubber & fastener.

Frunk detailed

My little setup.

Before of the front end. Really gross..

Right front fender before. Equally as gross.

Biggest chips on the car, front left fender. Looks bad but cleaned up well, see below..

Dr. Colorchip with the AMMONYC fine line paint pen technique to touch the chips up, pretty easy to learn and get good results.

Same fender after chip repairs.

What was hiding under the front license plate frame...some paint damage but nothing too bad.

Had to put both 1500W heaters on different circuits so I wouldn't trip the 15A breakers...

Front windshield glass polished, wiper arms will be painted soon.

Front emblem area before.

Same area after compounding & polishing.

Top old, bottom polished.

Spoiler removed for access. Very annoying with blown trunk struts and the 3rd brake light wiring connector grommet on the left side.

Headlights polished though pop-ups mean little to no oxidation anyways.

Door sill plate polished, not great lighting but I like that they're in good condition.

The fallen soldiers

Overall picture after polishing, some final touch-ups

Morning after in the sun, naked paint since I didn't have the time yet to devote to ceramic coating.

Rear quarter shot

This is a few weeks later after all the coating and things, though I didn't get a chance to wash it before the show and it got rained on :eek:. Still, the ceramic coating made most of the dirt slide off, though it seems to love collecting crap on the top of the rear bumper and lower skirts.

Overall, very happy with how the car turned out. There are some spots here and there that I would have to devote more time and wet sanding/compounding to take care of due to some minor texture issues from the repaint, but overall the paint is in very good condition now aside from the black B-pillar trim, belt molding, door handles, and A-pillar/drip panel trim. I have the matched paint/clear on hand now, just a matter of finding the time to disassemble the pieces and carefully prep, paint, and sand them to a smooth finish to match the OEM look. Shouldn't be too bad since they can all be taken off the car pretty easily and get individually painted.

I'd like to do the upper windshield molding and door seals at the same time since everything will be apart already, just waiting on the molding (and type-S door emblems :cool:) to ship from MITA along with some new keys and trans swap parts. Since the keys take "14 business days to cut", they're probably holding up the shipment.

If you have any questions on the process I used, feel free to ask. Just completed the TB/WP/etc. major service, took a lot out of me physically and mentally but will see the post soon..
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Special delivery from [MENTION=10956]whrdnsx[/MENTION], the plan is all coming together now...leftover items include the two M/T engine mounts, SoS sport clutch kit & damper delete, and some misc. nuts and bolts, and my shipment from MITA. Otherwise, besides the trans I still want to rebuild first, the hour of putting in the proper transmission approaches :smile:.

I've heard good things about the foundry3 billet mounts, though $900 is a hard pill to swallow. Second option would be the SoS Sport Engine mount rebuilds x2 for ~$450 (or all 4 for $900 also), but my other two mounts would still be original. Regardless, my usual cheap route of ordering from Amayama would only work for the OEM rear mount ($150), as the left mount (also $150) is out of stock.

Most economical is the Innovative Mounts kit for $450, though the fitment issues and materials of construction I've read about here on Prime give me pause. I tried messaging them for some clarification on this, but after one response they seem to have forgotten about me. I want the swap job to go as smoothly as possible, and don't want to be hung up on incorrect fitment or wrong bolt sizes. They can't even get their left/driver or right/passenger sides right on their website...not reassuring overall, so I'll probably have to bite the bullet on the above options.


Go Foundry or SOS and don’t look back. I went with Foundry and have no issues.

Sent from my iPhone using Tapatalk

Go Foundry or SOS and don’t look back. I went with Foundry and have no issues.

Thanks for the input xrc. Do you recommend the street 62A or the race 75A poly bushings? Did you use all factory hardware?

Cool Car, keep the pixs and updates coming.....Big expensive job!

Thanks Bram, I just finished the big TB/WP/etc. job but have to open up the heads again to re-check my timing as I'm paranoid it's off slightly from a crank gear misalignment. Write-up in progress.

Even with all the expensive parts, still significantly cheaper than buying a factory JDM manual oddly enough. Plus I get all-new master & slave cyls, clutch/flywheel/throwout, damper delete, rebuilt NSX-R trans, shifter assy and bushings, engine mounts, etc. Plenty of preventative maintenance and upgrades, though obviously a big time investment :redface:
I'm glad to see more people doing AT2MT conversions nowadays. That conversion used to frowned upon years ago. My car was converted two years ago. By the way, I'm current using Innovative Mounts without any issues.
Thanks for the input xrc. Do you recommend the street 62A or the race 75A poly bushings? Did you use all factory hardware?

Thanks Bram, I just finished the big TB/WP/etc. job but have to open up the heads again to re-check my timing as I'm paranoid it's off slightly from a crank gear misalignment. Write-up in progress.

Even with all the expensive parts, still significantly cheaper than buying a factory JDM manual oddly enough. Plus I get all-new master & slave cyls, clutch/flywheel/throwout, damper delete, rebuilt NSX-R trans, shifter assy and bushings, engine mounts, etc. Plenty of preventative maintenance and upgrades, though obviously a big time investment :redface:

I went with the 75 and you use the factory hardware. I’m also turbo but I don’t think one can feel the difference between 60 and 75.

Sent from my iPhone using Tapatalk
I'm glad to see more people doing AT2MT conversions nowadays. That conversion used to frowned upon years ago. My car was converted two years ago. By the way, I'm current using Innovative Mounts without any issues.

And you're in the US, right? I haven't seen many conversions documented here, most seem to be in Japan/Aus/NZ/UK/etc. where the supply of autos makes the entry price for conversion attractive enough.

Have you also done the M/T cams and harmonic balancer? I'd like to at some point while I tear into the engine again for the LMA update.

Thanks for the data point on the mounts. I'll follow up with them to see if they could help out with fitment/bolting.

I went with the 75 and you use the factory hardware. I’m also turbo but I don’t think one can feel the difference between 60 and 75.

Thanks. I'm about as low power as you can get right now, might go with the 60's anyways to help out a bit with NVH.
Hey man, i saw your car at caffeine and octane, but i didnt see ya.
i have the red 95 with spoon mirrors on prodrive wheels, we usually park in the same lot:cool:

There are a few of us NSX owners around here, im in lawrenceville. hit me up
What's up man, I've seen you and Benson a few times at C&O but didn't know you were on Prime.

You let me sit in your car just over a year ago back when they had the show in the front lot :biggrin:.

Barely made it to the last show, not sure if they're gonna hold the next one at this rate :smile-freehand:.

I'm in north ATL too, took tomorrow off to do more maintenance...

Now that I think of it, have any local shop recommendations if I want to offload some of this work to someone more qualified? I tried calling Eiffel from the Prime shop map, but he didn't seem to want to bother with the car and said I should be able to take care of everything myself since I had just done the TB/WP/etc. Would be kinda nice to have a fallback.
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And you're in the US, right? I haven't seen many conversions documented here, most seem to be in Japan/Aus/NZ/UK/etc. where the supply of autos makes the entry price for conversion attractive enough.

Have you also done the M/T cams and harmonic balancer? I'd like to at some point while I tear into the engine again for the LMA update.

Thanks for the data point on the mounts. I'll follow up with them to see if they could help out with fitment/bolting.

Thanks. I'm about as low power as you can get right now, might go with the 60's anyways to help out a bit with NVH.

Yep, I'm in the US (PA). Most people here didn't see the conversion as worthwhile since the delta between AT and MT prices were minimum back in the day. There were more ATs sold in other regions, so MTs brought a premium in those markets making the conversion more justifiable.

I'm actually still using my stock AT valve train, power steering, and ecus with my conversion. I didn't feel the need to seek out the MT counterparts since I would probably upgrade down the road anyways. Plus, there's a rumor that AT cams might actually be better if you plan to supercharge your car.
Yep, I'm in the US (PA). Most people here didn't see the conversion as worthwhile since the delta between AT and MT prices were minimum back in the day. There were more ATs sold in other regions, so MTs brought a premium in those markets making the conversion more justifiable.

I'm actually still using my stock AT valve train, power steering, and ecus with my conversion. I didn't feel the need to seek out the MT counterparts since I would probably upgrade down the road anyways. Plus, there's a rumor that AT cams might actually be better if you plan to supercharge your car.

Interesting, I will probably keep the power steering regardless. Mostly interested in converting the cams since I would want to update the LMAs soon anyways, replace the crank pulley, and gain another 500 RPM, all of which would be a "while I was in there" type of thing.

Anyways, here's a peek at my suffering over the past week. I re-did my timing job and decided to throw in the O2 sensors and replace the oil pan for good measure. Guess where the other half of this O2 sensor still is? Lol.
Timing Belt/Major Service

Hello from quarantine everyone, I hope you're having a fun time "working" from home like I am.

Here's another big item crossed off the list, and I only had to do it twice.

I put more detail in the photo album below since it's easier to scroll through, but will put the highlights here. Prepare your scrolling finger. Much of my commentary is the same in the album or on here.


EDIT: Sorry for the massive pictures initially, I've reduced them by about 4x for easier forum viewing.

Here's my setup for the job. Not my lift, but I can reserve it as long as no one else wants to use it. Pretty ideal for this type of work.

Removed the strut bar, rear defroster panel, and engine cover for more access.

Advance Auto rental coolant pressure tester at 17 psig, only lost coolant to a petcock O-ring on the bottom of the radiator. Fortunately I have new ones already from reading through Kaz's parts list.

One of the first orders of business, seeing if I could get the crank pulley bolt off before getting too deep into the job. Tried 3 different 1/2" impact guns with no effect, maybe one of those big 19mm harmonic balancer sockets would fare better. Made the mistake of using a 3/8" adapter at one point, that didn't last long.

Finally, a 1/2" breaker bar with another 3 or 4 feet of jack handle provided enough leverage to budge the bolt, sounded like a shotgun when it broke loose. The crank itself was held in with another 1/2" breaker bar wedged against the lift, and a 50mm crank holder tool from Amazon ($12). Nice alternative to the Honda tool, but I think most M/T cars have a 45mm pulley hole which is harder to find a tool for.

Old air filter and air box removed to get at the left side trans mount bolt, and working on detaching the coolant tank to allow engine tilting.

I removed the oil pedestal completely to replace the two short coolant hoses, and man, was it fun getting these things off their hardlines. Long nose pliers are needed to fit in the tight space needed to remove the clamps, some silicone spray to loosen the hoses, and finally needle vice grips to get enough leverage on the hoses to yank them off. They were super stiff and likely original. Nice new hoses and 4 new clamps were installed.

Head gasket leak :eek:? No, just oil pedestal juice that drained out. The old coolant was likely some generic green stuff, good chance to replace with the new Honda blue-spec coolant.

Rear bank ignition coils that tend to get rusty from water leakage from above. My coil covers had some felt material glued to them instead of the Honda rubber gaskets, and they seemed to be doing a good job so I just left them on. Plus I don't really get how to attach the Honda gaskets to the covers, lol..

Finally cracking open the head covers for the first time. Somewhat of a moment of truth considering I had no prior service info, but everything looked very good, so someone did their regular oil changes. There didn't seem to be any gasket leaks, but obviously I have new ones to put on.

I didn't go quite as far as Kaz did to take out the cams themselves and replace the caps/LMAs/etc. yet, but they're on the list for a future service. I didn't want to get too ahead of myself considering this was my first time doing this complicated of a job.

Rear head looks good too. A little more shiny since I think this bank doesn't get all the gross recirculation gases.

View right before timing cover removal. Finally I could see that, in fact, a TB/WP service had been performed at some point in the past due to the presence of the updated WP/lower timing cover weep tube. Still, they had obviously been on there for a while and there was no weep tube grommet.

Old belt removed. This did not go as well as I had hoped, because when I went to mark the old belt before removal to match up the belt teeth with the new belt, my timing marks didn't seem to align properly. Honestly don't know exactly how it happened, but likely somewhere along the line I did something out of order and skipped a tooth, or I wasn't looking at the right timing marks (didn't know about the oil pump/crank gear arrows yet), so I could only mark the crank gear and the front intake pulley. I think it was mostly my lack of experience that caused the confusion, and the result was that I didn't put the new belt on exactly right since my crank gear wasn't perfectly at TDC. More on this a few pics below......

Anyways, the old belt looked good, pretty much exactly the same as the new belt but more brown. Probably would've been fine for quite a while longer, but you never know, especially since I had no idea how old it actually was.

Similarly, the old tensioner pulley felt solid, but I ordered new factory parts in preparation anyways, including the adjuster bolt, spring, grommet, and pulley. Why not, right?

New water pump, kit comes with the new lower timing cover and grommet too. You can see on the old pump, the top left dowel pin stuck in the old pump without me noticing, and since the dowels weren't called out in the DIY guide (only labeled in the SM), I forgot to transfer over one of them to the new pump. From a thread I started in the DIY forum during my second timing attempt, the missing dowel might have allowed the WP pulley to shift very slightly and prevent the rear intake pulley from lining up perfectly with the rear exhaust/cover mark during tensioning. Fortunately, hasn't caused any noticeable difference yet.

Old, crusty thermostat removed from under the intake duct in a nice nest of vacuum lines and wires. Bruised another knuckle yanking this thing out of the housing with a pick, the gasket was really fused in there.

Timing covers set up for re-installation with new gaskets all around. Amayama has much more competitive prices especially for the lower gasket, around 40 bucks instead of over 100 in the US. Sometimes I wonder about Acura prices...

I used a fair amount of Hondabond on the new gaskets to hold them in place as I wedged the covers through the rat's nest of crap in the way. Tilting the engine as high as reasonably possible helped a great deal for increasing the clearance between the belt and the right side frame, but still took a good 30+ minutes to finagle each cover in the perfect way to allow it to slot into place. A little silicone spray helped the gaskets slot over one another.

Another thing not really mentioned elsewhere, the lower cover bolts seemed to go in just fine (and I installed the A/C idler pulley before the upper covers), but the front and rear cover bolt holes almost never lined up enough for the bolts to thread in properly. Pro-tip, leaving those bolts out until the head covers went back on helped push down on the upper timing cover "slots" that fit over the lower cover gasket and allows the holes to align much better.

Torque on the cover bolts is only 9 ft-lb, but my cheap Amazon wrench apparently couldn't handle my gorilla-like hands and exploded into its constituent parts. I can only be thankful that didn't happen as I was torquing the valve adjustment locknuts.

Oh yeah, and not pictured is the valve adjustment, not much to see there. It took about 2-3 hours, but I was rushing myself at this point and didn't take as much care as I should have. The next time I gave myself enough time to recheck everything after final torquing.

Not pictures is, y'know, putting everything back on the car. 3 days in, about 40 hours of work, and I only fucked up a little bit, but the car made it to the monthly show again :).

Here's something I missed, there was a new squealing sound from the accessory belts but I had chalked it up to the rattling A/C idler pulley bearing I noticed when I had taken it off, but I didn't have the new bearing on hand yet. Welp, turns out I just forgot to tighten the center pulley bolt after tensioning the A/C belt (needed to be loose for the adjustment nut to move the pulley), and the whole pulley ended up sitting cocked on the bolt. Fortunately someone at the show had a spare 14mm wrench I could use to slowly tighten the bolt until the pulley was properly aligned, no more noise though I'm sure the bearing didn't enjoy it.

And well, I wasn't perfectly happy with how the car was running after I buttoned everything up the first time. A little more valvetrain nose, and the car just seemed to vibrate a bit more at idle. I was convinced I was imagining it, but I couldn't be satisfied until I checked over everything again. Obviously you should be 100% sure everything is perfect to avoid this, but I time constrained myself too much and honestly the first job took a lot out of me physically and mentally. I was very close to getting the car towed to a shop and have them finish it up, and I tried briefly to look for one that could help check my work, but I decided it was up to me to fix.

2 weeks later, built up enough courage and time to take the head covers off again and check my marks. This time went a lot faster now that I knew where everything went, what sockets to use, didn't touch the coolant or oil pedestal, that sorta stuff. And well, below is the crank position when the upper cam marks were aligned. Safe to say it wasn't perfect, and due to my own inexperience I have to do the job again.

Plus, I had a new oil leak waiting for me. It appeared to be from the oil pan flange next to the timing covers, and since the whole pan was rusty, grimy, and had some small past dents in it, I decided to order a new one and install it for piece of mind. I already had the new gasket and new bolts on hand, but oh well, hopefully this is a one-time cost.

Here's a straightedge on the old pan. I read another build thread (think it was MotorMouth's) where the cams and journals were scored due to low oil flow since the clearance between the pan and pickup is so small, so this is extra incentive for me to replace the pan all together. I'll keep the old pan to see if I can restore it a bit and have the pan baffles and an extra NPT plug welded in to swap on later.

Removing the front header downpipe to drop the old pan. Penetrating oil and a propane torch to start, and my 1/2" impact and swivel socket to crack the nuts loose. Very lucky I didn't end up with a stripped nut or broken stud here, especially with how rusty the whole exhaust system is. Pretty sure the impact gun on max speed provided enough, well, impact to shock the nuts loose instead of rounding them off/snapping them like a breaker bar would. Can't wait until I toss out the entire exhaust system for a nice full stainless manifold-back exhaust system.

Pressing in the new A/C idler pulley bearing, like $10 off Amazon for the OEM NTN bearing. 6203LLU is the part number, 6203LU is a single sealed bearing and you need the double sealed one. Used a shop press and some big sockets to push on the outer bearing race, very easy removal and install. The old bearing was definitely on its last legs, very rattly and spun with no resistance.

Here's the crank gear during my second timing attempt. Now that I knew about these two arrows at TDC, I could make certain that I was at true TDC instead of eyeballing the keyway like a moron.

Rear cam timing marks and the cover divot mark aligned. Behind each picture is about 6 hours of messing with the belt position and tension to try and get all the marks dead perfect. Really gives you perspective on why so many shops drop the entire engine and rear suspension for this job, it must be so nice to have all that room to get everything lined up, but that's not something I feel comfortable doing at the moment.

Front cam marks and timing cover mark in alignment. These are much easier to manage than the rear cams. Again, this whole alignment procedure took almost the entire day until I was satisfied with the marks and final belt tension.

After putting most of the engine parts back together (timing covers, another 2 hours of adjusting all the valves again, head covers, air box, left/right engine mounts, alternator, belts, spark plugs, coils, etc.), finally ready to put on the new oil pan. Look how shiny it is, and with new bolts too.

The old pan came off easily, and I spent another 2 hours or so cleaning off the bottom of the engine, which was very, very grimy from the past 30 years of never being touched. Someday with the engine out I'd like to give everything a nice deep scrubbing. Cleaned out the oil pickup screen and scraped off the old gasket material.

Mmmmm, so satisfying with the new pan in place. I used some electrical tape on the bolt heads to hold them up against the pan flange and through the gasket to make sure it went on perfectly when I lifted the pan into place, which did the job well. Followed the factory torque sequence and subtracted some in-lbs from the factory specs so I didn't squish out the new gasket past the pan flange. No leaks so far, very happy with the result.
EDIT: A few weeks later the pan is leaking oil drops onto the ground, so decidedly un-happy with the result. I will drop it again during my next oil change and use some Permatex or Hondabond on the sides of the gasket to make a better sealing surface. Some discussion on this here (http://www.nsxprime.com/forum/showthread.php/213589-Oil-Pan-Gasket-Leak/page2?p=2015434#post2015434).

And finally, the Japanese timing service sticker was installed on the driver's door sill. I couldn't read any of the instructions for it but Kaz's posts explain most of it :). I was so happy to be done at this point...
By the way, I think I mixed up the date positions...this is supposed to read 16 March 2020, FYI for future owners lol.

I always drag my feet going to start the car after a major job like this, and finally got in to turn the key. Happy to say that the car runs perfectly, much smoother than before, no detectable valvetrain noise yet, everything is quiet and not squeaking.

I spent about 40 hours over 3 days for my first attempt, including coolant/belt/tstat/WP/valves. Add another 40 hours over 4 days for the second timing go around, which included timing/AC idler/O2 sensors/valves/oil pan. I would really like not to do that again for as long as possible.

The only lasting issue is that I broke off the rear O2 sensor in the header and was unsuccessful so far in removing it, so I plugged the bung temporarily with...a screw extractor. Actually haven't noticed an exhaust leak yet, just the smell of burning penetrating oil from my removal attempts and a CEL for the rear heater circuit since there is no rear sensor to connect to at the moment.

I have some ideas to try in the next week to extract the broken threads, otherwise I'll need to remove the old header and either extract the sensor on the bench or just replace the whole header with a new one. I would go aftermarket but I think the set I want only fits M/T cars. Anyone have a NA1 rear exhaust header lying around :biggrin:?
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With all the extra time on my hands, I decided now would be a good time to start taking care of some of the interior & appearance issues.

First order of business was to remove the gauge cluster for servicing. The interior panels weren't too bad to remove, but both knee bolster bolt straps were broken off already. I should be able to glue them back on.

Once I knew how to press all the 4 green wiring connectors out, the rest came out pretty easily. Sliding the cluster out was more difficult than expected because there's really not enough room to get it out from behind the steering wheel without it being telescoped/dropped as far as possible, and held further down past the lowest detent position.


Taken mostly apart at my desk so I could see what the damages were. I'm sure putting the brass PCB conductor screws back in without breaking the speedo/tach wires will be a fun time.

The lens was fairly scratched and dirty from the past 30 years, so now's as good a time as any to drop another $40 for a nice new lens from the dealer. Seems worth it to me.

Also, this would be a good time for me to swap my A/T tach face for the M/T one I have waiting around, though it'll be a while longer until I can do the whole job. Anyone have tips for pulling the needle off without breaking anything or pulling the needle post magnet completely out of position? I've read through a few posts on here, but they always seem to stop short of actually providing useful info.

In some places on Board B, it looked like someone had attempted some resoldering repairs before I got to it based on the leftover flux residue on some components. Nevertheless, it doesn't look like anything was replaced, and there was still some damage around the usual place near capacitors C12, 13, and 16. Interesting that my board is missing some components in the middle of the below pic, I think that might be a difference between regional cars.

Certainly not as bad as other boards I've seen, but hopefully replacing all the caps and re-flowing the solder joints will fix my brake warning light and tachometer issues. If the HC1 chip component on the right is bad and not just the traces, I might be screwed since I've read here that it's a proprietary part. Hopefully none of the diodes or transistors went bad since I couldn't find close enough matches or enough specs on them to order new ones.

Anyways, I've made a parts list of every capacitor on both boards (electrolytic, ceramic, and tantalum, might be a bit overkill) and ordered matching replacements from Mouser. They should all match in voltage rating, capacitance, temp rating, and tolerance, and I tried to select ones with the longest lifespans. I've dabbled in some smaller electronics projects before so this will hopefully turn out to be a fun and low-stress alternative to the heavier mechanical stuff.

And well, if I can't drive the car until I get the gauges done, I might as well take care of some other stuff too, right? Took the opportunity to strip the pillars for refinishing in Berlina Black. Just a lot of stiff metal clips and tapping screws to remove. The door weatherstripping came off easily, and the drip moulding/A-pillar cover, but the B-pillar covers were a little more annoying because I needed a deep 8mm socket and had to drop the headliner slightly to get to the 2 small nuts on each cover holding them in place.

The studs for the B-pillar nuts are buried in the body and way too easy to drop somewhere they'd never been seen again, which apparently was true before because both covers were already missing their upper nuts. Once the lower ones came off, the cover just popped off easily. Spent another hour cleaning all the ancient shit caked behind the panels, not pictured.

Pieces to be repaired sitting and waiting on my workbench. Hopefully the weather stays nice for the paint to go well, if it's too cold or too humid it probably won't turn out the way I want.

It wouldn't be a used car without some dumbass hacking up a wire somewhere. Once I pulled off the driver's side rear panels to expose the ECU (and bolts for the outer trim), I found this nice "repair" half covered in electrical tape. It looks like it was cut once, soldered and taped, cut again, and then twisted together like a "My First Lemon Battery" kit. Really? I did a little more digging and haven't found any more wires like this yet.

I believe the wire is the red/blue to connector C475, which leads to the A/C clutch relay. I'm pretty sure my A/C was working fine, which is fortunate because when this wire would've let go I would have had a fun day of electrical diag to do. Maybe it was done during a past A/C compressor troubleshooting?

Before I put stuff back together, I'll solder this permanently and seal with some heat shrink and grease.

So, now that I have everything sitting in front of me, just a matter of waiting for parts to arrive and taking the time to do some workbench stuff for once.
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I must commend you on your perseverance and documentation skills. I have a medical condition called "Gethomeitis" that doesn't allow me to take pictures along the way of accomplishing anything. I really appreciate you taking the time to do this.
Not that I'm trying to tempt you to do this, but you certainly CAN drive the car with the gauge cluster removed.....just stick a GPS up there for your speedo, and GO!

BTDT :wink: