For those of you who have been following my build thread, you've already seen some of my plans for this engine, as well as all the past plans that were either interrupted or I changed my mind about. I'll spare you the gritty details and sad backstory here.
At the time of this writing I'm waiting on the pistons to come back from having coatings applied, waiting on wrist pins to get DLC coated, then I'll send the block off to have it honed out another 0.0006" to hit target clearance with the pistons, then finally have the rotating assembly balanced.
(Build revised 12/26/2023)
Block
The plan is a 3.2L engine based on a 3.0L block with wet sleeves bored to 93mm. I chose 93mm since pistons are widely available from a variety of manufacturers and it gives me a lot of room for rebuilds in the future at 93.5, 94, or 95. Sleeves - especially MID sleeves - are extremely expensive to have installed in a C30 so I don't want to have to do it again anytime soon. The pistons I've selected are actually 20g lighter than the factory pistons so combined with the OEM titanium connecting rods the rotating assembly will be lighter than a 3.0L rotating assembly. Throw a lightweight flywheel on top of that, and this should be a very rev happy engine.
Endyn ported cylinder heads. These heads were done over by Endyn 10-15 years ago, then I bought them used and had a trusted local cylinder head machinist go through them to make sure they were good to go. He honed the valve guides a bit since they were tighter than he likes to run and touched up the valves and seats since they were in very good condition already.
Transmission
The transmission build is a more recent development, it was going to be a future project but with the favorable USD/JPY conversion rate I decided to go for it now. This is going to be a custom built 6 speed transmission made from mostly new OEM parts and reusing some parts from my 5 speed such as the bell housing and differential. The 6 speed went through a few changes from 97 to 05 so this is the ideal spec in my eyes for a high revving N/A NSX. Transmission assembly thread here.
@A.S. Motorsport billet ITB system with 50mm throttles, trumpet length TBD.
Exhaust
Lovefab headers, not sure on catback yet.
Engine Management
Chipped factory ECU running a hybrid MAP/TPS based load calculation algorithm based on Megasquirt "ITB mode", as discussed in my build thread. Might switch to Link.
Pictures
I have a buddy who does vapor blasting on the side so I've had him do pretty much everything that will easily fit in his cabinet. I'm only having stuff done that can be thoroughly cleaned of abrasive media afterwards. Here's a few examples.
One of the more time consuming projects here has been deburring the block both inside AND outside. There's lots of ridges and sharp spots and I wanted to knock them all down and maybe vapor blast the block too.
Before
After (not blasted yet)
In addition, I took some ideas from @Mac Attack and smoothed out the sharp edges of all the main caps especially around the oil holes.
I fabricated these 2 tapered delrin rods on my lathe and cut M11x1.5 threads onto them to help align the cylinder heads during installation and prevent gouging the delicate aluminum surface on the sharp edges of the dowel pins
The Endyn heads were pretty dirty when they showed up. They had also been installed on their previous engine with MLS gaskets and copper spray which is a bit of a no no so needed a good cleaning before going for vapor blasting then to the machine shop.
Fair amount of grinding in the bowls underneath the oversize 36mm valves. You can also see quite a bit of smoothing in the chambers and the area around the outside of the valves has been smoothed a lot. The cylinder heads were also surfaced on an old belt sander type resurfacing machine which is kind of an archaic method. The heads are at a local shop now (the guy who rebuilt the heads that are in my car now and did a beautiful job) getting worked over and checked for any issues and will be properly surfaced on a fly cutter and come back looking like a mirror. The valve job still looks great, the story was these heads were only run for a few hundred miles before the motor spun a rod bearing. They'll be pressure tested to see how well they actually seal though and then recut if needed.
After vapor blasting the outside looks incredible.
Sharp edges on the cam caps cleaned up as well. Once I get the heads back I'm going to do break them down fully and do a few quick passes with an 800 grit flex hone in the cam tunnels to add a nice crosshatch pattern for oil retention. C30s aren't particularly friendly to their cam caps so this is just a bit of extra insurance for turning north of 8000rpm, this method has helped on other engines with similar issues and shouldn't change cam clearance by any meaningful amount, but I'll measure with a dial bore gauge before and after to be sure.
12 brand new OEM rocker arm sets, given the price of NSX cams, I don't want to take any chances with wiped lobes or rocker pads so brand new rocker assemblies to get the best possible results with the Toda cams. I spent a long time trying to figure out possible ways to refinish rocker pads but since they are ground together as a set and to a specific radius curve (and that curve is different on the middle rocker) I decided OEM was the only solution. If your rocker pads look perfect this is unnecessary but mine had a bit more wear than I was comfortable running.
Port work on the Bad Guys heads, he cut the valve guides off which I don't particularly like but says he's never had any issues with doing this even on street motors.
Prepping the Toda pistons for ceramic thermal barrier top coat. I wanted to have them fully ceramic anodized then have top coat and skirt coats applied but the guy who was applying the coatings said he didn't want to try to remove the Toda skirt coating since it's adhered very well and would feel a lot better just doing the top coat. There was lots of very sharp edges from machining the valve pockets so I used a small file, 600 grit sandpaper, and very fine steel wool to knock the edges down and clean everything up. This isn't just for looks, sharp edges don't shed heat well and can create hot spots on the piston and cause detonation. Doing this can actually let you get away with a few extra degrees of timing in knock limited motors and just provides more safety margin in engines that reach MBT before then, and since I'm running a fairly high compression ratio I think is worth the time investment.
Check out the domes on these 12.1:1 pistons.
Toda Spec A cams. I would have liked to do B or even C cams for the extra duration on the middle lobe but those have a crazy amount of lift (11mm) on the primary and secondary (non-vtec) lobes so would really hammer on the valvetrain even in regular driving.
That's all for now, will post more photos as this progresses. Next thing is to finalize the main clearances after I had to order more bearings due to a problematic batch that had inconsistent thicknesses, I have the bearings but still need to go through the process of torquing up the bottom end and double checking everything.
At the time of this writing I'm waiting on the pistons to come back from having coatings applied, waiting on wrist pins to get DLC coated, then I'll send the block off to have it honed out another 0.0006" to hit target clearance with the pistons, then finally have the rotating assembly balanced.
(Build revised 12/26/2023)
Block
The plan is a 3.2L engine based on a 3.0L block with wet sleeves bored to 93mm. I chose 93mm since pistons are widely available from a variety of manufacturers and it gives me a lot of room for rebuilds in the future at 93.5, 94, or 95. Sleeves - especially MID sleeves - are extremely expensive to have installed in a C30 so I don't want to have to do it again anytime soon. The pistons I've selected are actually 20g lighter than the factory pistons so combined with the OEM titanium connecting rods the rotating assembly will be lighter than a 3.0L rotating assembly. Throw a lightweight flywheel on top of that, and this should be a very rev happy engine.
- 3.0L core block that once lived in @docjohns car.
- Billet Speedworks (SoS) billet main caps, line bored by Mountune
- 3.0L crankshaft (from the original engine in my car)
- Darton Sleeves bored to 93mm by Mountune
- Block fixed by Grim Reaper Motorsports when Mountune screwed up the P2W clearance.
- Timeserts in the block deck
- ARP head studs
- ARP main studs
- ARP rod bolts
- Factory titanium connecting rods, weight matched and balanced end to end, resized with ARP bolts
- Toda 12.1:1cr 4032 alloy forged pistons, weight matched, tops smoothed, ceramic thermal barrier coating
- Total Seal gas port top rings, napier 2nd ring
- Precision Products Performance thick wall tool steel wrist pins, WPC treated
- Toda oil pump gear, WPC treated
- Bad Guys ported oil pump
- Toda (Daido) main bearings, coated by Calico
- OEM rod bearings (Taiho), coated by Calico
- OEM thrust bearings (Daido), WPC treated
- ATI super damper
- Factory oil pan with CRF baffle and temp sensor
- Eventually: Dry sump system custom built by @Mark911 (post break in and assuming engine is running well)
Endyn ported cylinder heads. These heads were done over by Endyn 10-15 years ago, then I bought them used and had a trusted local cylinder head machinist go through them to make sure they were good to go. He honed the valve guides a bit since they were tighter than he likes to run and touched up the valves and seats since they were in very good condition already.
- Toda Spec A camshafts
- Toda adjustable cam gears
- Toda timing belt
- Toda single valve springs
- New OEM seats, retainers, keepers, and seals
- Supertech bronze valve guides
- Supertech 36mm +1mm intake valves
- Supertech 30mm STD inconel exhaust valves
- RFY billet cam plugs
- New OEM finger follower assemblies to guarantee proper run in with the cams. Possibly DLC coated or WPC treated.
- Deburred, vapor blasted
- Cam tunnels lightly honed for oil retention (little to no dimensional change)
Transmission
The transmission build is a more recent development, it was going to be a future project but with the favorable USD/JPY conversion rate I decided to go for it now. This is going to be a custom built 6 speed transmission made from mostly new OEM parts and reusing some parts from my 5 speed such as the bell housing and differential. The 6 speed went through a few changes from 97 to 05 so this is the ideal spec in my eyes for a high revving N/A NSX. Transmission assembly thread here.
- Dual cone synchronizers on all 6 gears (early models only had dual cones on 1-4)
- 4.23 NSX-R final drive ratio
- Wavetrac differential
- NSX-R twin disk input shaft
- REM polished and WPC treated internals.
@A.S. Motorsport billet ITB system with 50mm throttles, trumpet length TBD.
Exhaust
Lovefab headers, not sure on catback yet.
Engine Management
Chipped factory ECU running a hybrid MAP/TPS based load calculation algorithm based on Megasquirt "ITB mode", as discussed in my build thread. Might switch to Link.
Pictures
I have a buddy who does vapor blasting on the side so I've had him do pretty much everything that will easily fit in his cabinet. I'm only having stuff done that can be thoroughly cleaned of abrasive media afterwards. Here's a few examples.
One of the more time consuming projects here has been deburring the block both inside AND outside. There's lots of ridges and sharp spots and I wanted to knock them all down and maybe vapor blast the block too.
Before
After (not blasted yet)
In addition, I took some ideas from @Mac Attack and smoothed out the sharp edges of all the main caps especially around the oil holes.
I fabricated these 2 tapered delrin rods on my lathe and cut M11x1.5 threads onto them to help align the cylinder heads during installation and prevent gouging the delicate aluminum surface on the sharp edges of the dowel pins
The Endyn heads were pretty dirty when they showed up. They had also been installed on their previous engine with MLS gaskets and copper spray which is a bit of a no no so needed a good cleaning before going for vapor blasting then to the machine shop.
Fair amount of grinding in the bowls underneath the oversize 36mm valves. You can also see quite a bit of smoothing in the chambers and the area around the outside of the valves has been smoothed a lot. The cylinder heads were also surfaced on an old belt sander type resurfacing machine which is kind of an archaic method. The heads are at a local shop now (the guy who rebuilt the heads that are in my car now and did a beautiful job) getting worked over and checked for any issues and will be properly surfaced on a fly cutter and come back looking like a mirror. The valve job still looks great, the story was these heads were only run for a few hundred miles before the motor spun a rod bearing. They'll be pressure tested to see how well they actually seal though and then recut if needed.
After vapor blasting the outside looks incredible.
Sharp edges on the cam caps cleaned up as well. Once I get the heads back I'm going to do break them down fully and do a few quick passes with an 800 grit flex hone in the cam tunnels to add a nice crosshatch pattern for oil retention. C30s aren't particularly friendly to their cam caps so this is just a bit of extra insurance for turning north of 8000rpm, this method has helped on other engines with similar issues and shouldn't change cam clearance by any meaningful amount, but I'll measure with a dial bore gauge before and after to be sure.
12 brand new OEM rocker arm sets, given the price of NSX cams, I don't want to take any chances with wiped lobes or rocker pads so brand new rocker assemblies to get the best possible results with the Toda cams. I spent a long time trying to figure out possible ways to refinish rocker pads but since they are ground together as a set and to a specific radius curve (and that curve is different on the middle rocker) I decided OEM was the only solution. If your rocker pads look perfect this is unnecessary but mine had a bit more wear than I was comfortable running.
Port work on the Bad Guys heads, he cut the valve guides off which I don't particularly like but says he's never had any issues with doing this even on street motors.
Prepping the Toda pistons for ceramic thermal barrier top coat. I wanted to have them fully ceramic anodized then have top coat and skirt coats applied but the guy who was applying the coatings said he didn't want to try to remove the Toda skirt coating since it's adhered very well and would feel a lot better just doing the top coat. There was lots of very sharp edges from machining the valve pockets so I used a small file, 600 grit sandpaper, and very fine steel wool to knock the edges down and clean everything up. This isn't just for looks, sharp edges don't shed heat well and can create hot spots on the piston and cause detonation. Doing this can actually let you get away with a few extra degrees of timing in knock limited motors and just provides more safety margin in engines that reach MBT before then, and since I'm running a fairly high compression ratio I think is worth the time investment.
Check out the domes on these 12.1:1 pistons.
Toda Spec A cams. I would have liked to do B or even C cams for the extra duration on the middle lobe but those have a crazy amount of lift (11mm) on the primary and secondary (non-vtec) lobes so would really hammer on the valvetrain even in regular driving.
That's all for now, will post more photos as this progresses. Next thing is to finalize the main clearances after I had to order more bearings due to a problematic batch that had inconsistent thicknesses, I have the bearings but still need to go through the process of torquing up the bottom end and double checking everything.
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