Eleven months later...
I'm finally back on the road with a 1.8 and 6spd swap. Last January I broke a tooth off of 3rd in my 5spd, and decided to build a 1.8 and install my 6spd when the engine was done. Well, I didn't think it would take this long, but I did resurrect a '90 with a broken crank in the meantime by swapping in the de-boosted 1.6 from this car so I got my Miata fix that way.
Anywhoo, here are some pics and all that went into it. I did everything except the balance job, sent that off to the machine shop we use at work. Worked in a reroute with a Skou spacer as well, but changed it up a little by using an inline t-stat housing under the TB, under which I gained space via an FIAV delete. Adapted my DSM TPS to the 1.8 TB by cutting new keyways in the shaft and trigger plate (was 90* out otherwise). Gasket matched the head on both sides, and the IM. Lapped the valves. Picked up some 15x8 Kosei K4R wheels and in the downtime I borrowed a roller and flattened the inner fender lips, and installed a Wilwood prop valve while the bay was empty. Also put some heat shielding in the trans tunnel.
'96 1.8 donor, 97K miles in good condition
Eagle rods with ARP 2000 hardware
ACL Race rod and main bearings
ACL thrust bearings
Rotating assembly balanced; crank polished
Head ports gasket matched, mild port in runners
Head and block decked
Cometic MLS head gasket
ARP head studs
Intake manifold gasket matched
Coolant reroute with Skou billet spacer, Kia waterneck, and inline t-stat housing; long section of typical GM reroute hose runs up to the TB area, then the inline housing sits under the TB, finished off with a Dayco 71950 from the housing to radiator inlet (goes around the driver side of the TB inlet)
Front water neck deleted; freeze plug and blockoff plate fabbed/installed
Fan control moved to FPS output at ECU
EGR delete; blockoff plates fabbed/installed
TPS from 1g DSM adapted to the BP throttle body
Turbo oil feed from sandwich plate, OEM oil cooler retained; coolant outlet on oil cooler feeds turbo
New crank seals front and rear
New water pump/timing belt/pulleys
New valve stem seals
New cam seals
New intake and exhaust manifold gaskets
New valve cover gasket
New knock sensor
New O2 sensor
-10 AN bung welded to pan; 5/8” drain from turbo
Comp ceramic 6-puck sprung clutch disc (“Stage 4”) with FM Level 1 pressure plate
New pilot bearing
6spd from '01 Miata, new output seal installed
Motorcraft synthetic fluid
Braided long line to replace the rubber and curly clutch lines
FM throttle cable and coilpack relocation parts
Cleaned up/repaired a lot of brittle wiring
Heat shielding added to trans tunnel
Wilwood prop valve just for kicks
Retained from previous build: 1.6 CAS; 1g DSM coils, TPS, engine harness, ECU; all fuel related items; FM Level 1 pressure plate, lightened stock flywheel, 2.5” exhaust
Still needs a touch-up on the clutch adjustment and break-in miles on the disc itself before I bump the boost up. Shooting for 300wtq/350whp. Rough tune at 12psi is netting about 210wtq/230whp per VD, so I'm thinking 22-24psi ought to do it.
'96M 1.8 donor
Block looked good, crosshatch still visible.
Nothing burned up here.
Nice and clean for all the mileage.
Nervous about mixing caps up so I got a little an4l with the head disassembly.
Lapping the valves. Our head guy at work always makes a nice, wide edge in turbo applications, so that's the way I went with it.
Ground out, and then finished with scotchbrite wheels.
Granite sanding block to flatten the head. Was only out a couple of thousands so nothing major needed to happen.
Waterneck blockoff with a freeze plug, then knocked out a plate to cover it.
Block all smoothed out on the granite, too.
Polished and balanced.
Adapting a 1g DSM TPS to a Miata 1.8 TB. Trigger plate is 90* out, so the shaft and plate are modified to work together.
Adapting a 1g DSM TPS to a Miata 1.8 TB. Vees cut into the plate and shaft so it will be held in place.
Adapting a 1g DSM TPS to a Miata 1.8 TB. All wrapped up with locktite.
Ultrasonically cleaned TB.
FIAV blockoff plate.
A ******* mess under the intake manifold. Knock sensor hidden up top, OEM oil pressure sender on a 20mm steel extension (to clear the knock sensor), aux oil pressure sender (since eliminated), oil temp sender, OEM oil cooler, sandwich plate, turbo oil and water feeds. My biggest fear is that there would be leaks under here. There were two!
Competition Clutch ceramic 6 puck. Sticking with the lightened OEM flywheel and the FM Level 1 pressure plate.
Balanced bottom end, with assembly marks on the clutch.
Six speed going in as well.
A little clean up before the stabbing.
Hopefully my feet wont melt any more.
Supervision kitty approves.
Coolant reroute using Skou spacer/Kia neck, typical GM long hose, but with an inline t-stat housing and a short S-shaped hose from a GM V6. Dayco 71950 is the part number.
FIAV delete makes room for the inline housing.
Another view of the GM V6 hose.
All wrapped up.
Fender rolling while the weather cooperated.