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50 Shades Of Silver (Na Eunos)

62392 Views 686 Replies 22 Participants Last post by  Zed.
in January I bought my Eunos, I'd liked the idea of one for maybe 10 years but I'd not had thew time or space for one.
so, heres my '50 Shades-of-Silver (amongst other colours)

as bought and home (ok, I've too many cars....)

replaced the TSW wheels with BBS from a BMW E30 :thumb-up:

the car was imported in 2000 so had avoided UK's salted roads for it's first 8 years life, being a Eunos the online vin decoders are next to useless and the dvla's regestration details are 'suspect' to say the least (it's regestered as a 1992 mx5, I guess thats the importer creating a car thats easy to sell & insure)

the previous owner had replaced the clutch, cambelt & waterpump, swapped to a mk2 dashboard conversion, fitted a cobalt stainless exhaust and a few other jobs like rust prevention.

when I was inspecting the car before purchase I noticed that the pedlebox was cracked with the throttlepedal almost hanging off, this had a major impact on the cars performance (possibly why it was for sale?)

when I got the car home I decided to remove the dashboard to investigate the wiring conversion as well as check the heater pipes & fix the pedlebox (the throttle pedal had actually dropped off after I got home!)


while the dash was out the seats & carpet followed, then I noticed that a rollcage had been fitted previously with holes drilled in the front & rear floors as well as the parcel shelf being cut (not a problem to me as I'm looking at fitting a cage :yes: - wonder what cage had been previously fitted? )

when the dash was out I decided that the conversion wiring was a bit of a mess so started looking for a replacement, this was put on hold for a while untill I spotted an advert for a UK spec 1990 MX5 for sale as a breaker...

1990 UK spec '5 with 1.8 conversion
as you can see, my 1991Discovery working for its living :driving:


little while later, some bits removed :whistle:
was easier to remove the engine by chopping the front of the bodyshell off, nice un-rusted chassis rails - unlike the sills, wheelarches & floors :rant:


dashboard loom needing repair, one of the reasons behind the tango'd 5's purchase....

annoyingly theres diferent looms fitted - unknown if this is age or engine related :rant: :rant: :rant:

discovered after re-building and fitting a mk1 dash into the Eunos :yes: :rant: :baseballbat:

so, ended up repairing the Eunos's origonal....

call for the solder & heatschrink......

bought some Compomotive wheels, unsure if they are destined for the Eunos or my mk2 Golf tdi....


another purchase, set of Ohlins adjustable dampers with springs & rosejointed topmounts, these were 'pre-loved' so a lot cheaper than new (although cost £400 so almost the same as the Eunos)
had fun when fitting, both rear damper bottom bolts were not wanting to undo as their 'captive-nuts' were 'UN-captive' :whistle:


:rant: :rant: :rant: :rant: :rant: :rant: :rant:

so had to remove both lower wishbones....

3 out of 4 camber-adjustment bolts snapped :rant:


weld to the rescue & re-captive nuts :thumb-up:

random stupidity & reading crap on forums later ('Coil-On-Plug' conversion ideas :dance: )



ready for future turbo conversion (thats my excuse....... :whistle: )

twin cylinder adjustable bias pedlebox :thumb-up:

Another 'Random-boredom' idea, I've always had bias/adjustable pedleboxes on rallycars so as the Eunos is hopefully going to hillclimb & sprint its getting one :yes:

this is the 'mk1' design, not a working prototype but just pushing ideas....

the standard NA pedal ratio is 4:1, this is fine with servo asssistance but un-assisted will be harder than hell and a massive effort to stop the car so I'm looking at 5 or 5.5:1 ratio so that means shortening the pedal & moving the cylinder position.

also, I've picked up some new AP-racing 'dumpy' mastercylinders on egay for a very reasonable price :dance:

more to come once I've recovered from typing this........

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diff time;)

the 4.778:1 cwp in a pigshead, buried unloved :unsure:

time to assemble the 5.38:1...

the bit that's going to spin a lot!

the pinion flange test-fitted, no collapsable-spacer or oilseal yet as this is to check the pinion's 'intrusion' into mesh with the crownwheel. I've used the pinion-shim that was previously fitted to this pigshead & 4.1:1 - hopefully close enough🤨


time to fit & torque the crownwheel to LSD bolts (Locktite used as locking compound)
60ft/Lbs in opposite / circular position motion, repeated twice.

3J's Plate LSD.

ratio marked be manufacturer, bought through Bofi but resold frpm Paco in USA (unsure of actual machineshop that cut these gears)

looking through one of the 'windows' into the LSD, can see one of the 'sunwheel teeth and unused crosspi 'ramp' cutout.

this is dangerous, if you've never encountered then best stay away if possible o_O:eek::confused:

the Antichrist of engineering, 'Engineers Blue' or marking blue ('Blue for short?) spreads fear into the hearts of mortal men🤭
basically a blue coloured grease BUT gets everywhere....

aplied as a whitness mark onto a few (5 here) of the driveside teeth then turning the pinion while adding a 'drag' or brake force with hand on the crownwheel to squeeze the blue onto the pinion...

after one revolution...

another revolution, looking promising...

the pinion from below the diff spool / LSD.

pinion teeth viewed from above.

close-up (ish) of the pinion teeth, the marking blue has transfered nicely showing an almost perfect mesh pattern 😎

you know it's a low ratio when the crownwheel is near the pigshead centreline 😎

hopefully tomorrow I'll get time to check the 'coast' side teeth and if good will set diff bearing preload and fit the pinion bearings 'collapsable-spacer' then drive-flange oilseal and reset the pinion bearing preload :D

enough for tonight...

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smeared marking-blue on the 'coast' teeth to check the overrun mesh (it's my expensive diff so check everything!!!)

spun the pinion a few times (again adding a 'brake' effect to the diff spool)

another view.

the pinion markings (drive & overrun)

another view...

pinion from below, gives a different view...

crownwheel again, the origonal aplication of blue after rotation...

and finally, the last photo!

I've uploaded this photographic overkill as a record, in the future OI can re-blue & compare the wear marking (& wear? :unsure: to judge the lifespan as the pinion will get a lot of abuse due to the low ratio 😕

strip, fit pinion spacer & oilseal then rebuild to follow tomorrow hopefully....

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collection of 'bits'...

pinion parts order, new collapsable spacer to fit between bearings.

in their order.

and the pinion back in the pigshead...

I've collapsed the collapsable spacer to set the preload on the pinion bearings BUT not not finally fitted the oilseal & flange as I'm thinking of making a solidspacer as this would allow for 'idiot-proof' flange removal & replacement, will think about that tomorrow....

will this be the longest diff build?

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recieved a new (in box) but secondhand and somewhat discounted Stack ST3403 Lambda gauge kit with Lsu4.9 02 sensor, these are not cheap so when one appeared on ebay with a bin or best-offer I couldn't resist being cheeky 🤭
being cheeky paid off and it was bought for a significant discount 😎

8 pages of distractions 🤨

I'll probably just plug it into the ecu for tuning not pretty lights :unsure:

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another order to Mx5parts, pair of genuine front lower wishbones (mk2 type) mk1 wiper linkage and assorted bolts...

the front suspension / subframe moneypit will hopefully be sound for a while 😎

back to the engine fitment,its raining todat so I'm staying indoors :unsure:

thinking sumps (well, drysump)

theres a minor steeringrack clearance issue, ok the cylinderblock is supported on wood to raise slightly but my plan on using redily available cast aluminium pand is under threat & I might have to resort to fabricating / modifying a 'standard' Vauxhall steel oil pan..

I have a 'Pace' drysump pan, this has the front and rear scavange pickup points as 'wells' in front and rear with a 'trough' to collect the oil.

I also have (on an engine) a 'Titan' drysump pan, this has the front scavange pickup point more central and might work with Mazda's enginebay layout.

otherwise its time to chop&weld...

more thinking to follow....

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so, whatsinthebox? 😮

Mx5parts pulled out the stops with this order, less than 24 hours from pressing the 'buy' button to delivery :cool:

2 x Front Upper Wishbone Arm Nut, MX5 Mk1/2/2.5
1 x Front Lower Suspension Arm, MX5 Mk2 & 2.5 (left)
1 x Front Lower Suspension Arm, MX5 Mk2 & 2.5 (right)
2 x Windscreen Wiper Arm Nut, MX5 Mk1/2/2.5
2 x Split Pin, MX5 Mk1/2/2.5
2 x Front Upper Wishbone Arm Bolt, MX5 Mk1/2/2.5
2 x Front Upper Arm & Track Rod End Castle Nut, MX5 Mk1/2/2.5
1 x Windscreen Wiper Linkage, Complete, RHD MX5 Mk1

so, front suspension nearly all new components / top & bottom genuine wishbones & new tubular front subframe 😎
why new wishbones? all my 'spares' are scruffy to say the least, new are clean (obviously?) and hopefully straight as used components can be 'weathered' from ~30 years use.

overkill maybe but wishbones are an expensive futureproofing and I've the possibility of using them to make jigs from:unsure:

the wiper linkage was a 'because it was available' and my 'old' linkages were scruffy & siezed / worn...
one less thing to worry about.

hopefully sort the diff tonight and maybe drop the complete drysumped XE in the silver car to assess fitment & 'see' problems 🤨

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Black friday discounts i hope.
Ive been on bofi site...sat on my hands.

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Black friday discounts i hope.

Yup, still spent too much though 🤭

Lol. Didnt buy. But was tempted.

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back to the diff...

cleaned the pinion flange & removed the ballance-weight thing, refitted the oilseal protector / guard plate as theres a chance this diff may end up in dirty conditions 🤨

test-fitting the oilseal....

the oilseal has a 'lip' that protrudes into the protector so checking it fits togther...

flange fitted & tightened to the previously decided preload.

Lsd fitted & backlash set @ 0.004", the bearing preload needed setting when this was photographed hence the locktabs were not fitted.

subject of diff spool / Lsd bearing preload, enter the micrometer.

tomorows job, re apply 'blue' and inspect the teeth-mesh then put it ready to bolt onto the car.

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final mesh pattern checks done, goodenoughforme 😎

crownwheel drive.

crownwheel coast.

pinion drive.

pinion coast (top) and drive (bottom).

Locktabs fitted to the diff bearing adjusters and Done:cool:

just paint on the pinion / propshaft flange and forget about it untill rear suspension assembly time 😎

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5.3:1 Lsd / diff filed in a cupboard ready for use (& forgotten - with the 4.778:1), started tidying the workshop 😮

made a dent in it and can see some floor (no photo's sorry BUT IT HASHAPPENED!)

next job is (probably?) the welding table and altering & painting the tubular subframe 🤨


tripped over another Tony Law manifold that I'm hopingto modify for the car.

as I've a tubular suspension subframe theis shouldn't be a problem with the collectors clashing as on a standard subframe / Mazda enginemount setup.

other busness, been busy so no actual progress but I have bought an Rx8 gearbox with Vauxhall adapter-plate so hopefully I can build a hybrid of the Rx front / bellhousing & input shaft with the Mx5 tailhousing so keeping the ppf & origonal gearstick position - will be collecting the box this week so will have more to say about it later (if it'll work????)

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Idiot award time.....

I already have a capable ecu, a DTA S40 but ideas of grandeor pushed me into buying a 'bigger' DTA S100 so now have even more options to ignore (like 16 hours of datalogging etc?)

more tech & cost 🤨


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Had a play with the S100 ecu, I can see plenty of possible 'oops' moments here BUT also plenty of great options :cool:


Crank Shaft (Magnetic and Hall Effect)
2 x Cam Shaft (Magnetic and Hall Effect)
Throttle Position
Coolant Temperature
Air Temperature
Manifold / Barometric Pressure
2 x Lambda
Oil Pressure
Fuel Pressur
Oil Temperature
Battery Volts
3 x User Defined Analogue (Shared Use), 1 x User Defined Switch
Launch Switch, 2 x Traction Control Switches
Shift Cut
4 x Wheel Speed
ALS / Second Map Switch


10 x Coil Drivers
10 x Injector Drivers
Fuel Pump Relay
Turbo Pressure Valve
Turbo ALS Valve
Cam Control Valve
VTEC Valve
Idle Valve
Shift Light
9 x User Programmable Aux (Shared Use)
obviously I'm not going to use all of these but launch control, 4 wheel traction control (wet & dry?) are easily connected on the 5 due to oem abs sensor mounting / wiring thats retrofittable - just need to find sensors now....

more complications...

photo update time, just to shitpost a bit more....

my 'old' Dta S40 and 'new' DTA S100 ecu, the S40 was good enough to run the XE but the S100 has a 'few' more options and outputs 😎

I've also bought a pro-built engine loom (excuse the photo's, they're from it's advert)

the loom is 'stand-alone' so carries fuelpump and rad / cooling fan relays (more can be added like wb02 sensor heater power feed - usefull as the ecu / ignition can be 'on' but you're not burning out an expensive 'LSU4.9' sensor).

the 'interesting' bit, these wires will terminate in switches to operate their functions, obviously at another 'end' the loom will connect with 4 x wheel sensors (I'm hoping to use abs sensors as mx5's had this as option & standard fit depending on age - wondering how few 'teeth' I can use on the abs 'rings' but still carry sufficient resolution :unsure:) and obviously the ecu needs to do it's part...

too many ideas but Launch and traction control would be realy nice 'extras'

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Hi Rich.
Do you know what's the maximum hz the DI on the DTA S100 can read?
Also how you plan on adding the sensors on your vehicle?
Do you know what's the maximum hz the DI on the DTA S100 can read?
er, no:oops:
will have a read round the internot...

Also how you plan on adding the sensors on your vehicle?
I had planned on using the Mazda abs sensors but the ecu seems to want 3 wire as opposed to the abs sensor's 2 wire so some reserch to be done here:unsure:

it will work out in the end


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okey, been tidyin the workshop and tripped over a standard Vauxhall 'XE' 2L conrod so decided to weigh it and compare to the ebay (chineese?) 'Nevlock steel / forged rod and a 'Plankl' narrow-journal / longer centre length conrod...

652g with bolts (and rust!), these are good rods, accepted as 'safe' past 7.000rpm but getting old now....

578g (no b/e bolts fitted as I forgot!) but a direct replacement for the standard item.

480g with bolts, this is a lovely piece, shame it needs different pistons and a specific (non-standard) crankshaft to use :(

so, scientific experiment over & back to tidyup.....

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