DanM's Westfield Miata

[DanM]

Speedo Driven Gear replacement

 

From the factory my donor 1990 MX-5 had a 1.6L engine, 5 speed gearbox and 6" ring 4:30 ratio fixed differential.  As the car is over 30 years, had over 230k Km on the clock and the 6" ring has a reputation for weakness in the MX-5 community, I decided to upgrade to a more robust, 7" ring LSD.

 

I now have the following Engine, Gearbox and Rear end differential combination:

• 1.6L (1990)
• 5 Speed (1990)
• 3.9 LSD ('99-'05 Torsen/Taguchi Fugi Super LSD, 7" Ring)*

This combination has provided a couple of small problems to overcome.

 

1. The speedo would read incorrectly due to the different gear ratios (3.9 vs 4.3)

2. The 3.9 ratio gear was not an option for NA MX-5s

3. The speedo mechanism from a 5 speed gearbox is not compatible with a 6 speed gearbox and vise versa. One is mechanical and the other is electronic.  

 

After lots of research on the subject I found Maruha Motors in Japan that manufactured an aftermarket part that would match this combination. 

 

3.9 Speedo Driven Gear (NA)

 

They connected me to their Canadian agent Chikara Motorsports and although it is not on their website, they were able to source it for me without too much of a lead time.

 

Installing it was a doddle.  Just one bolt to remove and the unit pulls out in one piece.

 

Within 10 mins the job was done!

 

The next and (hopefully) last job on the gearbox list will be the gear shifter refresh....

[DanM]

Upper steering column and bracket

 

I have decided to wait until the gearbox is in the car before I refurb the gear shifter turret. I figured that having one less thing to get caught on the chassis would only be a good thing.

 

So, while I get myself organized for the engine install (hopefully next weekend), I thought I'd have some fun prototyping a bolt on bracket to get the steering wheel a bit more central in the cockpit.  Looking at the pedal positions I'm not sure if I can get it fully central but, I'll be happy with what ever I can get.

 

Cutting off the tabs

 

After the grinding

 

After some chat on tech talk I went for a simple exhaust bracket and flat steel bar from the local hardware store.

 

 

I then used some M8 x 45mm bolts with a coupling bolt cut to size to hang the bracket at the right height.

 

It ain't pretty, but it certainly proves the concept for now.

[lg2k]

This was the part of my build where I had to go buy a welder and learn how to weld. I removed the steering column tabs and welded new ones to center the steering column. They were positioned exactly like yours and I ordered my kit in 2009! 

 

 

[DanM]

@lg2k how central were you able to get it before interfering with the brake pedal? 

Edited October 17, 2022 by DanM

[MV8]

It looked to me from the available pics that the lower column lateral location was the issue. Did they kick it out to the side for header clearance?

[lg2k]

7 hours ago, DanM said:

@lg2k how central were you able to get it before interfering with the brake pedal? 

The steering wheel is pretty well centered. I don't remember having an issue with brake pedal interference.  I took some pictures to better show you.

 

 

[DanM]

5 hours ago, MV8 said:

It looked to me from the available pics that the lower column lateral location was the issue.

Thanks for the feedback.  I checked the lower bracket and it is slotted so I am able to slide the lower column to a more central position.

[DanM]

2 hours ago, lg2k said:

I took some pictures to better show you.

Thank You! The visuals are a great help! 

[DanM]

Engine Install

 

Today is engine install day. I have my Brother in Law coming over to help me in an hour or so. I’ll try my best to post some pictures as we go!!

[DanM]

So its been a long day and I would say I am 90% complete on installing the engine into the chassis.  As always it didn't quite go to plan but its off the stand and in the car, although time and parts ran out before we could drill the engine mount holes and bolt it down.

 

First off we hooked up the hoist and removed the engine from the stand.

 

Then we attached the flywheel and clutch

 

and finally the transmission and starter motor.

 

I make it sound so easy, but it took us a while to remember where the different length bolts went, get it all together and torque it down.

 

Then on went the engine and gearbox mounts.  This is where it started to get frustrating for me.  Once again hardware was missing from the kit, and so I had to go to the hardware store to pick up more supplies, and guess what, the store didn't have what I needed so I came home short of 8mm 1.0 nuts for the transmission mounts.

 

So, although we were missing a few nuts we decided to press on regardless as the hoist was on rental and Chris was only available to help today.

 

Engine in position.

 

Going in.

 

eeny, meeny, minee......Which hole to use? Logic told me to choose the round one in the middle, but unfortunately the transmission mount would be nowhere near the mounting plate in the tunnel.  The slotted hole to the left put it bang on!

 

Note the thicker engine mount rubbers.  members of the UK forum shared the part details and I collected them when I was in the UK a few weeks ago.  They come from Burton Power and are about 1/2 inch thicker than the standard mounts, helping me get a bit more ground clearance for the oil pan.

 

https://www.burtonpower.com/engine-mount-hd-rs-mexico-capri-52mm-thick-fp292.html

 

So, sadly time ran out and that's as far as I got today.  Overall it was a great day, the weather was great, the garage doors were open, the music was awesome, I got to spend quality time with the family and I finished the day with a few beers.  Tomorrow I will drill holes for the LH engine mount bracket and gearbox mounts and secure down everything that I can.

 

 

[DanM]

Finally managed to get to the fastener store to pick up my missing 8mm nuts and washers for the gearbox mount and finished bolting everything down.

 

Gearbox mounts

 

LH Engine mount.  As you can see I had to drill some new holes so I didnt interfer with the chassis rails below.

[DanM]

On 10/22/2022 at 10:25 PM, DanM said:

Then we attached the flywheel and clutch

 

So I forgot to mention that while I kept the existing flywheel from the donor, I decided to replace the clutch disc and plate.  No performance upgrades here, just a new OE equivalent from Exedy.

 

https://www.amazon.ca/EXEDY-10036-OEM-Replacement-Clutch/dp/B001B592VQ

[panamericano]

Are you getting excited?  When are we going to fire that baby up?

[DanM]

1 hour ago, panamericano said:

Are you getting excited?  When are we going to fire that baby up?

You're not going to believe this, but I haven't even thought about it! lol  The penny still hasn't dropped that this is going to be an actual car that I can drive around in.  In my mind it is still just a model kit! 

[DanM]

She's on the ground! (For now)

 

After the high of installing the engine over the weekend, I decided to clean up the garage and do a bit of tinkering.

 

First, I installed the upper steering column.  I shaped and painted the bracket one night last week so it just needed assembling and bolting down.  I'm happy with the final result, considering I cant weld.

 

 

With time to spare and an itching to do something else, I went out into the yard and found the wheels from the donor car and decided I would throw them on the car to see what it looked like.

 

The front wheels went on with ease, but unfortunately the rear wheels interfered with the quickjack stand.

 

After a bit of head scratching I jacked up the back of the car and lowered the quick jacks to the ground which then gave me the space to install the rear wheels.

 

Wow! Its low!! 🤣

 

Now that its down, I guess the logical next step would be to tighten the bolts down, correct?

Edited October 25, 2022 by DanM

[MV8]

If you have not already, be sure to paint the exh clamps. Maybe clear?

[DanM]

2 hours ago, MV8 said:

If you have not already, be sure to paint the exh clamps

Thank You! I hadn't thought of that.

[DanM]

This evening I spent some more time tinkering around with stuff while I figured out my next move on the build.

 

Steering column control refresh.

 

When I disassembled the MX5 I noticed that the steering column stalks for indicators and wipers etc., were worn and the print had rubbed off.  This would be a safety fail.  As luck would have it I found another old unit at the salvage yard that had worn on the opposite side to mine.  I decided to combine the two to make one useable unit.

 

 

Removing the stalks

 

One complete unit. Not a great photo 'cos of the light, but both sides have good print!

 

Shifter Rebuild

 

The other job I was waiting to do once the gear box was in the car was the shifter rebuild.  The donor shifter boot and internals were not in a good state so I ordered a rebuild kit from treasurecoastmiata.com

 

Unfortunately, the boot is not shown, but its an original OEM part (R501-17-47Z).

 

There are lots of rebuild videos on Youtube.com.  Once again I used thecarpassionchannel as one of my my main sources.

 

Assembled, ready for install.

 

Final washer and bushing

 

Followed by approx. 90ml of gearbox oil

 

...and in she slides.

[DanM]

So I made a decision on my cold air intake.  Not a very exciting one I'm afraid, but necessary.  To get through my initial inspection I want to have the engine and peripherals as close to stock as possible.  With that in mind I will be installing the original airbox and as much of the air intake as I can, to make it all work.

 

So this evening I reluctantly dug out the old MX5 intake parts that were tucked away and covered in rust, dust and cobwebs and gave them a quick wipe down.  I have no plans to spend any time or effort on them, because as soon as I am registered I will replace them with one that that is more aesthetically pleasing and hopefully performs better.

 

Wiped clean. Ready for separating.

 

The bit that I will use.

 

The airbox.

 

You can tell that the whole donor airbox thing is a complete over sight.  None of the mounting holes lined up and they also too small for the recommended bolt size.  Once again, the powder coating on my bracket was also flaking off and surface rust had appeared.  

 

Anyway, I'm in the rhythm of things now, so once I had found work arounds for all these features, I had both the intake and airbox installed.

 

[Austin David]

The original intake isn't bad.  How does inspection work up there?  Is it a one-time event when they assign the registration?

 

When you get around to turbo you'll want to gut the intake entirely (and maybe add an intercooler).  As a naturally-aspirated car with 1/2 the weight it probably doesn't matter as much.