Miata seat speakers

After upgrading my seats to early Miata Seats (Click Here), I finally decided to open up the headrests and install speakers.  The nice thing that Mazda did was they carved out the foam and had it all ready for the speakers to go in, highly recommended for anyone who's swapped seats.  I ended up using some leftover speakers (~2.5 inches) that I was getting ready to donate.  After a bit of fishing wire through the seats and connecting them to the speaker feed in the driver's rear corner of the trunk, I was quite pleased with the results.  As I'm still using the Datsun OEM radio, which is mono, all speakers sound the same, but when wiring I chose to make the connections and wiring an easy switch to stereo if I ever upgrade the head unit.

For anyone looking to but a complete retrofit kit, check this website out -- http://www.3rdstrategy.com/

Here's a great write up from a Triuph guy -- http://tr6.danielsonfamily.org/MiataSpeakers.htm

Headlight wiring harness with relays

After reading horror stories about the headlight/wiper combo switch melting due to the full amperage of the headlight beams going through the switch, I decided to install a wiring harness with a set of relays.  MSA sells a great plug-and-play unit which is built by an avid Datsun Electrician, although I decided to save some money and build my own.  At the end, I invested about $40 and have much better low and high beam headlights, and will save the combo switch.

I started off with a cheapo pre-made relay wiring harness which I acquired from Amazon for pretty cheap (Amico Car 30A Fuse 2 H4 HID Headlight) and a set of harness plugs and some wire/shrink wrap.

 

I next needed to extend the wiring harness and include the correct harness plugs to allow me to plug directly into the Datsun wiring harness as a feeder and then into the headlights directly.

 

Then it was as simple as unplugging the existing headlights and plugging in my new harness, including connecting it to the battery to power the relays.

As reference, here's the best diagram/explanation I can find.  Thanks go out to the original author.

Door weather seals

After 42+ years of service, I decided it was time to seal up the doors better so if I get caught out in the rain I wouldn't be sitting in water.  What was left of the old seals was quite a mess

   

When I purchased the car, I was excited because it came with what appeared to be a full set of rubber weather seals for the doors, hatch, etc.  The seals that came with the car were made for the 240z, although as many have experienced they were from a company called Precision, the doors would not close, even with a hip slam.  And it was more than adjusting the door striker plate would resolve.  Luckily I did not glue these in place so they came off very easily.

Upon further investigation, I decided to look for other vehicle weather seals that would fit the 240z.  The best option would have been an early 2000's Kia Sportage, which my local junk yard (Victory Auto Wreckers) said they had.  After a pilgrimage to Victory on my way home from work one day I was unable to find the Sportage.  I did however start looking at all of the other cars that they had.  The next best option appeared to be a late 90's POS Chevy Cavilier.

After removing and then finally cleaning up the weather seals, I was quite happy with what I had obtained for $5.00

 

Once installed (without glue for the first try), I found that I needed to cut about 8" off and then bend the straight seal around the 90 degree corner of the 240z's door.   I do plan to glue these in place eventually, but the wealting appears to hold it on very well.

   

Throttle Jerk Fix

So my 42 year old car has always had a very jerky accelerator pedal, which is a common issue for early Datsun Z-Cars with the mechanical linkage.  After looking at my options, I decided to change over to a throttle cable (similar to modern cars) which should deliver a silky smooth pedal and acceleration.

First, I decided on a Mr. Gasket steel braided throttle cable kit from Amazon for  (#5657)  and an aluminum throttle arm from Speedway Motors for (## 91018400)

In addition, I needed to figure out a way to hold the cable housing at the carburetor.  For this I chose a hardened L bracket that I had laying around & mounted it to the exhaust manifold heat shield.  As there's not much pressure being put on this, it should hold up well.

 

I next had to modify the accelerator pedal, including bending it & then determining the best way to mount the cable end.  I chose to not drill it, rather use an "S" connector.  Longer term I may drill it out, but for now this works.

 

I think needed to hook everything up and adjust for the proper amount of slack.  I also greased the cable very well, although it probably could use some more.  Please note that I did change the L bracket that was used as I needed it to be in a better position over the carburetor linkage.  

 

Overall, I'm very satisfied with the outcome.  I'm now able to accelerate from a stop very smoothly!  The only downside that I've identified thus far is that I needed to replumb the breather from the valve cover as the throttle arm blocks the path of the original hose.  I also need to change the color of the linkage arm as they sent me a purple one...probably some sandpaper and it'll brush right off.

Here's some additional info that I've run across throughout my travels:

Miata Seats Installed

Last fall I was able to pick up a pair of early (NB) Mazda Miata seats, including sliding rails.  There is a little wear on the side bolster, but the seats are in much better condition than the 42 year old Datsun seats.  They also hold me in much better and resemble a similar look to the original seats.  Make sure to check out how to add speakers to the miata seats --> LINK

My goal was to not modify the body of the Datsun any more than I needed to but still allow me to sit comfortably.  Most people agree that using slider rails with the Miata seats raise the seat up several inches, and as I'm 6'2" my head was touching the ceiling in all comfortable positions of the seat.  I did not want to remove the seat mount on the floor of the body as many people do, so I opted to fabricate my own seat mounts from some steel stock and bolt them directly to the body.  This does not allow for forward/backward movement of the seat, but as there is no need to move the seats, I thought this was an acceptable compromise.

I did go through several iterations of how to mount the seats including:
  1. Using OEM Datsun slider rails
  2. Using Miata slider rails
  3. Custom mounts without sliders

1. OEM Datsun Rails
This was by far the 'easiest' approach, although it does require several spacers to be inserted in the back of the Miata seats to allow for them to fit as well as to drill a hole in the Datsun seat rail.  A good write up can be found here:  http://forums.hybridz.org/topic/91742-miata-seats-installed-with-instructions

2. Using Miata slider rails
This is a better option as the rails bolt nicely to the Miata seats, the rails are much more robust than the Datsun (as they lock on both sides), although there is still the height challenge.

      

3. Custom mounts without sliders
This is the best option, in my opinion.  The seats are at the perfect height and the position is comfortable.  I purchased several steel bar stock (3/16") as well as some square tube.  After some quick measurements I was able to cut two risers for the back of the seat bracket (to prevent the 'bucket' effect common when putting new seats in a Datsun) and welded them on.  I probably could have used washers or some other method of lifting the back of the seats up, but I thought I should get some practice welding.  The one thing that I'm not happy I had to do, but it makes everything a lot simpler is that I cut holes in the floor pan to allow for a deepwell socket fit through in order to bolt on the rear mount.  As the seats don't slide, I wasn't able to fit my hand underneath to bolt the mounts down once the seat was placed.  I did get some body plugs to cover the holes to prevent water and fumes from entering the cabin after I painted the freshly drilled floor pan.

 

Test fit on the driver's side

First mounted the mounts to the bottom of the seat

Another view of the custom mounts

Its been a long winter!

Well spring is finally in the air, although the temperatures are still not as warm as we'd all like here in Chicago.  The Z has been in hibernation for the long winter, but it started right up and performed great.  Over the winter I did perform a couple of projects which I'll speak to in future blog posts including: New Seats, Front Wheel Bearings, and a redesigned Throttle Cable.  Still on deck for this spring/summer will be Rear Wheel Bearings, New Exhaust, and repairing minor rust damage from the undercarriage.

Brake Booster

While out driving a couple weeks ago I noticed when I pressed the brake pedal that a loud "hissing" sound began as well as the engine RPM changing quite a bit.  After further diagnosis, it appeared that I had a major vacuum leak coming from the brake booster.  Most likely the 41+ year old rubber diaphragm just deteriorated.  Apparently in 1972 the brake booster changed mid-year.  Jan-Aug 1972 used a 1971 brake booster and the Sept - Dec 1972 (and all the way upto 1978) used the later brake booster.  The holes in the firewall are different and the older (which I have) booster is a 6" smaller diameter.

Original brake booster removed:

 

I was able to slide the brake booster out without having to disassemble the master cylinder

Remanufactured Cardone brake booster (compliments of Amazon.com).  I did need to change the engagement pin on the booster and I'm still in the process of adjusting it to ensure the brakes engage at the proper pedal pressure.  There are stories of the reaction disk (a small rubber spacer in the booster) slippping out, but I did confirm that mine is securely in its place.

 

While I had the accessibility, I swapped out the steering coupler for the rack & pinion steering.  The old hunk of rubber had certainly seen better days & the new one dramatically  improves the handling & responsiveness of the car.

Other useful bits I've found along my travels...