- Alternator Upgrade (using an internally regulated 60amp 280zx)
- Carburetor Float Sight Glass
- Differential Side-Seal Replacement
- Front & Rear Suspension Rebuild
- Electric Fuel Pump Upgrade (eliminate mechanical pump)
- Fuel Tank Vent Hose Replacement
- DIY front alignment
- Throttle Jerk Fix
- Installation of Miata Seats
- Miata Seat Speakers
- BRE Rear Spoiler Installation
- Headlight Relay Wiring Harness
03 July 2013
240z How-To Links
Below are several of the larger projects that I've completed on my car which I documented as much as possible to allow others to learn from my restoration. The rest of the blog entries track the progress of my restoration.
Alternator Upgrade
So while digging through my box of parts that the previous owner provided me, I ran across a brand new alternator, which ended up being a 280ZX internally regulated 60amp model. After upgrading to the Pertronix electronic ignition last year, I began to hear that the 240z's voltage regulator and 40amp alternator might not be powerful enough, so I investigated upgrading. All it cost me was the price of a diode ($2 @ Radioshack) as I had all of the other parts already.
I was able to find a good article at ZHOME.COM (http://www.zhome.com/ZCMnL/tech/280Alt.html) but it lacked the detail and pictures that I needed.
After removing the voltage regulator I found out why its recommended to go with an internally regulated alternator -- look at how the backing plate has melted!
Once installed with the waterproof boot that I had laying around (which fit perfectly), I was able to tuck the jumper harness under the wires and it looks like its always been there.
I was able to find a good article at ZHOME.COM (http://www.zhome.com/ZCMnL/tech/280Alt.html) but it lacked the detail and pictures that I needed.
After removing the voltage regulator I found out why its recommended to go with an internally regulated alternator -- look at how the backing plate has melted!
In order to eliminate the external voltage regulator I needed to create a jumper, including a diode to allow the car to turn off when the key is removed. Here is the best diagram I was able to find on the internet:
I ended up using a spare voltage regulator connector (and kept the somewhat working voltage regulator in one piece in case I ever needed to switch back). This connector then plugs in just like the voltage regulator would.
Once installed with the waterproof boot that I had laying around (which fit perfectly), I was able to tuck the jumper harness under the wires and it looks like its always been there.
Now that I've been driving on the new alternator without the external voltage regulator I can honestly say the car is running better than it probably did when it was new. This was a great upgrade and should be done by anyone having ignition or performance issues (I thought it was my carburetors, but all along it was electrical issues).
24 June 2013
Carb Float Levels & Sightglass
Background
Thanks to gravity and atmospheric pressure, water (and other fluids including gas) seeks its own level. What this means is if you take a tube and hold it in a “U” shape and fill it partially with water, no matter how high you hold one end of the tube, the water will be the same height on both sides. This is the basic function of the sightglass. The level of gas shown in the sightglass is the same height as the fuel in the float bowl.
Don't forget to reference the FSM (Factory Service Manual) which can be found at:
http://www.xenons30.com/reference.html
Setup Procedures
1. Disconnect the coil plug going to your distributor and put the car in neutral, parking brake on, and chock the wheels. This will allow for cranking of the engine (powering the fuel pump) without starting the engine and without the car moving.
2. Remove the air cleaner assembly, including the air horns (leaving just the carburetors showing)
3. Using a caliper or accurate ruler, measure down 19 mm from the lip of the float bowl top and draw a horizontal line. You can use a pencil which is erasable, a permanent marker, or even a piece of blue painter’s tape depending on the quality/condition of your carburetor. Although the Factory Service Manual (FSM) states it should be 23mm, that is from the roof of the inside of the float bowl lid. 3mm is subtracted from this FSM figure to allow for easy measuring on the outside of the float bowl. This newly drawn line is what the fuel level “should be”.
4. Place a dish or tray or disposable rag underneath the carburetor bowl
5. Disconnect the fuel hose coming out of the fuel bowl. Gasoline (~4oz) will drip out. Dispose of the rags and empty the tray/dish
6. Connect the Sightglass to the bottom of the float bowl and tighten the hose clamp. Do not over tighten as you will crush the nipple!
7. Bend the sightglass up and tuck it behind the carburetor flange/body
8. Adjust the sightglass up & down to line the mark on the sightglass with the line on your float bowl
9. Repeat steps 1-8 above for the other carburetor (unless you’re just measuring one at a time)
Usage/Measurement Procedures
1. Once the sightglass is setup as per the instructions above, activate your fuel pump
- For mechanical fuel pumps (stock 240z), you must crank the engine
- For those who have upgraded to electric fuel pumps, either active a hot-wire
switch or crank the engine
2. Confirm nothing is leaking, if it is, retighten the hose clamp on the sightglass
3. Continue to activate the fuel pump until the fuel level in the sightglass no longer rises;
this is the current gross-mixture fuel level setting for the float bowl.
- Fuel above the 22mm line indicates a rich gross-setting
- Fuel below the 22mm line indicates a lean gross-setting
4. Once the current setting is identified and if not to your desire, you must remove the float bowl lids (4 screws)
- 3 screw SU’s require the float bowl lid to be rotated before they’ll lift off.
- You may need to replace the float bowl gasket if its old or you tear it while removing the float bowl lid
5. Once removed, adjust the tang on the float itself to allow for more or less fuel in the float bowls. Additional detail can be found in Appendix A (FSM)
6. Reassemble the float bowl lid and repeat steps 1-5 above and then move onto the next carburetor.
- If the fuel level was too “high” (rich) during the prior test, you will need to empty some fuel
from the sightglass/float bowl. The simplest way is to angle the sightglass down & let a
little bit of gas drip out into your dish/tray.
- I’ve found that by leaving the float bowl gasket out while fine tuning the float bowl
tang reduces the chance of damaging the gasket and/or wasting a lot of new ones.
Just remember to reinstall the gasket prior to full usage of the car.
7. Once completed, ensure tray/dish, rags, etc. are properly cleaned up.
8. Reattach the coil wire and proceed to fine tune the carburetors as per the factory manual.
I just saw this device which someone created on classiczcars.com. Very ingenious device! Basically its a 12 oz water bottle which has been cut with a line drawn parallel to the top and then rest the float bowl lid on top. This way you can see the fuel level and modify the float tang without having to mess with the gasket and pulling it out & back in.
Thanks to gravity and atmospheric pressure, water (and other fluids including gas) seeks its own level. What this means is if you take a tube and hold it in a “U” shape and fill it partially with water, no matter how high you hold one end of the tube, the water will be the same height on both sides. This is the basic function of the sightglass. The level of gas shown in the sightglass is the same height as the fuel in the float bowl.
Don't forget to reference the FSM (Factory Service Manual) which can be found at:
http://www.xenons30.com/reference.html
Setup Procedures
1. Disconnect the coil plug going to your distributor and put the car in neutral, parking brake on, and chock the wheels. This will allow for cranking of the engine (powering the fuel pump) without starting the engine and without the car moving.
2. Remove the air cleaner assembly, including the air horns (leaving just the carburetors showing)
3. Using a caliper or accurate ruler, measure down 19 mm from the lip of the float bowl top and draw a horizontal line. You can use a pencil which is erasable, a permanent marker, or even a piece of blue painter’s tape depending on the quality/condition of your carburetor. Although the Factory Service Manual (FSM) states it should be 23mm, that is from the roof of the inside of the float bowl lid. 3mm is subtracted from this FSM figure to allow for easy measuring on the outside of the float bowl. This newly drawn line is what the fuel level “should be”.
5. Disconnect the fuel hose coming out of the fuel bowl. Gasoline (~4oz) will drip out. Dispose of the rags and empty the tray/dish
6. Connect the Sightglass to the bottom of the float bowl and tighten the hose clamp. Do not over tighten as you will crush the nipple!
7. Bend the sightglass up and tuck it behind the carburetor flange/body
8. Adjust the sightglass up & down to line the mark on the sightglass with the line on your float bowl
9. Repeat steps 1-8 above for the other carburetor (unless you’re just measuring one at a time)
Usage/Measurement Procedures
1. Once the sightglass is setup as per the instructions above, activate your fuel pump
- For mechanical fuel pumps (stock 240z), you must crank the engine
- For those who have upgraded to electric fuel pumps, either active a hot-wire
switch or crank the engine
2. Confirm nothing is leaking, if it is, retighten the hose clamp on the sightglass
3. Continue to activate the fuel pump until the fuel level in the sightglass no longer rises;
this is the current gross-mixture fuel level setting for the float bowl.
- Fuel above the 22mm line indicates a rich gross-setting
- Fuel below the 22mm line indicates a lean gross-setting
4. Once the current setting is identified and if not to your desire, you must remove the float bowl lids (4 screws)
- 3 screw SU’s require the float bowl lid to be rotated before they’ll lift off.
- You may need to replace the float bowl gasket if its old or you tear it while removing the float bowl lid
5. Once removed, adjust the tang on the float itself to allow for more or less fuel in the float bowls. Additional detail can be found in Appendix A (FSM)
6. Reassemble the float bowl lid and repeat steps 1-5 above and then move onto the next carburetor.
- If the fuel level was too “high” (rich) during the prior test, you will need to empty some fuel
from the sightglass/float bowl. The simplest way is to angle the sightglass down & let a
little bit of gas drip out into your dish/tray.
- I’ve found that by leaving the float bowl gasket out while fine tuning the float bowl
tang reduces the chance of damaging the gasket and/or wasting a lot of new ones.
Just remember to reinstall the gasket prior to full usage of the car.
7. Once completed, ensure tray/dish, rags, etc. are properly cleaned up.
8. Reattach the coil wire and proceed to fine tune the carburetors as per the factory manual.
I just saw this device which someone created on classiczcars.com. Very ingenious device! Basically its a 12 oz water bottle which has been cut with a line drawn parallel to the top and then rest the float bowl lid on top. This way you can see the fuel level and modify the float tang without having to mess with the gasket and pulling it out & back in.
24 April 2013
Radiator Upgrade
The next project I just completed was to install an aluminum radiator in the 240z. After looking at the copper unit that was installed by the prior owner, it was a 280z 3-row radiator. Unfortunately the lower hose pipe was straight rather than crooked up like the 240z requires, so I needed to install a matching unit. I chose an American Eagle 2-row aluminum radiator with a lifetime warranty. The install was fairly straight forward and the hoses line up now, and the bottom of the radiator does not hang below the front cross member as the prior one did.
18 April 2013
Front alignment
As required by installing the new tie rods, I needed to perform a front wheel alignment. Rather than paying $150 to a local shop, I decided to use the old string & tape measure(caliper) method. Overall it worked fairly well. The pictures of the wheels are before I did the alignment. In the first shot you can see the toe-out of the driver's side.
I found this great image which describes alignment terms with pictures:
02 April 2013
Differential Refresh
Next I removed all of the pieces from the differential, including the half-shafts
I then began to work on the side seals, as that was new territory for me. After removing the half-shafts, its as simple as removing the the center bolt and pulling out the axle stub. I'd recommend working on one side at a time, rather than pulling the entire thing apart. Also, its easier if you drain the differential before you start pulling the seals out.
Keep in mind these are keyed (one side does have a flat-face)
After buttoning up both side seals, I pulled off the rear differential cover to clean the surface and replace the gasket. I did use a very very very thin layer of high-temp RTV.
 |
| Reassembled and on the jack ready for installation |
 |
| Everything back together and new license plate installed; ready to cruise! |
13 February 2013
Suspension Rebuild
The next (big) project I have for the 240z is to rebuild the entire suspension system. I recently picked up the Tokico suspension package for the 240z off of Amazon.com (free Prime shipping) as well as the Energy Suspension polyurethane bushing kit. Although I need to save up for the rest of the parts I need, I've been carefully planning and preparing.
Check out this great site with pictorial instructions on replacing the struts/springs:
My shopping list of additional parts includes:
FRONT SUSPENSION
Removal of the front suspension members went fairly well. My impact wrench and shop-press were life savers and time savers; I highly recommend getting proper tools if you tackle this job. While pressing the outer bushing sleeve out of one lower control arm, I did end up deforming the piece. Luckily I was able to pick up a replacement on eBay for a very reasonable amount.
While everything was apart, I did clean the parts with TSP and then primed and painted with Rustoleum Professional enamel.
The new strut inserts and springs assembled very easily and the replacement tie-rods and ball joints fit perfectly. The only issue I had was with the rack & pinion boots being a little short, but I was able to modify them to make them work properly.
REAR SUSPENSION
Thanks to the help of my dad, we began to pull apart the rear suspension. Everything seemed to be going easy until the dreaded spindle pin removal of the first control arm. It wasn't nearly as bad as many of the stories I've heard, but not fun and not as easy as the service manual shows (see picture of just pulling the pin out). Then came the removal of the bushings which proved to be a challenge again.
After breaking my 12-ton shop press, I decided to go another route of using an air hammer to knock the bushings out; that proved to work very well. When I went to tackle the other side, everything came apart much quicker since I knew what I was doing. Now its onto paint and reassembly.
Check out this great site with pictorial instructions on replacing the struts/springs:
- http://atlanticz.ca/zclub/techtips/suspension/tokicoupgrade/tokicoinstallfront.htm
- http://atlanticz.ca/zclub/techtips/suspension/rearend/index.html
My shopping list of additional parts includes:
- MOOG U-joints (driveshaft & half-shafts)
- Rear spindle pins & lockbolts (maybe)
- Outer tie-rod ends
- Ball joints
- Strut mounts
- Front strut bearings
- Differential seals (sides, rear, pinion)
- Half-shaft boot kits
- Transmission seal (rear)
- Rustoleum professional rust-primer, enamel, and TSP
 |
| Tokico suspension kit (springs, strut inserts, gland nuts) |
 |
| Energy Suspension Polyurethane Bushing Kit |
FRONT SUSPENSION
Removal of the front suspension members went fairly well. My impact wrench and shop-press were life savers and time savers; I highly recommend getting proper tools if you tackle this job. While pressing the outer bushing sleeve out of one lower control arm, I did end up deforming the piece. Luckily I was able to pick up a replacement on eBay for a very reasonable amount.
While everything was apart, I did clean the parts with TSP and then primed and painted with Rustoleum Professional enamel.
The new strut inserts and springs assembled very easily and the replacement tie-rods and ball joints fit perfectly. The only issue I had was with the rack & pinion boots being a little short, but I was able to modify them to make them work properly.
 |
| Dirty & grimy pieces |
 |
| Looks like something is missing |
 |
| Damaged LCA |
 |
| Painted & ready for reassembly |
REAR SUSPENSION
Thanks to the help of my dad, we began to pull apart the rear suspension. Everything seemed to be going easy until the dreaded spindle pin removal of the first control arm. It wasn't nearly as bad as many of the stories I've heard, but not fun and not as easy as the service manual shows (see picture of just pulling the pin out). Then came the removal of the bushings which proved to be a challenge again.
After breaking my 12-ton shop press, I decided to go another route of using an air hammer to knock the bushings out; that proved to work very well. When I went to tackle the other side, everything came apart much quicker since I knew what I was doing. Now its onto paint and reassembly.
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