'73 240z - Project Build

[Crashtd420]

I'm not sure if all su have it but dont the use some sort of oil in them....

I dont even know what it does...

 

Also how do the plugs look....

Could you be running too rich?

 

I had issues restarting when my setup was too rich....

[demo243]

24 minutes ago, Crashtd420 said:

I'm not sure if all su have it but dont the use some sort of oil in them....

I dont even know what it does...

 

Also how do the plugs look....

Could you be running too rich?

 

I had issues restarting when my setup was too rich....

I don’t think they have any oil in them but could be wrong.

 

It is definitely is running a bit rich, but I dont think it’s too bad. I need to get a o2 sensor bung welded in so I can hook that wideband afr up. Might grab one of those clamp on ones for a quick fix just need to get under there and measure the tube diameter 

[datzenmike]

Called the damper and the oil is 'damper oil' duh. The viscosity of the oil slows and prevents sudden rising of the slides when floored suddenly. This in effect acts like the accelerator pump in a regular carburetor and causes the SU to run slightly rich till everything gets caught up. Obviously if no or low oil it will probably balk off the line. Important that both carbs are filled equally and use the same oil. Popular wisdom says 3-in-one oil though ATF also works well.    

[demo243]

10 minutes ago, datzenmike said:

Called the damper and the oil is 'damper oil' duh. The viscosity of the oil slows and prevents sudden rising of the slides when floored suddenly. This in effect acts like the accelerator pump in a regular carburetor and causes the SU to run slightly rich till everything gets caught up. Obviously if no or low oil it will probably balk off the line. Important that both carbs are filled equally and use the same oil. Popular wisdom says 3-in-one oil though ATF also works well.    

Good to know- still in the know nothing phase of these

[Stoffregen Motorsports]

A lot of tuning can be done on the SU carbs. Different weight oil, piston spring rate, depth of needle, profile of the needle, etc. So many tweaks to get power.

[demo243]

6 hours ago, Stoffregen Motorsports said:

A lot of tuning can be done on the SU carbs. Different weight oil, piston spring rate, depth of needle, profile of the needle, etc. So many tweaks to get power.

Im sure they are great carbs. Just not what I’m after. I would love to throw a set of triple Mikunis on there to match the 510- also great carbs… never had a problem with them (knock on wood) even cold starts and no choke…- but Mikuni sidedrafts are way out of my budget.

 

There are a few Zs floating around with 6 Mikuni HSRs that seem like a really cool option. I dig the look, that they are mikunis, and are readily available although I think need a little tweaking. I guess I could just throw 2 on there to replace the SUs… but what’s the fun in that- go big or go home! 

[demo243]

Thread is due a photo too

 

Proof that it left my driveway again 

 

like I said the car drives pretty well- it’s just very picky about starting…

Edited July 28, 2023 by demo243

[demo243]

Did the basics -

 

Reset the idle and balanced the carbs, purrs now at ~750rpm.

 

Reset the fuel mixture knobs underneath to 2 turns out. Tried messing with them a half turn in and out and didn’t make a difference in the idle speed so I just left em at the baseline 2 turns

 

Definitely better! 

 

Don’t have a color tune or afr to mess with it more.

 

Definitely starts easier- still requires a quick blip of the throttle but seems much easier and not as picky.

[demo243]

Should also mention I got the Speedhut speedo working. Ditched the ProTuners adapter and installed an  S13 240sx speed sensor. Literally bolts right in to the 280zx trans. The S13 sensors have a pigtail coming off the sensor so I got the matching connectors from wiring specialties and wired the black wire to a ground and the green wire as a signal to the gauge. Works perfect.

[demo243]

Played with the distributor timing a bit this morning to see if it helped with start up at all… it was at 20 degrees when I started tried dropping it back to 15 and 10 but not help. Pushed it back up to 18 degrees and 35 all in with advance. 
 

Also did the Miata wiper arm swap- used 2 ‘99-05 driver side wipers. This was partially for the j hook since the pins on my stock wiper arms were pretty toast but also for black arms.  No good junkyards around so ebay specificals. Cleaned em up and hit with a quite coat of paint, same as I used on the tail light panel. Got 16” blades for them , but 15”‘might have been better… oh well. They are a little “taller” but I don’t mind and I like the black, goes with all the other black on the car.

 

 

 

Quick shot from the parts store run for the wipers. Yes I parked like shit… Hahha… still learning to park this thing, it’s weird sitting so far back and has a terrible view out the hatch.

 

 
Then I got to work replacing the ball joints. Driver side had a torn boot, just did em both anyway.

 

 

[demo243]

I don’t know what else to do for the hard start issue…

 

it seems like you need to be “light” on the key - ie hold it just as it kicks the starter, but don’t turn it all the way and hold it. Then takes just the right blip of the throttle to get it going. I’m getting pretty good at it so I don’t mind… but every year the inspection guy is gonna need to start it… 

 

once it’s running it idles nicely and runs great. Good power down low and up high. 
 

don’t want to replace the ignition switch since I have the original keys and it matches all the doors…

 

don’t really know what else to try.

[demo243]

Next step is coilovers.

 

I was planning on BCs since the price is good and I like their camber plate…

 

I am hoping to pick up a spare set of struts , just need to coordinate with the guy. They are supposedly already shortened… which got me thinking maybe I should go the T3 route with shaft collars… then I could run some nice Koni sport or race dampers (Upon further research I think race dampers are too stiff)- which must be better then the BC stuff… but maybe not… idk…

 

I’m not after a race car in this car…  I’ve got the 510 for that… but I want or spruce this one up a bit and drop it.

 

__________________________

Edit... Back on the BC bandwagon. T3 has Koni struts on their site, but there is no way they sell 4 Koni Race dampers for $560... that would be a buy one get one deal! I have to assume their sport dampers @ $460 are the same (for a pair...) - At that point one is $1000+ over the cost of BCs... so that I think answers the question... Back to BCs.

Edited July 31, 2023 by demo243

[demo243]

Just one thing after another….

 

Went to go try and get the car inspected again this morning. Opened up the garage and …. GAS! The garage  stunk of gas…

 

A quick look under the car and then bottom of the tank was wet, looks like it was coming from the fuel sending unit. I guess I just haven’t had that much gas in the car yet, and when I stopped and added 5 gallons on Sunday it put the level high enough to reach the sending unit.

 

A quick search shows this is pretty common… 

 

Drained the fuel tank using the pump- glad I installed that overide switch! Pulled out about 10 gallons.

 

I was then about to order the o ring and lock ring online … but figured I’d try the local dealer first. Parts are still available and the same price as Z car depot but no shipping cost and faster. Should be there tomorrow- $26…

[datsunfreak]

On 7/30/2023 at 7:14 PM, demo243 said:

it seems like you need to be “light” on the key - ie hold it just as it kicks the starter, but don’t turn it all the way and hold it. Then takes just the right blip of the throttle to get it going. I’m getting pretty good at it so I don’t mind… but every year the inspection guy is gonna need to start it… 

 

don’t want to replace the ignition switch since I have the original keys and it matches all the doors…

 

don’t really know what else to try.

 

There's really isn't anything else. In my experience, this is a common issue with Datsuns that can only be fixed with a new switch.

 

The contacts inside the switch when you turn it "too far" are not sending power to the coil, then as you ease off of it, it suddenly makes contact and the car starts (sometimes). I like having the OG keys, but nothing beats a nice new ignition switch.

 

FWIW, you can often buy a new switch that comes with new door/trunk locks too, then your keys match? 

[demo243]

4 minutes ago, datsunfreak said:

 

There's really isn't anything else. In my experience, this is a common issue with Datsuns that can only be fixed with a new switch.

 

The contacts inside the switch when you turn it "too far" are not sending power to the coil, then as you ease off of it, it suddenly makes contact and the car starts (sometimes). I like having the OG keys, but nothing beats a nice new ignition switch.

 

FWIW, you can often buy a new switch that comes with new door/trunk locks too, then your keys match? 

I did a little more digging since that post and found a few other references of the same thing.

 

It seems like I may be able to replace just the switch part- 

 

https://zcardepot.com/products/ignition-switch-oem-240z-260z-280z-510?variant=19275160191089

 

I ran my 510 with out the key and column lock using just that switch for a hot sec till I replaced the whole unit… I wonder if I still have the old switch … hmmm

 

i know I’ll have to notch the screws to get it off don’t remember what’s entailed to change the switch, will have to look

[datsunfreak]

5 minutes ago, demo243 said:

It seems like I may be able to replace just the switch part- 

 

Yes, you can. I totally forgot about that. 😋

 

6 minutes ago, demo243 said:

i know I’ll have to notch the screws to get it off don’t remember what’s entailed to change the switch, will have to look

 

I don't think you have to do anything special to get the electrical half of the switch (lower) off of the mechanical half (upper key part). Just the ones that hold the whole assembly to the column. 

 

If you want to pull the assembly off the column, using a dremel and a cut off wheel you can make a slot in the screws, then you can turn the screws out with a flat head screwdriver. 

[datsunfreak]

FWIW, most of the cars I have replaced the switch on, the mechanical half was pretty well worn out also, so I just replaced the whole thing. 👍

[datsunfreak]

Here's a view of the back. You just need to remove those two phillips screws and the elctrical half pops out.

 

[demo243]

17 minutes ago, datsunfreak said:

Here's a view of the back. You just need to remove those two phillips screws and the elctrical half pops out.

 

just looked at the same photo and saw that. 
 

need to go dig through my old 510 parts and see if I still have that switch- might as well try the one I have already.

[demo243]

1 hour ago, demo243 said:

just looked at the same photo and saw that. 
 

need to go dig through my old 510 parts and see if I still have that switch- might as well try the one I have already.

found my old switch … but the acc tab was already cracked and breaking off… guess I’ll just have to order a new one. 
 

I’ll wait till I get the sender o ring replaced and then I can order a couple extra of those with the new switch

[demo243]

Photo dump...

 

Got the O-Ring and Lock Ring swapped out this afternoon- early enough to make it to the inspection station.

 

Hold your breath! The guy at the register was literally laughing at me when I asked about getting a safety inspection done.... "On that thing! Will it even pass?!?"

 

 

But we did pass! E-brake was a little loose, and the guy said there was a little play in the front.... but still gave me the sticker.

 

 

Sooo that meant time for a quick joy ride and some photos.

 

 

 

 

 

 

[demo243]

 

Seemed to have picked up a shake in the steering wheel at highway speeds after doing the ball joints. Was hoping to do some work today... but ended up replacing the U-joints and carrier bearing on my Tacoma... Gonna go back in and double check my torque specs on the Ball joints and all the hardware removed/replaced to do the job. Ill try another driveway alignment after that and rotating the tires after that just to rules things out. Really should get it in for a pro alignment... but seems so wasteful since only toe can be adjusted... 

 

Hoping to take it for its first long drive next weekend... but it a bunch of highway so well see...

[Stoffregen Motorsports]

On 8/3/2023 at 6:36 PM, demo243 said:

Hold your breath! The guy at the register was literally laughing at me when I asked about getting a safety inspection done.... "On that thing! Will it even pass?!?

Fuck those guys. Didn't their mamma teach them to be courteous?

 

So after replacing balljoints, got a wobble. Go back and check that all balljoints are tight in their tapered bores. Sometimes the machining is off and the nut will bottom out before the taper is tight.

 

And when you say balljoints, you mean balljoints or tie rod ends?

[demo243]

3 hours ago, Stoffregen Motorsports said:

Fuck those guys. Didn't their mamma teach them to be courteous?

 

So after replacing balljoints, got a wobble. Go back and check that all balljoints are tight in their tapered bores. Sometimes the machining is off and the nut will bottom out before the taper is tight.

 

And when you say balljoints, you mean balljoints or tie rod ends?

Went back in and double checked torque specs and everything on the ball joints (connecting the suspension to the steering arm, not the tie rod ends - although those may need replacing…)

 

Driveway checked the alignment as best I could - shows ~1/4” toe in - which is a little much- I think a 1/16” - 1/8” would be better….

***Edit^^^***  This driveway toe was measured in front of and behind the rear tires so at the wheel it would be less… so maybe I’m ok 🤔 

 

Took it for a spin. It was a bit better. I think it may actually just be the road. The shake only seems to be above 60, but if I stayed to one side of the lane or the other it seemed to be better. Left lane might have been a little better hard to say. I the narrow track width on these cars doesn’t do well in truck ruts. The 510 tends to wander in them, but never shook that I recall.

 

Should probably just get it to a shop for a more precise toe alignment.

 

Need to get it to the exhaust shop too to get an o2 bung welded in.

Edited August 13, 2023 by demo243

[datzenmike]

Yes 1/16 is better. My 710 is just a couple of mm. Tires aren't perfectly symmetrical so I used the outer edge of the mag rims front and back. Also on my lowered car it's hard to measure across between the 9 and 3 o'clock positions on the rims. One goes through the transmission bell housing the other through the oil pan.