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Retro's 76 2+2 aka Fat bottom girl! New Shoes


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Perhaps this is a later L28 and the Su carbs retro fitted instead of EFI for simplicity back in the day. Having a look at the carbs there are a lot of hoses missing of the air filter box and some diaphragms that are not connected up? could someone in the know give me an idea of what should be connected to the air box etc.

 

The wheels are lighter than Alloy wheels of the same size, i have some 16x8 superlites and they are heavier than the 15x10 steel. not sure of exact weight though.

 

Surface rush on the rotors is nothing a bit of hard breaking and it comes right off.!!

I Will be getting new pads and having rotors re ground to make sure they are not warped etc. as long as they are not below min width.

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The inlet manifold looks like the original emissions 260Z (with everything) and I think someone just bolted up the SU's to that. Where those missing hoses go and connect to are gone; they used to connect to the 260 flat top carbs. All those diaphragm's on the manifold can probably me disconnected/removed anyway. Or find a balance bar from a set of 240Z Hitatchi carbs.

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ok i get ya. dose anyone have any pics that might help for reference. im going to cut of an weld up the holes in the filter box as i want to keep that.  and tidy up the manifold remover diaphragms etc.

or maby i should just get that side draft and turbo it!!!  ;)

 

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Replaced plugs today and attempted a tune. I used a rubber tube in the ear to listen for the difference in pitch while adjusting each throttle stop screw. I think i got it pritty close. Carbs had been set crazy rich, then slowly leaned it off till i was happy, engine sounded pritty good, small amout of smoke still. Definatly going to try and track down a colourtune. I let the car cool righ tdown then tonight i poped out and gave her a cold start, she fired up well. while i was staring in owre (or it could of been the petrol fumes) i notice a few small drops of water leaking from the back of the head. once the engine warmed up to temp they stopped.  ::) Guess im going to have an adventure into the engine soon!

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Hey mate,

 

I would happily lend you my colortune if you were a bit closer (btw can you fill in your location?). They making tuning SUs really easy. Also those Unisyn airflow meters are good.

 

The two small blanked off hoses on the airbox are usually connecting the float chamber on the carby to the filtered air in the air box. Their purpose is to ensure that the fuel inside the float chamber is kept at atmospheric pressure, which when using correctly adjusted floats ensures the fuel inside the jet is at the correct height. If I was you I would reconnect them as the SUs were designed to run with atmospheric pressure fuel in there. Also, if the float mechanism get stuck open then the extra fuel usually travels through this hose into the airbox where it pools safely. Currently I guess a fuel overflow would all leak into the carby or out the gasket and drip onto the exhaust manifold.

 

Here is a pic of my old 260z flat top carbs. My airbox appears to be different to yours, I don't have those two small hoses, mine was from 74-75:

IMGP0440.jpg

 

And here is a pic of the 240z round tops after the conversion (these are 4 screw round tops, which are only slightly different to your 3 screw ones) You can clearly see the two lines I have running from the airbox to the float chamber of each carby

IMGP0471.jpg

 

I would have said that the other blanked off port on your airbox was to connect to the engine head, but it looks like you have two of those so I'm not really sure what it does.

 

The big tube on the bottom of your airbox used to be connected via hose to a plate around the exhuast manifold. This would allow hot air coming off the exhaust manifold to warm up your carbys and engine more quickly on a cold day. I took mine off with no dramas to performance on a cold day.

 

If you are chasing HP I suggest you get a 240z airbox, as some members here have dyno'd various airbox styles and the stock 240 airbox gives the highest HP. Also, if your airbox is from a 260z then it will have square holes in the airbox matching to round holes in the carbys, which isn't ideal.

 

Edit: In order to tune without the colortune, I think the best way is to drop the RPM to the lowest it can be without stalling, and then adjust the carbys trying to achieve the highest RPM possible. As you get the mixture more correct the RPM will rise, and if you go too lean or rich then the RPM will lower.

 

The Ztherapy guy suggests that you start at the lowest RPM the car won't stall on, approach the ideal setting from the leaner side, adjust it until you get it to be the highest RPM possible, then richen it up until you see the first sign that the RPM is dropping due to being too rich, and then lean it out either 1/4 or 1/2 of a turn. That way it is running on the richer side of the best tune you can achieve with this method, which is good for SUs.

 

Let me know if you want to give it a go and I'll try to explain it better.

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yeah im gonna try and get a colourtune and unisyn of ebay.

I approched my tune from the rich side.

The difficulty i had with the throttle stops was, when i had it set just before stall. Using the tube in the ear technique i couldn't hear a clear suction tone between carbs. So i had the idle set a bit higher so i could listen to the suction tone, then I set the mixture and then dropped the idle back down.

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The wheels are lighter than Alloy wheels of the same size, i have some 16x8 superlites and they are heavier than the 15x10 steel. not sure of exact weight though.

 

Superlites are the exact opposite of their name.  My 17X9 Rotas were lighter than the 15X7 Superlites that were previously on the car!  Superlites are a very strong and well designed wheel though.  This is why they're popular for motorsport.

 

Zedevan, I've heard steel wheels aren't really suited for track use, they end to flex alot more than good alloys. For the street they are fine, but for track work you're better off with some good quality wheels.

 

The steel also doesn't dissipate heat as well as alloy so in longer races the tyre gets hotter and will go off quicker.

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  • 9 months later...

ok so an update,

Front and rear foot work done!;

new ball joints, tie rod ends, bushes, shock and springs. put a set of offset control arm bushes in for a bit of camber and replaced the rear strut tops with front tops i got from a yard. car sits nice now. havnt been able to go for a spin yet need battery, wheel alignment and rego!

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Also picked up a set of triples, price was right and they appeared to be alright set up. 45 mikuni solexs.

using some long ram tubes with oiled ram flow filters over them, Mounted to the manifold with redline soft mounts. linkage is a bit tatty im going to replace the rods and rosejoints with some better stuff. manifold is a lynx. will get some pics tonight.

 

also test fitted my mirrors. also did a play around with them on the fenders.

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I might get some spacers for the front the 8" look like there hiding in there. The mirrors are only balancing on the fenders so i didn't want to put them to close to the edge. I don't really like em on the fenders because the stalks are not the right length, they are shorter than originals.

I guess it give a streamline profile front the side but it just looks off!

I also got an ADR approved boss for my little SAAS wheel to complete the vintage look.

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While i had the struts ect. dismantled i cleaned it all up and recoated in enamel black.

also stripped back inside guards and painted black, no holes found very impressed. Previous owner painted inside metallic blue!

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during removal. Front end came apart quite quickly, found pedders sticker on strut inserts, they must have done it a few years back. That would explain only one bump stop on the front and one of the sway bar link washers used on the control arm bolt on one side. quality

i bought two strut mate kits from monroe so new bump stops and dust boots for the front, price was absolute rip off!

PB200714.jpg

 

 

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  • 3 weeks later...

Well i have been working the the engine bay removing as much as i can to check for rust and get ready for paint, only rust is the support under the radiator. So next weekend i will be cutting and welding it up. Once the bay is painted i will be installing my triple solex carbs.

Mikuni_solex-triples.jpg

There is so much ugly anti pollution junk in the bay, some of which i am unsure what it is! can someone identify this for me as i want to rip it out for simplicity.

image found on the web for reference;

img_0176_small_113-1.jpg

 

 

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I have removed the charcoal canister however i might put it back in to keep it looking legal.

Dose anyone have more info on how they work, or if they are needed for the air cond?

I have this silly feeling i want to try and get the aircond working.

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Think the large bottle thing acts like a ballast to keep the vacuum more stable as your manifold vac changes. This vac is switched via the couple of solenoids circle on the right hand side. This then switches the vacuum to the appropriate actuators in your blower assembly to switch modes by opening or closing flaps.

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You pretty much should just replace all those vac hoses as I've cheated by shortening and have had to redo about three times in last six months. It's on my to do list.

They're just too old and split soon after.

Think I have a good drawing at home how they connect. Will try to find it for you.

You will need it to switch modes as hot air comes out on feet only and aircon through the main vents.

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i found a 280zx PDF manual and read thru the description of how it works. Im guessing that in the event of removing the aircond the heater will not block off some of the vents etc. so i guess it may not heat as well. I will remove as much as i can so i can paint the re attach it all and see if it can hold gas/work. Would be nice to have air in summer. The only thing is that the triple manafold dose not have a position for the vac line to attach so i will have to make a t piece where the brake booster vac tube attaches.

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  • 3 weeks later...

Spent last weekend repairing rusted out lower radiator support area. I also treated the area with POR15 metal ready. The metal ready treatment has been on for two weeks and there is no sign of surface rust. I left it unpainted to see how it worked.

I also reinforced the strut towers, additional spot welds along the inner guard and around the strut tops.

Also while im in the process of cleaning up the engine bay I had my cam cover coated. Linished areas need more polishing.

 

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What do people think of Uni filters, i heard some people say they are a fire risk! any thoughts?

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Looks good! as for fire hazard, I have seen a set of filters go up in flames on the dyno, on a 180b SSS (L18?) there are some that are on the market that are shyte, then some that are not.... got no-idea which is which though...

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  • 1 month later...

Slowly plodding along with work, I stripped out the engine bay as much as possible before painting, Pulled out air cond, i also added additional spot welds where the inner guard attaches to the strut towers. Radiator support was rusted out so that was cut and shut with new steel plate that wraps underneath the support. Took a few hours to cut cardboard templates then transfer to steel. I had to keep crawling under the car for test fitting and small adjustments. So after the weekend i had a stiff back at work from laying on the cold floor.

 

While i was there i couldnt help loosly bolting up the carbs for a glamor shot. I also made up new linkage, i found some 5/16 rod end and 5/16 stainless main bar. the bell cranks are original, they look like plated steel. I also got a set of redline links for the throttles, much better than the lynx ones, lynx had plastic ball joints that were looking crusty. Only thing i had to modify was the thread extenders/mounts for the rod ends. My manifold has 3/8 unc thread and the rod ends have 5/16 unf. So i bodged up the thread extenders by welding on 5/16 nuts to the tops. you can just see in the pic the spot weld joining the 5/16 nut to the 3/8 extender.

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My carbs have the cooling bodies underneath. two little outlets for fuel to return to the tank thus cooling the carb slightly, however im a bit lost as how im going to plumb up six outlets to one fuel retune line, i search for some pics on google but have not found anything, anyone  have any ideas ?

I will put this pic up, optional part 85 replaces 55. thats what on the underneath side.

MikuniPHH-24.jpg

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  • 3 months later...

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