Vos 260Z 2+2 Build

[gilltech]

That's pretty exciting that you have quite a bit of info on the car, (even back to '78!!). As long as those receipts definitely match your car (is the VIN listed? - a colour change might be a problem) then they could provide proof that your car has been registered on Australian roads in a previous life. And is not just some grey import for parts or racing with no Import Approval.

Surely also the old rego number(s) in SA or wherever, and contact details of previous owners, meaning you might be able to trace it's background further if you were so inclined.

I'd go talk to the NSW rego authorities next so you know what you need to do to satisfy their rego requirements. Hopefully they will be accomodating given what info you have.

PS. I recall blank repro data plates for a 2+2 model being made available via this forum a while back, maybe still available? I know there are several styles, the 2+2 ones being slightly different to the 2-seater ones, and early and late versions. But a nice finishing touch.

[vosadrian]

The engine number we have also matches the paperwork for the car back to original sale. The colour of the car is unchanged (but resprayed), and we have photos from decades ago of repair work from a minor front end accident. I will definately get onto the rego stuff. We need to know what needs to be done before doing any work on it. At the moment, I really just want to get the car together and running and try to get it rego'd. We can do wheels/suspension/brakes etc. later. I'm just not sure how difficult this will be with the RB engine. I was hoping if we went for a RB25 with similar (less) capacity than stock and no turbo that this might be easier, but not sure of that. 

[gav240z]

Much easier to get it registered with the original L motor. Then modify after that.

[vosadrian]

We have the matching engine numbers L26, but it is not complete. Basically just the long motor. Also we have no gearbox to match. Not sure if it is more effort to go L series first and basically do all the work for an L series that we intend to remove later.... or try to rego with the RB and have the hassles of rego of a different engine, but just do it once.

If we were after an L series box, clutch and everything as well as L series ancillaries (carb, manifolds etc.), is this sort of thing available for a reasonable price? 

[vosadrian]

Hi All,

We are beginning to go through our car and work out what we need to source. We are realising we are missing a lot. So much that it may be expensive to source parts individually. Is anyone aware of a 260Z 2+2 being wrecked? Hopefully a car of low value that is beyond restoration potential. An example of some of the parts I know I need:

* Significant part of the wiring loom. We seem to have a the instrument harness and the rear harness and the engine harness, but are missing where it all attaches together with the fuse box etc. under the dash.

* Brake lines - We have a master cyclinder installed and the distribution valve and connecting lines, but not the hard lines going to the 4 corners

* Windscreen wipre assembly.

This is just what we know now and is probably the tip of the iceberg. Ideally we find a car we can get stuff out of. If not we are going to be searching for lots of individual bits. 

Any advice on how to proceed?

Cheers!

[Millerman]

12 hours ago, vosadrian said:

Hi All,

We are beginning to go through our car and work out what we need to source. We are realising we are missing a lot. So much that it may be expensive to source parts individually. Is anyone aware of a 260Z 2+2 being wrecked? Hopefully a car of low value that is beyond restoration potential. An example of some of the parts I know I need:

* Significant part of the wiring loom. We seem to have a the instrument harness and the rear harness and the engine harness, but are missing where it all attaches together with the fuse box etc. under the dash.

* Brake lines - We have a master cyclinder installed and the distribution valve and connecting lines, but not the hard lines going to the 4 corners

* Windscreen wipre assembly.

This is just what we know now and is probably the tip of the iceberg. Ideally we find a car we can get stuff out of. If not we are going to be searching for lots of individual bits. 

Any advice on how to proceed?

Cheers!

There is one in Adelaide that has been going down and down in price. The shell and interior looks too far gone but if you only need it for the thing above he has listed it as complete. Maybe have a chat to him and see what you can come up with. Myself and a few others from the forums have spoken to him and tried negotiating but his wife at the time was the problem (i think its sentimental).

 

heres the link anyway:

https://www.gumtree.com.au/s-ad/peterborough/cars-vans-utes/1976-datsun-260z/1286887476?

 

Edited January 27, 2022 by Millerman

[vosadrian]

Hi All,

We recently picked up another 250Z 2+2 that is well beyond rebuilding to use as a parts car as our project car has a great body but is missing many parts. We should get 80% of the missing parts we need from this car, but it is partially parted out so we won't get everything.

One thing it does have is an L26 that seems complete. I spent a bit of time on the weekend cranking it by hand and then turning it over with a starter motor and it seems to crank smoothly and have compression (although uneven probably). I am considering trying to get this running and in our main car blueslip and rego. So far I can crank it. I should be able to work out the ingition side of things as I have a good Auto electronics background. I have not done heaps with carbies, and I don;t know the state of these carbies, so I have a few questions:

* I believe the engine has a mechanical fuel pump on the front opposite side to distributor. Can I just stick a hose from inlet to this pump to a jerry can with fuel and use this to get the enigne running?

* I am not sure which version of carbys this engine has, but they seem complete with twin carbies and air intake etc. How likely is it that these carbys are in a good enough condition to start an engine after sitting in a paddock for 20 years? Is likely that seals and diaphrams etc. have persished and it will no longer run?

* I am going with the old adage that all it needs is to crank with the right amount of fuel and ignition in the right timing and it should start. Anything I am missing here with these engines?

Any help appreciated!!

Cheers,

Adrian

[1600dave]

Yeah, just stick a fuel hose into a jerry can or mower fuel tin and away you go.

If it has twin carbies, I'll assume they are SU's. Two types - early ones with float chamber separate and off to the side of the carb, later ones had an integral float chamber that you don't see. 260Z typically would have the later ones but heaps of cars had them converted to use the early ones.

Not much in the way of seals and diaphragms in the earlier SU carbs (assuming that's what it has). Small fuel line from float camber to carb could have hardened and cause the choke to stick, rubber tip on the "needle" in the needle and seat that keeps float level correct could be perished but it should still fire, may leak fuel if anything is perished but should run briefly even if you have to shut it down to prevent it spewing fuel everywhere. It may take a bit of cranking at first, the pump will have to fill the float chambers first, its not like a car with an electric pump - fuel only gets pumped while the engine is being cranked over as the pump runs off an eccentric on the end of the cam. Bit of "Start ya Bastard" down the throats of the carbs will get it to fire sooner and fill the float chambers.

Disclaimer-I've never pulled the later "flat tops" carbs apart to see exactly how they work, may be more rubber "workings" that can deteriorate in them.

You're not missing anything, fuel and spark and it should at least fire and try to run. 

Edited March 8, 2022 by 1600dave

[vosadrian]

Thanks Dave. I will let you know how I go!

[gav240z]

If it is an early set of SUs with the float chamber visible, you can remove the breather hose that goes to the airbox and use that to fill it with fresh fuel (as a primer) so you don't have to crank it for ages to get fuel into them. I use the little cup you fill water into an Iron for the steamer (perfect size) and has a little tip to guide the fuel in nicely (don't tell the missus :)).

Half the challenge in starting these cars is priming the fuel, if the plugs are ok and you have compression it should run. Takes a fair bit to kill an L-series motor and if the motor freely turns that's probably a good indication it will run.

If you have a photo of the carbs that will help.

260z ones are flat top dashpots, early (or most British ones adapted to Z's) are round tops.

[vosadrian]

Thanks Gav,

I did a little googling for photos of carbs, and it appears we have the flat top versions which I believe would have been standard on a later 260z that this is. I might need to take them off and give them a bit of a cleanup as it appears some birds and insects had found there way in there. 

I am going to work on getting ignition working first. Then I will move onto fuel.

I believe the car drove to where I picked it up from and had not too higher kms... so we will see what years of sitting around have done to it. I was surprised it moved so smoothly when I cranked it by hand with a 1/2 drive ratchet. It has oil in it, and it seems pretty thick and sticky, so that might be a good thing. It cranks a little unevenly under the starter motor, so I presume some valves that were open may have gotten some corosion on the seats and reduced the compression. That may fix itself a bit over time. I really just need an engine that runs well enough to get rego. I'll spend a few to see if this can get running, but if it turns into a big job I will give up.

 

[gilltech]

AFAIK all the 260Zs had the 'flat top' Hitachi carbs from new. I think the last year of the 240Zs for the American market did too. Mine did, and it's a very early 260 2-seater. Like many 260 owners though I did replace them with a set of 240Z 'round tops' later, under advice from other club members that they are the better option. Other 260Z owners have installed English SUs, easier to obtain I suspect.

IMO the flat tops get a somewhat undeserved bad rap. In my experience they tend to run a tad lean (exhaust emissions era), have limited adjustability, and internal parts to tweak them are pretty much unobtainable AFAIK. Yet, when cleaned and serviced they work as they are designed to do; I ran mine for several years before installing the round tops. The only problem I had with the flat tops was a fuel starvation issue I experienced at a Z Club track day; eventually, after a very slow trip home, I discovered a little concealed filter screen at the fuel inlet on the side of each carb which just needed cleaning. Otherwise no issues.

Your car sounds like a great project to tinker with! Good luck with it.

Edited March 9, 2022 by gilltech

[vosadrian]

Thanks @gilltech!

We have made some progress. Ignition system working, and I even got the car started spraying some "start ya B^&%&^" into the intake. Not that it was smooth sailing. It seems this engine has the shaft that drives the distributor fitted 180 degrees out of whack. So eventually I worked out it was firing spark in the wrong phase, and swapped leads around and it ran as long I sprayed in the intake.

The mechanical fuel pump seems to be pumping fuel, as I removed the outled and pumped some fuel into a bottle. We are getting fuel pumped to the carbys, but there is no evidence of fuel making it from the carbies into the engine. We cranked it quite a long time and the plugs were dry. 

I am no expert on carby fuel systems. It seems the mech pump pumps fuel to the carbys, and then there is a fuel return line that goes back to the tank. There is a largish vacuum diaphragm on the pipe that joins the two intake manifolds. Is this a fuel pressure regulator. Is there any resource I can use for a detailed description of how the carbys work so I can try and debug them?

Alternatively, we were lucky to grab a set of round top carbs from a local selling a set for a good price. They were apparently running an engine with no issue about 10 years ago, so maybe we swap to them. They seem simpler. The set we have has a block plate on where the vacuum diaphragm I mention above it and a few connection pipes blocked so I assume it has had some of the emissions stuff removed. 

Any assistance appreciated... even if it is just a link to another post with similar issues!

Cheers!

 

[gilltech]

Well done! So grab a Haynes or Nissan WSM and it will explain how the flat tops work. Take them apart and clean them. Check the hidden filter screen at the fuel inlet on the side of the carb, that's what tripped me up that time.

Or, put your energies into the round tops. I've seen service kits on eBay Australia. Or if no joy then get a pair sent over from one of the USA suppliers. It would help to know what year 240Z the carbs came off, as there were differences.

I can't help you with the carb bridge pipe vacuum diaphragm question, my car was NZ-new and didn't have all that emissions stuff that Aus-new 260Zs seem to have.

[AndBir]

4 hours ago, vosadrian said:

a set of round top carbs

You will need to check if they are the Datsun or British SU round top carbs.

This is what a set of the British SU type look like on the Datsun intake manifold.

[voslachlan]

Hey all!

I’m the previously mentioned son, thought I’d chip in on the discussion. 
 

The carbs we got were taken off a 260z, and I believe they replaced the stock flat tops as an upgrade, so I’m not sure what year the carbs originally came off. They seem to be 3 screw Datsun (ie. non British) round tops with no tab on the inlet flange, I have attached photos for reference. Hopefully less effort to get running? They were taken off a running car and left in a box since then. Also are we missing the float chambers?

The flat tops did not seem to be working properly, although with our limited experience we can’t really say if it’s the fuel pump or carbs that are the issue. When fed from a funnel, fuel passed through the pump even before cranking, although once cranking it sped up a lot, in pulses. Is this expected? Fuel was also flowing through the return line at pretty much all times. 

If there’s some easy things to check or fix regarding fuel pump, regulator, etc, we’ll try them with the flat tops first, or otherwise, if the carbs seem to be the issue, we’ll order a service kit for the round tops and get to work on them. 

Lachlan

Edited March 20, 2022 by voslachlan

[1600dave]

They're British HIF SU carbs, the most recent variation on the old SU carb. The "IF" in HIF is "Integral Float Chamber" - they don't have the float camber stuck on the side, its built into the bottom of the carb. 

These guys probably have parts / rebuild kits - https://www.sumidel.com/ 

As far as how they work, they are pretty simple carbs. Pump sounds fine, it'll pulse fuel as it runs off an eccentric in the engine. You don't need much pressure, all the pump does is keep the float chamber full, the carbs suck fuel out, unlike an EFI system that squirts fuel in so will squirt more or less if pressure is higher or lower.

Float chamber works exactly like the cistern on your toilet. Its a little bucket of fuel that feeds the carb. It has a little float that acts on a valve to cut off fuel when its full, then opens to let more fuel in as the engine uses fuel. Just like your toilet cistern has a float that acts on a valve to allow water in when you flush, then shuts it off when the cistern is full - only difference is the float chambers keep fuel at a more or less constant level by continuously opening and closing at even slight variations in fuel level.

From there, fuel goes into a little vertical tube at the base of the carb (the jet) and just sits there waiting for engine vacuum to suck it into the engine.. A tapered needle rises and falls in the jet, which alters the amount of fuel going into the engine. Needle is attached to the bottom of the piston which runs within the "suction dome" on top of the carb. This is open to engine vacuum so it rises and falls (and therefore needle rises and falls) according to the needs of the engine. This is the only real "trick" part of an SU.

One suggestion - since you're not familiar with carbs, are you using the choke to try to start it ? There is no notion of "cold start" like there is with EFI, the only way to give it more fuel when its cold is to pull on the choke which will richen up the mixture. You can't even pump the accellerator like you can with other carbs as there is no accellerator pump. 

Edited March 22, 2022 by 1600dave

[vosadrian]

Thanks for the info @1600dave!

That is interesting. We assumed we were getting the earlier round tops. Are what we have any good? Did they come out on any version of S30? Or is this an aftermarket upgrade from flatops?

I am familiar with carbs in that I drove cars with them early in my driving life, and I fiddled a bit with them and even put some rebuild kits through some. So I am familiar with choke. I am not familiar with the implementation in the S30. Is there any fuel system diagram with major components shown? I am trying to get my head around the plumbing of the system. There are several diaphragm looking things in our flat top setup. I initially though one was a fuel pressure regulator in the return line, but not so sure now. It sounds like the float system makes the system less dependant on fuel pressure than with fuel injection as the float system maintains a float level that probably effectively sets the pressure by the level. I notice that the hard return line has a restriction in it, so I assume that maintains a bit of positive pressure in the line from the mech fuel pump. Is the connection to the carb fuel inlet a one way connection? As in there is no fuel return line connection to the carb? And the float overflow, is that typically left vented to atmo pressure or to the charcoal canister?

Cheers!

 

 

[gilltech]

Yep, as Dave says! Same set-up as came on a spare 260Z motor I once bought.

I think it's a case of people bolting on what they can easily get hold of, which are SU carbs from any number of once fairly numerous British cars. As opposed to most likely waiting in vain for a set of Nissan round tops to come available from a written-off 240Z, which would only happen once in a blue moon given the limited number around. Or a 240Z owner going racing and upgrading to triples, which is how I got mine.

[vosadrian]

Makes sense @gilltech. I think they will be good enough for what we want which is to get the car running initially for rego. Our intention is to swap to a later engine in time. We just need something to get it running OK. We got the carbys and manifold for $250, so hopefully we can recover that cost when we upgrade the engine. But it would have been nice if they were the earlier round tops that are well known and valuable.

[gilltech]

The Hitachi flat tops are pretty simple, I wouldn't have thought they'd be too much trouble to get working as long as they are complete.

As for the British SUs I had, IIRC I on-sold them to a British car owner as they were slightly bigger than the ones he had so a worthwhile upgrade for him.

But 240Z Hitachi round-tops do come up for sale occasionally, as people up-spec to triples or swap in different motors or fuel injection or whatever.

My NZ-new early 260Z has the simple mechanical fuel pump and the double metal tube fuel rail, ie. one inlet and one return, with the latter having a restriction formed at its downstream end. Whereas some Australian 260Zs I've seen have a triple tube system and I have no idea what that third tube is for, something to do with emissions or maybe to do with the electric fuel pump which the later cars had?

Edited March 24, 2022 by gilltech

[abzcar260]

The british SUs on my 240hp LCR built engine are not as much as a limiting factor as the monkey in the drivers seat

[1600dave]

I can't comment on emissions type plumbing on a 260Z, the one I used to mess around with had this all removed and ran a pair of British SU's that had been fitted early in its life.

Connection to the carb is one way, fuel only flows into the float chamber not back out again. Again, can't comment on where the overflow is vented to on a 260Z but the overflow only comes into play when something goes wrong to cause the float chamber to "flood" or overfill with fuel (sticking float chamber valve / sunken or holed float). If all is working correctly, you should have nothing coming out the overflow. On one of my other Datsuns with SU carbs (a 180B SSS) the overflows are simply plumbed back into the air filter. My race car (Datsun 1600) has the overflows dumping onto the ground via a long hose to stop them spilling onto the exhaust and causing a fire - its never had anything come out the overflow for this to be an issue (and maybe scrutineers haven't noticed......)

Carbs don't really need any pressure to work. They would run quite happily if you sat a mower tin or similar in the engine bay and ran a fuel line into the carbs (providing the fuel level in the tin was slightly higher than the carbs), bypassing the pump completely and running on whatever pressure you get by a few inches of "head" in the fuel line. 

The British HIF SU's you have should be fine, assuming they are in reasonable condition and jetted OK (only way to change the jetting is to swap needles for ones with different taper). They will most definitely be way easier and cheaper to get parts for than Datsun / Hitachi type SU's. The HIF SU's were fitted from the factory to a number of British cars of the early-ish 70's

[vosadrian]

I got it worked out now. Thanks for that.

We have a 76 2+2 we are trying to get running. It seems to have considerable emissions plumbing and much of it is perished from age, so it seems much more complex than the basics we need to get it running. I am hoping we can get it blue slipped with a lot of the emissions stuff removed. I guess it depends how much the blue slip guy knows about this stuff. 

We have the 3 fuel lines. I believe there is a feed line that goes up and back with outlets for the carbs and then back via the return line which has a restriction at the return outlet of a small hole. I presume that is to provide a little positive pressure. The 3rd line appears to be for the charcoal canister for evap emissions. So we can ignore that for the time being. 

With the flat tops on the engine, I was able to confirm fuel flow to each carb. We cranked the engine for some time, and then checked the plugs and they were dry. It seems that the carbs have something stopping fuel flow. We also got the engine running by spraying "start ya B&%&^" into the intake and could run it for 20-30 seconds which I would have though was enough to get the float chambers full etc. But the engine stopped as soon as we stopped spraying. I suspect something in the carbs has jammed in place from sitting around a couple decades and there is no fuel flow. 

We will try two things.... remove the flat tops and fit these British SUs and see if we can get it running on them. Also we will try dissassembling and cleaning the flat tops and see if we can get them working. Then we will use whichever works best I guess.

Our plan is to get this engine into our yellow car for blue slip. We still need a lot of bits to do that. Can anyone give tips on where we might find the following bits:

* Fuel tank..... this seems to be the big one. My son found one for sale interstate for $1200 that looked in good condition. Is that the going rate?

* Gearbox.... we were thinking of using an early RB25/30 smaller gearbox... but we need a bell housing from a S30 manual to use that we believe. Does anyone know where there is a S30 manual gearbox... or just the bellhousing on a blown gearbox? The car we have is auto and we don't want auto, but I guess we could blue slip with auto.

* Door internals. It seems doors for there are quite rare, as people are after them to repair rust. Is anyone aware of someone who did this, but had the bits leftover from inside the doors.... brackets for glass/regulators/rods for door latches etc.? I am sure there are people who got complete doors for rust repair but did not need the internals, so hoping we can find that. 

* Drivers side seat rails... not sure why we only got the passenger side??

There will be many other things we find as we go.... so that is just what we know currently.

Cheers!!

[gilltech]

Quote

 we will try dissassembling and cleaning the flat tops and see if we can get them working. Then we will use whichever works best I guess.

Yes I reckon do that. They're pretty simple to work on. My guess is that the central fuel jets are blocked with residue and corrosion build up after fuel evaporation and from sitting unused and will just need a very careful disassemble and clean of all the orifices. The slides and needles should freely lift up and return down with the overhead spring pressure without sticking. Also make up some new gaskets for them especially for bolting up to the intake manifolds.