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Wanted to share and archive this great article from The Gentleman Racer. Datsun 240Z Rally CarsbyMichael Satterfield 6 years ago 2 mins read We stopped in to visit the Datsun 240Z Rally Cars at the Nissan Heritage Center in Japan; for more from our visit to Japan, CLICK HERE. In the early 70s, Nissan wanted to make a splash in the international sports car world with its new 240Z; while famous road racing teams like BRE were becoming a force in SCCA racing, much of the world saw Rally as the ultimate test of a car’s endurance, so from 1970-1973 Nissan backed factory rally teams in some of the most grueling and prestigious races in the world. Rally had been dominated by European cars like the Volkswagen Beetle, Peugeot 404, Mini Cooper, and Ford Escort for over 20 years. However, Nissan and their Datsun 240Z Rally Cars would be the first Japanese manufacturer to challenge the old guard and win. Nissan’s first overall win was at the Safari Rally in 1970, with the Datsun 1600 SSS Rally car driven by Edgar Herrmann and Hans Schüller. They repeated their success in 1971 in a Datsun 240Z rally car. Nissan would be the first manufacturer to win back-to-back victories in Over-All Victory, Class Victory, Team Victory, and Manufactures Championship at the Safari Rally. In 1972, Mitsubishi won with their new Lancer 1600 GSR, but Shekhar Mehta and Lofty Drews brought home the win again for Nissan in 1973 in a Datsun 240Z rally car. While East Africa is hot, dusty, and wild, Monte Carlo is a completely different kind of rally, teams start from nine different European cities for the first stage headed to Monte Carlo, from there the stages take the teams from the coast of the Mediterranean into the hills of the French countryside. The final stage is a 12-hour overnight race through the icy roads of the Alps. The ice and darkness make it one of the most difficult stages in the world of rally racing. The first year Nissan finished 2nd in class and fifth overall, in 1972 Nissan saw a podium with a third overall finish, and in 1973 the team finished ninth overall. It wouldn’t be until 1990 that a Toyota Celica GT-Four ST165 would bring an overall win at the Monte Carlo Rally home to a Japanese manufacturer. The Southern Cross Rally ran from 1966-1980 and was held in New South Wales. Australia was an important export market for Nissan and the factory had been supporting motorsports since the mid-50s, so it was no surprise that the Datuns 240Z rally campaigned Down Under. The rally started in Hyde Park, Sydney, and followed the coastline towards Port Macquarie. The bulk of the stages were at night with just two daylight stages, the total distance of the race in 1972 was just under 2,000 miles. Dan White has an amazing album of period photos, including lots of great shots of the Datsun 240Z. You have to check out HERE. While Nissan 240Z never won the Southern Cross overall, in 1971, Datsuns took fifth and sixth overall, and in 1972, the team took first in class and second overall. 1973, the best a Datsun 240Z rally could muster was an eighth place overall. Nissan later dominated the Southern Cross from 1977-198,0, winning overall victories with the Datsun 710 and Stanza rally cars. Today, many of the original rally cars are kept in the Nissan Heritage Collection at the Zama Operation Center in Kanagawa Prefecture, Japan. The collection can be visited most days between 10 AM-12 PM and 2 PM-4 PM, and there are only 40 visitors at a time. You must make an appointment to tour the collection. Enjoy more photos from our visit to the Nissan Heritage Collection to see the Datsun 240Z Rally Cars below: Historic Photos Courtesy of Nissan Heritage Archives

Oh, and about that short rich spike when you blip the throttle on a downshift? I see that as your dampers working and doing exactly what they are designed to do... Provide a short term enriching of the mixture when the throttle plates are opened. Just like an accelerator pump would do.

Carbs do unusual things (and typically unwanted things) fully closed at high manifold vacuum. The typical thing the SU's do is go very rich though, not very lean. So how about you put a vacuum gauge on it and drive around a little with it connected? Maybe you are looking for a vacuum leak. And... Do you have the throttle opener device installed, connected, and working? It's only job is to prevent the carbs from doing unwanted things at very high manifold vacuums.

Thanks @Captain Obvious - little late is better than never I guess! But I did check the springs yesterday vs. a spare one I have and I checked the dampers. Both of the springs appear to be original and in good condition. They are the same free standing height as the spare one I have. I bought a carburetor rebuild kit from ZcarDepot a while back. The diameter of the brass barrel on the old dampers was not measurably different from the one of the new dampers that came with the kit. Interestingly, the barrel heights are shorter on the new dampers... and the distance they move on the stick is larger. And the new sticks don't have oil height marks. I choose to stay with the original dampers and springs. I changed the oil from straight 20 weight to 10W30 because I have that on hand and then went our for a few more AFR checking runs. Here is what I am looking at when letting off the throttle. This is cruising in 4th, then a rev match downshift to 3rd with throttle completely shut shortly thereafter for decel. From around 14.7 at cruise, when I blip the throttle to rev match, the mixture changes to around 12, but with the throttle plates shut entirely, after a second or so, the AFR starts to climb quickly, spiking north of 22. Unsure what that drop in AFR is at 9 seconds - I may have touched the throttle briefly. here is a lot of popping out of the exhaust during any overrun like the above. It seems odd that with the mixture looking pretty good under idle and cruise, and not far off under power that I am experiencing this. I will check for leaks at the carb manifold next, as maybe air is bypassing the carbs under high manifold vacuum conditions.

Obvious questions of course! ;)

Other than that anomaly in third gear, I think the numbers look excellent. My understanding is that you WANT to run a little rich at WOT, and from watching the engine experts on "Engine Masters", I believe that 12 would be great. In general, the it seems the desired conditions are: A little rich at idle (because engines never want to run at idle, so you reward their good behavior with a little more fuel). A little lean at cruise (because you can, and gasoline is expensive). A little more than a little rich at WOT with 12 being just about ideal (because the extra fuel helps keep cylinder temps down which helps prevent pre-ignition). I'm no expert, but that's what I've gleaned from listening to people who claim to be. Now that anomaly in third gear... That's concerning. I remember asking a bunch about fuel delivery earlier. And just to be annoying, I remember asking about dampers and springs earlier as well. Haha!! 😄

I’m looking for someone who may have a hand throttle cable. I would like to reproduce one but hoping that I could get some detailed pictures and would really like some measurement's of the outside housing length and inner cable length. Let me know if you can help….thanks

Thank you, yes that is what I was looking for

Is this what you're looking for? Here's a couple more pics

Thanks for the offer Cliff! I actually already bought a new set. I finally got the car up on the cubes on some dollies. It was a little sketchy but I got it up without dropping it Evidently the water pump on this engine is bad... :( I worked on the original door sills some today. They were pretty rough. I used the bead blasting cabinet with low air pressure and some crushed glass After that I used some glass beads on really low pressure to shine them up a little more. I found the location of the inner black sill cover by using a pick and locating the original screw holes. The new black covers only have three holes; the originals had five but I think I'll leave it this way for now. The screws are stainless and I polished them up before putting them in I also bought the speedo seals from Zcardepot and put those in yesterday. We'll see if that fixes it...

Are the original holes still present? I bought new ones and they matched the holes in the body. What measurement are you needing?

I have a set that I've never used if you need any measurements let me know. Any way these might be helpful?

I need some reference dimensions for where the door sills go on the rocker panel. Mainly the interior black one. Maybe use the rocker seam as a reference?

Hi Dave, I totally get that about the repairs. Here are a few pics.

I'm sure I could manage to do the necessary repair work on the scoop, although I'd prefer not to! @CanTechZ , if you could send a couple of pictures that would be great. @Yarb, let me know whether yours is fiberglass and what sort of shape it's in. Thanks to both of you for responding! I'd really rather have a used part than a newly manufactured one!

Since the very rich AFR at idle I am experiencing with the N27's is not acceptable, I decided to order some SM needles and give them a shot. A comparison: While the differences at each used station are "small", they are evidently quite large when tuning SU carburetors, as I found out watching How SU carburetors work parts 1 through 4 here: https://www.youtube.com/@ACDodd/videos Anyway, they were only $40 delivered, so not an expensive thing. I swapped those in last weekend and made a few more runs to collect AFR. Doing so, I saw some changes and made some new observations. First the plots: Idle: I am quite happy with that. 14.7 to 1 is stoichiometric. For idle speed, I think that would be ideal. But I think this is great. cruise: For the recording of cruising above, I was mostly on flat road holding the speed at an indicated 50 mph in third. My RPMs are now being recorded, but honestly, I don't know which to believe, my tach, or the LM2, as there is a notable difference off of idle. Generally, the LM2 is reading higher by as much as ~500 rpm. I plan to notate some speeds in gears and tach and LM2 rpm readings and compare with calculated info based on transmission and differential ratios and tire diameter to see which is more accurate. Again, for cruising, I like the AFRs I am seeing here. I do not notice any surging or anything out of usual when slightly lean by this much while cruising. It should be good for fuel economy. acceleration: Now, for acceleration, I am less pleased. The first steep rise is first gear. I think I pressed record just after the light turned green and applied full throttle in first, then shifted to second and applied full throttle, then shifted to third and applied full throttle - very briefly. My focus points are seconds 2-3 and 6 to 8 and a half. For those, I am in a steady state - full throttle - flat road. In first, the AFR is a bit under 12. In second, it looks like about 12 to 12.2. So, rich. What got really interesting is that when I shifted to third and again applied full throttle, the engine essential "stopped" as the AFR spiked up to north of 20. I suspect the float bowls went dry. I was able to repeat this a second time. So, I will need to investigate this further. Now that I have watched the video series mentioned above, I will plan out my next steps differently. I won't be messing with needles for now. I need to check the springs in the carburetor to see if they are original and in good condition. And I need to investigate my dampers. They may have too much wear. One of the indications that I have an issue with either the springs or the dampers is that (and this is with both the N27 and the SM needles), the AFR is going extreme lean on throttle off deceleration. It is worse with the SM needles - going north of 20. But it is bad with the N27s as well, going north of 18. Lots of popping out of the exhaust... Based on the info in the videos, that is either spring or damper.

I've got one that is in fair shape, It is FRP. It does have a few cracks and one of the studs is broken off half way down, but definitely still useable with a bit of repair work. Let me know if you would like some pics. I'm in BC.

So Driver’s side fiberglass. Let me put a magnet on it just to check. I have both left and right hand sides. I’ll check it out when I get to my shop today.

Indeed I do. I gave up on finding one used, and ordered one from MSA, who originally said they had one in stock, but a week later found that they didn't and are now forecasting 6-8 weeks to get one. If you have one, I'm interested!

Almost any condition will do. Just needs to be able to light up. The cheaper the better

Do you still need the scoop?

I had the thought that there is probably some patent literature about it out there and found one that describes a design whose purpose is to isolate the sound/vibration from the car body. It's translated from Chinese so makes for a weird read. In short, I think it stops the people in the car from feeling the vibration. Buzzy butt, probably. It's from 2008. https://patents.google.com/patent/CN201300772Y/en I tried to find a patent from around the Z time frame but patent searching is hard. I did find this though. Radar equipped cars in 1972. https://patents.google.com/patent/US3833906A/en

Thanks Alan, that was one of my suspicions for the reason but they changed the horn mounting to a steel bracket but mounted on a center rear stud in later years. So I wasn't sure... I have looked at them pretty closely. It is one of the parts I have considered reproducing. Because of the construction they are difficult to coat properly and they corrode badly because of the spaces between the plates. Not a complicated part to reproduce but they would probably be sort of costly because I would have to have someone cut me all the plates

As far as I understand it (and I've seen the same thing on several different makes of old cars) they act as a spring/damper, which has a positive effect on the sound quality and also insulates the mountings from high frequency vibration when the horn sounds. But they certainly have an air of late 1860s rather than late 1960s, so I empathise with your curiosity.