Project Hakosuka: Now Going.

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After a quite a long period of firstly waiting for the car to arrive from Japan, and then a seemingly-even-longer period of fixing the various issues that the car came with, it was with a certain trepidation that I fired her up and gingerly backed her out of the garage under her own power for the first time.

Now that all the various mechanical issues were sorted, and the electrics were all working again, I put everything back together again in the engine bay:

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And the interior was converted from a mess of hanging wires back into something resembling a normal dashboard:

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Those readers who’ve been following the buildup over the past mth or so will know that I’ve had quite a few attempts at tuning the Webers without actually getting it right! But now that the car was ready for the road, it was time to have a last go and this was the result:

Although I think it still isn’t perfect (and the driving impressions below suggest that there is some room for improvement) I think this is the least-worst result I’ve got so far :) It idles steadily at 1200rpm, starts easily, gets off idle quite cleanly and doesn’t diesel-on like it did before. Good enough as a starting point I think.

But one last job I did before rolling her back out of the garage was a little mod I was saving for later. Now, the engine was upgraded to a 280ZX electronic distributor in Japan, which isn’t compatible with the stock GC10 tachometer. The stock tach relies on an inductive loop principle, which assumes that you have a flow of current through a set of old fashioned points in the distributor. The later electronic distributor doesn’t have this so the stock tacho is dead.

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So I did a mod which has proven to be surprisingly divisive. Most modified Hakosukas you see in Japanese magazines are fitted with Autometer tachs, and of course Autometers have been popular with the 240Z guys in Japan and everywhere for a very long time. So I removed the stock tach and fitted an Autometer 3’3/4 tach in its place.
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The Autometer slotted snugly in place, and to my eyes, looks subtle and very appropriate. The font and colours etc are more oldschool than say a modern Defi gauge, and I like the fact that it sits deep in the instrument cowl, and you don’t really notice it unless you’re sitting in the hot seat.

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But like I said, it’s been quite a divisive little mod in that some people are so upset about it that you’d think that I’ve just ruined the whole car :) Of course it’s 100% reversible should I want to return it to stock in the future, but I guess some were disappointed that I didn’t go for a JDM brand instead. But if it’s good for Hakosuka guys in Japan then it’s certainly good enough for me and I think to drive the car without a working tacho would have been a disappointment. After all this work I wanted the car to be as “finished” as possible when I hit the road for the first time.

And with that….I fired her up and drove her out of the garage for a quick wash!

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The next day….I had an appointment at an inspection station to get the car certified for road use, and so it was hugely nerve wracking to take the Hakosuka out onto morning rush hour traffic, a car that was pretty green and unproven when I first got it a mth earlier, and a a car that I had only ever driven up and down my driveway.

But I need not have worried. The car sat happily in peak hour gridlock with the water temps holding steady between 70 and 80 degrees, and she didn’t stall, smoke or eat her plugs or get sucked into a wormhole or anything like that. To my relief, it’s a very solid, tight car with no rattles or squeaks and I have no doubts about being able to drive it anywhere now. The downsides at this point are that the suspension and brakes are simply awful.

The suspension is soft and way too low (more of this anon) and in fact is resting on the bumpstops at the front, so is very bouncy and pogo-ey as we negotiate Sydney’s bumpy roads. Not confidence inspiring at all, and the shocks also seem to be quite worn. But even less confidence inspiring are the brakes. The pedal goes a long way to the floor before anything really happens, and then in that last centimeter of travel, it’s a fine line between stopping safely and locking up the front wheels. This is usually the symptom of a worn mastercyl, so I suspect that the rebuilt master cylinder may be the culprit, so I’ll give the brake shop who did the job a call. Old cars are reknown for poor brakes, but my old 63 Beetle had much better brakes than this, so I think something is definitely amiss.

On the good side, the engine has plenty of power even though it’s not quite 100%. Nothing smokes or rattles and oil pressure is a steady 1.2bar at idle, and the sound from the Webers under full song is simply unbelievable. Give it more than 1/2 throttle and you get the Italian National Anthem being played at deafening volume out of the Weber carbs and it’s a wonderful thing!

The response at low rpm is quite fluffy however, and the powerband hits a real brick wall at about 5000rpm so the powerband is a thick slice of torque between 3000 and 5000rpm. The low rev response is due to the 280ZX not having enough static advance. Big carbs and big cams need to have about 18~20 degrees of advance at idle, but the 280ZX distributor has 18 degrees of (rpm based) mechanical advance built into it, so if I set it up with 20 at idle, then I would end up with 38 degrees of advance at high rpm which I think would be too much. So the current setup is 14 degrees at idle, which translates to 32 degrees at redline, which is not optimal for low rpm running but is safe and won’t hurt the engine at high revs.

I have some parts coming from Japan however that should address this issue so watch this space. As for the power tailing off abruptly up high, I think that is something that I won’t be able to diagnose properly until I get the car on a dyno. At the moment the car is stable and driveable but feels a little out of sorts and you get the feeling that there are just a few tweaks that are holding it back at the moment, and once those are sorted the engine will really be unleashed.

As for the registration inspection, well we didn’t pass. But there are only 5 items that I need to address and we’ll be legit. All of the electrics checked out, and rather surprisingly the hot, big cammed and multiple carbed motor actually PASSED the pollution test (maybe that tune isn’t so bad after all)! But the issues I have to fix are:

1. The car is too low and needs to be raised 25mm at the front. The sump is only 7cm off the ground, and given the poor driving characteristics of the current setup, this is a problem that I am looking forward to fixing. I think I’ll remove the front struts, and convert them to coilover so that I have height adjustment, and also put in a Koni insert while I’m at it. Changing the rear shocks should be a quick job though.

2. The car is slightly too noisy. The legal limit for a car of this age is 96dB and the Hako tested at 95.7dB. While it’s under the limit, it’s borderline and technically I have to pay for a second, drive-by noise test to reconfirm that the noise level is legal. However the engineer at the inspection station suggested that if I put the K&N air filters on the car the next time I have it tested, it would probably take the edge off the noise level enough to pass without a drive-by test.

3. Inoperative horn. Believe it or not, one electrical item I didn’t check was the horn! But I guess since I mainly work on the car at night maybe I subconsiously didn’t want to wake up my neighbours!

4. Fit rear seat belts. I fitted front seat belts but rear ones are required for a car of this age too. I believe that the holes and mounting points are already in the chassis, so this might be an easy mod.

5. Fit a stalk buckle to the front seat belts. The mounting point for the lap part of the front belts is very far behind the front seat on the trans tunnel. And the longest buckle on a stalk I could find from an Australian supplier was 450mm, which is about 100mm too short. But the rules say that the buckle can’t be on fabric webbing, since the movement of the seat may abrade the fabric over time. So the answer is probably to bite the bullet and redrill new mounting holes further forward on the trans tunnel so that I can use the approved stalk mounted buckles. Motorsport shops sell FIA-approved harness plates with a seatbelt sized nut welded to a thick steel plate, and I can rivet one of these to the inside of the trans tunnel as the new mounting point, so that shouldn’t be too much of a headache.

And that’s it! All I have to do is address these 5 things and I will get that precious piece of paper that will allow number plates to be issued to me. For an old modified car I think I got off very lightly and I think that anyone will agree that the modifications they want made are quite reasonable. After having driven the car properly for the first I’m more relieved than excited I think. The car still needs a lot of work before I can really enjoy it and I think the excitement will come later when the car is in a more refined, finished state.

The build continues…but hey…it runs!

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14 Responses to Project Hakosuka: Now Going.

  1. derux said:

    Waiting to see what you do with the suspension. I am in the same boat with my car. Thanx for the wiring file..

  2. twincammy said:

    ive been watching this project over the last couple of weeks. you must be so happy to get to drive your new ride. i can empathise, after buying a car myself from japan last year.

  3. Speedstar said:

    congratulations!!! have been following the build since day one, very exciting stuff, will you show the car? I would imagine it would freak a few of the boy racers out lol!

  4. panda said:

    ^ dunno what happened there, but anyway i lurrrrv this car!
    i’m mainly a honda man and i don’t even follow honda builds this closely

  5. DJLotus said:

    Congrats on getting her running! My 510 should be back on the road in the next week or so. Not as cool as a Hako, but a cool little car nonetheless

  6. MrHijet said:

    Gratulations!

    To be honest: you were extremly quick. I never thought you will make it to this point in just one month. I would never ever get it done in that short time (okay I am working 50-60 hours per week and could do it at the weekends only).

    Cheers,

    Daniel

  7. ultraman019 said:

    Nice build! I’d rather have something working and aftermarket, like your tach, rather than have something original but wasnt working.

  8. Arnel said:

    WOW look at what I’ve miss… sorry I haven’t been on line in a while, great looking hako Kev looks a lot better than my car by far. Man so much to read but yup almost the same story when I got mine. But hey great job, looks like you’ve got every thing figured out. Love the engine bay its so clean….congrats.

  9. kai said:

    *jealous* hehe nice going!

  10. Ethereal510 said:

    Loving the documentation or this project man. Talk about a dream come true for like 90% of the ppl who view this website!

    keep up the great work.

  11. zcar4me said:

    Congrats man!
    She sounds great idling… can’t wait for in car video with Webers wide-open!

  12. Kev said:

    Thanks for all the kind words guys :)

    And that’s some high praise comin from you, Arnel! As someone once said, you know my car ain’t all that…. :D

  13. importjap said:

    Nice work mate, well on your way now!