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The bastard Z that won't die.


CobaltFire

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A little background: I bought this car from my uncle when the number of problems exceeded his willingness to fix them. I paid the princely sum of $1000. The history as I know it is that it was previously a semi-serious race car in the San Francisco Bay Area as late as the early 90's, and it's been my uncle's Ratsun since. What I got is this:

 

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Fun Facts: the Vin is 74948 ('72) and the car was originally Orange. Other than that good luck. 

 

I don't know exactly what's on the car yet, but so far it's been like a treasure hunt. Items positively identified so far include a set of three Mikuni 44PHH's, a set of Hella H4 E-Code headlights (proper LHD ones), a four spoke Personal steering wheel, a pretty legit bolt in roll cage, strut tower bars front and rear, an E88 head with a 280Z block, and some Carroll Shelby 15" Minilites. 

 

I had no idea what direction this build was going, and that's what I went up there this last weekend for. I dug into the car a little, investigated the condition, where the rust is, etc. What I found is that the car as a whole is more solid than I thought, but the effort and expense of bringing it up to show standards isn't warranted. I can purchase a clean shell around here that needs very little for $5k or so, and given my time and the expense of panels that would be a wiser start. 

 

That said, keeping it a Ratsun is entirely possible, and that looks like what we will be doing. 

 

A side note: the car is located over 6 hours from me at my father's place. The upside of this is I have access to a lift, power tools, every type of welder imaginable, a rotisserie, a tow rig, and tons of space. I live in a condo where I can't even wash my car. Updates will be staged due to this, so expect no more than 1-2 a month if you end up watching this. 

 

First steps this weekend were to pull the intake and exhaust (exhaust is TRASHED). I got fortunate and found a 240Z header and exhaust to the rear axle for $100 in LA, right on the way up to my dad's place. Picked this up at a really nice old guy's place who restores Z's as his retirement project: 

 

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That solves that, though we haven't decided on the muffler yet. What's on it won't stay...

 

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Next up were the carbs this weekend. I got some rebuild kits from Futofab (real nice guy, shipped mine over the holidays) and pulled them this weekend:

 

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As you can see, I was poking around the front at the same time. I ended up figuring out that the lip on there was attached with 10 self tapping sheet metal screws to the bumper mounting area. It's a COVER for a stock Z lip, or something to that effect; it's not a full valance and it was mounting completely wrong. 

 

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Once I was finished I ended up with this to work on until next month:

 

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I'm also eyeing a few non-standard suspension and steering upgrades. I've got a few kinematic drawings and am taking measurements from a couple of other cars that have promising knuckles and steering racks that will take minimal work to swap in (GC/GD Impreza and E46 BMW; currently the E46 looks better for a couple reasons). This is for both front and rear. Once I get a hold of some struts from a junkyard and make a few measurements I'll see if it's feasible. The main goal of THAT is that it's cheaper, easier, and better to run the newer stuff from one of those than old Z stuff if you only need custom control arms, steering rack mounts, and axles. 

 

Other things on the planning list are a swap to a 5 Speed from a 240SX (it's got a 4 Speed), an STi R180 (torsen, 3.90) diff swap (the LSD in it is done, and the diff grinds), and some fender mirrors (sport bike mirrors with integrated turn signals). 

 

Input and comments welcome!

 

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01FEB2017 Update:

 

I've been pretty busy with work, home renovations, and other stuff, but I made a little progress I thought I'd note. I got one of the carbs apart, and holy crap was it nasty. Varnish, tar, you name it. I couldn't even get it apart without risking damage to it it was so glued together.

 

So I took it apart as far as I could, then got myself a heated ultrasonic cleaner!  

 

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I've run it through there with some gun parts cleaner for an hour at 140F now, and it's freed up considerably, as well as most of the stuck pieces falling off. I've been able to remove the tarred up and gummed stuff for the most part, and will start in with a toothbrush soon. I'll have a results update in the next day or two for this carb, with a comparison to a still nasty one.

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240sx trans is pointless when a 280zx unit is a bolt in affair with everything lining up properly.

I'm not sure we have the same definition of the word "pointless". 

 

To me it means that the one being described as superior (280ZX) has every advantage and then some of the one being contrasted to (240SX). Given that the mods required to mount the 240SX transmission are required for it's advantages (newer metellurgy, larger shafts, larger gears, widely supported, easy to obtain parts, newer transmissions with fewer miles available, all at a similar price and with a larger supply), and that those mods are easy and cheap (clearance 4 speed's bellhousing for larger shafts, shorten driveshaft 2" for the longer body)  I'm not seeing how it's "pointless". 

 

Look, I'm the new guy here, great. But we each build our cars OUR way. You don't think I'm doing it the wrong way, cool. My way probably doesn't work for you for some reason I can't fathom. You've got your own to do your way. Telling me that a mod I'm about to do is dangerous, costly, etc. because you've seen it before is appreciated. Especially if there's an option I missed. I'm here on this forum because I've seen a lot of good info, and I think my car fits the theme of this place. Part of that theme is building it my way, based on my goals, experience, and parts/equipment on hand. 

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Feel free to spend extra time, money, and effort for a trans thats not really any better, more power to ya. The zx trans will hold more power than your triple carbed l28 could think of making and has better suited 1st, 3rd, and 5th gear ratios for a straight six...but I have no idea what I'm talking about.

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Optimal for what? Ka makes power at different points than an L. Cars weigh different amounts which affects how they accelerate. Rear gearing has huge effect on total performance, changing how each of the transmissions gears feel. You decide what is "optimal" for how you plan to use it.

 

Most all the gear ratios are available online with only a little research.

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Feel free to spend extra time, money, and effort for a trans thats not really any better, more power to ya. The zx trans will hold more power than your triple carbed l28 could think of making and has better suited 1st, 3rd, and 5th gear ratios for a straight six...but I have no idea what I'm talking about.

This is good info, but I'll have to look it all up. Dyno time is on the list as soon as the car runs, so before trans swaps (unless it simply doesn't work). Need to get a baseline and see where we are really at. 

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Optimal for what? Ka makes power at different points than an L. Cars weigh different amounts which affects how they accelerate. Rear gearing has huge effect on total performance, changing how each of the transmissions gears feel. You decide what is "optimal" for how you plan to use it.

 

Most all the gear ratios are available online with only a little research.

Thats the big reason we want a wideband o2 sensor, programmable EDIS, and a dyno run at the end before we start swapping parts. Whether that happens, we will see. 

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71b 71c

1st 3.062 3.321

2nd 1.858 1.902

3rd 1.308 1.308

4th 1 1

5th .745 .759

 

 

 

L28 has a flatter curve with max torque coming from around 2k rpm to nearly redline, ka24de max torque around 4k rpm and much more pronounced curve-especially in lower rpm. Think about it, the 71b is built for an l28 curve and 71c for ka curve...it's not rocket science. I guess it depends if you're a stoplight warrior or you actually drive your car. It's not like 1st and 2nd are too tall in a 71b, a stock l20 will pull that gearing fine, but with the smaller gap between 2nd and 3rd you will hit 3rd and accelerate better with the b's close ratio. 5th will give better cruise rpm as an added bonus. All above benefits have to be applied to the cars purpose 71b gearing is most suitable for a car driven on the street or road course type track with proper rear end gearng for the situation. 71c gearing seems more compatible with wannabe drifters, drag racing, autocross etc. Again, it's just my experience and fairly informed opinion speaking.

 

 

Edit: post was in response to cgraves

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Optimal for what? Ka makes power at different points than an L. Cars weigh different amounts which affects how they accelerate. Rear gearing has huge effect on total performance, changing how each of the transmissions gears feel. You decide what is "optimal" for how you plan to use it.

Most all the gear ratios are available online with only a little research.

Great point, with the sx weighing more and having taller diff gearing, the short lower gears make sense with a 71b for it's intended application.

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71b 71c

1st 3.062 3.321

2nd 1.858 1.902

3rd 1.308 1.308

4th 1 1

5th .745 .759

 

 

 

L28 has a flatter curve with max torque coming from around 2k rpm to nearly redline, ka24de max torque around 4k rpm and much more pronounced curve-especially in lower rpm. Think about it, the 71b is built for an l28 curve and 71c for ka curve...it's not rocket science. I guess it depends if you're a stoplight warrior or you actually drive your car. It's not like 1st and 2nd are too tall in a 71b, a stock l20 will pull that gearing fine, but with the smaller gap between 2nd and 3rd you will hit 3rd and accelerate better with the b's close ratio. 5th will give better cruise rpm as an added bonus. All above benefits have to be applied to the cars purpose 71b gearing is most suitable for a car driven on the street or road course type track with proper rear end gearng for the situation. 71c gearing seems more compatible with wannabe drifters, drag racing, autocross etc. Again, it's just my experience and fairly informed opinion speaking.

 

 

Edit: post was in response to cgraves

 That is interesting. The 71b 1/2 is similar to the (expensive) close ratio gear set that you can get for the 71c. It also lets you run deeper rear gears without throwing first away. I may have to rethink. 

 

The issue then is finding one in good condition for a reasonable price, but I'll start keeping my eyes open. 

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That is interesting. The 71b 1/2 is similar to the (expensive) close ratio gear set that you can get for the 71c. It also lets you run deeper rear gears without throwing first away. I may have to rethink. 

 

The issue then is finding one in good condition for a reasonable price, but I'll start keeping my eyes open.

 

You want '81-'83 for the close ratio gearset. The '80 model has the same 1-4, but a .773 5th. Best bet to find one is a wrecking yard. I got one for $200 a while back that was in excellent shape.

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So I've had a few inquiries about buying parts off of this car if I change directions and it's given me pause. I'm honestly not really attached to the drivetrain as it is, and would be fine with swapping it for something else. I'm just not familiar with the market. That said, I'm now looking into a reasonable price for selling off my current drivetrain and moving forward from there. My question to anyone reading this is this: Am I better off selling the drivetrain as a running one, or breaking it up and sending it on it's way that way? I'm not averse to pulling the head, cleaning it up, etc. to sell it. I also have no real idea what everything is worth. I know the Mikuni's can be pricey, but I've seen a pretty wide range of prices. I have NO IDEA what intake manifold is on it, and I can't find a picture anywhere of one like it. If anyone knows that would solve that mystery for me as well.

 

Regarding what drivetrain I'd install, my current thought process says SR20DE (non-turbo). Reasonably cheap, light, fun, etc. There is also the Autech version that I'm quite interested in for about 2.5x the price, but it has all the goodies you'd want from the get go and is factory rated to 200HP with a 6 speed. If I could get anywhere around $3k for the drivetrain I'd seriously consider going for the Autech motor.

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I'm not sure about a price for the mikunis but keep in mind you can buy a brand new set of triple webers+intake for $1650 BUT I'm not sure how that would impact the price of the mikunis.

 

As for the engine and trans I've bought a bunch of L28s for $300 with no trans and I sold my L24+trans with bad piston rings for $300.

 

If you do decide to sell the mikunis I'd be interested to a degree.

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Just tossing this out there. I have a 280zx 5 speed mounted to a ka in my 510.  I had to clock the motor to be perfectly straight up and bend the shifter so it was not stabbing me in the leg. 

 

If you stick the ka trans on the l28 you going to have to fab a trans mount and its going to be at a funky angle. you will have to heat and bend the shift rod.

 

Can be done... I did it my way because im a cheap ass.

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I think you can just swap bellhousings. The Z22 transmission bellhousing will match up to that 280ZX 5-speed and also to the bolt pattern of the KA24. Then you'll be clocked at the correct angle.

That's what I understood to be the case.

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I'd vote on restoring it to its former semi serious race car glory with those triples. Something about that nostalgic feel/sound you can't replicate with a modern powerplant. Nice project btw, definitely following

I keep going back and forth, but that's what I'm considering at this point. Still in process of rebuilding the triples to start it up and see how it runs. I've never rebuilt carbs before, so it's slow going as I don't want to screw anything up.

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For anyone watching this topic, I have a question: Is there a bracket or something to support an airdam? There's NOTHING under there for this car, and I don't know these cars. If there is a bracket, is there anywhere I can get one?

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