TR's 260z L28 Build Thread

[k14]

Thanks for the info on the calcium carbonate bath. I'm going to give that a try

 

Hope to meet you at Branson Z Fest, you are going aren't you?

[TrumpetRhapsody]

N/P

 

I'm hoping to, but the whole Mother's Day weekend thing is a curve ball. She puts up with all the car stuff year round, so she wouldn't be thrilled about it on her day. We'll see though, I'd sure like to.

[TrumpetRhapsody]

Alright well i went and picked up my valve cover gasket, front calipers, and front brake hoses today at autozone. I also grabbed a cheap fuel pressure gauge to make sure I'm getting enough flow at high rpms, some e and c clips for various things, and the inline fuses I need for the elec fan and custom run fuel pump switch.

 

I also swung by Bumper to Bumper and grabbed some Rust-Mort and a quart of black epoxy primer and hardener. Hopefully this weekend I can at least get the bare metal coated and primed. The rest of the body comes later. First I have work on a few dents and get rid of the heat baked paint flaking off in the back.

[TrumpetRhapsody]

It moves! I finally got to drive my Z, and I was ecstatic.

 

After having to track down the mail carrier (didn't bother coming to the door, just honked and left, $*#$), I got my throttle linkage and ballast resistor. I got the front calipers and soft lines, inline fuel pressure gauge, and fuses for the fuel pump and elec radiator fan installed, and drove it around the driveway. I got a couple of quick 1st to 2nd shifts, and it was awesome. I wasn't even winding it up much and it still felt pretty quick (plenty of adrenaline coming into play though so...). I took a vid, so I'll edit and post that when I get back to broadband.

 

I'm thinking about taking it on the blacktop tomorrow for some 45mph test runs, so I'll take some video of that too. I'll also make a stab at adjusting the valves (now that I have a gasket just in case), and see if I can neutralize and primer over some of the major rust areas.

 

[TrumpetRhapsody]

Well I didn't get around any bodywork this weekend, but I did get to drive it on the blacktop.

 

I got all the valves adjusted like they're supposed to be (I think?). One of the cam lobes is pretty worn pretty for some reason... not sure what that's all about.

 

I'm about 60% sure I got my coolant leak around the thermocouple stopped.

 

And then there's the drive. Probably was a mistake after all this rain, I got mud EVERYWHERE. It sucked with no fenders, mud just everywhere. Oh well, it was fun and I got a video.

 

 

A couple of problems though:

 

I need to check my tranny and diff fluid. I felt alot of vibration though the shifter, and when decelerating there was this friction noise, didn't sound normal. Further investigation is necessary...

 

Also I'm getting some misfiring when the engine is under a load. Heavy accelleration, especially around 3500rpm (never was able to get much higher), caused the car to buck and misfire. I think these carbs are going to need a rebuild if I expect to use them on the road.

[TrumpetRhapsody]

Alrighty, well as of today I have on the way my 240z xenon air dam with signals and front & rear bumpers. The front bumper has a ding or two, but I think I did pretty good on the package deal, so it'll buff out.

 

 

So the list of things to do has shrunk to:

 

Neutralize the rust, possibly leave repair for later when it's in fayetteville

Put the fenders and hood back on

Modify and attach the 240z parts - i.e. bumpers tail lights etc

Sand and put the body in primer

See if the vaccum advance is sticky on the dizzy

Work on getting the carbs happier - adjust mixture, maybe check the float bowls

Re-check the valves with the engine hot

Weld my exhaust together

Check and replace the diff and tranny fluids (bought some Lucas 80w-90 gear oil today)

[Daeron]

your vibration/noise problem might well be an issue with any of the U joints in the drive shaft or half shafts (more likely driveshaft) OR it could be a bad throwout bearing. Changing the trans and diff oil is never a bad idea, but if you do so and it doesnt go away then I would check any U joints for any slop, and if they seem fine then it might be worth dropping the trans (or pulling the engine if you think thats easier?) to get a good luck at that throwout bearing. Never hurts to know where your clutch is at, either.

 

The carburetors NEED to be properly synchronized and tuned.. there is a WORLD of difference between a Z car with SU's that run OK and SUs that are REALLY properly tuned, and its less than $100 worth of tools to do it right. Look up SU tuning and you can find more information from someone who knows more about it than I; carburetors are something I haven't handled on any of my own cars, just Z-cars belonging to my dad, uncle, or one of my brothers. Because of that, my knowledge is theoretical, or "asymptotic" if that makes sense to you.

[TrumpetRhapsody]

That's a good idea, I'll check all the joints as well.

 

I put the motor and tranny together and in myself, so I've seen the clutch and bearing. Although, I wouldn't have known if the bearing was bad or not , so if it's still giving me problems I'll drop the tranny and check it.

 

I'm trying to spend as little on the carbs as I can, but we'll see. They're only to tide me over till I get the L28et I have put together and swapped in with Megasquirt. They just need to run decently, not perfect, so I think I have them pretty well sync'd for my purposes. I have a feeling I'm going to need to rebuild them with new needles and jets though, but that $180 hurts for just a temporary setup.

During the cleanup stage I also um... might have... dropped a piston and bent the crap out of the back carb's needle, then straightened it back , but the pistons don't stick at all, and it looks very straight watching it go in and out. If it keeps giving me problems I'll break down and buy the rebuild kit from Ztherapy .

[Daeron]

the bearing is bad if it spins with any roughness whatsoever, or if it makes a grinding/rolling noise (as opposed to an un-impeded rolling noise) when rolled in your hand; when in doubt, replace it.. but, like I said, may as well wait until a U-joint inspection and changing your oils before jumping to that conclusion, since it IS such a PITA.

 

Regarding the carb tuning, I wasn't realizing that the SU's were a temporary solution when I went into that.. I was just trying to convey how easy it is to troubleshoot a problem that can sound like yours, and presume your carbs are "good enough" only to find months, or sometimes years down the road, that it was the carbs the whole time. As long as you are aware of that possibility, then you are clear enough.

 

Hope I have been of some help, and good luck.

[TrumpetRhapsody]

Yep, and thanks Daeron!

 

Now then...

OIL PUMPSThe 1981-83 Turbo 280ZX came with an oil pump that put out more pressure and volume than standard oil pumps. The automatic trans 280ZX turbo version has a higher CC volume per rotation than the manual trans pump. The reason is that the auto trans cars came with an oil cooler and needed the extra "ummph" to supply to it. So upgrade your L series motor to a turbo pump and pick up better lubrication, and get your oil needle off zero. Mine hovers at about 15 psi at idle and goes up to about 65 at speed. If you're lucky you can pick one up in the junkyard for next to nothing. [/size']

Hmm, get my oil needle off zero eh? So maybe it's not just a poor PO engine rebuild giving me near 0 oil pressure at extended periods of idle...

Maybe it's... normal??

 

EDIT:

OIL PRESSURE GAUGE READS LOW AT IDLE

If your oil gauge starts reading zero at idle don't freak and start tearing into the motor. Everyone always wants to blame the oil pump, but I've never heard of one wearing out on a Z. It's nearly always the oil pressure sensor on the right side of the block. Nissan makes great motors but after 30 years these little sensors lose their abilities at low pressure. About $20 to replace. There are 2 types though: bullet lug connector (early Z) and spade connector (late Z).

Also, if your engine has a lot of miles this can be caused by large bearing clearances due to wear. The pressure goes up while driving but will be very low at idle. Instead of rebuilding the motor, install a 1981-83 turbo 280ZX oil pump and pick up some pressure.

W00t. I'm betting that's my problem. (the former, hopefully not the latter)

I've got a L28ET block laying around, I guess I could borrow its turbo oil pump too, at least until I decide to swap the motor in.

[TrumpetRhapsody]

Woohoo! Got my body parts! Poor Regal, workhorse again, lol.

Thanks 1 tuff z!

[dsommer]

Hmmm wonder if a front fender will fit inside my Infiniti???

[TrumpetRhapsody]

Lol, I doubt you'd want to dave. You're seats are too nice, a scuff would be... unfortunate.

 

Today's Progress:

 

Ok so I'm officially an idiot. So yeah that weird feeling and noises I was concerned at from the transmission on the first drive... No fluid. The tranny was bone dry. I sure hope I didn't kill it. I put 64oz of Lucas 80-90w gear oil in, and it still lacks about 1/4 inch to fill it to the fill plug (knew I should've bought another one).

 

I checked the plugs, and the front three looked to be running lean, so I richened up that carb one notch, and the back three varied. I also gapped them down from .040 to .035, and it seems to like that better. I re-sync'd the carbs by ear, and was able to get it to free-rev up to 6,000, which was a first. I'd been too skiddish to rev it that high till now, but it felt good.

 

I got my shift knob and rubber boots installed. I had to pull the center console to get the rubber shift boot put in right, and I had to remove the slave cylinder to get the stupid tranny one in right, but now they're both in and I officially have a shift knob. Gotta be the most satifsfying progress yet... a shift knob.

 

I'll take it for another spin tomorrow and see how it feels.

[TrumpetRhapsody]

So after filling up a gatorade with fuel overflow today, I decided to rip apart the float bowl on the back carb. After making adjustments... twice... it no longer spews fuel out the overflows. Both carbs do still drip fuel out the venturis after the car is turned off, but all I have to do to avoid that is turn off the fuel pump and let the car run down the bowls a little. No biggie.

 

I'll take a test drive after lunch, then get to work on the rust so I can put the fenders back on and mock up the front end tomorrow.

[TrumpetRhapsody]

Woohoo! Just got back from the drive, and it went great! Two things though: Anytime I tried to shift into 5th it popped right back out, looks like it's shot, great, and my battery tried to escape a couple times, so I'll need to get a tie down strap for it.

 

As far as driving, it felt awesome, but I need to work on the throttle. It's really stiff right at the beggining, then loosens up exponentially, so it's really hard to only barely give it any throttle. Also the front carb's linkage is still sticking open a little and not letting the engine rev back down. Thought I'd fixed it but I guess not. The tranny seems to like having fluid in it, lol. Decelerating I still heard/felt a little bit of something, but it was MUCH better.

 

Now it's time to get to the real work, rust neutralizing.

[TrumpetRhapsody]

Well talk about a day that went from good to bad real quick.

 

I got the fenders set on the car, and found out that there are a few broken off bolts that will have to be removed, and that I'm missing the ones that attach the bottom. I also tested out the headlights, which don't work except on bright (not even that bright really).

 

I pulled the car back into the garage, and wondered why it wasn't sounding right. I noticed I had left a papertowel plugging the back carb from when I was cleaning up the inner-fenders. When I pulled it out and started it back up I noticed something ticking quite noticably from the valve cover region.

 

I pulled off the valve cover and the #5 intake lash pad had come off. No idea how that would've happened, but I got it put back on and re-adjusted the clearance. When I went to torque down the valve cover, the back right bolt snapped off, and the one in front of it stripped out. Mind you I was barely tightening them.

 

So that's where it stands. After all that I've lost the heart to work on it anymore tonight.

[TrumpetRhapsody]

Well after eating some dinner, I felt a little better about it, and went out to survey the damage.

 

I got REALLY lucky. It broke off with enough sticking out for me to grab with some vice grips, and I was able to get it out pretty easily. The stripped one I'll have to address later. To be honest I think it's been on its way out for awhile, and I just pushed it over the edge.

 

Here are a couple pics, one of the shift boot and knob, and the other two of the broken bolt.

[Daeron]

Good show on not giving up on her, nice to see that she rewarded your persistence.

 

Regarding the headlights, there is a common relay install procedure that takes the switching load off of the stock wiring and headlight switch and that usually fixes all your headlight problems; you can search for the TechTips page that Blue posted (I know there is a Z-specific explanation there) or you could go to http://www.ultimatesubaru.org/forum/showthread.php?t=74632 and read a general purpose relay install guide that I wrote up on my Subaru forum. I don't have the link to the "Z headlight upgrade" write up anywhere handy, and my write up was very broadly oriented.. but you ought to be able to figure out how to do it from either.

 

I have heard people SWEAR by various transmission oil cocktails or additives; the simplest is to add a quart or so of ATF into the oil, run it for a hundred miles or so, and then drain and refill.. There are a few different commercial products (GM Synchromesh, among others) that amount to about the same thing, but are labeled for use in transmissions. I don't know if it will bring back your fifth gear or not, but from what I hear it usually does wonders for a sticky, old gearbox that could otherwise get scrapped or rebuilt. My brother swears by Synchromesh, but its PRICEY.... so maybe try a little ATF flushing first, and see if that wakes fifth up at all?

 

Regarding the throttle.. http://www.zhome.com has a write-up about the throttle linkage right at the firewall, and setting the relative angles at that joint where the up-down motion from the pedal gets rotated into the motion of the carb linkage.. maybe that will help your problem there?

[TrumpetRhapsody]

Thanks for the tips Daeron...

 

Yeah i've been up at the shop for the last 3 hours or so trying to track down the wiring. The first thing I did was the combo switch cleanup procedure (found via search at some point). It wasn't bad enough to be causing a problem, but I'm glad I did it. I'm actually blowing the 15A fuse for the dash lights, low beams, and running lights. I tested for continuity and I'm getting a complete circuit from ground through the green/white stripe line that supplies positive to the circuit. It's pretty obvious I have a short somewhere, which is wonderful, lol.

 

I was wondering if synchromesh might be worth a try. I'll do some reading. It looks like I'm slowly loosing oil out the front seal, so I'm probably going to have to drop it and replace that anyway at some point. That explains the tranny being dry when I got it though.

 

Thanks for the lead, I'll search around over there for that writeup.

[TrumpetRhapsody]

Another weekend of work concluded. I didn't get as much done as I wanted, nowhere close, but I did get some important stuff done. Some ups and downs though...

 

Like I mentioned before, I adjusted the back carb's float and cleaned up the needle valve. Now it no longer spews fuel out the overflows. The carbs still drip fuel out the throats after you turn the car off and there's pressure in the lines, but all I have to do is turn the pump off before the car and let it relieve the pressure. Good enough for now.

 

Instead of starting body work I tore into the electronics, and figured out that I have a short in some of the wiring. Finding it will be difficult, fixing it is probably going to be nearly impossible, I'm not looking forward to it.

 

Today we also got my exhaust welded up. The 2.5" pipe was cut for a turbo manifold, so I had to cut it shorter for the headers and weld up the flange. It took my dad and me about 5 hours to finally get it right. Unfortunately, in the process of bolting the headers back on I broke a stud and stripped out a bolt. Joy, more work for later. I didn't get to hear it run b/c of that. I still need to get the 3" adapter for the muffler and get them welded on too.