1976 Datsun 280Z - Boomer Spec Resto

In reply to classicJackets (FS) :

I just bought the STL from him and printed it myself, well worth it but if you have a motor out of the car already I'd just take some measurements and make my own

In reply to dcreech0 :

Sorry man I hadn't looked at this thread in a while, I'll shoot ya a text in a sec

Oh man its been a while since I updated this thread, guess its time to dust it off a bit. I've been a good bit busy with both this car, life, other projects, new job, new place, etc etc. But that doesn't mean I haven't been touching the Datsun! While I spent quite a bit of my time just enjoying the car (from Feb to around October I put almost 7000 miles on the car!), I've been doing some big things to the car recently (spoiler alert the engine has been out and the stock EFI is in the garbage).

In July after putting in the 5 speed I took the Datsun up to Nashville to visit some friends and hit some fun mountain roads. The car did pretty well minus some minor mishaps involving getting stuck in the rain while a windshield wiper flew off and having no headlights due to the wiring overheating from a build up of corrosion on the switch contacts and causing the wires to desolder themselves lol. But luckily a quick fix with some solder and zipties.

After this trip I decided my exhaust was a bit too janky and completely re-did it with 6-1 headers, v-band flanges, an O2 sensor bung for future plans, and just a single vibrant resonator. The straight pipes sounded sweeeeet but was a bit too obnoxious for me to drive regularly so I eventually ended up throwing a magnaflow straight thru muffler on which helped make it a much more plesant car to drive.

The fat exhaust tip was to try and help with the fumes (it didn't)

OSHA approved welding gear

Some noises: https://youtu.be/4ESiMRcylsM

After all that I hit another road trip in the car again in August this time to NC to hit the tail of the dragon! Some friends and I made a weekend cabin trip out there for a fellow GRMer's (mgfoster) bachelor party. Was an excellent time rockin straight pipes all through the mountains.

After that it was mostly just more riding around and enjoying the car.

Did some small things here and there like trying out a few different steering wheels or designing some small gauge plates

But eventually the disease struck and I couldn't just leave this car alone. I might have mentioned it before but this thing burns a LOT of oil (you can see it in the videos pretty well lol), like a quart every gas tank or so. I did a compression test and it was about 120psi across the board. Oil catch can didn't help, nor did a fresh PCV valve. My guess here is some worn oil control rings or worn valve stem seals or some combination of both who knows. Either way, to me it was time to pull the motor and give it a refresh. I've never done a bare block rebuild before so I also figured this is a great motor to learn on before rebuilding some more complex motors like I plan to.

DISASSEMBLY

So a little bit of fast forwarding here but this is basically the easiest engine ever to pull minus maybe the carb'd versions so boom here it is outside the car.

Suprisingly little grime for a 45 year old nissan engine. Tearing it down I didn't see anything obvious wrong with the motor, minus quite a lot of carbon build up on the pistons/valves. It does appear like someone has been in here before though as the Felpro head gasket on there was definitely not OEM.

And fully apart! Not too bad honestly for how old the thing is. Bearings weren't showing crazy signs of wear either minus some scoring on a few of the main bearings.

INTERMISSION

So obvious first step gotta paint the block. Can't be working on a busted lookin motor. I wanted to match the OEM baby blue but didn't feel like dropping 35$ on a pint of the paint from some seller on the internet. So instead I found out the VHT Pontiac Blue is a pretty close match so I drove around to 2 different NAPAs to pick up 2 cans and paid 24$. Snazzy stuff

In the meantime I basically spent all my time cleaning and cleaning some more and spending lots of money lol. Got the heads cleaned, decked, valve job'd, new stem seals locally for ~300$ which wasn't too bad imo. Very shiny.

Also did some inhouse machine work with a little dingus ball action to the cylinder walls. I haven't been measuring anything but there weren't any crazy lips and the bearings were standard size so we're doing this the sloppy way because its a tractor motor anyways.

REASSEMBLY

Basically just following the "How to Rebuild Your Datsun L series" book thats all over the place (except I'm ignoring the parts where he throws out the word 'measure'). Fairly straight forward stuff. I'm running standard size Hastings piston rings, Clevite mains, Tahno rods. The Hastings rings were a little funky, ring gap was measuring somewhere between 0.018 and 0.024 for everything which is beyond what the book calls for. Personally I have it on some decent authority that ring gaps for this application don't matter too much but I was a little amped up to be filing some rings. Guess we're just gonna run it.

While I was at it I also took some time to clean up my engine bay. Pretty nice paint under all the dirt in there! Also threw some rust converter on some parts of the rails that we're starting to see some surface rust.

EZ part was done lol

FANCY EFI

As I mentioned previously the stock EFI was now in the garbage (well actually I'm selling it off on facebook but whatever). I'm running a RusEFI Proteus, a full-featured open source standalone ECU developed by also a fellow GRMer! Will hopefully allow for some future power mods and much nicer running, economy, emissions etc.

I'm building my wiring harness from scratch using a universal harness I had lying around from an old MS3 install. Running all the wires was pretty straight forward as this is gonna be a pretty bare bones install (no idle controller, single crank sensor no cam). I'm trying to use as many modern components as I can. Basically think anything off an LS lol. Running junkyard LS ignition coils, GM MAP sensor, GM IAT. Running the factory CLT sensor because I didn't feel like tapping it for a different sensor and its a pretty simple one anyways. For injectors I was hoping to get away with running some free 5.3 LM7 injectors but unfortunately they do not fit the adapters I bought so I had to nut up and spend coin on some fancy Deatchworks injectors. Oh well it'll be nice having injector data for once. 

Send Cut Send coilpack bracket I designed, need to remake out of some thicker material for sure.

So many wires...

Nice little amazon fuse/relay box

Spaghetti monster harness

Also some more custom sensor work: the factory TPS sensor is just an on/off switch. Luckily the key'd shaft fits a more modern Nissan unit, so a $3 send cut send adapter and I now have a 300ZX TPS attached

Also of course since these were dizzy cars factory, there is no crank sensor. Lots of ways I've seen people do it but they all seemed a little convoluted to me or had a few aspects I didn't like (like using a portion of the crank pully thats bonded with rubber to attach a trigger wheel or using a Jeep sensor off the dizzy shaft). I took a scan of the timing cover with my phone and measured up my crank pulley to come up with a solution.

\

I'll used a 3D printed tube to align the laser cut trigger wheel to the pulley where I can then just weld it on. Ez 5 minute job, sensor gap is designed for 1mm so should be plenty of clearance in case of any small runout.

Also took the opportunity to ship my balancer out to Dale Manufactoring to have it rebuilt as the rear pulley looked like it was ready to fly off lol.

The sensor bracket is 3D printed using an SLA resin printer out of some high temp Formlabs resin with a heat deflection temp of 238 C, should be able to withstand an engine bay environment though I am worried a bit about it being brittle. I plan on eventually making it out of aluminum.

And thats basically where I am right now. I've made some more progress on the harness though I haven't taken pictures. I lost my connectors to the ECU so waiting on those to arrive, also waiting on injectors and new adapters as I am a doofus and bent them during the first install. Fingers crossed I'll hear it run this week!

How does one scan from phone and translate to solid software?   I would love to scan a few things and get them into Solidworks.

akylekoz said:

How does one scan from phone and translate to solid software?   I would love to scan a few things and get them into Solidworks.

I used an app called polycam, gives you an STL you can import

In reply to papamilad :

ive made a lot of parts out of that resin, i would not trust that for long if i were you. Yes, its temp resistant but as you suspected its pretty brittle

Whoops I am pretty bad about updating GRM threads lol. The long and short of it, I got the car running well and have put ~2000 miles on the new motor since Feb! 

As predicted that 3D printed crank sensor mount didnt work very well. Mainly it flexed so much that it caused the motor to loose sync as soon as it fired off. Redesigned it to be made out of some laser cut 0.25" steel and welded together. Worked great and got the car running well.

Surprisingly very few issues with the new motor, only a slight mishap involving a rubber cap for a coolant barb bursting on the highway.

Still working on dialing in the tune, I think my provided injector data is off and I am also getting some weird very occasional intake backfires but apart from that it runs good and most importantly no longer crop dusts everybody on the road.

1st mountain run

2nd mountain run!

Working tach and LED lights

More to come for sure, next big plans are redoing the interior, AC, maybe an LSD...

Love to see it up and running. Inspiration for sure!