GTSBoy

I think every Nissan since then LOOKS like a Renault.

These come from the era where the Nissan-Renault tie up was not doing Nissan product any favours. Started in 1999 and has made almost every Nissan since then a French influenced turd, compared to what it might have been if the insanity of the 80s and 90s had been allowed to continue (assuming that it could continue without Nissan going broke, of course).

The different markings are probably just binning. mass manufacturers don't blueprint engines to have matched components. They have bins of different sized pistons and just throw the appropriate sized piston into each bore to match the off-tools dimensions of the bore. The damage is called a cracked ring-land. It is frequently caused by detonation, although there is not a lot of indication for that on the piston crowns. Anyway, it's f**ked. Needs a rebuild. Clearly the last person to have it apart was a clumsy f**k, because the cam timing was out.

At this point, any death of a gearbox speed sensor or a cluster component should really just be a trigger to put a Haltech/etc dash in it and move on with life.

So the RCA is of course the video signal cable. The 12V and earth wires associated with the camera itself are meant to be connected all the time (by the looks of that wiring diagram). I am guessing that you are supposed to provide a signal from the gearbox's reverse switch to the head unit so that it knows that you're in reverse. I have no idea which wires you have shown us are these. Where is the purple wire from? The head unit? Where is the red wire from? The camera, or the car's 12V supply? From what I can gather, you will need to do as I said above. Camera gets power and earth all the time (switched from ignition, of course). Head unit reverse wire gets a signal from the cold side of the reverse switch. That's it.

No. You can't power something with just 12V. You need somewhere for the electrons to go.

Did you solder a bare wire to bare steel? Crazy. Do as @Duncan said. Even better, there's already a bolted connection right there that you could slip a eyelet under. As to the copper wire / plain wire question.....the silver coloured wire will be tinned/plated copper. Still copper underneath.

if it looks like a Renault and smells like a Renault.....

Fours'n'more, Pooraka. He'll hate you for bringing a dirty French Datsun, but will have absolutely no problem doing the job properly.

That is the cooling loop and you shouldn't delete it unless you are replacing it with an actual cooler. I replaced the loop in front of the radiator with the cooler from an R34 auto transmission for a substantial upgrade in power steering cooling.

Have you done any investigative work at all, looking for split cooler hoses, lost hose clamps, blown out manifold gaskets, popped off boost/vacuum hoses? Checked the valve timing? Checked the ignition timing? Checked to see if the IACV is working?

Motor too mall to be useful without power adders, as above. Work it (cams, porting, compression, etc) and you will simply make it even more torqueless down low than it already is, and it will suck more.

Nearly 25 years of ownership of an R32 I have have never once bumped the prop out. And I have an Al bonnet that puts less compressive load (ie a little less secure) than the steel bonnet on a GTSt would do.

You want to go cheaper than only $120? Are you sure you didn't just buy an R31? Fo' serious. $120 is nothing.

Have you tried the simple expedient of rotating* the whole gearbox a little to engage the splines properly? * a little clockwise, a little anti-clockwise, wiggle and jiggle at the same time.

Nah, there's no point in either mentioning what Australian state you're asking for, or looking it up on the rego authority website for that state.

There's no commonality between 25Neo and 26 ECUs, so it won't want to be from a 26.

The Nissan speed sensor just sends an AC (actually it's more of a saw-tooth waveform, but it fluctuates +ve and -ve) signal to the (factory) dash. That signal's frequency is proportional to the speed. The speedo head then converts that to a square wave 0-5V PWM signal that is put out on the "speed signal" bus wire that is connected to the ECU and any other CU that wants to know vehicle speed (which in an S15, is....probably not very many. Did they have HICAS?). That signal can be fed directly to the Haltch, the same as it is fed to the factory ECU. All this is in the factory service manuals. You just need to read the Haltech manual on what you need to do to configure an input to read a PWM signal like that and connect the wire. But that's assuming that you are using the S15 dash. If instead you are going to use a Haltech dash then you could probably also read the Haltech manual to find out what you have to do to instead connect the AC signal direct from the speed sensor.

It seems that following wires is becoming harder and harder as the years go passing by.

It shouldn't be too difficult to find an arduino based display for these speed sensors. 150krpm sounds like a lot to us, but it's nothing to a microprocessor these days.

This really depends on what you propose to do with this vehicle. Are you just driving it around the on the road? Drag racing it? Sandhills? Dakar? Mud plucking? Rock hopping? Assuming that it's not competitive, not stupid (mud plucking, rock hopping, etc), then....something smallish. G30-660 perhaps. One of Tao's (Hypergear) highflows or ATR turbos rated in the same 600ish HP territory. BW 7163.

Yeah, nah. If a turbo is big enough to make more power than is reasonable on the street, and small enough to come on and be useful on the street - you have the right turbo.

Will actually make a tiny bit less power, because the RB ECUs are not clever enough to wind in extra timing to take advantage of the extra octane, and the further away from the detonation threshold you are, the lower the power the engine makes.

18x9 +30 will fit on an R32 GTSt. That is R33 GTR width and offset - goes on OK. 18x9 +22 is going to poke out and will absolutely need work done on the guards to fit them. I wouldn't do it.

An external leak is so much more likely to be an external leak (drain, etc) than internal seals.