jiffo

On over-run with throttle closed, the engine will pull max vacuum. Worn valve stem seals will allow oil to be sucked down the valve stem into the combustion chamber. Worn guides make the whole show even worse. These engines are getting old and often the valve stem seals, if they're still there, have gone brittle. You probably find under normal driving, you wouldn't see any smoke but a long downhill is a good test.

Valve stem seals springs to mind.

Some posters are missing the point. If the belt runs silently when the engine's cold, then becomes noisy once at operating temp., something's wrong…... Too tight. What astounds me is that after years of discussion about noisy belts, growling idler bearings etc, a topic like this is still posted. It's old news. Just do the job right.

The 2500rpm etc all points to an AFM problem. Would also pay to thoroughly check the wiring to the AFM. I've seen one harness so badly squashed it gave the owner an intermittent fault.

Same thread appears on GTROC forum. Apparently crank was cleaned and grub screwed but not all grub screws were installed ?????? Did well to survive at all.

Tiny stud and tiny torque, about 10ft lbs from memory. Although they're a puny stud, the weakness is the nut. It tends to bind up in the thread and if the OP had them on and off so many times, I'd say for sure that's the problem. Torque reading would be useless and with bound up threads, you reach a situation where you can't tighten or loosen. Next thing snapo. Would be a rotten job to get out unless there's some stud protruding?

Any evidence that someone has been there previously? I too would be concerned, where did it go.

Yes this topic has been discussed countless times and it's always the same reply, incorrect tension. Set the tension correctly and your belt will run as silently as a stock belt. Set it too tight and once the engine's hot, the belt is over tensioned. That's the idler bearing you can hear complaining, noise will reduce once the bearing tolerances increase. I saw this mod on the GTROC forum. Would still be a finicky operation and totally unnecessary if the owner had used a Nissan belt.

Pretty sure I can see the previous seal's wear mark on that yoke, looks about 10 -15mm off.

Did you bleed all the air from the coolant via the purge valve?

A batch of Rb20's had the setscrews that hold on the pump backing plate, come loose. Oil pressure would gradually decrease until she eventually died. Such a long time ago, you'd have to be extremely unlucky (or lucky) to have one that was still operational.

O.P. is apparently using stock ecu so anything much higher than 1.0 bar (depending on weather conditions) will probably have it coughing and farting. I fitted a 25 turbo on my 20 in the Rustia, used the 20 actuator and it went very well. Added a bleed valve to increase boost and it didn't like it. So I left it at the stock 20 actuator boost but reading the signal after the cooler. Obviously the 25 turbo is not working as hard to pump a given boost on the 20 as it was for that same boost on the 25. A good cheap upgrade for a 20 in my opinion.

Not knowing your future power goals for the vehicle, I'd say stick with your stock ecu. The only reason to upgrade the ecu is when chasing hp. As for fuel savings when driving a GTR ???? I'd have to be the steadiest GTR driver on the road, highway cruising I get 10L per100 consistently. Stock ecu and the Rb26, I'm never going to see fuel usage down in single digits. The GTSt used to do 9 to 9.5 despite having a lot more hp on tap, the Rb25 with VVT is simply more economical at cruising speeds. If you've got a heavy foot there's no miracles, economy is all about driving style. A PFc will set you back around $800 and much the same again for the tune. You'll never see that $1600+ returned in fuel savings, so forget that argument. But if your plan on hp upgrades, money doesn't come into the equation, it all disappears.

20' container is good cover.

Not to worry, here's some extra info which may help others. On the solenoid, there's 2-large terminals. One is your power in (from the battery) and the other is power out from the solenoid to the starter motor. The solenoid is activated by connecting the start terminal (usually a spade connector) across to the power in. As the solenoid is activated, its magnet pulls the plunger and via a lever, drags the pinion into mesh. When the plunger reaches the bottom of the solenoid, it hits spring loaded high amperage contacts which then bridge the power from the battery across to the power out to the starter, and things start to turn. With a low battery, the magnet will pull the pinion into mesh but as soon as it bridges the high amp circuit, there's insufficient battery grunt to hold the magnet in, so it releases. Electric load is gone so magnet comes good again, and so on…….clack, clack, clack. Every time it clacks, it's arcing the high amp contacts. Doesn't take long before they're melted bits of copper. Some of us are old enough to remember rubbish like Lucas starters with no throw in solenoid. (early Minis etc) The starter motor just spun and the inertia was sufficient to wind the Bendix into mesh with the flywheel.

You didn't answer the question though. Did it crank over properly when you inadvertently supplied power to the wrong side of the solenoid? The solenoid doesn't just throw the pinion into mesh, it also switches the high amperage current to the starter at the same time. So you can have a situation where the pinion is thrown into mesh but the high amperage contacts at the end of the solenoid may be cooked from previous arcing. Just a thought. From lots of starter repairs over the years, I always go the extra and overhaul the solenoid, replacing the contact section if it shows well arced contacts.

Can you elaborate on your comment, "I accidentally supplied power to the starter side of the solenoid"? IF the starter was installed on the car, AND you supplied power to the starter side, AND it cranked over fine……. THEN the solenoid is your problem. (as you've by-passed it in that test) Solenoid is often overlooked when trouble shooting starter motor faults. Continual use with a poorly charged (or low output battery) arcs the contacts in the solenoid. Solenoid can be dismantled and successfully repaired, but most designs will need the coil wires de-soldering.

I found a Gates belt can run as silently as a stocker, it's all to do with belt tension. Unless you're fitting belts everyday, you lose the "touch" and kevlar belts require slightly less tension than factory. So the average handy-bloke ends up doing the job twice, or perhaps get the job done poorly by an expert and believe their spin that the noise will go away in time. Nobody likes pulling it all down (especially an Rb26) just to slacken off a tad, which is why no more kevlar belts for me. Who else remembers Rob (RIPS) offering his car if anyone could find a non-factory Nissan engine part on his early R32/Rb30? It made considerable Hp.

I found a Gates belt can run as silently as a stocker, it's all to do with belt tension. Unless you're fitting belts everyday, you lose the "touch" and kevlar belts require slightly less tension than factory. So the average handy-bloke ends up doing the job twice, or perhaps get the job done poorly by an expert and believe their spin that the noise will go away in time. Nobody likes pulling it all down (especially an Rb26) just to slacken off a tad, which is why no more kevlar belts for me. Who else remembers Rob (RIPS) offering his car if anyone could find a non-factory Nissan engine part on his early R32/Rb30? It made considerable Hp.

Yeah Zed, been there done that, who needs to do the job 2X ??? Will never touch another kevlar belt. Nissan belt FTW.

Do you have the knock reading on "Peak Hold"? You're not going to register max knock numbers otherwise.

Hard to diagnose faults like this on the net but you're getting 5psi which is waste gate actuator pressure for a stock setup. Is the "high boost" bleed solenoid plugged in and working?

Yes it's easy to slip a tooth on the crank gear so you're doing the right thing, checking the marks properly. What brand name belt did you use? (Makes a difference setting the tension)

So how was the oil pressure on this backwards-running Rb?

You'll remove the rod and work on it at the bench. Don't need a press, a big vice will do the job. If you're any good, one hit with a sledge hammer will pop the new lubed bush straight in. (The poly bushes come with a lube sachet to help them pop in) Getting the old bush out of the rod is harder than popping in the new one. As the poly bush has the eccentric, you'll need a wheel alignment after you fit the new bushes.