~Slideways~

Fuck yeah that looks fucking awesome! I used to have one of these, had it painted bright red too, but it was orange. Those arches really suit it too.

Will get back soon with some photos of the ign map. Have been looking at images of bearings for far too long now...

Yeah no definitely not, my original plan was to get a SOHC 4g93 short block from pick a part which would have been around $100 (and hours or stuffing around in the mud) and I wouldn't know if it was good. Then aftermarket rods and pistons since it is the main issue with even the GSR 1.8 turbos. From what I understand the crank is the same across the 4g93 range. But I came across this GDI engine for so cheap it made more sense. Basically its a donor for a block and crank. Possibly some ancillaries. I did entertain the thought though that these high compression piston could actually make for a good N/A setup using the Mivec head.

Definitely worth testing, I'll wait till they are back from testing etc. That description does kind of match the intermittent misfire problem where it would happen at low load then go away it you let it drop down to idle, but I am sure I've been over logs and the voltage was fine. It's all in pieces now though so will press on with at least making a rebuild plan as well as trying to test all possibilities for the failure.

This engine will be the Cedia/Ralliart wagon type thing. Weird high compression, small turbo, direct injection, plastic intake manifold weirdness. It'll have tiny rods and high compression pistons so really wanted it for a good low k's base to build a Mivec turbo 1.8 Those turbo Colts look pretty cool, they are 1.5l though so not much use in this case.

Picked up this 4g93 GDI turbo for a really good price. I guess they are simply not sought after engines. The GDI's were a bit of a disaster really, but the block and crank should be good since it is a clean low km's engine. Plus handy to have spares and different variations of brackets for alternator/PS pump etc.

That does look very familiar! But on the fuel pump, it has a big dedicated power wire directly from the battery through a relay. Way bigger than the factory wiring etc. I checked the fuse a few times after that happened and it showed no signs of burning again, although I had crimped it down so the connection definitely has good contact. I'm pretty sure now that it was caused by a bad contact. The thing that gets me is that there doesn't look to be any damage to the other pistons, just number 4 and it is serious damage. Possibly long term, is its is likely a long term problem there. It has been suggested that it may be an injector driver fault with the Link g4+. I've been told of a similar story where an RB filled a cylinder with fuel after having similar misfire problems. Right now I'm working on getting the block ready to be measured and see if it needs over sized pistons or not. Then make a list of everything I need and figure out the best place to source them. There look to be supply delays on bearings etc. Will go with genuine Toyota headgasket etc though.

Yeah this is interesting because the big end on number 4 is actually pretty 'good', some scoring but nothing like number 2 with the pitting/corrosion. Out of all of the mains and big ends, it is only number 2 that had the weird pitting. The others are either good or light scoring. This is number 4:

Automotive sadness ensues: The piston looks far worse than I expected. The ring lands look intact too. Another unexpected thing is number 2 had what looks like corrosion on the bearing? And some of the others have scoring which is maybe piston material going through the system since I can now see that the piston particles/melted bits worked their way below the rings. Everything went pretty smoothly with the disassembly except this one bastard allen bolt on one oil squirter. It was so tight that it rounded the inside of the allen head. I ended up having to chisel a groove into it to use an impact driver. No other damage though so just need a replacement bolt. Going to send the ECU off to Link to see if they can test the injector driver on number 4. Will contact to find out what can be done, even just paying to have it replaced just incase. Dropped the injectors themselves to be tested late last week.

I reckon the block needs machining so probably 0.5mm oversize since that is a commonly available OS forged piston. I didn't do a 1NZ double windowed job at least, right?

Will still see if the injector is the culprit but it doesn't seem likely as it is all filtered properly and they were cleaned and tested when trying to find the misfire cause. Haven't made much plan for the rebuild yet except looking at piston prices and deciding I don't really need to replace the rods since they are more than enough.

While I did build it with Ethanol in mind, E85 was gone by the time it was ready for it so it never actually ran Ethanol, not even E10. Only ever BP98. Good thought though as I changed everything to ethanol safe but didn't think of the fuel rail. The injectors are powered with their own dedicated relay and fuse but no ballast resistor no. EDIT: will be getting the injectors tested again.

I ran the Xspurt ones for a while but changed to st215 injectors about 1-2years ago as the spray pattern was better. The Xspurt ones appear to spray directly at the wide port divider on these heads so lose atomization.

This would be a silver lining really, finally having an answer for the the intermittent misfire. So much so I feel like a broken record writing the words 'intermittent misfire' so many times. I don't think it was a tuning issue, it has been on the same dyno 4 or 5 times now using knock headphones and the fact that it was only one piston while the others don't appear to have any signs of damage. Right now the most likely theory is that it already had piston damage from it's previous life, maybe ring lands from too much boost on stock ecu back in Japan? Thanks for throwing some of your experience at this, really helps getting my head around what could have happened etc.

It does seem like it was gradual yeah. And it makes some sense that it just got to the point where it let go. Cooling looks ok but haven't had a good look yet, the thin black layer of the metal headgasket has stuck to the head and makes it look like the cooling passages are partially blocked but its just that thin later left behind. Will have a better look though. I imported the engine in a car from japan (jzx100 earlier in this thread), drove it around the block and compression tested ok. It had the stock turbo and ecu but it was a basic amature drift car type thing so more than likely had the boost increased. So maybe it had a cracked ring land all along but was able to hold compression most of the time? Never had the head off no, didn't have a reason to. Would have been interesting to see if there was any damage that slowly killed it though.

Took the exhaust side off and did the kerosene test there too and it looked fine. So took the head off and found this, fuck. Number 4 is melted on the exhaust side and pitted on the intake side. All the other pistons look fine. The headgasket looks fine too. So I'm guessing it went lean on just one. But was this a short term thing or long term? The bore has light scoring when the others don't. It feels smooth though so not too deep. You can see the exhaust side of the cylinder has a build up of what must be melted piston. It's like tiny bits of the piston built up since it protrudes from the cylinder wall rather than eaten into it. It does look to have removed a coating from the wall, not sure what's going on there. The same build up is on the head. It doesn't look to have eaten into the head material though. The head looks worse in the photo than it is. Hopefully skimming it will be enough. As you can see, the valves look good and were likely never the issue. So at this stage I am leaning towards the injector on number 4 having a flow problem. But am open to suggestions. At this stage I think I will go with oversized forged pistons and use the stock conrods since they are meant to be plenty strong for the kind of power I wanted from this. The intermittent misfire could be the cause, if I only knew what caused it, not from a lack of bloody trying... The same thing happened with the Xspurt 1000cc injectors and with the 550cc 3sgte injectors. Both of which had been through an injector cleaner. Swapping coils with a known good one made no difference either. Or it could be a faulty ECU causing the misfire. Maybe the intermittent misfire isn't the cause since it happened at light load. Either way it needs rebuilding, but how do I stop it happening again?

Yeah I guess I'll still check the exhaust side but either way the heads going to need to come off. Cars can be a bit of a dick sometimes

*Searches Real Street Performance...

Well this throws the intake valve idea out the window, as a test of the sealing of the intake valves on number 4 I squirted enough kerosene into the port to cover both valves and nothing drained away. You can kind of see the fluid here: So I took the exhaust side cam cover off and checked the buckets, they look to moving perfectly and the clearance is good too. Compression tested again and still zero. Squirted a bit of oil down the spark plug hole and it made no difference to the compression reading. So now I guess it is either the exhaust valves not sealing, the headgasket or the rings/pistons/bore. Won't be able to do anything on it for a while now but just wanted to try confirm what the problem was... I guess I've confirmed what the problem isn't. I suppose when the head is off it will make it obvious but I didn't want to take it off until I'd done some testing. Fearing the worst now, bore damage, broken ring lands, something went through and damaged the combustion chamber too. Confused how the leak down test indicated the intake valves on number 4 were leaking into the intake.

OK got the intake manifold off and first thing I notice is that number 4 intake port has a decent pool of oil. The other 5 are clean and dry, so that isn't a good sign. EDIT: unless they put oil down the spark plug hole to confirm is the rings are gone? Not sure they would have. So is this coming from a buggered valve stem seal or sucking up past the rings, explaining the lack of compression. Removed the second part of the manifold so I can see in the port, I can see a large area of the valve and they look super clean and I see no damage. But I cannot see the whole surface, its possible the inner edge is where the problem is. Very hard to focus when the valve is open. So the oil isn't a good sign, maybe it really is the bottom end even though the leak down test didn't indicate this. But I guess the next step will be checking the exhaust side or maybe taking the intake cam out and removing the buckets on the 4th one.

Have pulled the intake side cam cover off and on number 4 the clearance on both shims is the same and within factory spec of 0.15mm to 0.25mm. Turned it over with the key a few times to see if there was any sign of a bucket getting stuck and it looks totally fine. Compression tested number 4 and it's got nothing, to confirm I tested number 3 and it has good compression. So that at least tells me the bucket isn't getting stuck and keeping the valve open, because its all the way up and there is no compression. Next I'll take the intake manifold off and see if it's possible to see the back of the valves.

Yeah I think you might be right, I guess maybe the adjustment is for sensitivity to the swiping over the magnet.

Haven't had much time to do car stuff but good news is I've got the 4g15 wiring sorted and it runs now! It was previously firing once then dying, every time you turned the key it was a half second fire then dying. This was after finding the neutral switch wires so it would turn over at all now that it has a manual gbox on the side. Checked everything and found this black box under the dash, unplugged it then it started and ran first time! Yay. So it must be some kind of immobilizer, it has an LED that blinks maybe once every 5 seconds and a rubber bung covering an adjustable knob thing. Looks like maybe a relay at the bottom there with a magnet? On the casing there are two holes above that spot, is it meant to have something sit there to move the magnet? Why does it run when it is unplugged? What is the adjustment for? A mivec controller? But why would it stop it from starting? Weird.

I've come across some old forum posts talking about 2jz's having buckets get stuck so this is definitely a possibility, I'll hopefully get into it soon.

Yeah definitely will be interesting to see if there is a bigger gap, binding could explain it. That's definitely better than the alternative of the valve being damaged because I'd want to know why it happened.