My black forged Piazza

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IZU069
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Post by IZU069 »

Starter ring gears on manuals can be removed and rotated 90°.
My Wasp even has a reversed ring gear whose "new" gear face was chamfer filed by hand. (Easy and still fine after 100,000km, and lots of reduction starter out of bogs & over hills type cranking.)

Though the gear can be cold-bashed off (working around the gear to avoid distortion), I suggest heating when replacing. An oven is probably best.
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archangel62
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Post by archangel62 »

Check-in.

Re-fitted the gearbox inspection plate and lower gearbox support brackets. Changed leaky lower radiator hose with one that I found in my spares pile, which *hopefully* won't leak. Removed the dead turbo, then removed the header for good measure (yes, separately - apparently it's easy if it's recently been off - LOL) and managed to remove a broken exhaust stud from the head - sweet!

Tomorrow I'll block off the turbo coolant lines, and have a crack at fitting the other turbo.

The sump bolts seemed a tad looser than I thought I did them, so I nipped them up a reasonable amount, will be interested to see if it makes any difference to the leak (for better or worse)! Lastly, the power brakes SEEM to work, based on pedal feel the last time I started it, although I haven't tried stopping with them yet.

Things seem to be on their way up! Hope it goes well.
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
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Piazza_man
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Post by Piazza_man »

Fingers crossed.
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archangel62
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Post by archangel62 »

Okay, so.

Started it, no more scary noises. No more coolant leak. Still leaks oil from something vaguely near the oil filter, I'm suspecting the oil pump, which is weird.

The brakes work fine now.

It runs nice and smooth when not giving it stick, but still runs like crap whenever it seems to make boost - it doesn't miss, it just completely runs out of power. I'm not sure if the timing's wrong, or the mixture's wrong, but the ECU (or mechanical timing) is utterly failing under boost.

Gave it some around the block, got home, and the exhaust side of the turbo was GLOWING! So was the manifold around the collector area - so there's massive heat in the exhaust header, above the norm. Any ideas? I'm tempted to bin the whole ECU right away. The car itself didn't seem to overheat on a short trip (going by feel, because the gauge itself is mental).
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
IZU069
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Post by IZU069 »

Lean mixture?
If the pistons melt, it probably was.

And fix any oil pump leaks - you don't want lost pressure!


PS - Archy, I just "crapped" on the twincam thread regarding GW oil-feed issues - especially the crap about removing the dummy cam.
[ Ooops - I didn't highlight that the head oil feed does NOT go through the dummy cam, but I assumed all understood that that was obviously crap. (How can people confuse the through-cam feeds to other dummy cam bearings with the feed to the head?) ]

And eyecon below is probably right....
Last edited by IZU069 on Thu Apr 12, 2012 7:06 pm, edited 2 times in total.
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Piazza_man
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Post by Piazza_man »

Sounds like a turbo issue to me.
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archangel62
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Post by archangel62 »

Pretty awesome Piazza update today!

So the keys had some dodgy broken Tonkins remote attached to them, but it never did anything, and I always unlocked the car with the key. Today, I opened up the remote and made it work, albeit in pieces that you have to hold together. Not only did it work the locks, but it also switched off a little flashing red light ("immobiliser" maybe?) on the steering column. The car now starts by key, not from hotwiring, and starts a lot easier without spluttering.

It also runs a lot nicer under load.

I chucked a boost gauge on and took it for a quick spin. I had to run the line through the bonnet rear seal, and I think it crushed it a bit as it was quite slow to react (only with the bonnet shut), but I think the car is actually overboosting. I saw 10psi at one point, and I think the gauge was creeping up much slower than the pressure actually was. I didn't hear any pinging, although Wide Open Throttle still seems to hesitate or be held back a little. All in all, though, it runs a LOT nicer than before, and produces perhaps nearly the expected stock power.

I kept running it in the driveway, free revving etc, and it didn't seem to overheat. The turbo manifold didn't glow, although it wasn't loaded up for quite as long this time. It still pumps oil out, but I've established it's now from one point only, behind the timing cover. That's "easy" fixed. I'm sure it'll take a few solid days' work, but I know vaguely what to do now. Pending that being fixed, I think I'd be ready to take it on a proper drive, although I wouldn't give it much stick because I don't trust it under load.

Massively on the right track! Once I fix the oil leak, I'm going to think about much bigger injectors and either a tune, or a whole new ECU. I think I'll order some Koni Red shocks for the rear over the next few weeks, too.

Other small points:
- Fitted my ISUZU rear garnish, it looks sooooo much better!
- Lubricated and adjusted the bonnet latches, they now open easily from the cable, not requiring jimmying and a few attempts
- Whilst attempting to mount a boost gauge discreetly and non-invasively by the driver's left knee, the drill bit broke and I gouged a slit in the interior. FFFUUUUU!!!! but alas, it's small, hard to notice, and can probably be fixed.
- Little things work now that the immobiliser sodded off, like the blower fan. Headlight covers still a no-go though.
- "Adjusted" (read: delicately bent) the bonnet "closed" switches, so it's stopped telling me the bonnet's up. I know they're threaded, but I don't think the threaded adjustment "works" as there's nothing to lock it.
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
IZU069
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Post by IZU069 »

Why bigger injectors?

They won't inject more fuel (unless the existing ones are too small).
Is it running lean?
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archangel62
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Post by archangel62 »

I think it's overboosting, and therefore leaning out when the ECU simply can't give the injectors more duty cycle. This is a really vague guess at the moment, because it leaks oil too fast for me to really drive it for long - and I don't want to drive it too far if it is leaning out!

Of course, if I just upgrade the injectors, all hell will break loose with the tune and stock ECU in general - so whenever I get around to upgrading the injectors, I'll be changing the ECU as well - and locking the dizzy to set it up for spark control too. Once I fix this oil leak I'll set the boost gauge up properly and take it for a little drive to confirm things. If I can amend any boost issues and run standard boost for a while, I might just enjoy the car stock for a bit before fiddling with it!

However, after obtaining part numbers for Koni Red shocks for the Piazza, I'm thinking of ordering rears real soon, to complete the set and make the thing turn corners.
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
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wedgenut
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Post by wedgenut »

It can't really over boost unless the over boost valve is seized shut or has been removed and the hole plugged off. It is the round thing on the front of the plenum, to test it take it off and connect to a regulated air supply it should start to bleed air at between 7 and 10 psi. They usually fail the other way and a typical fault is opening at say 8psi but not closing again until about 3psi so the car behaves normally in normal driving until you stick your hoof in it hard one day and it opens under high boost. If it doesn't close properly again after that you get the symptom of low power under load. Of course if you take your foot off all the way the high vacuum in the plenum usually closes it again. If it doesn't close properly at closed throttle you have in fact a vacuum leak and the O2 sensor will enrich the mixture to compensate, and the outcome is a rough and stumbling idle.
So many cars, so little cash
IZU069
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Post by IZU069 »

archangel62 wrote:...therefore leaning out when the ECU simply can't give the injectors more duty cycle.
Ah - so it's only at high RPM; it's fine up to (say) 40000RPM, or 3k etc, and no problems at low RPM?
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archangel62
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Post by archangel62 »

It still has the overboost valve on the front of the plenum - you make a fair point, provided this is still functional, the boost could only get so high. My reason for suspecting overboost is that the boost gauge I was using was quite slow to react, due to the vac line being pinched from my ahh, dynamic install (read, fed through the bonnet's rear rubber seal) but it climbed to 10psi before I had to lift. I didn't have long driving it, but I felt like the gauge still had catching up to do. Maybe not - I think I'll need to fix this damn oil leak and install the gauge properly to figure it out.

I've traced the oil leak a bit more, it's blasting out of the little hole in the bottom of the timing cover, so it's definitely something behind there. I've established that it's the engine fan blowing it back that makes it look like it's coming from everywhere - it actually just looks like the one point, which is nice. Now, to begin the fun task of removing the timing cover (again)... It's not the easiest thing to do! I hope the new timing belt is still okay...
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
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wedgenut
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Post by wedgenut »

Leak points,
Crank seal, sump front hump corners, cam cover and cam dseals (it can run down behind the tin back plate and get blown out the bottom.) Or more commonly the oil pump, it has an O ring seal to the block face and a lip seal on the shaft. This would be my pick.
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archangel62
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Post by archangel62 »

Excellent info - a few I was suspicious of, a few I hadn't thought of. Thanks Wedgenut! I'll see if I can pull the b*****d down over the weekend! :D And go BACK TO THE -

- Isuzus. Instead of driving the Skyline everywhere. What?
Indigo - '76 TX Gemini sedan, G180W+T project,
Abigail - '81 TE sedan, white, G180W ITB project,
New Hotness - TG Gemini drift car, orange, 4ZE1+T
Tardis - 1986 Piazza 4ZC1-T, black, forged, 136rwkw @13psi
Coupe - TX coupe grip car, "do it later", G180W+twin carbs
Trevor aka Jimmy's Gem - Grandpa-spec TD
BA Falcon - Tow car
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wedgenut
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Post by wedgenut »

Right o, seeing as how you are going to investigate everything, you already know about where the cam cover goes over the front bearing but it would also pay to check they put sealant on the joint between the cam cap and the head. Oil can weep through there as well. Especially as there is a little gap behind the where the seal sits that fills with oil and it can gently leak out of the seam and slowly trickle down behind the tin plate.
So many cars, so little cash
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