My black forged Piazza

Showcase your rides here. Read "Picture Help" to find out how to host your pic's
Post Reply
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

My black forged Piazza

Post by archangel62 »

My image hosting site carked it, so I've made the Facebook album public. This may not be permanent, in case it falls into the wrong hands... But you can find the images here:

IMAGES:
https://www.facebook.com/eli.duykers/me ... 902&type=3

Hi everyone,

Well, this thread is going to be a work in progress for a little while, but it's long overdue.

About two years ago, I saw a Piazza come up for sale on GemiSA, complete and running, for $3500 ono. I didn't have that kind of cash, but remembered thinking it was cool, and wanting it (for a Piazza, not as a donor for my 5 Geminis). Anyway, someone else bought it to rip the engine out and put in their Gemini. It spun a rod bearing on the way home, but he pulled the engine out for his Gemini anyway. A month or so later, I saw it back up for sale, no engine, for about $700. I couldn't let such a nice, shiny, unique Isuzu end up getting crushed! So, not knowing what I was really in for, I bought it.

I knew it'd be a tough task getting a Piazza running again. The over-complexity, the cramped engine bay, the scarce parts (at least, those not useful for Geminis). I even drove to Melbourne for a 4ZC1-T engine, since nothing was available locally. That was a nightmare trip, don't get me started, and the POS Gemini of the time didn't make it all the way home. Alas, I digress.

I've rebuilt the 4ZC1-T with forged pistons (custom JE pistons, around $1200-worth), and ARP head studs. I had everything cleaned, balanced, and bought a head that had already had lots of money spent, from Ethan (hachikansai77 to some of you). I also had the original clutch rebuilt as a heavy duty, 6-puck cushioned button, with organic material. That cost about $550 I think, but the result is very light pedal feel, and (hopefully, going by my track car) very linear drivability with massive clamping force.

Over the last year and a half or so, I've undertaken the monolithic task of reverse-engineering the Piazza; figuring out "what the hell is that", piecing it all together, sourcing and purchasing the bits that were missing, and cleaning/servicing those I had. The plan is to run it stock for the time being, and then upgrade to Megasquirt, a Gemracing turbo manifold, T28bb turbo and a cam, and aim for around 200rwkw, but still have it drive nicely and be fairly original throughout.

Presently, the engine is in, I cranked it the other day but had to wade through the usual first-start issues. I'm hoping to drive it and bed it in over the next few days, time pending, and then take it from there.

I also fitted some Koni Red oil shocks to the front, and will be doing so for the rear when money allows (I had these sitting around). I have a full factory bodykit to fit, when time allows, and will actually wash the thing (and cut and polish imperfections) later on.

I'll post up pictures steadily over the next few weeks (he says), and update you all as I go. Watch this space!

Eli/arch.
Last edited by archangel62 on Thu May 08, 2014 11:05 am, edited 1 time in total.
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
User avatar
Piazza_man
Site Admin
Site Admin
Posts: 863
Joined: Sun Dec 12, 2010 9:53 pm

Post by Piazza_man »

Cool man. Can't wait to see the pics. Don't leave it too long.
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Okay, here we go, I'm going to try and put these in rough chronological order!

Before I got her, when she was for sale, complete:

Image
Image
Image
Image
Image


When I'd just got her home, without an engine:

Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
Image
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
User avatar
Piazza_man
Site Admin
Site Admin
Posts: 863
Joined: Sun Dec 12, 2010 9:53 pm

Post by Piazza_man »

Good stuff AA. Glad to see it's finally resurrected.
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Update, IT RUNS! It was running on 3 the other day, turns out it's a loose electrical plug on the #1 injector. Jammed it on tighter today and it ran fine! So I'll have to fix it properly, then bed it in, hopefully tonight...

However, in the process, I discovered #1 pot has 160psi cold, dry, pre-bed-in, with a CR of 8:1 (and being cranked with compression in all pots, ie, slow). Pretty good!

I'll post the build pics up soon, but they're all out of order which his a bit of a pain... and there's billions of them...
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
User avatar
Bugle
A total post whore
Posts: 953
Joined: Sun Jul 17, 2005 11:41 pm
Location: Sydney

Post by Bugle »

Nice, lucky it didn't get too messed up by the person who took the engine out! They usually end up with the wiring and gearbox ripped out too..
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Well, the novelty of "my Piazza runs" has been replaced with the standard frustrated suffix of "-like shit."

Problems:

- Doesn't seem to be making boost, maybe it's leaking, maybe the pop-off valve is playing up, maybe the ECU's just shitting bricks and running it crap

- Something's making a rattley, rotational noise. Sounds like the turbo, in which case I don't care (pity I wasted $170 on lines for it)

- The one main coolant hose I couldn't replace (couldn't find one to suit) has sprung a leak on a hairline crack. Typical.

- It's sprung ANOTHER oil leak. Are these cars usually complete sieves or what? Fking bucket, aaaarrghhh!!

- Eyelids/light covers don't budge, or make any noises etc

- Car still needs a wire in the engine bay to start

- Brakes are ROCK hard. I think they worked nicely once. Booster isn't working, maybe it's hooked up wrong.

- The vac advance makes no difference whatosever at idle - I tried timing it to 10BTDC with it blocked off, and it remained there once connected. So I tried setting it at 18BTDC with it connected. Wtf should I time it to, given vac adv does nothing?

Beyond that, I'm pretty sure the LSD does absolutely nothing. I can get it shimmed (I'm assuming), I just hope it's actually there full stop. The car seems to have an understeer balance, and is still a bit soft even with Konis in the front, but I suppose rears will help that a lot, as will springs.

Jesus christ. I added about 8 months and five hundred headaches trying to get this thing stock to start off with, so it would be "hassle-free", and it's been nothing but. To hell with this, I'm on the verge of binning every stock accessory and going aftermarket, so the bucket of crap under the bonnet actually works.

On the plus side, I did enjoy driving it... and I love the car itself. I just want it to bloody work... headdesk.
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
User avatar
Piazza_man
Site Admin
Site Admin
Posts: 863
Joined: Sun Dec 12, 2010 9:53 pm

Post by Piazza_man »

Well that sucks. Question is if the ECU is even working. Also would a leak down test exposé any leakage in the system?
User avatar
Bugle
A total post whore
Posts: 953
Joined: Sun Jul 17, 2005 11:41 pm
Location: Sydney

Post by Bugle »

The original turbo is shit even if it's working, put something better on.

I never had problems with big oil leaks, power steering on the other hand..

With the eyelids, i'm guessing the car has been running without a battery bracket? The eyelid motor sources power off the horn circuit. The horn relay is mounted to the panel infront of the battery. Battery smashes into horn relay, crushing it and causing it to short out and blow the fuse.

Is the booster line hooked up with the one way valve the right way?

Does the vac line you're hooking up to the vac advance actually have full vacuum?
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Thanks for the replies guys. Sorry I take so long to respond - I'm just busy leading up to the next Stadium Drift event - but I really appreciate the input! Agreed on the turbo. I just want the engine to run right, or I'll convert it to aftermarket EFI.

Well, started it and ran it in the driveway and it didn't leak any oil - so it was either residual spilled oil from the last run (very optimistic) or it only leaks around corners/once it's properly revved/upto temp. Which points me in a few directions. Namely the hoses on the driver's side of the sump. TBC.

Eyelids - well, it didn't have a battery bracket when I got it (lol) and I ran it without one, temporarily, mind you it doesn't move much. I had a look at the relay in question, and it was floating around somewhere it shouldn't be. I'll check the fuses (and the horn).

I removed the booster line from the other car and tested that one - it's all good, so I'll swap them over and see what happens! Thanks for the tip-off, looking at the hose I wouldn't have realised it had a one way valve in it (although it makes a lot more sense knowing that it does!)

Here's some interesting information. The vac line that hooks up to the vac advance as per factory (as far as I can tell) snakes around the metal line and then terminates on the throttle body itself. The line then goes through a Y-join inside the throttle body itself and goes to TWO holes - one either side of the throttle butterfly! We tried blowing in it and blocking each hole off, and couldn't believe it. So there's a small channel inside the throttle body that bypasses the butterflies altogether, and ON that line, is the source for the "vac advance" for the dizzy! WTF! Resultantly, it seems to work *sometimes*, but not on idle, contrary to what the Isuzu tune-up information says!

This explains why the vac advance seemed not to do anything whatsoever. So I pissed off that arrangement and finally it seems to do something! I sourced the new vacuum from the line in the plenum, just under where it says "TURBO". Now, however, it retards the timing quite a lot when I rev it (but if I block off the vac line, it advances it with revs instead). It pops and splutters every now and then, but seems to vaguely run okay. I still don't think the intake air side of things is right though, can't really say til I drive it. And can't really drive it til I fix the following:

...

The bad news is, the car still makes scary noises. We're pretty sure that it's something around the flywheel however, not inside my shiny (read: expensive) engine. My money's actually on the inspection plate in the front of the gearbox catching on the flywheel itself - it seemed pretty dodgy when I fitted it, and would explain the terrible noises. Euuucckk. Wish me luck. Here's what it currently sounds like *cringe* ... I hope it's something insignificant.

Also note the slightly hard starting...

http://www.youtube.com/watch?v=4DQzLGNrZbk
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
User avatar
Piazza_man
Site Admin
Site Admin
Posts: 863
Joined: Sun Dec 12, 2010 9:53 pm

Post by Piazza_man »

Good luck. Hope it's an easy fix. :rolleyes:
User avatar
wedgenut
Site Admin
Site Admin
Posts: 1520
Joined: Mon Jul 04, 2005 9:39 pm
Location: Hibiscus Coast NZ

Post by wedgenut »

Ye gods buddy thats running like a bag of arseholes, first thing to do is rip off the tin plate on the bell housing to eliminate that as a cauise of all the clattering. If it is till there i suspect a broken or displaced clutch fork. If the clutch seems normal it probably is just the tin plate. I assume when the engine was built there was no excessive crank end float? The crank will move back and forward with revs if it has too much and that might be enough to allow it to touch the plate if it is already a bit buckled inwards.

Just a small thing but why are you timing it on no. 1 cylinder? Piazzas time on no. 4.

One other thing. If you need to use a jump wire to start the car under the bonnet my guess is someone has dicked about with the radio harness. On manual cars there is a jumper plug at the end of the radio loom tucked down by the gear lever. It is there to complete the circuit that is normally open on Auto cars when not in park or neutral. If this plug isn't there or the harness is cut or butchered you need to fix that and starting off the key will return. It also interlinks through the fuel Pump relay so may help with your hard starting problem as well.

Go back to basics and disconnec the vacuum line to your dizzy and block it off. Set timing to spec off no. 4 cylinder at around 800 rpm. You can worry about the vacuum advance later. Once timed to spec rev it up and down and check it is advancing properly on the mechanical side firstby watching the timing marks on the crank. If all of that works then check the diaphragm pot is okay by sucking on it and checking it pulls up and stays there with your tongue blocking the end. If it is all okay find a hose that will give you max vac at idle and drops off when you open the throttle and connect it up.

Bobs your auntie

Common oil leak sources are, front and rear crank seals if the shaft surfaces are grooved, If so they shoulkd have been sleeved or repaired before rebuild. Another bitch source is the oil pump shaft seal. SOMETIMES people forget to renew that one and it will drive you nuts until you fix it.

My engine is just on 170,000k's and I don't have any oil leaks coz i fixed them. Also on the sump and cam covers you need sealant in the corners where the gasket goes over the shaft humps or those corners WILL leak bucket loads.

I hope some of this helps. When a Piazza is tuned right it will idle like a swiss watch and rev cleanly. Almost all of them these days do have a bit of top end rattle. Such is the scenario with the isuzu valve train. It should NOT sound like a diesel with a bad case of the flu!
So many cars, so little cash
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Headlight covers - this is confusing me. I removed the relay, replaced the fuse, and the horn worked. Switched on headlights and ate the fuse. Changed the relay with one from the other Piazza, replaced the fuse and instantly fried it when the battery was connected, headlights off and no horn! I'm slightly stumped, maybe BOTH relays are stuffed, in different ways... Although I *think* I tried putting a fuse in with no relay at all and it still ate it. Maybe my horn circuit (of all things) is stuffed.

1 and 4 should have the same timing on the crank, old habits die hard - I'm not entirely sure why they say to time it on cyl.4, as long as the dizzy lines up with the cam it should be all the same, but I'm open to being corrected here!

Agreed on removing that plate - I squeezed under the car the other night with it running and pushed on the plate, it didn't seem to make any difference, but I'm not ruling out the bolts for that plate being a little too long - so when I get the chance, I'll rip it off altogether. It's just a slight pain because you have to take the big gbox brackets off to get to it. Hopefully on Saturday.

Clutch feels ridiculously light, but works fine. It's aftermarket, so I wouldn't be surprised if the weighting's different or fiddled to offset the springrates on the pressure plate! I've been considering putting a spring on the fork to give it a little more weight. I'm fairly sure I used a new clutch thrust bearing, I wonder if it could be thrust bearing noise? Although you'd think pushing the clutch would alter that, and it doesn't seem to.

Interesting point on the starter jump wire, I'll have to check it out - I assumed it was an immobilizer, since it has a little flashing red light on the dash that continues to do so, and the remote doesn't seem to do anything. I was going to have the remote looked at - maybe - or just sod the stupid thing off. I'll look for this plug!

Mechanical adv is working fine which is a good start. I'll check the diaphragm as you've said. I'm now happy with my vac source near the join of runners/plenum, but haven't driven the car to test it, since it's making scary noises. Hopefully I can get to the bottom of that and actually drive the thing again.

I ran new front and rear crank seals and (by memory) oiled them before install, but in the driveway it didn't seem to make any more oil... still scratching my head about that, will report pending another drive. Seems to be originating from near the oil filter, perhaps above it, but not from the join with the block. Oh hell, figure it out later. I put a new oil pump in with the build, hopefully that would have sorted out any leaks around there - or HAS it... Hmm. I should take the top timing belt cover off - I'm sure the belt would be oily if it's from there. I used non-hardening sealant (vegemite stuff) on sump and rocker cover gaskets :D
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
Power Moderator
Power Moderator
Posts: 962
Joined: Wed Sep 14, 2005 2:59 pm
Location: Melbourne (Orstralia)

Post by IZU069 »

Seized headlight cover motor?. Disconnect it and try.

You mean yours doesn't have sequential spark? How primitive, though typically standard. (LOL)

Flywheel bearing is noisy when clutch down and box in gear. And maybe when clutching in neutral.
Thrust bearing is noisy when clutch in. (Assumes proper clearance between lever arm and pressure plate - ie, a gap when not pushed.)
Mainshaft center bearing is noisy when EXCEPT with clutch in or in 4th gear.
Other gearbox bearings... well, er....


Wash engine and car BEFORE concluding oil leak sources. Not only makes tracing easier, but even I'm amazed how oil travels (and hence misleading causes).

Light clutch? Probably an Exedy (quality, and OEM) unless custom from a few good places.
Remember - power increases do NOT effect clutches, only torque increases do.



PS - I always change thrust & flywheel bearings bearings during box/clutch replacements. That may be overkill, but it's their new price versus the hassle of a later replacement. Having said that, my current quiet thrust has at least 100,000 km with LOTS of engagement - I sit idling with clutch in (see noisy gearbox mainshaft center bearing above).
Rear gearbox seals aren't too bad to replace at anytime, but I'll do the front seal for a new box, and maybe if removed. (Same logic as flywheel & clutch thrust bearings, albeit more hassle but more damage if the seal leaks - ie, oiling of clutchplate.)
And I replace engine main seals (except the internal rears on my typical G-OHV & some G200Ws). My working 4ZE1-t is still on its stand awaiting this minor job (since its extraction in 2005).
Dizzy & gearbox-speedo O-rings can be replaced anytime. (Got a good tool for removing the dizzy cap in situ?)
Oil pressure switches and senders should be checked at intervals (loose progressively leaks until the final drop out and engine seizure).
And of course check all hose clamps at regular intervals - they will loosen, especially on new hoses.
IZU069 - ISUZU means a lot to me.
User avatar
archangel62
Senior Member
Senior Member
Posts: 233
Joined: Sun Aug 14, 2005 7:07 pm
Location: Adelaide, South Australia

Post by archangel62 »

Good idea Peter, I'll give that a shot.

PROGRESS. It's the turbo.

After getting the car on stands, pulling off the gearbox brackets and inspection plate, discovering the flywheel teeth are a little chewed, and spacing the starter motor with washers.... it was still doing it.

Then my mechanic mate rocked up and used the screwdriver-to-ear trick and decided it was the turbo. So I removed the dump pipe, and through the noise it was still very present (didn't narrow it down much). Decided to check that the turbo was getting oil.....

......

Well, there was oil RESIDUE there, but it wasn't getting any oil supply. Seems that whilst I was putting the engine in car, some stupid f***ing insect packed all of the small holes in the engine with dirt. I thought I'd cleaned it all out, but some dirt had completely blocked the turbo oil supply from the block, starved it, and absolutely LUNCHED the turbo.

Checked the shaft play - it's around 8mm!!! She is BONED!

Cleaned out the oil fittings and blasted tons of oil out cranking, so I'll try the other turbo (now the "less f***ed of the two) and see if it runs properly. It'd also explain why it wasn't really making boost/power.

Still no bloody idea with the oil leak. Thinking oil pump, sump gasket, or front/rear main seal(s). It's not super fast, but definitely (annoyingly) present.
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
Post Reply