Due for engine rebuild? What's worth upgrading? Sensible budget?

Just chuck in new rings and bearings.

Spend the rest of exhaust manifold/turbos/dumps/fuel flex sensor/injectors/fuel pump

I got 330rwkw on E85 with a conservative tune. (300kw on 98)

 

Cheers.
Unfortunately I didn't get around to re-testing compression.
I assume turbos; for the most part, would dictate airflow and power, therefore predict loads/stresses on all other components, unless these are mitigated by de-tuning.
So just rings or pistons too? (I assume mine would be flogged)

What turbos would you recommend? GT28? Where would you source your parts from?

 

Unless you are chasing 400+rwkw, i wouldn't bother with pistons and rods etc. I run it all on an unopened motor.

You can get your nistune upgraded to flex fuel, then just change fuel likes to support E85.

This is the turbo kit I have:
https://www.z1motorsports.com/z1-products/z1-motorsports/gt600r-bb-turbo-kit-p-1451.html

 

Is yours one of those 29 year old 1989 Z's with 80,000 kM's on the clock?

If it's not, then chances are the bores in the block are worn & contributing to the loss of compression.
It may have done over 3 or 400,000 km's.

If it's averaged 15,000kM/year that'd be 435,000kM's.

You'd be wasting your time putting new rings in it if the bores are worn or damaged.

You'd be wasting your time & money spending anything on that engine, until you rectify the cause/s of the low compression.

Engine oil pressure will indicate what the bearings are like, unless you're using heavy weight oil.

 

You don't need a rebuild mate. Regardless of the actual compression numbers, all are in spec of the mean except for cyl3, and it's not too far off that upping your oil viscosity would probably bring it all back to even. It's likely a small amount of wear on the valve seals or rings.

If you want more power, plenty of replies previously. If you just want to drive it, do a thorough service and put your wallet away.

 

Ok, so I've taken some annual leave for tues & wed. That should give me some time to take it for a spin and do a proper compression check. It may well be higher than the original readings. However, I'm supposed to be doing my wifes visa right now so I'll try to keep the vehicles history brief.

I've owned it since 2012. Bought it from melbourne and drove it back to sydney. The guy I bought it from was super sus. it's a 1991 model imported in yr 2000. At the time I bought it, it only had 140+k on the clock. car was not as advertised and was very rough and bad lifter tick. Wheel fell off not to long into driving it back to sydney. Was told that the slight vibrationg was just new pads bedding into the new slotted brake rotors. nek minute i'm in the middle of nowhere with 5 missing lug nuts... His name on this forum was lico... though I've never mentioned him on this forum. Nor is my name bobbs lol. I was just concealing my name in case he'd bring more drama.
Anyway... after getting it back to sydney, I flushed the crap out of the crank case a few times with about 20 litres of diesel. then did 2 normal oil changes after that. Finally started to come out clean. But one of the lifters was well seized. I think it may have been crap build up in the oil supply in the head. So I installed brand new oem lifters. Lifter tick had briefly come and go between long periods of sitting. But has now come good.
I've always used good oil. replaced filter with every oil change. I use always penrite full synthetic 10w-50 extra 10 with full zinc. I have noticed a few years ago that the oil pressure gauge was always showing very low pressure, sometimes almost zero, but I've been told that its most likely crap built up in the oil port that feeds the sensor... and the sensors are not accurate anyway.
Since I've had it since 2012... it's reading 155k on the odo. I really barely drive it, so I can believe that the kms i've added are correct. Though it wouldn't surprise me if the odo has been wound back a few times as with any import from the 90s or has passed hands through Mr 'Lico' my balls...

Speaking of balls... I'm almost tempted to just go balls to the wall and just build another motor. $12k to whatever it costs to build a 400+rwkw motor. If I fall a little short, or have to cut a few corners to save a little bit of money, it's not a big deal. Though one thing is for certain, I wont be frivolous with the parts in my budget. e.g. I'm not going to be spending $1000 on overpriced bling like adjustable cam timing sprockets etc.

This build will be strictly function over form. Any amount of bling will be in the form of a rattle can, sand paper and elbow grease.

I guess I'll have to plan out the build budget by what core hardware would be necessary to make that power, then double that figure for parts to handle that power, then double again for parts to put it all together + tuning etc etc. So I can see this becoming very expensive, very quickly.

Another personal point to note is: In the next 5+ years or so; I may permanently move back to japan with my waifu. If that indeed happens, I will be taking the zed with me. Sure, I'll have to deal with shaken etc, but as far as I see it, this is the last sports car I will ever own, let alone build. I've learned this lesson twice already when I sold my old celica and motorcycle which i fully rebuilt from the ground up. So any money I spend on this project will stay with me until either government takes away my license when I'm an old fart.

Having said all of this, I don't want to be making so much power that I'll shred the freshly rebuilt gearbox or splitting the engine block in half, throwing a rod out the side, spitting out an exhaust valve or completely ruining a nice set of turbos. I'm not 100% sure of what I should expect a stock block to take or what it would cost to get anywhere near that limit, though I assume costs would increase exponentially and I'd probably be better off with a VR38DETT swap or something... Though historic rego is then out the window...

Anyway, hopefully thats enough background for now. I've procrastinated enough with this visa application... I'll report back mid week.

 

Have you thought about making this into a mini series? Sounds like you have already made up your mind and going to build another motor! Just do it, you are never going to be happy with this engine.

 

LOL I kicked up a big stink at the time on another forum. He was since banned from there, so I was just glad to get away from it. I've usually made detailed build threads for other projects before, but I've found it just becomes a hindrance... I'll probably take a few pictures during the build though. I'd probably share them when either the build is finished or if I need help. On the other hand, I've found that having positive encouragement from people helps keep me motivated to get the job done. Now that I think about it, when I just leave it to myself, I never really make any serious progress... So maybe I will start a build thread... It might even be fun

 

Mate, do yourself a favor, give it a good service, put a couple 1000kms on ut then do a compression test. If its been sitting, seals go hard, valves and rings have bern sitting in the same place etc, needs a good run to really free everything up. Those figures are fine, if you decide your pulling it out to upgrade turbos maybe look at a hinecand re-ring at the same time depending on the power your chasing. Personally i would run it as it is, wind the boost up a tad if your keen but 245rwkw is pretty damn good, being an auto that will be punchy off the line.

 

Converted to manual actually. It is a bit punchy... but its not v8 level of torque. not much down low. mid range is good then feels like it runs out of puff on top end... less than linear I'd say.
What do you mean exactly by a 'good service'? I've only put down a few tanks of fuel since last oil change+filter. I've probably changed the oil less than every 4000km. I wish I could drive it more often.
not that I really care for the stock turbos... so if I were to, as the kids say: "send it"... how much do you think I could push the stokies without leaning out on the mixtures? I suppose the sooner they blow, the sooner I can go shopping

 

It's already at 15psi... so I guess its got nothing left in it then :/

 

Cheers. I guess its no slouch. Suppose I'll just have to enjoy driving it as much as possible before I torture myself with another rebuild project.
Perhaps maybe upping oil viscosity might help bring back a little compression in the meantime?
I suspect maybe 10w-50 might be too thin on a worn motor, especially in summer?

 

Sorry for zombie thread revival... But it looks like you were right... I think I now have blown the head gasket its now drinking water and blowing bubbles

So I guess the time has finally come for the dreaded rebuild. After getting rego, I'd be lucky I drive it even once a month out of fear of making things worse, so I don't think there is much point sourcing another engine to build as apposed to just rebuilding the engine I already have.

So I guess the question now is what would be a good budget shopping list of parts I should be looking into? I'm guessing a modern turbo kit, new bearings, oversized forged pistons, bore, hone, deck and blueprint. Though is it even worth looking into rods, cams or even porting and valve job?

It's easy to see how a simple blown head gasket can snow ball into a $10k+ headache... which is not ideal as I'm not that much closer to buying a house here or over seas as the Aussie dollar has been hit hard... speaking of which, buying parts from overseas is going to sting... $1 AUD to $0.67 USD... ouch. Or maybe I should just slap on a new gasket and hope for the best and just wait it out for a bit?

 

I'm happy to take it off the road for a while.

The bigger problem is I have no idea what I'm doing in terms of part selection lol. My thought process is usually - "oh that looks cool - i want that" Though it's not necessarily the wisest of ideas...

After a little bit of online clueless clicking, I've made 2 silly wish lists which are very detached from reality and what some would consider reasonable and rational thought... Try not to laugh too hard

Local Supplier UAS
ACL/Ross Racing Pistons $1,250
ARP Main Stud Kit $185
Nismo Fuel Injectors $220
Scat Forged Conrods $895
Supertech Valve Springs $645
Supertech Valves $950
Valve Guides $495
Walbro E85 416L/h Fuel Pump $240
GT28 Ball Bearing Turbo 400kw kit $4,200
5 Bolt Dump and Engine Pipes $1,295
Total Price $10,375

Alternate Parts List CZP
Wiseco Piston & Eagle Connecting Rod & Rebuild Kit + bits $2,870
Supertech Valve / Dual Spring / Titanium Retainer / Viton Seal $1,696
JWT Camshafts $1,379
Low Profile Engine Mounts $575
ARP Chromoly Head / Stud Kit $435
JWT Sport 700 Ball Bearing Turbos w/ 3" Downpipes $4,749
Total Price $11,704

And thats just some of the big ticket items that first came to mind, so thats excluding all machine work and all other minor/sundry items. So the price tag is really getting up there

Clearly my heart needs a reality check with my wallet. I mean I have more than enough cash... it just doesn't seem like a balanced build... So what sort of list would you guys recommend? I'm sure there are better value for money options and I'm sure some of those parts I've chosen are a waste of money. Thoughts?