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Correct me if im wrong but isnt the 4ZC1 an 86mm bore whereas the G200z uses a 87mm bore?

G200w would be an aftermarket setup as the only factory turbo petrol engine built by Isuzu was the 4ZC1. Im currently looking at building a G200 DOHC Turbo for my Gemini.

Nick-

Correct the G200Z book says 87mm bore 82mm stroke for 1949cc.

The 4ZC1 is an 88mm bore and 82mm stroke. Not sure on the cc.

At 1mm O/S you could fit the turbo 4Z pistons one would suppose provided they had the right pin to deck height etc.

But then you have to get good pistons worthy of fitting, If you were getting that serious one would doubt the std pistons were up for the duty.


Ive been meaning to ring and ask about O/S pistons for the RB30ET. Im sure you could get them forged in 2mm O/S. Trouble is you have to build 3 motors to make it worth while. And you would have to make sure that the two sets of pistons you used were from the same manufacturing batch to be on the safe side.

Cheers. Bob.

What I was saying before in response to a previous question was that the rings for the turbo and non turbo are the same for 4zc1 engines but the compression ratio is higher on the non turbo

wedgenut wrote:What I was saying before in response to a previous question was that the rings for the turbo and non turbo are the same for 4zc1 engines but the compression ratio is higher on the non turbo

That was being debated over on the ozgemini site.

Some litrature says the Piazza has the same comp ratio as the shuttle. In different material the Piazzas comp ratio is refered to as 7.9:1 and 8.2:1 the same as the shuttle. Ive got a sales brochure here for the Holden Piazza and it says 8.2:1 on the back cover, it also gives the bore as 87mm for the piazza.

Untill i strip a Piazza bottom end no one will know for sure.

On the bore sizes, im guessing that theres a bit of rounding up or down going on. The two larger motors (2.3 and 2.6) have point something bore sizes.

The 4CZ1 is 1994cc which would have slightly bigger bore than the G200 at 1949cc

Cheers. Bob.

I have both G20o and 4zc1 enguines in pieces and the manuals are correct regarding bore sizes of 87 and 88 no question. There are also two different compression ratios in the 4zc1 for turbo and non turbo. This is achieved by the shape of the piston top. but no difference to bore or rings.

The G200 engine also has two different comp ratios for different markets/fuels and again piston shap is involved as well as the compression lenth (pin to crown measurement) Two ring types as well in both ratios so you have to be careful what you buy regards matching

yeh bob
the cc that is current on 4ZC1 is 1994cc

cheers

Josh

I can say that the Holden workshop manual states the static CR is 7.9:1. That sounds about right for a turbo engine with a wastegate setting of 6.9psi - 7.4psi (which are the specs noted in the same manual).

Also, ACL produce aftermarket replacement pistons for the 4ZC1 used in the holden Shuttle van but not for the 4ZC1-T Piazza engine so one can assume there must be a significant difference in the two pistons or they would cross reference.

Oh they are different for sure, I have some of each (buggered ones) the non turbo is a flat top where the turbo is dished down

wedgenut wrote:Oh they are different for sure, I have some of each (buggered ones) the non turbo is a flat top where the turbo is dished down

Ive got a shuttle short motor here and its got dished top pistons in it. Ditto with the 2.3L and 2.6L motors.

Bob.

Something has occured to me, not sure if anyone else has caught on...but..

Anyone ever thought that the CR may be listed as different values in different brochures [theres the biggest clue ] due to the market the car is being sold in? From what ive seen/researched, i think the Jap Piazzas had 8.3:1 where as the aussies had 7.9:1 - Japan has 100RON fuel, where as Aus only had what, a measly 92 at the time?

Would also explain the differences between the shuttle compression ratios too. Somehow, Australia gets watered-down everything. As if being entirely surrounded by water wasnt enough...

Nick-

Yeah wedgenut you quoted 8.8:1 for the 4ZC1 non turbo in that other post since the ones here have 8.3 that probably explains the dish.

JDM Piazza power is quoted at 150hp, so is the Australian one and they both have the same engine management and run the same amount of boost. I would've thought it would not be possible for them to have the same power if one had a compression ratio less than the other.
On the other hand the American Impulse had 140hp although with different engine management and the compression ratio is specified as 7.9:1.

Only 2 documents i've seen on the Aus Piazza specs is the brochre (8.2) and service manual (7.9). The service manual does have a few mistakes though with LHD stuff put into it so they might have got the engine specs mixed up or something.

Found this mistake recently cant remember where the others were though..

Yeah I saw that one in my maual as well, all the ones I have seen have a pedal box with a lateral shaft taking it over to the right but who knows look I have a gearbag i took out of a 1983/84 manual and it had a cable clutch with the pedal in the same place as the hydraulic ones and a different fork of course. The pedal box was different too to allow for pull instead of push Even bonnet release is a lottery as some have cables and others have the lever action pull down. The solution to all of this is that it was conceived by an italian working with the japanese and neither of them can translate any word properly into english. Shit if you look at some professional translations they are lousy as well. It is surprising therefore that in the specs under compression ratio we actually get numbers at all! We could have got "sqeueeze amount is more than a bit to not very much" AH SO!

haha yea there are so many spelling mistakes heres a few I found


They've got a problem spelling "component" it seems. Different spelling every time but hardly ever correct. Oh and what's a door morro? and it's ECGI not ECG1 lol

The funniest i ever saw was in a Honda manual where it said, "it is not possible to be going too slow in the high gear" Oh really! Tell that to all the nuns driving honda civics in the fast lane at 1.3km/hr.

PS "Hondu" is not my spelling error , that's the way it was in the manual, they couldn't even get their own name right. Thot eyed beter ecksplane that in cais yo tink eye downt spel gud eethir