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Hi all, Need some help here…

Is it possible to install the mentioned 12:1 Wiseco pistons with 79.5mm without honing and boring out the 1zz cylinder? I am a bit confused why Wiseco makes the piston oversized but not stick to stock bore 92mm.
A million thanks in advance!
 

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Thanks!

I am not looking for much peak power gains. I am hoping for 170ish hp. I am aiming for a wide torque band and a useable engine on the street.

That's good enough for me. I am mostly interested in reliability of Wiseco pistons in the 1ZZ. The other option here is OEM 3ZZ pistons. 3ZZ is the 1.6l variant with 10mm less stroke. That gives the 1ZZ 11.67:1 compression. I have that 3ZZ in my 02 Corolla with 1ZZ throttle body and intake - has 130ish hp, but loves to rev. Great engine with the short gears.

Yeah and it is reeeeaaallly expensive. I pay 820€ per year for my MR2 (insurance and taxes which are 550).
Friend of mine pays 4400 per year for his R35 GT-R with 550hp.

Of course, we have a annual technical inspection, where you have like 1 month to come back after failing. Also they can put the subject tested to "fail" or to "dangerous", where the police can confess your license plates e.g. brakes with completely worn pads, or oil leak that catches the suspension. The technical inspection includes emission testing - limits for injected petrol engines with O2 Sensor and catalytic converter: 60 ppm of HC and 0,3Vol% CO and Lambda 0,97 to 1,03 at idle and high idle (2000-3000rpm engine warm).
Not really hard to fulfil. This is for every car from legislation EU1 to EU6d.

Here's the deal with tuner cars:
Every change in suspension geometry - even lowering, every change in power, lights, environmental subjects (i.e. noise) and so on has to be approved. So you can have a Nissan S14 with HKS silent high power exhaust legally, but you will have to pay a civil engineer to have a look and then write a certificate which goes to a department of the government. That's expensive as hell. We're talking 4 digit numbers for a tuner car, that has a coil over suspension, some wheels, and a exhaust system. I am not interested in those kind of payments....
Regarding power: You can up the engine's output to the limit of 30% more than standard. Over 30% you are asked to have a full emission legislation to insure that the a emission legislation is not under the car's basic legislation (e.g. MR2 is EURO 3). Such a legislation test is really expensive and also quite hard to fulfil with a tuning engine.
and with more power legally you will pay more taxes.

Those reasons lead me to an engine build which cannot be exposed by the police or the technician that does the annual test.

But I am grateful for any advice on 1ZZ builds and parts.

Mostly forgot - this is what it looks like now.
I really don't want to get rid of the little red sports car. :D

BR,
Dom
Mate, does it work installing oem 3zz piston into 1zz that will raise compression ratio? I wonder if 3zz piston would hit 1zz cylinder head. Thanks a lot!
 

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2000 MR2 1ZZ, 2002 Corolla 3ZZ, 2008 Avensis Estate 2AD-FTV
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Discussion Starter · #23 ·
HI,

first, no. the ZZ (except 2ZZ) have all the same bore: 79mm. so for 79.5mm.
92mm Bore?! The bore center of every ZZ (inlcuding 2ZZ) is 87mm, how would a 92mm piston fit?
the 1ZZ has 91.5mm stroke, the 3ZZ has 81.5 and the 4ZZ 71.3mm, respectively...1.8/1.6/1.4l.
Yeah you can swap the 3 or 4ZZ pistons into the 1ZZ. The difference is the depth of the piston cavity.
But be aware, that a 3ZZ raises the compression ratio to 11.3 (i did the calc some years ago,I hope i remembercorrectly.)
4ZZ to 12.5 or12.7 not sure anymore, but the vicinity was about that.

So with either piston, some recalibraiton of the ECU or different ECU will be needed.

There are 1ZZ heads out there which are virtually the same compared to 3 or 4ZZ. Thing is: 1ZZ have laser cladded valve seats and 3/4ZZ do not. But the lower power 1ZZ has the same valve diameter and lift. Only the celica/MR2 1ZZ has slightly bigger valves and different cams to gain the incredible 11 to 14 metric hp. But


br
Dom
 

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HI,

first, no. the ZZ (except 2ZZ) have all the same bore: 79mm. so for 79.5mm.
92mm Bore?! The bore center of every ZZ (inlcuding 2ZZ) is 87mm, how would a 92mm piston fit?
the 1ZZ has 91.5mm stroke, the 3ZZ has 81.5 and the 4ZZ 71.3mm, respectively...1.8/1.6/1.4l.
Yeah you can swap the 3 or 4ZZ pistons into the 1ZZ. The difference is the depth of the piston cavity.
But be aware, that a 3ZZ raises the compression ratio to 11.3 (i did the calc some years ago,I hope i remembercorrectly.)
4ZZ to 12.5 or12.7 not sure anymore, but the vicinity was about that.

So with either piston, some recalibraiton of the ECU or different ECU will be needed.

There are 1ZZ heads out there which are virtually the same compared to 3 or 4ZZ. Thing is: 1ZZ have laser cladded valve seats and 3/4ZZ do not. But the lower power 1ZZ has the same valve diameter and lift. Only the celica/MR2 1ZZ has slightly bigger valves and different cams to gain the incredible 11 to 14 metric hp. But


br
Dom
A million thanks for the great tip Dom. Kindly ignore and apologies for that 92mm bore for I am working on Subaru VAB EJ207 engine hence mixed it up.

Valve won’t hit if I use 3zz piston.. I hope?
 

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MWR used to sell an 82mm big bore Wiseco kit in both 12:1 and 8.8:1 for the 1ZZ, that required more machine work $$ than most wanted to put into a 1ZZ.

In order to use the kit, I had the oem liners be pressed out, the block bored larger to accept larger outside and inside diameter custom cast iron sleeves (from Darton or LA Sleeve), the block assembly final bored and honed, the and the block decked to get everything co-plannar for good head gasket sealing. A special Cometic head gasket is also required.

I used the 8.8:1 kit, and from my experience with other engines, would not recommend 12:1 for pump gas use (unless you can get 104 or greater octane at the pump down under, maybe E85 would work with bigger injectors and tuning). My rings seated quickly, it's been great for 30k miles, and has 100% stock appearance. The power increase from greater engine displacement is noticeable, the math says 7% or so, not comparable to say, a turbo. I've never driven a 2ZZ swap.
 

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Hi all, Need some help here…

Is it possible to install the mentioned 12:1 Wiseco pistons with 79.5mm without honing and boring out the 1zz cylinder? I am a bit confused why Wiseco makes the piston oversized but not stick to stock bore 92mm.
A million thanks in advance!
The simple answer is no. Piston-to-bore clearance tolerance is extremely tight and the only practical way to achieve correct tolerances is to start with freshly bored cylinders that are very slightly undersized and have the final honed diameter matched to the measured piston diameters. The machine shop will need your piston set. Also understand that piston design is much more complex than diameter and compression ratio. Every production piston has a custom-designed ovality and profile specific to the engine. That is why aftermarket pistons generally have poorer oil control and noise than OEM. Quote from Ernst Mahle, founder of Mahle Pistons Co,: definition of a piston: "A device equally suited to powering an engine as it is to making an engineer humble"

Dave
 

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The simple answer is no. Piston-to-bore clearance tolerance is extremely tight and the only practical way to achieve correct tolerances is to start with freshly bored cylinders that are very slightly undersized and have the final honed diameter matched to the measured piston diameters. The machine shop will need your piston set. Also understand that piston design is much more complex than diameter and compression ratio. Every production piston has a custom-designed ovality and profile specific to the engine. That is why aftermarket pistons generally have poorer oil control and noise than OEM. Quote from Ernst Mahle, founder of Mahle Pistons Co,: definition of a piston: "A device equally suited to powering an engine as it is to making an engineer humble"

Dave
Just to add to what you said Dave, the piston to bore clearance is determined by the combination of diameter and the larger variable, aluminum composition (which drives operating temp expansion). The latter is mainly driven by the percentage of silicon within the alloy.

As a rule of thumb, race pistons use lower percentages of silicon, which make them a little more malleable, but have a higher thermal expansion per unit bore diameter. Conversely, the additional silicon added to production car pistons reduces their expansion, with makes them quieter at start up, but makes them a little more brittle. This makes a difference when redesgning an engine to now rev much higher than the factory ever intended, accidentally over reving the engine in a race situation, and very importantly stroking an engine which increases piston speed, sometimes causes dangerously high piston speeds, which can rip the pin boss out of the piston, which is all bad in a race engine.

I love the quote; not to follow the rabbit hole too far, but I had the good fortune to talk with an aerospace engineer working a little out of his field, with Formula 1 team, on a novel piston design and very unique material. We had quite a conversation. I think he said the FIA 'leaned in' on the situation before the design was ever fielded, due to the toxic nature of the piston material. Development was stopped well before he and I talked.
 

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Just to add to what you said Dave, the piston to bore clearance is determined by the combination of diameter and the larger variable, aluminum composition (which drives operating temp expansion). The latter is mainly driven by the percentage of silicon within the alloy.

As a rule of thumb, race pistons use lower percentages of silicon, which make them a little more malleable, but have a higher thermal expansion per unit bore diameter. Conversely, the additional silicon added to production car pistons reduces their expansion, with makes them quieter at start up, but makes them a little more brittle. This makes a difference when redesgning an engine to now rev much higher than the factory ever intended, accidentally over reving the engine in a race situation, and very importantly stroking an engine which increases piston speed, sometimes causes dangerously high piston speeds, which can rip the pin boss out of the piston, which is all bad in a race engine.

I love the quote; not to follow the rabbit hole too far, but I had the good fortune to talk with an aerospace engineer working a little out of his field, with Formula 1 team, on a novel piston design and very unique material. We had quite a conversation. I think he said the FIA 'leaned in' on the situation before the design was ever fielded, due to the toxic nature of the piston material. Development was stopped well before he and I talked.
The high Silicon alloys are more brittle but have higher hot strength
 
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