2JZ Pistons
Which pistons for 2JZ?
Everything about forged pistons for 2JZ. Here we have gathered all the information about pistons for the 2JZ. Everything you want to know. Which pistons should I choose? How do I install them? And much more.
2JZ Compression Ratio
What is the compression ratio of the 2JZ?
Original compression ratio GTE: 8.5:1 (Turbo)
Original compression ratio GE: 10.5:1 (N/A)
When building a 2JZ engine with turbo, the compression ratio in the most common builds usually ranges between 8.0:1 and 9.7:1. Most who use ethanol as fuel can increase the compression ratio and thus achieve a generally stronger engine, especially at low RPMs.
2JZ-GE vs 2JZ-GTE Pistons
Is there any difference between 2JZGE and 2JZGTE pistons?
Answer: Yes! Since the GTE model has a turbo and the GE model does not, the compression ratio for the turbo model needs to be lower. The 2JZ-GTE has a compression ratio of 8.5:1, so the pistons have a recessed crown (dish). The GTE model also has oil cooling jets.
The GE pistons are generally weaker as they do not need to withstand the same combustion pressures as the GTE, which is the turbo model.
2JZ Original Pistons
Data on original pistons for 2JZ
Bore: 86.00mm
Compression Height: 34mm
Original compression ratio GTE: 8.5:1 (Turbo)
Original compression ratio GE: 10.5:1 (N/A)
Piston Size
What is the piston size of the 2JZ?
The standard piston measurement is 85.935-85.945 mm for 2JZ pistons. The cylinder bore is 86.000-86.013 mm inner diameter. When referring to cylinder bore or piston size, it is said to be 86mm. The piston is just under 86mm, and the cylinder bore is just over 86mm. The gap between them is called piston clearance.
Piston Pin
What is the piston pin size for the 2JZ?
Original Piston Pin
The original piston pin measures 21.997-22.006 mm. It is commonly referred to as a 22mm piston pin. A suitable connecting rod has a small end that is 22mm. There should be a sliding fit between the bushing in the small end of the connecting rod and the piston pin. Even though these values are very similar, this measurement can still vary between different manufacturers of piston pins and connecting rods. Therefore, the fit between the connecting rod's small end and the piston pin should be checked. If it is not a sliding fit, the bushing must be honed.
HD Piston Pin
An HD piston pin typically has a thicker wall thickness to withstand more power/force, but it can also be made from stronger materials that can handle more stress. This is done to keep the weight down. When upgrading pistons, it is also common to upgrade the piston pin, as this is a relatively inexpensive and straightforward adjustment when all the parts are already disassembled.
Compression Height
What compression height should I use for the 2JZ?
The compression height of the original 2JZ pistons is 34mm / 1.338". This is also the most common measurement in the aftermarket when tuning the engine. Sometimes a longer connecting rod or stroke length is used, and to compensate for this, one can use a lower compression height for the piston, such as 32mm, which is available for the 2JZ engine.
Pistons and Connecting Rods - Combinations
Toyota 2JZ Block Height is 219.00mm
Standard Crankshaft ~3 liters
Stroke Length: 86mm / 2 = 43mm
Connecting Rod Length: 142.00mm
Compression Height: 34mm
Total: 43+142+34=219mm
92mm Stroker Crankshaft ~3.2 liters
Stroke Length: 90mm / 2 = 45mm
Connecting Rod Length: 142.00mm
Compression Height: 32mm
Total: 45+142+32=219mm
94mm Stroker Crankshaft ~3.4 liters
Stroke Length: 94mm / 2 = 47mm
Connecting Rod Length: 142.00mm
Compression Height: 30mm
Total: 47+142+30=219mm
Stroker Pistons
The original stroke length of the 2JZ is 86mm with a compression height of 34mm on the piston. With a stroke length of 94mm, the piston’s compression height needs to be 30mm to compensate for the stroke. Both options are with a 142mm connecting rod.
With a 90mm stroke and a 142mm connecting rod, the piston’s compression height would need to be 32mm instead.
Piston Rings
What piston rings does the 2JZ have?
The original piston rings for the GT and GTE models are the same, except for the piston ring gap. The gap is larger on the turbo model. Aftermarket pistons usually come with piston rings. In this case, you need to set the correct piston ring gap yourself. If piston rings are not included, there is an exact part number available for purchase.
Thickness of piston rings for 2JZ-GE and GTE:
Piston Ring 1: 1.5mm
Piston Ring 2: 1.5mm
Piston Ring 3: 4.0mm
Piston Material
The manufacturing and design of pistons are the most critical factors in determining how durable a piston will be. Forged pistons for the aftermarket/tuning are made from 4032 and 2618 alloys. Depending on the intended use of the pistons, one material or the other will be used.
Pistons vs Power
Most aftermarket pistons can handle over 200hp per cylinder. OEM pistons are often not recommended to exceed 100hp per cylinder due to various reasons such as ring land, piston crown, casting, piston rings, weight, cooling, etc. Aftermarket pistons are designed to withstand more power than the originals and are therefore correctly adapted for the intended purpose.
While this cannot be said for all pistons, in general, a heavier piston is stronger than a lighter one, provided they are used in the same application with the same performance in mind. However, both pistons are likely capable of handling more power than what is needed.
Wiseco vs JE vs CP vs DP?
The different piston manufacturers all have their pros and cons, but in summary, they are quite similar to each other. If one manufacturer has a "street" variant of a piston, another manufacturer also has a corresponding piston with similar specifications. The same applies if they have a "drag" or "drift" variant. Reinforcement, ring land, and piston crown are some examples of what may differ, but none make a poor piston. Here, one can delve into the differences, where the saying "measurable but not noticeable" fits well.
Piston Clearance
Piston clearance is the measurement between the cylinder wall and the outer diameter of the piston. Outer diameter of the piston - Inner diameter of the cylinder wall = piston clearance. If you order a piston that is 87.00mm and the block is precisely bored to 87mm, then the piston manufacturer's predetermined clearance will apply. This can vary slightly between piston manufacturers but is similar if the pistons are made for the same purpose, such as street driving or drag racing. Piston clearance can also be adjusted by honing the cylinder.