RB26DETT Cam Timing Adjustment

Adjustable cam gear on the intake side of an RB26

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SLIDING ADJUSTER

Adjustable Cam Gears Assembled 　 Checking the pistons and camshafts position with dial gauges 　 Measuring crank angle with a scale board The simple graph makes it easy to change the engines characteristics with the simple sliding adjustments of the Cam Gear. If the intake valve timing is advanced (i.e. 120° to 110°) then performance gains are achieved at low RPM. If the intake valve timing is retarded (i.e. 110° to 120°) then performance gains are achieved at high RPM. Camshafts with no dowel pin attached will require you to check the timing adjustments with a dial gauge and scale board.

EASY VALVE TIMING ADJUSTMENTS WITH PONCAM
Cam gear adjustment RB26
	The Poncams valve timing has been preset at 110°. This Valve Timing has been calculated as the best setting for both performance and drivability. You can adjust the engines performance by making adjustments with the cam Gear carefully. This easy adjustable system is a great advantage over other conventional designs. 　 The engines output character can be changed just by re-adjusting the close timing over the intake valve as shown below. - Turn Cam Gear to anti-clockwise (advanced timing): torque at low RPM- Turn Cam Gear to clockwise (delayed timing): torque at high RPM The standard Valve Timing is set to “0” on the scale. When you adjust the scale to +/- 3 on the scale (3 degrees) that will be +/- 6 degrees on the crank angle. The maximum range is +/- 10 degrees on the Cam Gear which is +/- 20 degrees on the crank angle. Please don’t move the adjustable Cam Gear from zero position until the engine adjustment has been completed. If the cam Gear has been fitted without being setup on the initial key position then the engine wills not opperate normally. If the valve timing has moved too much from the setting due to engine vibrations then the operation of the engine will get worse or in worse case scenario the pistons may hit the valves.

Cam Timing adjustments.

Intake side
Advancing timing - turning the pulley counter clockwise - you gain power at low RPM.
Retarding timing - turning the pulley clockwise - you gain power at high RPM
Most adjustable cam gears can be moved +/- 10 degrees which is 20 degrees of cam timing on most aftermarket cam gears.

• Camshafts
• Intake 8.58 240 duration 113 deg Lobe Center -R34N1 117 deg Lobe Center
• Exhaust 8.28 236 duration 125 deg Lobe Center-R33N1 120 deg Lobe Center - R34N1 121 deg
• Camshaft valve clearance check and adjustment
• Camshaft Seals - 13042-16V00 (Same as 240SX)

Camshaft lobe centers in 106 and ex 108 is best starting place
264 or 272 up to 600ps (Advancing the intake cam a little +4 degrees really helps low end response)
* Type A
Designed to best suit the stock & N1 turbos for optimum performance balance of low to mid range torque.
The Exhaust cams duration was reduced to maintain best idling.
* Type B
By extending the duration timing compared to the Type A Poncams, both response and peak power was raised and these camshafts best compliment the mid to large size turbo charged applications. 

PONCAM SPECS

	Max Cam lift (°　)		Max Cam lift （mm）		Valve Timing Centerline (Deg)		Cold Valve Clearance （mm）［±0.01］
TYPE	IN DURATION	EX DURATION	LIFT(IN)	LIFT(EX)	IN	EX	IN	EX
A	260°	252°	9.15	9.15	110	115	0.45	0.38
B	260°	260°	9.15	9.15	110	115	0.45	0.38

RECOMMENDED SETUP 

	TYPE A	TYPE B
CATALYTIC CONVERTER	Sports Catalytic Converter or Straight Pipe	Sports Catalytic Converter or Straight Pipe
TURBO	Stock or Larger Bolt On Type	N1 or Full Turbo Kit Upgrade

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Type Application Duration(IN) Duration(EX) Lift(IN) Lift(EX) Part number MSRP(USD) R BNR32,BCNR33 250° 250° 9.15 9.15 143051 $580.00 BNR34 143052

* TYPE R(for Stock Cat. Equiped Cars)）
The Type R camshafts were designed due to popular demand from end users who are looking at upgrading the performance potential of their GTR while staying within the limits of recent street legal requirements. Recent laws on emissions and exhaust noise was made stricter in Japan so to have a quieter car by running smaller exhaust systems raises the exhaust back pressure which greatly reduces the response and hinder performance. Our engineers then designed these Type R camshafts to suit the needs of those who need to keep such setup and benefit with performance gains.

KEY DESIGN CONCEPTS * To improve performance gains on cars running catalytic converters * To maximise the stock turbos performance potential. * To reduce the exhaust back pressure → Improves overall throttle response and torque → To protect the stock turbos performance limits and minimise turbo failure.
Back Pressure (for Stock Cat. Equiped Cars) Engine RPM Exhaust Pressure 7,200 rpm 1.9ｋ * J-ING Test car setup during acceleration (in 4th gear from 2,000rpm to 8,000rpm)	Peak Power Comparison (for Stock Cat. Equiped Cars) TYPE A 405 ps TYPE B 406.33 ps TYPE R 404.65 ps The peak power output is less than the Type A & Type B camshafts but the response is better with the Type R camshafts.

　 
PONCAM TYPE R SPECS

TYPE	IN DURATION	EX DURATION	IN LIFT	EX LIFT	IN VALVE	EX VALVE	IN V- CLEARANCE	EX V- CLEARANCE
R	250°	250°	9.15mm	9.15mm	110°	110°	0.45mm	0.38mm

HKS V-Cam
Variable valve timing on the intake cam. 3 different setups. Seems to be popular on GT-R's in Japan now.

Buy HKS V-Cam here

STEP1

Features

• The intake cam side of the RB26DETT is changed to allow variable valve timing. The cam has duration of 248° which seem a little conservative. However, with the variable timing, power increases can be found at low or high RPM
• Whether you are looking to find some time on the circuit through improve acceleration out of lower speed corners, or simply want something which can overtake with ease on the street, the HKS V Cam System provides good power from low RPM reducing the necessity for excessive gear changes. This especially noticeable when going from vacuum to boost to give the feeling of increased displacement.
• Improved valve timing will allow for more complete combustion leading to improved fuel efficiency and cleaner exhaust emissions.
• HKS V CAM System is compatible with the stock pistons. (When using with the thinner head gaskets or modified cylinder head, the clearance between valve and piston may be insufficient.)
• Exhaust Cam should be selected dependent on turbo choice.
  (Recommended: GT-SS-256°, GT2530-264°)

Test vehicle specification

• Engine: RB26DETT(EX-side 256°)
• Turbine: GT2530 x 2
• Intake: Super Power Flow, Airflow-less
• Exhaust: HKS Metal CAT, Legal Muffler

• Cooling: Intercooler & Piping Upgraded
• Fuel: Upgraded Pump (280R/h), I/J 600cc
• Engine Management: F-CON V Pro (D-jetro), EVC

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STEP2

Features

• Specially designed cam for Step 2 has duration of 264°, valve lift 8.7mm. Acceleration at high rpm is smoother than solid Step 1 camshaft (272IN-272EX). Step 2 is suited to higher power output at all range of engine rpm.
• Strength is enhanced when used with upgraded Valve Springs at high RPM (recommended limit 8500rpm).
• Engine output and torque are substantially improved at all engine RPM range compared to solid Step 1 (272IN/EX). Step 2 was designed to show significant power and torque improvement for vehicles tuned to output 600ps or higher compared to old type Step 1 type B (256EX).

Test vehicle specification

• HKS 2.8LKIT STEP1 φ87
• HKS Racing Suction Reloaded Intake Kit
• HKS Head Gasket 1.2mm
• HKS Fuel Delivery Kit
• HKS GT2530KAI x 2
• HKS 1000cc Injectors
• HKS Head Bolts
• HKS Spark Plug M45
• HKS F-CON V Pro

* Boost Pressure - 150kPa

* This result on the graph above is obtained by in-house engine bench test. The result may vary depending on measuring instruments

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STEP PRO

Features

• V CAM system for higher levels of tuning compared to Step 1 and Step 2.
• Specially designed cam has duration of 264°, valve lift 10mm. Reviewing cam material, profile and valve timing change, Step Pro is suited to higher power outputs at high rpm.
• Billet camshaft is used to enhance strength even when used with upgraded Valve Springs at high RPM (recommended limit 8800rpm). Added strength facilitates a hollow cam design has allowing Step Pro to be 560g lighter than Step 1 and Step 2.
• Valve timing has 50° adjustment from 80°~130°
• Exhaust cam can be selected to suit vehicle specifications.
• Step 2 Valve Springs are required.
• Recess modification of the cylinder head is required.

Test vehicle specification

• HKS RB26DETT 2.8L KIT STEP2
• Exhaust Camshaft: HKS Camshaft STEP2 272°
  Valve lift-10.2mm
• Turbine: TO4Z (Boost-1.2kg/cm2)
• CAT: HKS Metal Catalyzer

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Complete Parts

	STEP1	STEP2	STEP PRO
Special Intake "V CAM"	248°	264°	264° (Billet Construction)
Variable Valve Timing Unit(High torque compatible Vane Type, Ni plated pulley)	Variable amount 30°	Variable amount 50°	Variable amount 50°
Special Intake Cam Cover	Unpainted	Unpainted	Unpainted
Control Unit *	F-CON V Pro Ver.4	F-CON V Pro Ver.4	F-CON V Pro Ver.4
OCV (Electromagnetic type)	○	○	○
Oil Filler Cap	HKS	HKS	HKS
Cam Angle Sensor (High accuracy type)	○	○	○
Oil Line (From Engine to Cam Cover)	○	○	○
Other short parts	○	○	○

* F-CON V Pro Ver.4

• Need to set with your own car For F-CON V Pro Ver.4 setting.
• Need to purchase F-CON harness.

Other Necessary Parts

	STEP1	STEP2	STEP PRO
EX Camshaft	Select according to turbo size
HKS Forged Piston Kit	Recommended	Required	Required
HKS Oil Pump Upgrade *	Recommended	Recommended	Recommended

* Stock f77 and N1 f81 are available but may not provide ample pressure at low rpm to adjust valve timing. For this reason, HKS Oil Pump is recommended.

Notes for Usage

[RPM Limits]

STEP1      : 8,000rpm (Stock rev limiter)
STEP2      : 8,000rpm (Stock Valve Spring)
               : 8,500rpm (Upgraded Valve Spring is required/Available separately)
STEP PRO: 8,800rpm (Upgraded Valve Spring is required/Available separately)

[Oil/Water Temperature]

When Oil is at lower temperature, higher viscosity may prevent valve timing from reaching the desired figure.
Cam will not advance if water temperature is below 20℃

[Engine Oil]

Recommended: SUPER OIL (RB), Racing Pro Oil 10W-50.

[Timing Belt]

Please check for the tension and wear in every 10,000km and adjust/replace if necessary.

Parts for RB26 Timing Belt Change

Timing belt -13028-20P25
Tensioner- 13070-42L00
Idler- 13074-58S00
Tensioner Spring- 13072-58S10

Water Pump - 21010-21U26
N1 Water Pump - 21010-24U27