Reinforced valve spring kit Nissan RB20DE RB20DET

€1,193.99 (tax incl.)

Reinforced valve spring kits for the Nissan RB20DE and RB20DET 2.0 24V engines.

Brand: SUPERTECH
Engines: RB20DE, RB20DET
Springs: single or double
Contents: springs, titanium upper retainers, lower spring seats

Nissan engines covered

These kits are made for the RB20DE and RB20DET, 2.0 litre straight-six engines with twin overhead camshafts and 24 valves, naturally aspirated or turbocharged, with hydraulic tappets, fitted to the Skyline R31 and R32, the Laurel C33 and C34 and the Cefiro A31.

Originally each valve is closed by a spring numbered 13203-58S00, and collets 13210-D4200 lock the assembly. The 24 valves therefore call for 24 springs.

SUPERTECH reinforced valve spring kit

Each valve must drop back onto its seat as soon as the cam lets go of it. If the spring lacks firmness at high rpm, the valve leaves the cam, bounces on closing and may end up against the piston crown; a higher load removes this valve float.

The two kits quote 311 N and 374 N at the seat, for installed heights of 32.8 mm and 39.5 mm.

Valve spring kit technical specification

Part number	Brand	Springs	Outer / inner Ø	Seat pressure	Open pressure	Rate	Max lift	Kit contents
SPRK-2081-RB20	SUPERTECH	Single	Outer 27.5 / 20.0 mm	311 N at 32.8 mm	694 N at 9 mm	42.7 N/mm	12.1 mm	24 springs, 24 titanium upper retainers, 24 lower spring seats
SPRK-M1005D-RB20	SUPERTECH	Double	Outer 28.1 / 20.0 mm Inner 20.0 / 15.2 mm	374 N at 39.5 mm		45.8 N/mm	16.0 mm	Springs, titanium upper retainers, lower spring seats

Valve spring kit fitting details

Part	Nissan original	Reinforced spring kit
Spring	13203-58S00	Kit specific; SPR-M1005D for the double kit
Retainer		Kit specific: RET-NVG1015/T1 (titanium)
Spring seat		Kit specific: SEAT-SS2820-2.2 (single); SEAT-RB25-E (double)
Collets	13210-D4200	Original kept

Each SUPERTECH kit includes the springs, the titanium upper retainers and the lower spring seats; the single kit covers 24 pieces of each, one per valve. The original collets stay in use.

With the valve closed, the fitting dimension separates the lower spring seat, on which the spring foot rests, from the upper retainer at the opposite end. It is 32.8 mm for the single kit and 39.5 mm for the double kit. The stiffer the spring, the faster its load drops as this figure grows; each kit is identified by its reference in the adjacent table.

	SUPERTECH
Installed height	32.8 / 39.5 mm
Seat pressure at this height	311 / 374 N

Technical guide

Our brands

SUPERTECH is a Californian equipment maker born in motorsport, which has designed springs, retainers and valves for engine builders for three decades. Each spring, coiled from chrome-silicon-vanadium alloy steel, goes through an ultrasonic and X-ray check before delivery.

How to choose

With a high load the valve hugs the cam profile all the way up the rev counter: raised red line, more aggressive camshaft, higher turbo boost on an RB20DET. The single allows 12.1 mm of lift and the double 16.0 mm; the chosen camshaft must stay below that figure. Beyond that figure the coils touch and the spring can no longer compress, so leave a margin between cam lift and the kit's maximum lift.

Criterion	Key point
Choosing the pressure	Lbs denote seat load in pounds: 70 lbs equal 311 N, 84 lbs equal 374 N. The single, softer, suits a reasonable build; the double, firmer, accepts higher lift and revs. Weigh camshaft, target revs and boost pressure; oversizing brings no gain and will tire the camshaft lobes.
Single or double spring	Compact and fitted with its own retainers, the single suits tidy builds; the double combines two concentric coils, each taking part of the effort while braking the other's vibrations, the solution for heavily stressed engines. In both kits the upper retainer is titanium. Each kit supplies the retainers it needs.

When reinforced springs become necessary

Camshaft with greater lift
Raised red line
Turbo added or boost pressure raised (RB20DET)
Head redone for circuit or rally work
Worn springs or valves floating at the top of the rev range

Compatible vehicles

Model	Engine code	Years
Cefiro I (A31) 2.0	RB20DE / RB20DET	1988-1994
Laurel (C33) 2.0 i / 2.0 i Turbo	RB20DE / RB20DET	1988-1992
Laurel (C34) 2.0 / 2.0 Turbo	RB20DE / RB20DET	1990-1993
Skyline (R31) 2.0 / 2.0 Turbo	RB20DE / RB20DET	1985-1990
Skyline (R32) 2.0 / 2.0 Turbo / 4x4	RB20DE / RB20DET	1989-1993

OEM part number (valve spring): 13203-58S00

Important: these kits are for the first-generation RB20DE and RB20DET with hydraulic tappets. The 12-valve RB20E, the RB20DE NEO (Laurel C35, Skyline R34, Stagea WC34), which has solid tappets with shims, and the RB25 and RB26 are not covered on this page.