4.5L 24v - 1FZ-FE

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4.5L 24v - 1FZ-FE

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Reinforced valve spring kit Toyota Land Cruiser 1FZ-FE

New product

Reinforced valve spring kits for the Toyota Land Cruiser and Lexus LX 450 with 1FZ-FE engine.

  • Brand: SUPERTECH
  • Engines: 1FZ-FE 4.5 24V (Land Cruiser 70, 80, 100, Lexus LX 450)
  • Springs: double
  • Contents: springs, upper retainers, lower spring seats and stem seals

More details

1 154,78 € tax incl.

  • Toyota 1FZ-FE engine covered

    The 1FZ-FE is the 4.5 litre, 24-valve straight-six fitted to the Land Cruiser 70, 80 and 100 and to the Lexus LX 450. A high-torque engine, it is used for towing and off-road driving.

    The kit replaces the original spring and its upper retainer; the original lower spring seat stays in place.

    SUPERTECH reinforced valve spring kit

    Valve float is what happens when a spring lacking firmness lets the valve bounce on its seat or reach the piston. On a straight-six that tows, no valve can close late.

    Seat pressure: 276 N at 36.2 mm for the SPRK-H100DR-1FZ, 365 N at 36.2 mm for the SPRK-H1000D-1FZ and 445 N at 36.2 mm for the SPRK-H1005D-1FZ, all with double springs.

    Valve spring kit technical specification

    Part numberBrandSpringsOuter / inner ØSeat pressureOpen pressureRateMax liftKit contents
    SPRK-H100DR-1FZSUPERTECHDouble276 N at 36.2 mmSprings, titanium upper retainers, lower spring seats, valve stem seals
    SPRK-H1000D-1FZSUPERTECHDouble365 N at 36.2 mmSprings, titanium upper retainers, lower spring seats, valve stem seals
    SPRK-H1005D-1FZSUPERTECHDouble445 N at 36.2 mmSprings, titanium upper retainers, lower spring seats, valve stem seals

    Valve spring kit fitting details

    PartToyota originalReinforced spring kit
    Spring90501-38006Kit specific: SPR-H100DR, SPR-H1000D or SPR-H1005D
    Retainer13741-66020Kit specific: RET-H70/T1
    Spring seat13734-66020Kit specific: SEAT-H/N240, original seat kept
    Collets90913-03027

    The three kits pair a double spring, SPR-H100DR, SPR-H1000D or SPR-H1005D, with RET-H70/T1 titanium upper retainers for 7 mm stems, the SEAT-H/N240 part and VS-T7E valve stem seals; the original lower spring seat is kept.

    Installed height, measured with the valve shut, is the span between the two retainers. The table loads hold for that exact span only; if it grows after the cylinder head face is machined, force drops in line with the spring rate. Each kit appears in the next table with its seat pressure, all three at the same 36.2 mm height.

    SUPERTECH
    Installed height36.2 / 36.2 / 36.2 mm
    Seat pressure at this height276 / 365 / 445 N

    Technical guide

    Our brands

    SUPERTECHSUPERTECH is a Californian manufacturer whose business, for over thirty years, has been valvetrain parts for motorsport. Before it is shipped, each lot of springs undergoes laser, ultrasonic and radiographic tests, so that no internal defect gets through.

    How to choose

    More force at the seat keeps the valve on the cam when the engine asks for more: a sharper camshaft, added boost, higher revs for the trail or the track. The three kits give 276, 365 and 445 N at the seat, quoted at the heights of the table above. Do not pick the firmest kit by default: excess load wears cams and tappets and returns nothing. The gap between the two extreme kits is 169 N.

    CriterionKey point
    Choosing the pressureThe pound figure (62, 82 or 100) refers to the force on the closed valve; the table translates it into newtons. To settle, compare your camshaft lift, the engine speed targeted and the boost pressure: each of them raises the need. Under the need the valve floats; beyond it you wear the valvetrain for no gain.
    Kit contentsEach kit contains RET-H70/T1 titanium upper retainers, the SEAT-H/N240 part fitted on the original lower spring seat and VS-T7E valve stem seals. A double spring nests two concentric springs on each valve, and it is the only thing that sets the kits apart: SPR-H100DR, SPR-H1000D or SPR-H1005D.

    When reinforced springs become necessary

    • New camshaft with more generous lift
    • Limiter raised to turn faster
    • 1FZ-FE fitted with a turbo or supercharger
    • Head restored for crawling, raids or track days
    • Original springs aged by years of towing

    Compatible vehicles

    ModelEngine codePowerYears
    Land Cruiser 70 (J7) 4.5 4x4 (FZJ75, FZJ78, FZJ79)1FZ-FE1992-2009
    Land Cruiser 80 (J8) 4.5 24V (FZJ80)1FZ-FE1992-1999
    Land Cruiser 100 (J1) 4.5 (FZJ100, FZJ105)1FZ-FE1998-2008
    Lexus LX 450 (FZJ80) 4.51FZ-FE1995-1997

    OEM part number (valve spring): 90501-38006

    Important: one kit is enough for the engine: pick the 62, 82 or 100 lb load.

    Related products

    Head on the bench? Check valves and guides now to spare a second strip-down. The links below open the 1FZ-FE inlet and exhaust valve pages:

    Toyota Land Cruiser 1FZ-FE inlet valves →
    Toyota Land Cruiser 1FZ-FE exhaust valves →