Air and Fuel› Superchargers, Turbochargers and Components

ScienceofSpeed

Lost Motion Assembly Kit

$487.00

SKU: HON-enpp-661

In Stock
In Stock
Ships by Sep 13
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The ScienceofSpeed Lost Motion Assembly (LMA) Kit is a replacement for the factory piston design found in early NSX models (1991-1999). This piston design is prone to seizing over time due to oil contaminants, leading to VTEC rocker rattle, potential damage, and a loud tapping sound. The ScienceofSpeed kit utilizes a more durable coil spring design, similar to newer Hondas, with precision stainless steel inserts for proper installation in early cylinder heads.
Show original supplier description
The ScienceofSpeed Lost Motion Assembly (LMA) Kit is designed to address a known issue in the 1991-1999 Honda NSX: the failure of the factory piston-style LMA. This component is responsible for pre-loading the VTEC rocker in its unlocked position, but over time, oil contaminants can cause the piston to seize. This seizure results in a rattling VTEC rocker, particularly noticeable at idle, which can lead to further engine damage and an audible tapping noise. The ScienceofSpeed LMA Kit replaces the problematic piston design with a more robust coil spring system, mirroring the design used in later Honda models. Precision-engineered stainless steel inserts ensure compatibility with the early NSX cylinder heads, allowing for a direct installation. This upgraded design is not only more durable but also offers an increased 28% stroke and a larger rocker contact patch, making it an excellent choice for engines equipped with high-lift camshafts. Installation of this kit requires the removal of rocker arm shafts. An optional seal kit, containing four O-rings and four washers, is recommended if the original seals are not to be reused. This LMA Kit is specifically compatible with 1991-1999 NSX models only.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandScienceofSpeed
Part NumberHON-enpp-661
CategoryAir and Fuel
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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