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Tillotson 196-212-225 Non-Hemi Rocker Adjusting Nut
Clone Non-Hemi Adjusting Nut
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Tillotson 196-212-225 Non-Hemi Rocker Adjusting Nut

Part Number: 138190034
Online Price: $1.99
Availability: In Stock.

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Description

138190034 Rocker Arm Adjusting Nut – For Non-Hemi Clone & Predator Engines

OEM-style lash adjustment nut for precise rocker arm control – critical for tuning and reliable valve operation.


The 138190034 Rocker Arm Adjusting Nut is a factory-style lash adjuster for non-Hemi GX200 clone engines, including Predator 212, Tillotson, and other popular small engine platforms. This nut threads onto the rocker stud and holds the rocker arm in place while allowing you to fine-tune valve lash clearance.


Proper valve lash is critical to engine performance, combustion efficiency, and ease of starting. Whether you’re assembling a performance engine or refreshing a stock build, this adjuster nut allows precise rocker arm movement and valve timing control.


Key Features:

  • Part #: 138190034
  • Function: Allows valve lash adjustment on non-Hemi clone engines
  • Fitment: Threads onto rocker studs to secure rocker arms
  • Material: Durable OEM-grade construction
  • Installation Tip: Do not overtighten – rocker must pivot freely


Recommended Lash Settings:

  • Cold Setting (Initial Setup): .003” or less
  • Warm Setting (After Heat Cycle): .003”–.006” (per camshaft manufacturer specs)
  • Always follow your cam manufacturer's recommendations for optimal lash clearance.
  • Use a 14mm Wrench to tighten the adjuster nut


Why Proper Lash Matters:

  • Too Loose: May prevent the compression release from functioning, making the engine hard to start
  • Too Tight: Can prevent valves from fully sealing, resulting in tuning issues and reduced performance
  • Overtightening Nut: May cause rocker arm friction, excessive heat, and valvetrain failure


Engine Compatibility:

OEM fit for non-Hemi heads on:

  • Honda GX200 & 196cc Clones
  • Predator 212 / 224 Non-Hemi
  • Tillotson 196R / 212R / 225RS
  • Wildcat 240
  • Ducar 196 / 224 Non-Hemi

FAQ

Q1: What does the 138190034 rocker adjusting nut do?

A: This nut secures the rocker arm on the stud and allows you to adjust valve lash. It is essential for proper valve function and consistent engine performance.


Q2: Which engines is this nut compatible with?

A: It fits most non-Hemi small engines, including:

  • Honda GX200 and 196cc clones
  • Predator 212 and 224 Non-Hemi
  • Tillotson 196R, 212R, 225RS
  • Wildcat 240
  • Ducar 196 / 224


Q3: What are the recommended valve lash settings?

A:

  • Cold engine (initial setup): .003” or less
  • Warm engine (after heat cycle): .003” to .006”
    Always follow the cam manufacturer's specs for best results.


Q4: What happens if I overtighten the adjusting nut?

A: Overtightening can restrict the rocker arm’s movement, causing friction, overheating, and potential valvetrain failure. It’s critical to tighten it just enough to hold lash settings securely.


Q5: How often should I check valve lash?

A: Check valve lash after the first heat cycle and then periodically—especially in performance or racing engines where lash can shift due to heat and RPM.

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