Rochester Quadrajet & Monojet Power Piston Spring Set S100

Quadrajet & Monojet Power Piston Spring Set – S100

Restore precise power-piston control in your Rochester Quadrajet or Monojet carburetor with the S100 Power Piston Spring Set. Engineered in the USA, this set includes three springs—light, medium, and heavy—allowing you to tune the power-piston lift to match your engine’s vacuum characteristics.

 Key Features

• Includes three spring tensions: Choose light, medium, or heavy based on your engine’s vacuum and tuning needs

• Medium spring recommended for most stock applications.

• Heavy spring prevents premature piston lift, maintaining sealed primaries until vacuum drops below ~15??Hg

• Longest spring included for Rochester Monojet power-piston setups

• Made in the USA, high-quality fabrication with immediate availability (when in stock)

 Benefits

• Addresses off-idle hesitation or flat spots by matching spring tension to engine vacuum.

• Helps optimize throttle response and driveability.

• Enables fine-tuning without modifying hardware.

 Frequently Asked Questions

1. How do I know which spring to use?
Start with the medium spring—if the piston opens too early (above idle), move up to the heavy spring. If it doesn't open under load, switch to the lighter spring.

2. Why are there three springs?
Engine vacuum differences (due to cams, compression, and condition) require different spring tensions. The set allows you to tune piston lift timing for optimal performance.

3. Which spring is for Monojet carbs?
Use the longest spring for Rochester Monojet applications to maintain correct power-piston function.

4. What issues can the wrong spring cause?

• Too soft: piston opens too soon—can cause bogging or richness at light throttle.

• Too stiff: piston may never open under load—can cause flat spots or hesitation.

5. Is it in stock and how fast will it ship?
Availability is displayed under the price. Most orders placed before 12?PM PST ship the same business day.

6. How is shipping calculated?
Shipping is calculated at checkout based on your location. For details, see our [Shipping Information Page].

7. How does this set compare to aftermarket versions?
The S100 set is USA-made, includes exactly three OE-spec springs tuned for Quadrajet/Monojet cars, and offers unmatched precision over generic aftermarket assortments.