25/05/2010
When delving into the intricacies of classic fuel injection systems, particularly those with a Rochester heritage, one component often sparks curiosity: the safety solenoid. Often referred to affectionately (or perhaps not so affectionately) as the "Rottenchester dribble system," these early fuel injection setups, while revolutionary for their time, can also present unique maintenance considerations. A key element in ensuring the longevity and proper function of these systems is the safety solenoid, a component that plays a vital role in preventing potentially catastrophic damage. This article aims to shed light on the necessity and function of this often-overlooked part.
What is a Fuel Injection Safety Solenoid?
At its core, a fuel injection safety solenoid is an electrically operated valve designed to control the flow of fuel. In the context of early fuel injection systems, its primary purpose is to act as a fail-safe mechanism. When the engine is switched off, the solenoid closes, cutting off the fuel supply to the injection unit. This is critical for preventing fuel pressure from remaining in the system, which can lead to various issues.
Why is it Necessary? Protecting Against Hydraulic Compression Damage
The primary reason for the inclusion of a safety solenoid, as highlighted by specialists in Rochester Fuel Injection parts and units, is to protect against hydraulic compression damage. This might sound technical, and indeed it is, but the concept is straightforward. Without a functioning safety solenoid, residual fuel pressure can remain in the fuel lines and injection unit after the engine is shut down. If the engine is then cranked or the vehicle is moved, this trapped pressure can lead to:
- Fuel Leakage: Over time, constant pressure can stress seals and gaskets, leading to leaks.
- Hydraulic Lock: In extreme cases, if fuel accumulates in the combustion chamber (which can happen if the injectors drip or if there's a persistent leak), it can create a condition known as hydraulic lock. Since liquids are incompressible, attempting to crank an engine with a cylinder full of fuel can cause severe internal damage, bending connecting rods or even cracking the engine block. This is the most significant risk the safety solenoid mitigates.
- Difficulty in Starting: A system that retains pressure can sometimes make starting more difficult, especially on a hot engine, as the fuel mixture might be too rich.
The safety solenoid, by shutting off the fuel supply when the ignition is turned off, ensures that pressure is released from the system, thereby preventing the build-up that could lead to these damaging scenarios. It's an essential safeguard, particularly for systems where the injectors might not have perfect sealing capabilities when subjected to continuous pressure.
Solenoid Type and Installation
For gasoline applications, the solenoids used are typically of an aircraft-style design. These are robust and reliable, built to withstand the demands of automotive use. The information provided by distributors and rebuilders of Rochester Fuel Injection parts strongly urges the installation of a safety solenoid on ALL fuel injection systems, regardless of year. They can often be discreetly hidden, for instance, under the plenum, maintaining the clean aesthetic of the engine bay.
The Importance of a Rebuilt Distributor
While focusing on the safety solenoid, it's worth noting the accompanying advice from experts in the field. They strongly suggest that your distributor be rebuilt concurrently with your fuel injection unit. This holistic approach to rebuilding ensures that all critical components work in harmony, guaranteeing total and proper operation. A well-functioning distributor is just as crucial as a reliable fuel system for optimal performance.
A Look at Available Parts
The availability of parts for these classic fuel injection systems is crucial for their continued operation. A comprehensive list of available parts reveals the dedication of specialists to keeping these systems alive. Here's a glimpse into the types of components that are essential for maintaining a Rochester fuel injection system:
Air Cleaners and Filters
Maintaining clean air intake is paramount. Various air cleaner assemblies and filter elements are listed, catering to different model years. For instance:
| Part Description | Model Years | Price |
|---|---|---|
| FI Air cleaner assembly–repro. Includes element, lid, stud, and wing nut, with tab! | '57 | £1150.00 |
| FI Air Filter Element--washable | '58-61 | £75.00 |
| FI Air Filter Element, Foam, correct thickness & porosity--Ours fits, too! | '62 | £35.00 |
| FI Clamp, Air Cleaner Duct Hose Clamp 4 3/4" CORRECT | '58-65 | £29.00 |
The choke mechanism, essential for cold starts, also requires specific parts:
| Part Description | Model Years | Price |
|---|---|---|
| Cover, Choke, with spring--perfect! | '63-65 | £140.00 |
| Cover, Choke, with wire assembly, bakelite | '57-61 | £220.00 |
| Spring & Seal Kit,chokeshaft | '63-65 | £7.00 |
The distributor is the heart of the ignition timing, and its components are critical:
| Part Description | Model Years | Price |
|---|---|---|
| Cap, nice replacement | '57 | £35.00 |
| Advance weights NOS 737 VERY limited supply | '58-65 | £40.00 (pair) |
| Gasket Kit, Distributor (5-piece kit) | '58-65 | £30.00 |
| Rebuild Kit, Distributor--all seals & gaskets (specify year/model) | '58-65 | £60.00 |
Fuel Injection Units, Distributors & Rebuild Kits
The core units themselves and the kits to rebuild them are also available:
| Part Description | Model Years | Price |
|---|---|---|
| Rebuild Kit, FI Unit, includes leg gaskets Viton seals | '57-62 | £220.00 |
| Rebuild Kit, FI unit with 1 piece plenum gasket Viton seals | '57-59 | £250.00 |
| Rebuild Kit, FI Unit, includes leg gaskets & lid gasket Viton sea | '63-65 | £230.00 |
Fuel Lines, Filters, Elements
Ensuring clean and consistent fuel delivery is vital:
| Part Description | Model Years | Price |
|---|---|---|
| Fuel Filter Element NEW NEW NEW!!!!!!!! GF 130 reproduction | '57-58 | £120.00 |
| GF90 Filter, Silver | '62-65 | £48.00 |
| Fuel Line, Fuel Pump to Unit (2 pieces with fittings) | '57-58 | £50.00 |
Gaskets and Hardware
The myriad of gaskets and hardware are essential for sealing and assembly:
| Part Description | Model Years | Price |
|---|---|---|
| Gaskets, Nozzle (seals nozzle to block) Viton | '57-65 | £15.00 (set of 8) |
| Gasket, Plenum (fits '57-62) ONE-PIECE | '57-59 | £50.00 |
| Hardware Kit (fasteners, etc.)--correct type | '57-65 | £55.00 |
Specific Solenoid Pricing
Crucially, the safety solenoid itself is available, with pricing varying by model year:
| Part Description | Model Years | Price |
|---|---|---|
| Solenoid, safety fuel shut-off--prevent hydraulic cylinder compression (kit) (will fit all) | '57-62 | £150.00 |
| Solenoid, safety fuel shut-off--prevent hydraulic cylinder compression (kit) (will fit all) | '63-65 | £175.00 |
Frequently Asked Questions
Do I absolutely need a safety solenoid on my Rochester fuel injection system?
Yes, it is strongly urged by experts and is considered a necessary component to protect your engine from potential damage caused by hydraulic compression. It's a relatively inexpensive part that can prevent very costly repairs.
Can I omit the safety solenoid if I'm careful?
While being careful is always good, the solenoid acts as a mechanical safeguard. Relying solely on careful operation is risky, as unforeseen circumstances can lead to the damage it's designed to prevent. It's best to install one for peace of mind and engine protection.
Where can I buy a safety solenoid for my fuel injection system?
Specialised distributors and re-builders of Rochester Fuel Injection parts, such as Gary Hodges Ramjet, Ltd., stock these essential components. You can find them listed with specific pricing for different model years.
Are there any alternatives to the original safety solenoid?
While aftermarket options might exist, it is always recommended to use aircraft-style solenoids designed for gasoline usage, as specified by reputable suppliers. Using an incorrect type could lead to performance issues or safety concerns.
What happens if my safety solenoid fails?
If a safety solenoid fails (e.g., it sticks open or closed), it can lead to fuel pressure issues, potential leaks, or the risk of hydraulic lock if it fails to close properly. Regular checks and maintenance are advised.
Conclusion
The safety solenoid might be a small component in the grand scheme of a classic fuel injection system, but its role is undeniably significant. For owners of vehicles equipped with Rochester fuel injection, understanding and ensuring the correct functioning of this solenoid is not just about optimal performance; it's about preserving the integrity of a cherished piece of automotive history. Investing in a safety solenoid, and ensuring your entire fuel injection system is properly maintained and rebuilt, is a wise decision that will pay dividends in reliability and longevity.
Remember, when dealing with these intricate systems, consulting with specialists and using high-quality, correct parts is paramount. The information provided here is a testament to the ongoing support and availability of parts for these iconic fuel injection systems, ensuring they can continue to be enjoyed for years to come.
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