Ford introduced the 351 Windsor engine in 1969. It was a response to the public’s demand for something more powerful in the automaker’s stock lineup. Since gas was cheap during that time, the most potent models easily topped 300 horsepower.
Once emissions standards started changing how automakers approached engine design, Ford reduced the power output for the 351. The 1973 Mustang is an excellent example of this work, with only 169 HP in the design.
Ford continued to use its stock 351 Windsor in vehicles for the next 30 years. With fuel economy demands rising, nothing after the 2014 model year comes with this engine.
You can still order a 351 Windsor from the motorsports division as a crate engine.
Ford 351 Windsor Firing Order
The Ford 351 Windsor has a unique firing order when compared to other V8 engines. It is 1-3-5-7-2-6-5-4-8. It is crucial to remember that Ford numbers the cylinders from the beginning at the front left. That means the first four are on that side, while the other half is on the right.
When you ensure the correct firing order for the Ford 351 Windsor, the proper spark plug fires to ensure the engine runs smoothly.
If the vehicle ran smoothly before the plug wires were removed, that means they were most likely in the correct order. It helps to label them to ensure they remain that way before taking out the spark plugs.
When the firing order gets inadvertently rearranged, understanding the 1-3-5-7-2-6-5-4-8 pattern for the 351 Windsor ensures that the correct wire gets returned to each plug.
That doesn’t mean you can expect the same firing order on all 351 Windsor engines from Ford. Assuming that the cylinders have the correct labeling, you can find some units have the 302 firing order instead because of modifications that have happened over the years.
If you find that the 1-3-5-7-2-6-5-4-8 firing order doesn’t work for your Ford engine, consider using the alternative of 1-5-4-2-6-3-7-8 to see if the engine performance increases.
You might also verify that your engine is a 351 Windsor. Some vehicles, such as the Cougars in the 1970s, were giving the 351 Cleveland instead of the Windsor.
The drivers who run into performance issues the most with the 351W are those using high-performance cams. You can change it to the standard 302 setup to achieve a better result.
If that is your engine profile, you’ll want to avoid using a dual-plane carbureted manifold. Most of them are tuned for the 137’s firing order instead. It’s an irrelevant worry if you have a single-plane setup or an EFI intake.
What Are the Symptoms of an Engine That Needs a Tune-Up?
Since Ford hasn’t included a stock 351 Windsor since the 2014 model year, most of them out there today are getting close to the 100,000-mile mark. That means it is time to start thinking about a tune-up.
Spark plugs and wires are consumable products, much like a battery is for an iPhone. Everything works great when the items come off the production line, but the ongoing wear and tear from use eventually cause things to wear out.
Some vehicles don’t make it to the 100k mark on the odometer before needing a tune-up. Others can go well beyond that mileage, so understanding the symptoms of an engine is crucial.
When you see or experience the following symptoms, you’ll know it is time to start replacing the spark plugs on your 351 Windsor.
1. The engine starts to misfire.
When spark plugs begin igniting at the wrong time, you have an engine misfire occur. This incident often causes the check engine light to turn on inside the cabin. You’ll confirm it through diagnostic testing.
The causes for an engine misfire are numerous, but the most common reason involves fouled or worn spark plugs.
You’ll experience sluggish acceleration, a lower fuel economy, and harder starts as the issue progresses. Engine computers can compensate for worn-out equipment quite well today, which means inspections should occur around 75,000 miles to avoid unwanted complications.
2. Your Windsor 351 has developed a rough idle.
When the spark plugs start failing, you’ll notice the tone and tenor of your engine idle changes. This issue causes vibrations that can reverberate throughout the rest of your Ford, eventually causing other damage.
You might notice shaking or body movement when the car is parked and idling when this issue develops.
3. The vehicle won’t start.
If your Ford doesn’t start in the morning when it is time to head to work, you might suspect low fuel or a flat battery. When it turns over without starting or clicking, you might have a spark plug failure to manage.
The engine won’t seize with spark plug failure. If you don’t have the 351 Windsor turn over at all, you might have a more serious issue to address.
4. Your engine surges at inopportune times.
When the engine doesn’t work efficiently, you might feel the acceleration jerk out momentarily as you’re trying to achieve highway speeds. The jolting motion can lead to an uncomfortable ride that increases the risk of bruising and other injuries.
There can be times when the engine starts sucking in more air than is needed for the typical combustion process. If you’re experiencing constant stopping and starting motions while trying to drive, you have the evidence that a spark plug issue is probably the result.
What Can I Do to Replace My Spark Plugs?
When your vehicle experiences the signs and symptoms of spark plug failure, it is time to take the Windsor 351 to a trusted mechanic.
The good news is that replacing the spark plugs for an engine is a relatively straightforward job. If you have some tools at home, you can even do the work yourself.
Your first step is to select a high-quality spark plug for your Ford. Although 30,000-mile products are cheap and easy to use, it’s often better to invest in the 100,000-mile option whenever possible.
You’ll also need to follow the recommendations found in your owner’s manual. It is usually okay to upgrade the equipment, but you don’t want to downgrade beyond the minimum specs set by Ford or another manufacturer.
When you go lower than what is recommended, you can hinder the engine’s performance.
You might need to remove the upper plenum or intake manifold to reach the spark plugs, which means a new gasket is necessary – in addition to the tools and plugs.
Here are the tools you’ll need.
- A ratchet set with standard sockets and some wrenches.
- A spark plug socket that works with the Windsor 351 engine.
- Anti-seize lube and dielectric grease.
You’ll also need the spark plugs that work with your Windsor 351. The Motorcraft SP-493 model AGSF32PM offers a platinum product that comes pre-gapped. You’ll still need to check them to ensure that they’re the write spacing, but you don’t want to gap them yourself as the coating will get damaged.
Once you’ve got everything, you’re ready to go with the following steps.
- Safety always comes first. Park your Ford on a flat, dry surface. The engine should be cool before working on it! Clean the area to prevent anything from falling into the cylinder while working on this project. It also helps to disconnect the negative post to the battery and check your owner’s manual to see if any other steps are necessary before starting.
- Remove the plug wire. Remove any interference items that get in the way of accessing the spark plugs. You might need to remove the upper intake plenum. Once you can reach the area, you’ll want to remove the rubber wire carefully. The inside terminals are quite sensitive, so please remember not to yank. Use spark plug wire pliers if you have one that won’t break from its bond.
- Take out the COP. The coil on plug attaches directly to the plug end with a long insulator boot. You’ll need to pull up or press down on the locking tab to generate a release. A small screwdriver is sometimes required to reach the tab. Once the connector is off, remove the bolt while twisting the coil a quarter-turn until it breaks. At that point, it should pull straight out. Any damage to the boot requires it to get replaced.
- Unscrew the spark plug. Once the engine is cool, the spark plug socket is used to remove the part. You can avoid thread damage by blowing air down into the well hole. It only takes a small thing to cause damage to the head. If there’s no way around the problem, you can correct the situation with a thread restorer. Turn the plug about a half-turn, use penetrant fluid, and continue. Some engines have additional steps to follow.
- Install the new spark plugs. After all the spark plugs are out, it’s time to put the new ones into their correct locations! Please review each thread set to ensure they are straight and clean. The tip and electrode should be intact. It even helps to match the part number to the box to confirm you’ve got the correct item. Install each one while carefully avoiding cross-threading.
- Reinstall the wires or COP and start the engine. This step is where you need to know the 351 Windsor firing order for your engine. Once you have the cables in the correct lineup, you’ll be ready to start the engine to see if the work was completed as expected.
If you experience a cylinder misfire, stop the engine immediately to double-check your work. You might have labeled something wrong.
When something isn’t covered here, default to your owner’s manual. You can also contact Ford or a local dealership’s service department for additional assistance. Your work is your own, which means we cannot be held liable for mistakes that happen on your end, nor are we responsible for any setup issues or steps you try from reading this content.
A Final Thought About the Ford 351 Windsor Firing Order
The Ford 351 Windsor firing order depends on its cams. Its standard setup might be 1-3-5-7-2-6-5-4-8, but what you have could be different. If you’re unsure how the wiring should be or don’t have anything stamped on the block, please refer to your owner’s manual or contact your dealership.
I’ve always found the Ford 351 Windsor to be a fantastic engine. It has an impressive acceleration profile, even if you’re driving a boat of a car like the Grand Marquis.
Although the fuel economy for it isn’t great, it’s still fun to push fast from a stop sign or red light to listen to it roar!
When you know how to change the spark plugs, you can help this stock engine stay alive so that you both can explore what the world offers.
