P-Pump Cummins Project: Timing Makes Power

12 to 18 Degrees–How Much Time Will We Gain?

We hear it all the time, timing makes power. But how much power? Well, there are a number of variables but it was a question we decided to try and answer with our pretty much stock 12v P-Pump Cummins project Green Monster. In our last installment we had put in a set of Scheid Diesel 5×0.018-inch injectors and gained a whopping 117 horsepower on the dyno. Since we were driving the turbo harder, boost also went from 19 pounds to 38 pounds which was part of our vast increase in power. To make the most of these new injectors though, we needed to add timing.

Injection timing in a diesel works very similar to the timing curve that you would find in a gasoline engine. One of the main differences however is that you can run a lot more timing with boost in a diesel engine thanks to their direct injection and robust nature. The factory sets timing at 12 degrees, which is fine for cold startups noise concerns and overall power, but we wanted to tell the balance a bit towards the power part of the equation. This meant ramping up the timing well above our 12-degree starting point.

One of the main considerations when it came to setting timing is that we were still on the stock 270,000-mile head gasket with factory re-tightened headbolts. We have run up to 30 degrees on trucks with ARP 625 head studs and fire ringed head gaskets but we would be limited (for now) by our factory parts. Many hot street trucks or folks that tow and want a little better mileage ought to go just a few degrees over stock which is what we did. We felt that a 5 to 7 degree bump would be adequate, and in the end we decided to go from 12 degrees up to 18 degrees of timing.

We had the folks at Brown’s Diesel help us in setting timing the “correct way” which is to use a dial gauge on the delivery valve holder. You’ll need the specifications of your pump (160hp, 180hp, or 215hp) but as long as you have that you should be good to go. The actual process didn’t take that long, but it was good to have two people on the truck. We also marked one side of the crank position sensor to see how far it moved for those who may not have a dial indicator. The rumor was that moving the engine from one side of the crank sensor pickup to the other with the pump gear off was worth about 10 degrees, as it turned out, the Internet was close, and it actually turned out to be closer to 12 degrees.

Once on the dyno the truck was a little louder, but nothing that bad, and cold start and other driving aspects of the truck remained unchanged. It should be noted that we did have to adjust the idle up which was performed at the back of the pump with a 19 mm wrench. On the dyno, we were quite pleased with the power game, as we picked up an additional 30 horsepower over what we had made with just the injectors alone. The additional timing also actually made the boost drop from 38psi to 35psi so in an apples to apples comparison the extra six degrees of timing may have been worth even more than 30 horsepower. With 400 in sight, our next move will to be to install a lift pump from Power Driven Diesel to see if we can break the 400rwhp mark. As for now, we learned that even six degrees will make quite a difference in power, and in our case was worth almost 10 percent!

FREQUENTLY ASKED QUESTIONS

What are some alternative methods for finding piston Top Dead Center (TDC) if the pump’s timing flag is not usable?

When it comes to locating piston Top Dead Center (TDC), especially when the pump’s timing flag is unreliable, you have a few viable options to consider.

Other popular methods of finding TDC are pushing on the timing pin right below the injection pump, or using a dial indicator set to the piston on the number 1 injector hole. These methods are straightforward and can be effective in many situations.

However, it’s crucial to remember that finding TDC alone might not be enough if the timing flag is bent or otherwise unusable. In such cases, understanding the pump’s position becomes equally important. While techniques like pushing the timing pin or using a dial indicator can accurately pinpoint TDC, they don’t provide information about the pump’s timing.

To ensure precise timing, you may need to explore additional steps or tools that help align both the TDC and the pump’s position accurately. This comprehensive approach ensures your engine timing is spot on, even when traditional indicators fail.

By combining various methods and understanding their limitations, you can achieve the precision needed for optimal engine performance.

What are the limitations of the drop valve method?

While the drop valve method excels at locating TDC, it does not provide information about the position of the pump. This limitation means that additional methods or information are required to fully assess and adjust the pump’s timing.

Why is finding TDC alone insufficient when the pump’s timing flag is unusable?

Knowing TDC alone isn’t enough if the pump’s timing flag is unreliable or damaged. In such cases, it’s crucial to also determine the pump’s position to ensure proper timing and functionality.

What is the drop valve method and why is it useful?

The drop valve method is a technique for accurately and easily determining the piston’s Top Dead Center (TDC). It is valued for its precision in pinpointing TDC, which is essential in engine timing processes.

Can a P7100 injection pump be timed without using the timing pin?

One of the main considerations when it came to setting timing is that we were still on the stock 270,000-mile head gasket with factory re-tightened headbolts. We have run up to 30 degrees on trucks with ARP 625 head studs and fire ringed head gaskets, but we would be limited (for now) by our factory parts. Many hot street trucks or folks that tow and want a little better mileage ought to go just a few degrees over stock, which is what we did. We felt that a 5 to 7 degree bump would be adequate, and in the end, we decided to go from 12 degrees up to 18 degrees of timing.

To answer the question, yes, the P7100 injection pump can indeed be timed without using the timing pin. You’ll need some special tools—available at most diesel performance websites. The process involves removing the #1 delivery valve and measuring the height of the pump cam lobe with a dial indicator. Once you have this measurement, compare it to a chart of known pump models to adjust the timing accurately.

We had the folks at Brown’s Diesel help us in setting timing the “correct way,” which is to use a dial gauge on the delivery valve holder. You’ll need the specifications of your pump (160hp, 180hp, or 215hp), but as long as you have that, you should be good to go. The actual process didn’t take that long, but it was good to have two people on the truck.

Additionally, we marked one side of the crank position sensor to see how far it moved for those who may not have a dial indicator. The rumor was that moving the engine from one side of the crank sensor pickup to the other with the pump gear off was worth about 10 degrees. As it turned out, the Internet was close, and it actually turned out to be closer to 12 degrees.

By weaving these methods together, you can effectively adjust your timing without relying solely on the timing pin, ensuring precise and reliable performance for your setup.

What is the process for timing the pump without the timing pin?

The process involves removing the #1 delivery valve, measuring the pump cam lobe height with a dial indicator, and comparing this measurement to a chart of known pump models to adjust the timing accordingly.

What tools are needed to time the pump without the timing pin?

Special tools are necessary, which can be found on most diesel performance websites.

Is it possible to time the P7100 injection pump without using the timing pin?

Yes, the pump can be timed without using the timing pin.

What are the benefits of using a nylon timing pin or locking washer during the timing process?

Tools of the Trade: Nylon Timing Pins and Locking Washers

While we were at it, we realized there are a couple of handy upgrades that can make the timing process a whole lot smoother. Swapping out the stock plastic timing pin for a nylon version (think offerings from familiar names like Bosch or Scheid Diesel) gives you a more durable and reliable way to lock the pump without worrying about snapping anything fragile mid-job.

Locking washers are another unsung hero here. Pop one on during reassembly and it’ll keep your timing gear right where you set it—no chance of things slipping or moving out of spec as you tighten everything down. Both upgrades help take a lot of the “cross-your-fingers” guesswork out of dialing your timing in, especially if you find yourself tackling the job more than once.

What are the features and benefits of using a magnetic degree wheel for engine timing?

Why Use a Magnetic Degree Wheel for Engine Timing?

Now, when it comes to setting timing with confidence (and maybe a dash of style points in the garage), a magnetic degree wheel is one of those must-have tools that makes life a little easier for us shade-tree mechanics and seasoned diesel techs alike.

Here’s why:

• Pinpoint Accuracy:The biggest advantage of the magnetic degree wheel is, hands down, its ability to give you highly accurate readings. You get a clear, exact reference for crankshaft position every step of the way—which is key when chasing after those extra horsepower numbers or dialing in a custom setup.
• Hands-Free Mounting:Because most magnetic degree wheels stick right onto the harmonic balancer or timing gear with a strong magnet, they stay put without fussing over alignment or having to hold them in place. This frees up a hand (or two) for wrenching and keeps everything steady while you work.
• Simplifies Complex Steps:Compared to old-school techniques with protractors or homemade marks, a degree wheel takes out a lot of the guesswork. Whether you’re advancing or retarding timing, the degree markings provide a visual cue so even small adjustments are easy to track.
• Reusable and Portable:Most magnetic wheels can be transferred to different engines and stashed in the toolbox when you’re done—so it’s a one-time investment that keeps on giving, whether you’re working on your own truck or helping out a buddy who “owes you lunch.”
• Added Confidence for DIY and Pros Alike:Whether you’re new to turning wrenches or you’ve got grease under your nails from years of builds, a degree wheel bridges the gap. It takes out much of the intimidation factor and makes timing something you can tackle in the home garage—without feeling like you need a Ph.D. In pump tuning.

If you want to avoid the guesswork and potential headaches that come with “eyeballing it” or relying on factory marks that may have disappeared somewhere around the Clinton administration, it’s hard to go wrong with a good magnetic degree wheel in your toolkit.

We had the folks at Brown’s Diesel help us in setting timing the “correct way” which is to use a dial gauge on the delivery valve holder. You’ll need the specifications of your pump (160hp, 180hp, or 215hp) but as long as you have that you should be good to go. The actual process didn’t take that long, but it was good to have two people on the truck. We also marked one side of the crank position sensor to see how far it moved for those who may not have a dial indicator. The rumor was that moving the engine from one side of the crank sensor pickup to the other with the pump gear off was worth…

Can the degree wheel be purchased separately from the rest of the timing kit?

Can you buy just the degree wheel, or do you need the entire timing kit?

If you already have most of the necessary pieces and only need a degree wheel, you’re in luck—you don’t have to purchase the full timing kit. Aftermarket degree wheels are widely available from a variety of suppliers, including performance brands like Summit Racing and Proform. These standalone wheels are compatible with many engines and can be paired with your existing tools, making them a convenient and cost-effective option if you’re just missing this one part.

So, whether you lost your old degree wheel or want to upgrade to a larger or magnetic one, there’s no need to buy the whole kit again—just grab the specific wheel you need and get back to dialing in your timing.

What is the process for using a P-pump timing kit to adjust engine timing?

Simplifying the Timing Process: Using a P-Pump Timing Kit

For those looking to streamline setting injection timing, there’s a modern alternative to the old-school dial gauge method—a P-pump timing kit. This handy setup takes much of the guesswork (and knuckle-busting) out of the job.

Instead of fumbling with a dial gauge and constantly checking lift, the timing kit includes a magnetic degree wheel which sticks right onto the front of your engine. This tool gives you a crystal-clear reading of crank position as you bring the engine to TDC and set your desired timing mark. There’s also a gear puller that makes removing the timing gear less of a wrestling match, and most kits come with a locking washer to ensure nothing slips while you make your adjustments. If you’re worried about busting another plastic timing pin, you can get a metal version from places like Industrial Injection or Scheid.

Here’s the basic process:

• Attach the magnetic degree wheel to the crankshaft pulley.
• Rotate the engine (by hand, always) to bring #1 cylinder to TDC on the compression stroke, then set your reference mark.
• Use the supplied gear puller to remove the timing gear from the pump gently.
• Unlock the pump and rotate it to align your new timing mark (say, moving up to that 18-degree sweet spot).
• Once set, lock everything back down—often using the kit’s washer or a factory nut.
• Double-check everything, reinstall components, and ensure the degree wheel still lines up before you button up.

This kit method makes precise timing accessible for DIYers and professionals alike, removing much of the hassle and minimizing errors that could cost you both time and engine health.

How does a P-pump timing kit simplify the timing process compared to traditional dial gauge methods?

Simplifying Timing with a P-Pump Timing Kit

Traditional dial indicator techniques for setting injection timing may get the job done, but if you’ve ever tried juggling locking washers, fine-threaded pins, and a dial that’s one accidental sneeze away from knocking your numbers off, you know it’s not always the slickest process. Enter the P-pump timing kit—a game changer for anyone looking to simplify things without sacrificing accuracy.

Instead of fussing with the dial indicator setup (and always seeming to misplace at least one of the tiny screws), the timing kit replaces it with a magnetic degree wheel that quickly attaches to the pump gear. This wheel reads out your timing degrees directly, which takes the guesswork out of angle calculations. Not only that, but the dedicated gear puller in these kits makes removing the timing gear a breeze—no more wrestling with stubborn gears or risking bent pullers.

For those who want an extra measure of stability, a nylon timing pin or a simple locking washer can help ensure the gear stays put as you make fine adjustments. The process as a whole becomes less about balancing specialty tools and more about straightforward, repeatable steps that even someone new to timing can follow. In the end, it’s a lot less fussy than the old-school dial gauge dance—leaving you more time to actually enjoy dialing in that perfect timing curve.

Are there any compatibility concerns regarding engine or vehicle modifications when using a P-pump timing kit?

Compatibility Considerations for P-Pump Timing Kits

If you’re looking to use a P-pump timing kit, you’ll be in good shape with most 3.9L 4BTs running a Bosch P7100 and just about any ‘94–‘98 5.9L 12-valve Cummins found in Dodge trucks. That said, there are a few caveats to keep in mind—especially if your engine or vehicle has seen its fair share of modifications.

• Swapped engines or hybrids, such as 4BTs shoehorned into Chevy C10s or custom projects, might have clearance issues, relocated mounting points, or unique front-end accessories that could interfere with timing tool access or installation.
• Performance upgrades—like aftermarket camshafts, custom timing gears, or non-standard injection pumps (think Scheid Diesel or Industrial Injection mods)—may call for tools or procedures slightly different from the basic kit.
• Any changes to your timing cover, such as billet covers or custom crank position sensor setups, can affect how the kit fits and lines up.

In essence, while the kit is bolt-in for most stock applications, non-factory builds might need a little extra creativity. Double-check your specific setup before diving in—just to save yourself a headache down the road.

Which diesel engine models and years are compatible with a P-pump timing kit?

Which diesel engines and years can use a P-pump timing kit?

A P-pump timing kit is designed to work with a range of classic Cummins engines, particularly:

• Any 3.9L 4BT engine fitted with a P7100 injection pump
• 9L 12-valve Cummins engines from 1994 through 1998

Keep in mind, while these kits are broadly compatible, extensive engine or vehicle modifications may affect fitment. Always double-check your setup to ensure a smooth install and accurate timing adjustment.

What additional tools or engine parts are frequently bought together with a P-pump timing kit?

Commonly Paired Tools and Parts for P-Pump Timing

While we had the timing pump gear nut accessible, it’s worth mentioning that certain tools and parts tend to make their way onto the bench whenever you’re dialing in P-pump timing. Over the years, a few essentials have become almost standard-issue for anyone wanting the job to go smoothly (and without excessive knuckle-busting).

Here are some of the most frequently paired tools and parts:

• Delivery Valve Sockets: These allow you to remove and install delivery valves without damaging them or the pump.
• Governor Spring Kits (3K/4K): If you’re already inside the pump, upgraded governor springs are a must for raising your RPM limit, offering more flexibility for tuning and performance.
• Crankshaft Barring Tools: Spinning the engine over by hand is a lot easier—and safer—when you have a proper barring tool instead of improvising with a pry bar.
• Replacement Delivery Valves: Swapping in a set of performance delivery valves can change fueling characteristics and are commonly tackled during a timing job to maximize gains.

Most folks find that having these parts handy makes setting or altering P-pump timing a much more straightforward affair—and you’re less likely to round off a bolt or miss out on power left on the table.

How long does it typically take to adjust timing with a P-pump timing kit?

How Long Does a P-Pump Timing Kit Adjustment Take?

If you’re wondering what kind of time investment you’re looking at for adjusting timing with a typical P-pump timing kit, you’re in luck—it’s a lot less daunting than it might sound. On our project and from what we’ve heard among our fellow diesel heads, you can expect the job to take about an hour to an hour and a half from start to finish.

Of course, this presumes you’ve got all the right tools on hand and aren’t stopping every five minutes for a coffee break (or to chase down a rogue socket that rolled under your toolbox). The process can move along pretty smoothly, especially if you’ve done your homework and have experience wrenching on these old 12-valve Cumminsengines. It’s straightforward enough that even if you’re new to the timing adjustment game, following along with a detailed walkthrough should have the truck back together within a reasonable Saturday morning project window.

The key, as always, is taking your time so you don’t skip any critical steps—accuracy matters when you’re dialing in that extra power.

What is included in a P-pump timing kit for diesel engines?

What’s Included in a Typical P-Pump Timing Kit

If you’re planning to set your diesel’s injection timing the right way, having the right tools in your arsenal makes all the difference. A standard P-pump timing kit should cover all the bases for a precision job. Here’s what you’ll usually find inside:

• A magnetic degree wheel, essential for accurately reading crankshaft position and ensuring your timing is spot on.
• A timing gear puller, which makes quick work of separating the timing gear from the pump without risking damage to any components.
• A dial indicator holder or bracket, allowing you to mount a dial gauge securely so you can measure pump camshaft lift with confidence.
• Optional extras can include a locking washer to help maintain your adjustments, and sometimes even a nylon timing pin for those who prefer an alternative method for finding TDC.

Having each of these tools at your disposal means you’re ready for anything, whether you’re timing your daily driver or a high-mileage workhorse.

What are customer experiences or reviews regarding the ease of use and effectiveness of a P-pump timing kit?

What do users say about using a P-pump timing kit?

Feedback from those who’ve used aftermarket P-pump timing kits (like offerings from Bosch or OTC) has been resoundingly positive in terms of both simplicity and effectiveness. Many users report the process going smoothly—even for first-timers—thanks to clear instructions and straightforward setup.

For example, several DIY tuners have mentioned bumping their timing from 14 to 18 degrees in just over an hour, with no guesswork or frustration. Folks appreciate how these kits make a job that sounds intimidating much more approachable, allowing for precise adjustments without relying on factory tools or procedures.

In short: If you have basic mechanical skills and the right kit, timing adjustments are not only doable, but refreshingly uncomplicated.

What optional components are available with a P-pump timing kit?

Optional Components for Your P-Pump Timing Kit

While a basic P-pump timing kit will get you well on your way, there are a few optional tools and parts you might find handy for the job—or for added peace of mind. Some enthusiasts opt to include a locking washer, which helps secure everything in place as you adjust timing. Another favorite is a durable nylon timing pin, making it easier (and cleaner) to verify TDC without worrying about the original steel version getting lost or bent.

Having these extras on hand isn’t essential, but if you’re the type who likes to double-check your work or prefers some backup options as you tinker, they’re worth considering.

What tools are necessary for accurate timing of a P-pumped diesel engine?

To answer the question, yes, the P7100 injection pump can indeed be timed without using the timing pin. You’ll need some special tools—available at most diesel performance websites. The process involves removing the #1 delivery valve and measuring the height of the pump cam lobe with a dial indicator. Once you have this measurement, compare it to a chart of known pump models to adjust the timing accurately.

We had the folks at Brown’s Diesel help us in setting timing the “correct way,” which is to use a dial gauge on the delivery valve holder. You’ll need the specifications of your pump (160hp, 180hp, or 215hp), but as long as you have that, you should be good to go. The actual process didn’t take that long, but it was good to have two people on the truck.

Alternate Methods and Helpful Tools

While the classic dial indicator method is tried and true, there are some alternative tools and techniques that can make the process even more straightforward, especially if you’re looking to avoid the hassle of traditional timing pins or dial gauges. Many modern timing kits now include features like:

• Magnetic degree wheelsfor accurate measurement of crank rotation
• Timing gear pullersto make gear removal much less of a pain
• Optional locking washers and nylon timing pinsfor extra convenience and reliability

These tools are designed to simplify the process so that even those new to pump timing can achieve precise results without the headaches. With the right kit, you can confidently set your timing at home, sidestepping some of the complexity that comes with factory methods.

Whether you stick with the established dial indicator routine or leverage some of these helpful new tools, you can accurately time your P7100 pump and ensure your engine is running just the way you want.