Ford’s V10 Diesel Killer Was A Total Disaster...Because Of The Spark Plugs

When you think of engines with more than 8 cylinders, you probably think about high revving exotics. Likely something Italian. But in fact, there was a time when not Ferrari, but Ford produced a V10. And this V10 was never aimed to have a moment of its life spent on the track. It was meant for America's workforce. And when this V10 worked, to give a credit, it worked really well. It had plenty of torque and plenty of power. It was exactly what you wanted as a diesel alternative. So one would think this is a good news story. Well, it's not. At least, not for a lot of people who owned one of these V10s. Because this Ford V10 had quite the bad habit. Every so often, it would love to shoot one of its spark plugs clean out of the cylinder head, taking the ignition coil and whatever else was in the way along with it. Ford eventually fixed that. And then they found a completely new way to have a spark plug problem. And this one took another 5 years to sort out. Add it up and you got 11 years of serious spark plug trouble for this engine. Which is why you can make a case it's one of the worst V10s ever made. Not that there is a huge amount of V10 competition out there to compare to though. But here's the really gets me. Ford was so done with this engine's bad reputation that by the end of 2010, they had quietly dropped the Triton badge altogether. They didn't stop building the V10. No, they kept on building it without the badge itself for another decade to try and at least save face with the fixed motor without the name that had gotten so much negative press. And something like a million of these V10s were made. So the question is, how does an engine that came with a record this bad stick around for that long? And to answer that, well, we have to go back to the beginning. And why the heck Ford built a V10 in the first place? See, back in the 90s, most of Ford's heavy duty motors were big diesel V8s. However, in 1994, Dodge released a huge 8 liter V10 gasoline engine that they called the Magnum. The gasoline engine had a few advantages over diesels at that time, such as being lighter, quieter, and requiring fewer emission control parts. Gasoline engines were also a little bit lower fuss in general. In heavy duty applications for engines like these, the limiting factor is usually torque, not power. You're not looking at a great top speed, but you need something that can overcome a lot of resistance. Diesel engines are great at making torque. Ford's 7.3 liter power stroke at the time made 250 horsepower, but 505 foot pounds of torque. Dodge's Magnum engine was one of the first to prove that you could get enough torque out of a gasoline engine comparable with diesel as long as you had the right design. The Magnum made 300 horsepower and 450 foot pounds of torque, which was a pretty good balance for medium and even some heavier duty applications. Ford saw a market for these heavier duty gasoline engines, and their new modular manufacturing process made it easy for them to change things up at the factory. They got to work on a new design that would extend their 5.4 liter V8 and turn it into this 6.8 liter Triton V10. It had the same bore and stroke as their most popular mod motor, which was 3.5 inches by 4.165 inches, but an extra two cylinders for added torque and power. The first Triton engines had two valves per cylinder and put out a respectable 305 horsepower and 420 foot pounds of torque. These again were low revvers, so peak power was at about 4,000 RPM, and there were pretty significant drop-offs in performance from there till redline, which was just over 5 grand. Now this did have less torque than the Dodge Magnum V10, however this was smaller and made about the same horsepower. Ford started out in 1997 putting the Triton engine in their E-series vans, from the E250 through the E450, as well as the F53 motorhome, but they started putting them in F-series trucks in 1999, and the F-series based excursion SUV in 2000. On paper the same engines that worked great for heavy duty vans should work great for trucks, and the option of a gasoline engine for the excursion was a huge deal, as many of the people buying this big SUV wanted the easier maintenance of a gasoline engine and not the added headaches and consideration of a diesel. However, this is where the first problems started to arise. With the early Triton designs, the engine had a deep well for the spark plugs, but there were only 3 or 4 threads that would hold the spark plugs in place, and those aluminum heads were softer than iron, so those 4 threads didn't necessarily have a lot of staying power. In a commercial van application, where the engine runs at low, consistent RPMs pretty much all the time, this wasn't a big deal. But in trucks and SUVs, when these engines were getting pushed a lot harder more often, let's say for towing or to try and pass somebody on the highway, that's when it would literally eject the spark plug out of the motor. You would hear a bang under the hood, and the engine might keep running, but it was obvious something was very wrong when one cylinder was no longer getting any spark. When pulled over, inevitably to look under the hood, you would find a path of destruction leading outward from one of those spark plug holes. The ignition coil would almost always be a casualty, and anything else the plug hit on the way out would take damage too. And now, instead of a threaded hole where the plug used to be, you might find a stripped out hole leading right into the motor. Now this issue got so common that Ford started offering repair kits to help you re-thread the spark plug holes with at least 8 threads worth of engagement. If you were smart, you would do this as preventative maintenance before the blowout happened. But again, that first wave of blowouts, nobody knew this was a problem before it started happening, and the fact that this didn't get caught in testing is mind-boggling to me. From 1997 all the way up through 2002, this was an issue on the Triton V10s. Finally, after that, Ford changed the head design to give the spark plugs enough grip to not shoot themselves out of the head without needing a modification kit. But for years, this was a serious problem that happened. And the craziest part is that wasn't the only spark plug-related problem that the Triton had. Believe it or not, from 2004 to 2008, Ford tried a two-piece spark plug that had a tendency to gather carbon deposits in places that restricted the motion of one piece but not the other. This meant that whenever you swapped out the spark plugs, there was a chance that one or both pieces of the plug could break. Now Ford sent out detailed instructions and special tools to mechanics, but the fixes were time-consuming, and sometimes you had to try multiple times to get the busted pieces of the spark plug out. And one mistake meant that sharp pieces of ceramic could fall into the combustion chamber. And if that happened, you pretty much had to take the whole engine apart to get them out. And the longer you left the plugs in, the worse they got. Again, this is another stupid issue, because why did Ford for the life of them decide, we had spark plug issues for half a decade, now that we fixed that issue, let's introduce another variable that could break that we didn't have to? Why could they not just use a regular spark plug? Again, it's baffling to me. And Ford's initial solution to this problem was simply to just recommend the replacement of plugs so often that they never had the chance to build up those deposits. But for a V10, this meant you needed to replace a lot of plugs all the time, which started to add up cost-wise. And even then, there was still a chance you'd break one. It took them until 2008 to go back to a one-piece spark plug design that finally fixed the problem for good, now amounting to 11 years of spark plug related issues out of that production run. There were plenty of other issues that this V10 had as well, with decaying PCV hoses, a weak oiling system, easily corroding exhaust manifold bolts, but all of those issues were less catastrophic, and were overshadowed by the spark plug problems. But let's go back to 2004. The Triton name was badly damaged from that initial spark plug ejection issue, so how would Ford try and get that reputation back? Well, they tried to make up for it with a new version of the engine that had 3 valves per cylinder. This was right around the time that Ford was converting the Mustang to be a 3-valve mod motor as well, which would hit the N05 market. This more complex design gave the engine a significant boost to power and torque in most applications. The typical 3-valve motors got 320 or 362 horsepower with 457 or 460 foot pounds of torque, beating out the now obsolete Dodge Magnum V10, which had been discontinued at the end of 2003. Those 3-valve motors went into Super Duty trucks, motorhomes, and even some buses. Oddly enough though, the F450 and the 550 series of trucks got a different version of the 3-valve Triton that only made 288 horsepower and 424 foot pounds of torque. The new City Flyer bus versions had 305 horsepower, but only 390 foot pounds of torque. I wasn't able to find any clear explanation of why these different versions of the Triton lost so much performance, but maybe it was due to a manifold change or compression. I don't really know exactly why it would be so much different. Anyway, Ford kept on making the 2-valve motors, but they were only available in the E-series vans. The power and torque boost was nice, and it got people excited about the Triton again once the 3-valve came around, but then the next spark plug issue showed up, and it probably just killed all the excitement that came from that power bump. In 2009, after Ford finally fixed the problem for good, they kept the Triton name limping along for another couple years. But the damage was just too great, and at the end of 2010, they dropped the Triton name from their badging and advertising. The 2-valve engines continued to work in cutaway vans until 2019, and a version of the 3-valve was still built for school buses until 2021. However, after 2010, most of the heavy-duty Ford trucks moved to the new 6.2-liter V8s or Power Stroke diesels. There was a short period in the early days of the Triton though that some big names in Ford racing, including the Powertrain Research and the Advanced Engine Development Groups, John Coletti of the Special Vehicle Team, and even Carroll Shelby were looking into making a V10-based race motor. They considered an all-aluminum version of the Triton, and built a couple concepts like the Ford 427 sedan. There was even one Triton V10 Test Mule Mustang in the New Edge platform. But it was quickly shown that that V10 probably wasn't the right path forward for the performance angle, and they stuck with the V8s. Since they built a million Triton V10s, they are pretty easy to find, and some people like to swap them into stuff that never came with them from the factory, but most Triton V10s are used now to source parts for other Triton V10 applications. Ford has made a lot of fantastic engines in their time, especially ones that went in the F-Series trucks. And while the 4.6 mod motor V8 was a fantastic motor, as was the 5.4, the V10 left a lot to be desired because of those spark plug issues. If those issues had never appeared, these motors might have had a totally different story, and maybe there's a chance they would still be making some of them today. Although the prevalence of diesel now, I do think they would have killed this off at some point. But I would love to hear from you if you ever owned a Triton V10 truck in the past. Let me know what you thought of it, was it reliable, and did you have the spark plug issues with it, and how did it stack up to any other V8 truck you owned or even a diesel? Anyway, thank you all for watching another Rare Cars video though. If you did enjoy this, please make sure to go ahead and leave a like and subscribe to the channel, it really helps me out. Otherwise though, I will see you all in the next one enthusiasts.