This is the melted and ventilated...
This is the melted and ventilated piston from the No. 3 cylinder of our project Mustang's 347 stroker. We're calling this slug "ground zero," as it's the most destroyed piston of the set. This kind of damage is caused by a severe imbalance in the boost/octane/timing ratio of a supercharged powerplant and the resulting detonation.
Horse Sense: Every once in a while, we experience an occasion where the negative outweighs the positive - by a lot. This is one of those times.
"Magazine projects never have catastrophic problems. If they do, we never hear about them." The opinion that a magazine editor's world is, well, perfect is a misconception that unfortunately is shared by more than a few readers of this and many other car enthusiast mags.
Sure, most of our content focuses on good-and cool-modern (Fox thru S197) Mustang parts, technology, events, and opportunities that we experience each month. Unfortunately, for all of the good, there are certainly times when things go wrong. When the problems occur, they're sometimes big enough to completely dispel the notion that mag projects know no evil.
You might recall reading about our prized '86 T-top LX's triumphant debut in our Aug. '07 issue ("Final Exam," p. 164). The article summarized the coupe's initial dyno numbers and cruise-mode performance. We also gave you the all-important timeslip data, detailing how quickly our Fox-Rod 'Stang motored down the 1,320-foot racing surface at Auto Club Dragway in Fontana, California.
While the T-top coupe scored high marks across the board (600-plus lb-ft of torque, good street manners, and low-11-second e.t.'s), there were a few new-car bugs at the track that we felt were setbacks. A slipping blower belt limited the Paxton Novi 2000's boost production, and spinning 17-inch tires almost certainly had a hand in keeping our Fox Rod out of the 10-second club.
We followed our gut instincts...
We followed our gut instincts and decided to check compression in each cylinder prior to removing the cylinder heads, where we thought we'd find a blown head gasket. After registering less than 25 psi in five holes, it was clear the coupe's bullet would have to come out for a better diagnosis of its problem.
A few months after making changes and correcting the glitches, we decided to give the car another workout, participating in the test 'n' tune segment of the West Coast Hot Rod Association's summer event at Auto Club Famoso Raceway in Bakersfield, California.
Despite our high hopes and good intentions, disaster struck our coupe roughly 800 feet into our first pass off the trailer. Although the rear drag radials didn't bite as hard as we hoped they would after launching with the transbrake (we changed the strut and shock settings for better weight transfer and traction), our 'Stang shot out to the eighth mile, tripping the clock for midpoint speed at 102 mph-about 6 mph higher than the 347's previous best speed (96.11).
We credit the gain to a taut blower belt and the big boost it helps create, achieved by a new larger-diameter pulley on the belt adjuster that our friend Marc Rubin made for us. Unfortunately, the coupe's best-ever eight-mile speed is the lone bright spot for the ill-fated pass.
Shortly after clearing 800 feet-and with your tech editor trying his best to bust his right foot through the floorboard and out to the bellhousing-the engine suddenly laid over, which is akin to someone unexpectedly putting a pillow over your face as you're inhaling. It belched what appeared to be white smoke through the exhaust and cut off just before the finish line.
Our initial thought was that a head gasket had let go. We later learned that the smoke was a lot darker than we thought. As you'll find out when you read further, we'd probably welcome 10 head gasket failures over the carnage we found inside our stroker. By the way, our Fel-Pro multilayered steel gaskets weren't blown.
Our effort to define the problem...
Our effort to define the problem and make necessary repairs wouldn't have been possible without the assistance of Sean Roberts of Extreme Automotive and lead technician Saul "The Surgeon" Gutierrez (left), who has always been at the ready to keep our projects on course. Saul and your tech editor had the Paxton Novi 2000 supercharger system, exhaust, radiator, starter, and upper intake manifold off in record time in preparation for yanking the engine.
The blame for this disaster falls solely on the shoulders of your tech editor and not any of the parts manufacturers or service providers we used to complete the coupe's 347. As a matter of fact, we're going to use the same brands (Scat rods and SRP pistons) to replace those that were destroyed.
Mistakes happen. Thankfully, we learn something from them in most cases, in addition to finding out how expensive they can be. The lesson of our engine mishap teaches us that while 91-octane pump gas served our street/strip supercharged engine well under 8- to 10-psi boost conditions, pump gas is no match for the heat and cylinder pressure of a 17-psi blast of forced air. Detonation is definite, and heavy damage is the result.
You may recall we worked valiantly to build our T-top Fox in time to participate in Hot Rod's Drag Week event in 2006. We fell short of making it, but in the spirit of challenging event deadlines, we're currently faced with an urgent need to get the T-top coupe back in action right away. We're not going to tell you where the thrash effort is taking us, but be sure to check out future issues for a better idea of why we're going all-out to fix our project ride.
Read on and learn more about the problem we encountered and the measures we're taking to make things right. Thanks to Federal Mogul, Moroso, Paxton, Royal Purple, Scat Cranks, SI Valves, Sportsman Racing Products, and VP Racing Fuels for turning product orders around for us in record time. Major props to Extreme Automotive and Big Terry's Engine Shop of Simi Valley, California, for going the extra mile and keeping the lights on late for us during an intense two-week thrash.
The first indicator of really bad news was the sizeable dribble of oil that Saul poured out of the runner for the No. 1 cylinder in the upper intake. Theoretically, an engine with proper ring seal and crankcase ventilation shouldn't have that much oil this high.