Some of you may recall my previous article that detailed out the problems of tuning an engine equipped with an inexpensive set of injectors. While it wasn’t I who blessed my engine with these pentles of pain, but rather a previous owner, it was the experienced tuner who at one point thought a flat-rate fee would be a great idea and my mental state that would be taking a major hit. You see, Part 2 was scheduled to be the triumphant return of my supercharged small-block, but as fate would have it, the damage from Part 1 was not quite over. We learned shortly after pulling the first set of injectors for testing that the injectors were indeed faulty. However, we had no idea the wrath these injectors had already reaped upon my engine.
While the choice of injectors was not my doing, my lack of forward-thinking had put me into a precarious position. I admit, I was so overly excited about having the supercharged engine back on the road that I didn’t consider just why the previous owner insisted he was lifting the cylinder heads. In my head, I attributed the problems he was having to poor tuning, judging primarily by the shops the vehicle had visited before my ownership. The fact that it was running relatively low boost with 1/2-inch ARP studs further pushed my theory to the point that I didn’t bother to put the injectors on a flow rate bench to start with. That was a grave mistake on my part.
Throughout my tuning process we kept running into intermittent lean conditions. It wasn’t on both cylinder banks though, but rather, the Bank 2 that was capturing the lack of adequate fuel supply for a proper air/fuel mixture. At one point we even swapped the wideband sensors to see if it was maybe a misreading. The problem persisted though, with the driver’s side wide band displaying a .77 to.79 Lambda, while the passenger side was seeing .97 to 1.0 lambda. These lambda readings showed roughly a 2.24:1 difference in air/fuel ratio for E85 between the two at times. It was at this point the tuner suggested we pull back on any more street tuning until we inspected the injectors, but the damage had already been done.
Instead of swapping out injectors and moving on like a normal person, I was determined to see just how bad the injectors were, and if they were indeed the source of my fueling problem. Once on the flow bench, it was determined the injectors were causing the majority of my issues. We saw variances as high as 20-percent throughout the injector set, but also erratic fuel spray and inconsistent fueling between rounds. Needless to say, I had rested my case and was excited to install a set of 1,500cc injectors that not only provided proper tuning data, but also had extremely low variances between the injector set.
Before we started to tune the new injector combination, my tuner had recommended we reset the dual sync distributor from 50 degrees to 30 before top-dead-center. We also had to input the injector data into my standalone ECU. Although I know these changes were for the better, I still felt a sense that we would have to iron out these kinks before we could begin the tuning phase again. As luck would have it, it only took a few minutes and a jumper battery before the engine fired off and the E85 began pumping through the fuel lines. While we had adequate fuel pressure, the engine was still running rough and sounded like a bad misfire.
Lacking a thermal-imaging camera, I resorted back to the old-school method of spraying water on the headers. One by one, the mist would sizzle off and it was evident that heat was being emitted from that cylinder and exiting via the exhaust, until I got to cylinders 6 and 7. These two cylinders were not cold to the touch, but unlike the others, they lacked the heat to dissipate the water quickly. I immediately shut down the engine and knew we had bigger problems on our hands. Although I’m not above using oven mitts while performing a compression test, I thought it would be best to let myself and the engine cool down before diving into diagnostics.
While the old injectors showed variance between the set, the spark plugs reverberated this information with a melting pot (no pun intended) of ground strap coloring. The ground straps varied from a light tan to charcoal gray to abyss black with a variety of lean, rich, and carbon build-up conditions evident. However, it was the cylinder 7 spark plug that brought the worst fears to light. The cylinder 7 ground strap appeared to have been melted or broken off completely. The welts surrounding the ground strap suggested melting, but the smooth break at the end suggested it had broken. In any case, the compression test would further prove that cylinder 7 had been the first fail point.
With the engine cooled down, it was time for the daunted compression test. I decided to start with the passenger bank to prolong my fears just a bit further, but it wasn’t long before I arrived at cylinder 6 and cylinder 7 reading 0 psi on my gauge. While the rest were 175 to 180, these two showed signs of another head gasket failure. The small-block is simple enough to take down to the head gasket, even with a supercharger bracket attached to the cylinder heads. The allen-headed ARP studs made removal even easier. Once I arrived at the head gasket there was no doubt there was more damage to be found in the engine.
Turning my aftermarket aluminum cylinder heads over revealed why cylinders 6 and 7 had 0 psi. A valley had formed between the two cylinders, with the only redeeming grace being that the cylinder heads took the brunt of the heat and not my block. However, this also meant a full teardown of the engine to get the block decked and prepared for an all-new build. While this engine lasted almost 20 years, it was a simple set of injectors someone swapped in just before my ownership that brought about its demise.
With one head torched, a block needing to be decked, and my future power goals in mind, I decided it was time to reevaluate the entire rotating assembly in the process. I’ll be modernizing the internals and stepping the build up a notch by shortening the stroke, boring out the cylinders, and creating one nasty forced inducted 427 cubic-inch engine. Oh, and don’t worry I’ll be putting those flow-tested, 1,500 cc injectors from DeatschWerks to good use.
It’s difficult to accept that the engine was toasted based on crummy injectors, I’m extremely excited to build a new engine, provide it with proper injectors, and make even more power. So, stick around as this project is about to lift off once again.