Cut-Rate Rallycrosser — Part 2: Twin Cams of Fun and Agony
Written by Per Schroeder
From the May 2009 issue
An empty engine compartment is a lot like a blank canvas: There are just so many possibilities. Sure, big parts like the engine block and transmission are easy to place in the right spots, but what about all of those bolts, brackets and bobble struts that are required to make the whole mess go “vroom”?
Our Dodge Neon ACR came to us without an engine, but it did include a box full of parts. We could take that pile of junk and create whatever we wanted, but only after we assembled the contents of those crumbly cardboard boxes like a three-dimensional jigsaw puzzle—a puzzle that was missing a few pieces. Plus, we didn’t really know the condition of those bits. The situation was like a Mensa brainteaser for car geeks.
Right off the bat, we decided to get the car running as inexpensively as possible. The goal was to attend a rallycross event without a heavy investment in parts or time. We managed the first half of that goal quite well, but the latter was a bit more difficult.
A Plan of Attack
We started the build by getting our hands on an engine block and twin-cam cylinder head. Fortunately, the guy who bought our first Neon—the Nitro Green coupe—gave us the engine parts in partial trade.
The 2-liter short block, which included the pistons, rods, crank and oil pump, was said to be in good shape with strong compression before it was removed from a car for a 2.4-liter swap. We were told that the head was also in good shape without any bent valves.
Our inspection of the lower end confirmed that the pistons and bores were in decent condition. We couldn’t detect any appreciable wear on the sides of the bores, and most of the cross-hatching was still present. We also didn’t see any vertical gouges that would indicate a cracked piston ring. Plus, the upper lip of the bore wasn’t higher than the walls themselves, indicating that minimal wear had occurred. So far, so good.
The cylinder head was a different story. To see if the valves were sealing correctly, we removed the camshafts and squirted some kerosene into each port. Several of the valves showed seepage, and one was downright gushing, indicating it was bent. Neon valves are very easy to bend, as even resetting the timing belt improperly can tweak them.
Our pile of parts also contained the original head from our ACR. While all of the valves in this head were straight and sealing well, the camshafts and their bearing caps were missing. These latter pieces can’t be replaced without line-boring the head and caps. Therefore, it made more financial sense to take the good valves from Head Number 2 and place them into Head Number 1. This would give us a chance to recut the valve seats as well, ensuring a good combustion seal. Now that we had the basics of an engine planned out, we sourced a full set of Fel-Pro gaskets. The Fel-Pro kit comes with the improved multilayer head gasket and a set of new head bolts.
The assembly process from there was pretty straightforward. We got a factory service manual from one of our online message board readers and set about to spinning wrenches.
Neons have a problem regarding oil control—they don’t like to be starved of this precious liquid—so we took a two-pronged plan of attack: We installed a Moroso baffled aluminum oil pan plus a crank scraper and windage tray sourced from Ishihara-Johnson. The oil pan and crank scraper should keep our engine happy and lubed during hard cornering on the track and rallycross course. While the Moroso piece holds more oil, the fact that it reduces our ground clearance remains a point of concern. To keep all of this oil clean, we also installed a Canton billet oil filter.
Five Speeds of Fury
With the engine back together, we turned our attention to the transmission. The ACR transmission comes with two performance-adding features, a close-ratio gear set and a lower final drive.
Unfortunately, the Neon’s price-leader status when new meant that extras like a performance differential weren’t in the cards. That was bad news for us, as a good differential is a must for any performance work—especially since this car is going to see a lot of off-pavement use.
There was good news, however: Since the transmission was already out of the car, adding a performance differential only required a few hours of additional work. We chose a Quaife ATB differential from Autotech Driveline—an $895 piece—as it offers a lifetime warranty and will work for rallycross, autocross and track days.
The Quaife is legal for the Rally Prepared class for 2009; the differential is also currently legal for Modified 2, the class that we’re going to run. Modified 2 is the fastest two-wheel-drive class and allows for a bunch of modifications. We’re concentrating on the simple things for now, like lightening the flywheel and clutch; those are two quick ways to cut weight and improve acceleration.
We bolted in an aluminum flywheel, pressure plate and high-performance clutch disc from Spec Clutches and Flywheels. The $360 aluminum flywheel and $380 clutch kit were attached using the stock hardware that we found in our box of parts.
Installing the engine came next, and we made a few easy, low-buck upgrades. We added a set of Energy Suspension inserts (about $50 for the set) and a $59 Poly Bushings adjustable bobble strut to keep the engine from rocking backward too much under acceleration.
The final elements of the installation included a long-tube header and an AEM intake system. We went with aftermarket parts here, as our assorted boxes and bins didn’t include the stock units.
We found a used Kirk Racing header and blanketed it with DEI’s high-temperature wrap. The AEM intake was also a natural choice, as it bolts on easily and comes with their cool patented Dryflow filters. We can just shake these off after a rallycross run to regain any flow lost to dirt and dust.
Getting the engine running was our next task. Once the wiring was hooked up, we filled the coolant system and added a fresh battery.
All that remained was a simple turn of the key. Okay, not really.
Several moments of cranking resulted in nothing more than some fruitless chuffing of the engine. A squirt of starting fluid down the throttle body brought the engine to life. That meant we had the spark and timing under control.
A quick jab of the test port on the fuel rail revealed that there was no fuel pressure in the system. We listened for the high-pitched whine of the fuel pump and heard nothing from the passenger side of the tank. Clearly, our pump was not running at all.
After we traced all of the wiring and made sure that everything was as it should be, we drained the fuel tank and removed the pump. Aside from the aroma of varnished fuel, the fuel pump seemed intact. We let the pump dry out and then hooked it up to a 12-volt power source. Nobody home.
Neon fuel pumps are a common failure point, and our local AutoZone had a new one in stock. For $220, we got a new pump and filter that did the trick. With a couple gallons of fresh fuel, we were on our way after just a few seconds of cranking. The car settled into a normal idle with no issues.
The next morning, we set out on the seven-mile drive to the office. The Neon was running very well and pulling strongly up to the redline. That is, until we heard a squeal from the engine compartment that was accompanied by a change in the power steering’s feel. We figured that it was something related to the power steering pump and kept on going.
A few miles later, the engine emitted a final squeak from the belts before quitting suddenly.
We towed the car back to our shop and let our blood pressure come down from the stratosphere before we tore into the car again. Images of sledgehammer- and beer-fueled mayhem danced in our heads for about a week before we felt calm and balanced enough to start the repair.
Our initial diagnostics showed that the intake camshaft had seized in its journals, shearing the drive pin off the cam gear and shifting everything out of time. The result? A bunch of bent valves. It turns out that the timing belt had stopped abruptly, causing the valves to crash into the pistons with rather bad results. Our fresh cylinder head was junk once again.
We’re not about to give up on this project and have been busy searching for another cylinder head to top off our engine. We’ll be back in the game shortly.
Dang I miss stuff like this. Per's projects were always the best!
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