Racing Engines - Crate Or Built?

Let's start summing up where we are with the crate motor. We have an engine that was not that expensive at about $5,000, less carb and distributor. But being competitive required that the engine, at the very least, be broken in and fine-tuned on the dyno. This method can find anything from 5 to 10 hp and is something KT Engine Development can do for $500. If this is done to a new, un-run engine, the output is likely to fade. This means that if you are running at a track that calls for a sealed engine, the odds are you will need a new engine about every third race to maintain power parity. A crate motor does not appear to be a great fit in this scenario.

If track rules allow the engine to be freshened, then things may actually be a little better-but now we are dealing with a built crate motor. Although I don't have any experience in the American Speed Association, it would seem that the deal used by ASA a few years ago had some merit. Here, if I remember correctly, the fuel-injected LS engines were handbuilt by Lingenfelter. The engines cost more off the bat but appeared to hold their output and stay competitive over a long period. If the point of using a crate motor was to keep costs down, then the built crate motor might have been the way to go.

Even though going the route that ASA did looks like a step in the right direction, we have to wonder how viable it is to operate an engine on a high-duty cycle virtually 100 percent of the time when it is designed for a low-duty cycle.

Although there are other minor issues, one that is important concerns the valvetrain. The hydraulic rollers used in most crate motors destined to be raced are ill suited for the job. Worse yet, based on conversations with a couple of top engineers at the factory, the lifter manufacturers don't even recognize a problem exists. Like it or not, hydraulic rollers are much more prone to rpm-induced lifter collapse than flat-tappet hydraulic lifters. As a result, some of the lifters collapse at high rpm, and the valve lift drops substantially. I have seen a hundred thousandths go away on the SpinTron, and 20 to 30 is not uncommon. Sealing lifters, then, becomes an issue. On the dyno, we found that the oil used can affect lifter seal/collapse to the tune of 8 to 10 hp. After running a lot of different oils through the engine, we came up with a blend that was worth about 8 hp and an extra 150 useful rpm on a typical engine. Of course, if you have one of those relatively rare engines from the factory that has lifters with all the right tolerances, then lucky you-you have a potential race winner on your hands. All of these valvetrain facts apply to the original small-block Chevy. If we use an engine from the later LS series, the valvetrain situation is far better.

At this point, here is what the built/crate situation looks like. To have power parity means having a new, dyno-proven, sealed motor about every third or fourth race or having rules that allow the use of a rebuilt crate motor. The first option looks expensive, but the second is not so bad as it involves a cheap built motor. If nothing breaks or wears out, then we can-for the most part-have satisfactory, long-lived power at a reasonable price.

Like many tracks that allow a single class to use a choice of engines, Hickory allows Late Model Stockers to choose between a crate and a built spec motor. Use of a built motor means carrying a weight penalty of 100 pounds. The reason, as you may guess, is that even with induction restrictions, they deliver more torque, power, and rpm. Numbers bandied about for power ranged from 450 to approximately 460 hp. As a result, the power-to-weight and power-to-torque ratios are higher with a built motor powering the car, even with the extra 100 pounds of ballast. Because the built motor makes power at higher rpm, it can be geared lower. This means the rear-wheel torque is up by about 20 percent compared to that of a car powered by a crate motor. That translates directly into 20 percent more acceleration off the turn-if you can hook it up.

Let's discuss output first. Andy's car had a built motor at the beginning of the season, and although it did not come with a dyno sheet, we assumed it was one of those 450-460hp units. As for performing like it had that much power, all that can be said is that the car won the season opener, along with scoring several runner-up finishes and pole positions. Nonetheless, Don Losito, being team boss, decided to create our own built motor, if for no other reason than to get our feet wet in this area.