Sealed crate motors are the...
Sealed crate motors are the current "next big thing" in stock car racing. They save you money but limit your tuning options.
Like it or not, the crate engine revolution is upon us. More divisions at more tracks are going with pre-fab power. That, however, doesn't mean there is nothing you can do to make sure you're getting maximum power from your engine. Your options are more limited, but the proper care and feeding of a crate engine can provide you with a power advantage on the track.
This story is aimed at giving you several ideas to chose from and try on your own crate motor. However, the rules are so varied that no list can apply to everyone. Some racers may be allowed to pop off the valve covers to adjust the lash, while others may not. And, of course, we're not so naive as to believe that all of you reading this are boy scouts, unwilling to bend the rules slightly if necessary. (Heck, a few of us are short on merit badges.) Knowing that, we've also provided a few suggestions that might push the gray areas of the rule book. All the original parts are kept; they are just modified a little. The key, if you are poking around in the gray areas of the rule book, is to work on parts of the engine that aren't normally checked. In other words, forget about your head porting tools. But we've got a good one to try if you're running a stock water pump.
Note: Just because we mention a few ideas that might not be legal where you race, that doesn't mean Circle Track condones cheating. Of course, we don't condemn it, either. We're not your momma-you can make your own decisions.
You religiously kept up a rigorous schedule of maintenance with your previous engines, right? Well, just because there's less you can do now, that doesn't mean you should ignore the things you can do. The variables you can control are now even more important. These include things like keeping fresh plugs, plug wires, and a clean air filter in the car. Crate motors don't run forever, and they can develop problems. In fact, because they are built on an assembly line and not one at a time in an engine builder's shop, crate motors are often not built to the same standard as older race engines. If your series has a certified rebuilder, contact that operation to set up a schedule for maintenance that you aren't allowed to perform.
OK, now that we've gotten the obvious stuff out of the way, let's get on to the good stuff.
Advancing your timing two...
Advancing your timing two degrees is usually safe without causing detonation and can produce power.
Engine timing is rarely set ideally from the factory. The manufacturers time the engines for smooth-running reliability; what we want is the most power available before the onset of detonation. According to several engine builders, you can safely get away with advancing the timing two degrees. You can potentially make more gains by taking it a little farther, but if you want to see what more timing will do, it's best to try it on an engine dyno in which you can keep a better diagnostic eye on everything.
Most series will allow simple carburetor adjustments, which is good because you probably will need to make a few. For oval track racing, crate motor setups usually run too rich at the top end. The quick fix is to pop in a set of jets a few steps smaller, but this isn't always the best idea because the engine is now lean at idle and at the lower rpm. The real culprit is a power valve that is too large and dumping in too much fuel when the revs are up. If you have this problem, try swapping it for a smaller power valve.
Modern cylinder heads have efficient combustion chambers, so indexing plugs isn't the trick that it was a decade ago. Careful plug selection can net you a small gain, depending on what the factory sent you. Here's the scenario: The flame kernel begins at the electrode and extends outward evenly until it hits an obstruction, which hinders combustion efficiency. The first obstruction is likely to be the top of the combustion chamber and the short side of the cylinder wall.