If, after flushing out all air pockets in the system, you still have trouble with air entering the cooling system, you might want to check to make sure you aren't somehow losing water. This can be from a defective pressure cap on the radiator or a leaking radiator hose. Often it won't show up until you are out on the racetrack when the water gets hot and the pressure builds in the cooling system-so it's hard to spot. One way to make sure this isn't happening is to use an oil pressure gauge plumbed into your cooling system so your driver will notice a drop in pressure.

Watch Your Filters
Filters are often an afterthought with most teams. As long as they are clean you are good to go, right?

Not exactly. Dorton says he has seen many racers running an inline rebuildable oil filter have serious engine trouble because they had the filter element installed backward. Inline filters use a removable element that is cleanable to increase the useable life of the filter. The problem comes when the filter is removed for cleaning and then either reassembled with the element in the canister backward or with the canister itself turned the wrong way. When this happens the filter can't flow enough oil, the pressure backs up behind the filter and the end result is usually a blown seal on the pressure section of the external oil pump or a thrown oil pump drive belt. If you are running such a filter on a wet-sump engine, the excessive pressure buildup can lock up the oil pump and cause the engine to either strip the distributor gear or even break the oil pump driveshaft.

The key, Dorton says, is to understand how all filters work. They are designed for the oil to enter the filter on the outside of the element, flow through to the inside of the element, and then leave the filter. So, if you have a cone-shaped screen filter element, it should always be inserted so that the oil sees the pointed end first, flows through the screen and leaves though the big end of the cone.

The same concept holds true if you are using a remote for a standard canister-style filter. The inlet hose should be connected to the fitting that's on the outside edge of the adaptor, and the outlet hose should be connected to the fitting in the center. Getting it backward can flush all the trash the filter has collected back through the engine. And you definitely don't want that.

Don't Switch the Leads
It's a good idea to make your race car's electrical system as weather-proof as possible. That's why many racers replace the standard connectors on their ignition system with weather pack connectors. These connectors are gasketed to seal out water, dirt, and other contaminants that can cause ignition troubles. But if you aren't careful, Dorton says you can get the wires switched, and that will leave you scratching your head wondering why your engine suddenly picked up a miss or simply isn't running like it used to.

One reason why switching the wires is so easy to do when installing new connectors is the two-wire lead from the 6AL box to the distributor on MSD systems is both wires are black. They just have a purple stripe on one and an orange stripe on the other. If you aren't paying attention, it's easy to get them backward. And the result is it will throw off the timing when the distributor sends the spark to the engine.

You can reset the timing by turning the distributor but this won't fix the misfiring problem that usually shows up in this situation. The test for this is to set your engine at its standard advance setting with a timing light. For this example, let's say 30 degrees before top dead center. Now, shut down the engine and turn it by hand until the pointer is lined up with the 30 degrees BTDC mark. Next, pull the distributor cap and take a look at how the rotor and pickup are lined up. If you have everything wired correctly, one of the paddles on the rotor should be lined up with the pickup, or slightly retarded. If the wires are switched, you will often find the pickup in between two of the paddles on the rotor. The current has trouble jumping the gap, and this is why the engine will miss or otherwise run poorly.