Before final assembly, Dorton prefers wiping mating metal surfaces clean with paper shop towels (stray cloth threads might clog a vital engine close-tolerance gap) dipped in lacquer thinner because it doesn't leave any oily residue that could affect a gasket's sealing. Naturally, take the necessary health precautions when using this volatile solvent and disposing of shop consumables soaked in it. Have plenty of ventilation available and use rubber gloves. Using a clean pair of light rubber gloves when handling gaskets is a good idea anyway because they keep grease or oil from your hands from fouling the gasket and affecting its sealing.

A clean mating surface is useless for superior gasket sealing if it is not flat or straight, so Dorton says to confirm surfaces are that way. One of the major sealing unions in the engine is between the engine block and the cylinder head(s), so make sure you trust your machine shop to get these true. You can do a quick coarse check for flatness of mating surfaces with a straightedge and a feeler gauge - lay it along the length and width of the parts and measure any gap. As a general guide, you want to hold this gap to be at a maximum of around 0.002-inch on aluminum surfaces and to 0.004-inch on cast iron ones.

Don't assume a gasket will fit correctly and is the correct one for the mating surfaces - it's prudent to trial-fit it to check its alignment and mating before installing the gasket and then torquing the surfaces together. Dorton admonishes, for cylinder head gasket installation in particular, "Don't install it upside down or backwards! It can happen. Make sure you follow any labeling on the gasket that tells how it aligns to the parts." He also makes sure that metal surfaces are not the only items you want to keep flat. He stores any gasket sets so the aren't inadvertently creased or bent.

Dorton has also seen this uneven gap on racing oil pans ranging in cost from economical to expensive. How do you seal it with a stock oil pan gasket? Hint: You don't use a hammer or RTV.

The bottom rubber oil pan end seal is the stock one supplied in a gasket kit. Dorton has modified the top one by buffing its outside radius with a belt sander to taper the seal's ends and thin its center section. This custom gasket will now conform to the irregularly gapped end-union between oil pan and block.

HEAD GASKET GUIDELINES

The union of the engine block and cylinder head is a major joint in a racing engine and deserves extra attention and a special gasket. Basically, this gasket has to function in one of the toughest environments in the engine: extreme temperature, extreme pressure, extreme shock loading by vibration and shearing forces, and the likely job of sealing a joint between dissimilar metals (cast iron and aluminum) while allowing fluids to be routed through it. There are plenty of opportunities for a head gasket to fail, but you can do your part to get a good seal. Don't scrimp. Pay for a premium head gasket designed for racing engines. That's your first line of gasket failure defense.