A depth gauge allows you to measure the depth of a hole, groove, recess, etc.
A depth gauge features a spindle that protrudes out of the flat base. Make sure that the base and spindle face are clean of any oil, dust, etc.
An internal caliper gauge features two arms with small contact tips on the outside of each arm tip. This tool allows you to measure the inside diameter of a hole that is otherwise difficult to access. Compress the arms together, insert them into the hole or recess, and release the arms. The tool features a lock that may be engaged before removing the tool from the hole. The gauge reveals the diameter. This type of gauge is available with either a needle dial gauge or a digital readout.
Pushrod length does not necessarily reflect overall length, depending on the pushrod style. You must consider the oil orifice at the end (if an oil hole is featured). If you measured an existing pushrod using a large caliper, you’d be fooled by about .017 inch or so (on the short side) because you’d contact the caliper against the small flat at the end that results from the hole opening. If you’re using a pushrod checker, this isn’t an issue, unless you’re also using an existing pushrod that you measured as a reference.
A digital inside caliper allows you to easily measure the inside diameter of a hole. The arms are spring-loaded and the measurement readout is displayed in the viewing window.
Compress the arms together to enter the hole, then release tension. The arms expand away from each other as the arm tips contact the walls. This type of gauge is very easy to use and is extremely accurate.
Also, if the pushrod style you intend to use features a top cup (female pocket instead of male radius), you need to remember that your measurement must take place at the female radius seat, not at the outer edge of the cup. The easiest way to accurately measure a cup-equipped pushrod is to drop a steel ball into the cup, take your measurement, then subtract the ball diameter. For instance, if you’re dealing with a 5/16-inch cupped pushrod, place a 5/16-inch-diameter steel ball into the cup. Then you can measure overall length (contacting your caliper on the ball). Then subtract the actual ball diameter from this measurement, which provides an accurate length to the radiused seat in the pushrod cup.
If you use a ball to help measure a cupped pushrod, take the time to actually measure the ball diameter using a caliper. Don’t just assume that the ball meets an advertised diameter. A 5/16-inch ball should measure .3125-inch in diameter.
Just remember that pushrod lengths refer to the distance between the radiused contact points at each end of the pushrod.
Before you can measure pushrod length, the cylinder head must be fully installed; that means that the head gasket must be in place, and the head fasteners must be fully tightened to their final value.
Verify that clearance between the edge of the valvespring retainer and the underside of the rocker is at least .040 inch.
A long-slide caliper can be used to measure pushrod length, or when measuring an adjustable checking pushrod when determining a custom pushrod length. If a cup-style pushrod is being measured, install a ball bearing into the cup during measurement, then subtract the diameter of the ball to determine the required length of the pushrod, from lower radiused tip to the seat of the upper cup. The ball should be sized appropriately for the radius of the cup (for example, 5/16 inch in diameter, or .3125 inch).
Checking pushrods are available in a wide variety of length ranges and styles.
When measuring for pushrod length, you must use the valvetrain parts that will be used in the final assembly, including block, heads, camshaft, lifters, valves, rocker studs, and rockers. When you’re ready to measure for pushrod length, the only remaining variable should be the length of the pushrods.
When measuring for pushrod length, swap out a valvespring for a light checking spring. This makes it easier and more precise to rotate the crank and eliminates the tension that a valvespring creates. A heavy valvespring can easily damage an adjustable checking pushrod.
A barrel-style micrometer is available designed specifically to measure valvespring installed height. Obtaining adequate valveseat pressure while avoiding coil bind is critical, especially for extreme valvespring pressures and radical camshafts. Although valvesprings should be tested on a valvespring gauge for seat and full-open pressure, the engine builder needs to be sure that the installed height dimension that’s required can be duplicated during assembly. If the measured spring height differs from the target installed spring height, the height can be corrected by adding a shim to the spring seat or by milling the spring seat base.
A valvespring checker allows you to monitor both spring height and pressure. As you compress the spring to its specified installed height (monitored on a separate indicator), spring pressure is monitored on the tool’s pressure gauge.
Checking the valveguide centerline relative to a valveseat is easily accomplished with a valveseat runout gauge. This gauge features an anvil rod that is inserted into the valveguide. The gauge features an adjustable contact that runs along the valveseat and a dial gauge. Slowly rotating the gauge along the valveseat reveals any runout of the seat relative to the guide. If runout is found, the seat can be resurfaced (or replaced and machined) to obtain zero runout.
A valvespring height micrometer is used to measure installed spring height on the cylinder head. The spring height checker is installed in place of a valvespring, with retainer and keepers installed. Adjusting the gauge to remove all slack with the valve in its fully closed position allows you to measure installed spring height. If this measured installed height is too tall for the specified installed height, shims may be added to the spring seat to compensate, or if too short, the spring seat may be machined to remove material.
When checking a block, cylinder head, or manifold deck surface for flatness/warpage,