Checking Disc Brake Runout A warped rotor can cause a pulsating sensation when you step on the brakes, and it can cause uneven pad wear and premature wheel-bearing failure. Use the dial indicator to check the runout of the rotor every time you change the pads, even if you buy new rotors or have the old ones turned. The reading should be no more that 2-3 thousandths in either direction of zero. Checking Disc Brake Runout A warped rotor can cause a pulsating sensation when you st Setting Up a Ring-and-Pinion Many home mechanics shy away from setting up a rearend, but the dial indicator is really the most exotic tool required for this job. Once the correct tooth contact pattern has been established, the indicator and base are essential for properly checking the backlash between the ring-and-pinion gears. To measure it, hold the pinion steady and rock the ring gear up and down while reading the needle. Follow the gearset manufacturers recommendations for proper backlash. Setting Up a Ring-and-Pinion Many home mechanics shy away from setting up a rearend, Dialing In a Bellhousing In a high-revving manual transmission car, the pilot-bearing hole in the bellhousing must be exactly centered in the back of the crankshaft to ensure smooth, high-rpm shifts. If the misalignment is great enough, the input shaft can bind enough that the trans wont shift into Fourth gear at high rpm. Most factory bellhousings are surprisingly close, but aftermarket scattershields are hit-and-miss. Weve used several that were spot on, while others were so far off that we guarantee there would be a shifting problem if not corrected. The bottom line is that every one needs to be checked. Setting up the indicator inside the bellhousing is the toughest part of the job because theres limited room for a bulky base. It may be easier to bend a short bracket out of a piece of metal strap and bolt it to the crankshaft. Once the indicator is zeroed, rotate the crank in the direction of engine rotation, take readings at the 12, 3, 6 and 9 oclock positions. Maximum runout should be no greater than +/- 0.005 inch from center in either direction. Offset dowel pins are used to correct any misalignment. Dialing In a Bellhousing In a high-revving manual transmission car, the pilot-bearing Checking Piston-to-Valve Clearance Weve written several articles on this subject in recent years, but its still surprising how many experienced car crafters still dont understand that net valve lift is far less critical to piston-to-valve clearance than camshaft duration is. As a rule of thumb, any cam with more than about 230 degrees of duration at 0.050-inch tappet lift is likely to be very close to interfering with stock piston valve notches. P-to-V can be checked with a dial indicator by installing checking springs on the valves, zeroing the indicator on the retainer, and depressing the valve while rotating the engine. This is best done in conjunction with a degree wheel, because the valves are always closest to the pistons at 9 to 11 degrees before top dead center (BTDC) on the exhaust side and 9 to 11 degrees after bottom dead center on the intake side. Checking Piston-to-Valve Clearance Weve written several articles on this subjec Checking Deck Height Piston deck height is an important measurement to have when calculating an engines compression ratio. With the piston at TDC, a dial indicator and base can be used to check the depth of the piston in the bore by zeroing the indicator needle on the deck surface, then swinging the needle onto the top of the piston and measuring the difference. If the rings are not installed, rock the piston to each side and average the two measurements. Checking Deck Height Piston deck height is an important measurement to have when calc Checking Crankshaft Endplay Installing a crankshaft with inadequate endplay will wipe out the main thrust bearing in a hurry. With the indicator and base set up to read off the crank snout, shift the crankshaft fore and aft in the main saddles with a large prybar and read the movement on the dial indicator. On a small-block Chevy, endplay should be about 5 to 8 thousandths, although many engine builders will tell you that some endplay is good enough. No endplay is the bearing killer. Checking Crankshaft Endplay Installing a crankshaft with inadequate endplay will wipe Degreeing a Cam In conjunction with a degree wheel, the dial indicator is mandatory for measuring lobe lift while degreeing a camshaft. Depending on the technique, a special cam follower fixture can be mounted to the dial indicator, or you can simply install a solid tappet in the lifter bore and read the lobe lift off the pushrod or the valvespring retainer. Degreeing a Cam In conjunction with a degree wheel, the dial indicator is mandatory f Some of the scientific measuring instruments you see in engine building articles might appear to be expensive, exotic implements far beyond the means of the average car crafter. And to the extent that you need a $1,000 Sunnen inside-bore micrometer to measure cylinder wall taper, wed agree with you. You pay your machine shop to have equipment like that so you dont need to. Even a complete set of micrometers might seem wildly exotic to someone whose basic tool inventory hasnt advanced much past the Bronze Age. However, if theres one machinists tool wed argue is a must-have for every home mechanic, its a dial indicator and magnetic base setup. Yeah, technically thats two tools, except you really cant use one without the other, so were counting them together as one. If you dont have a dial indicator, youve got no idea how much precision fun youre missing out on. These are just a few of the ways weve put our indicator and base to use in recent months. Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!