You can’t do quality work in an automotive machine shop if you don’t have the right tools and measuring equipment. “Must have” tools and equipment include those that are necessary for engine disassembly, for inspecting and measuring engine components, and for engine assembly.
While this should not be considered the only tools a shop needs, it does provide a good overview of equipment needed to handle today’s engine builds. And, it also is a useful list for shop owners looking to upgrade their tool needs for the upcoming racing season, or to take on additional niche projects.
Let’s start with basic engine disassembly tools. For starters, you need a good selection of SAE and Metric hand tools including open end and box end wrenches as well as standard depth and deep well sockets. Twelve-point sockets are more maneuverable and faster in tight quarters, but six-point sockets are usually stronger and less apt to round off stubborn fasteners. For faster disassembly, you also need a set of impact sockets (SAE and Metric) and a pneumatic, corded or even cordless impact driver (3/8 and/or 1/2-inch drive). Some of the newest professional grade cordless impact drivers pack as much punch if not more than many pneumatic and corded impact drivers, and with state-of-the-art lithium ion battery packs they can run a long time on a single charge. The cordless tools are gaining in popularity compared to traditional pneumatic and corded electric tools because there’s no hose or cord to get in the way or trip over, and many are lighter weight than their traditional counterparts (which reduces fatigue).
Specialty tools may also be needed for removing pulleys and harmonic balancers (various types of gear pullers), for extracting camshafts from overhead cam cylinder heads (OHC valve spring compressors and head fixtures), for removing or changing valve springs (a power or manual valve spring compressor), for driving valve guides in and out of cylinder heads and for replacing valve seats.
Although engines can be torn apart almost anywhere, it’s faster and easier to have the engine mounted on an engine stand or portable dolly. To lift the engine onto the stand or dolly, you’ll need an engine hoist or crane to save your back.
As the engine is coming apart, it’s a good idea to have a basket where all the fasteners can be stored for later cleaning and inspection. Fasteners that are reusable should be cleaned up with a thread chaser and wire brush. A tap and die set can also be used to clean and/or repair the threads in the engine too.
A stud removal tool is usually necessary to remove studs, and for broken fasteners you’ll need some drill bits and extractor bits to back out what’s left of the fastener. A thread repair kit with inserts may also be needed to repair damaged threads in heads, blocks and manifolds.
When old gaskets don’t come off cleanly, a sharp gasket scraper comes in handy and is faster than aerosol chemical gasket remover (although either can be used with equal success). A grinder/polisher with an abrasive disk can also be used to whiz off old gasket residue (if used carefully so the surface isn’t damaged).
For removing and installing wrist pins, you’ll need a hydraulic press and various drivers, which also come in handy for U-joint work if you repair drive shafts or replace wheel bearings.
Inspection And Measuring
Once you’ve disassembled the engine into its individual components, everything needs to be cleaned, inspected and measured to determine wear and whether or not certain parts needs to be reconditioned or replaced.
Measuring is what separates the men from the boys. Real men measure everything – at least twice to double-check their work, and maybe even a third time just to make sure. Late-model engines and performance engines allow almost no margin for error. If you want to do it right the first time, you measure, measure, measure.
You can’t determine how much a crankshaft journal is worn or tapered or misshapen unless you measure it with a micrometer or calipers. Digital micrometers and calipers have become “must have” tools because they are faster and easier to read, and reduce the risk of making mistakes. The same goes for digital bore gauges for checking cylinder bores, main bores, cam bores and rod bore openings. If you don’t measure the size of a hole accurately, you can’t determine if it is round or the proper bearing or ring clearances.
Many parts also have to be measured to determine relationships. This includes checking deck height, piston height, rod length, bearing clearances, camshaft and crankshaft end play, installed valve heights, piston-to-bore clearance, ring end gaps, compression ratio (CC the heads), valve guide clearances, even pushrod length. The “must have” tools here include a dial indicator, depth and height gauges, feeler gauges and a valve spring tester.
A valve spring test stand will tell you a lot about valve springs. You can eyeball or measure a set of springs to see if any are shorter (weaker) than the others, but unless you actually test each spring to see how much pressure each spring exerts you can’t be sure if the springs meet specifications or not. For ProStock drag racing applications, you’ll need a valve spring tester that can check pressures up to 2000 lbs. or higher. Useful test information includes such variables as open and seated spring pressure, spring rates at various heights, and spring bind height and clearance.
Another “must have” tool for serious performance work would be some type of camshaft analysis software, camshaft stand and electronic probe. This type of equipment and software can be used to check cam straightness, base circle run out, lobe positions, opening and closing points, lobe area, valve acceleration, duration and lift. The software can allow you to document every aspect of camshaft performance for customer reports or later reference.
Never assume a cam is correct out of the box, even with a stock engine rebuild. Mistakes sometimes happen, so it is better to catch a defective cam on the workbench than after the cam has been installed. Software that allows you to log critical dimensional measurements and list all of the parts you are putting into an engine is another “must have” tool for performance work. Some software allows you to build a virtual engine to check compression ratios, valve-to-piston clearances and more, so any mistakes can be caught before the parts are actually assembled.
Engine simulator software takes the process a step further to predict the outcome of various performance modifications. Simulations include things like predicted horsepower and torque, fuel flow, airflow, piston and valve clearances based on the information you input into the program.
For checking straightness across head and block deck surfaces as well as cam and main bore alignment, you need a straight edge ruler – one that is actually straight and true. The accuracy of your straight edge should be checked periodically by placing it on a flat surface and checking any gaps with a feeler gauge, then flipping it over to see if you get the same readings. If the readings don’t match, it isn’t straight.
Measuring is also critical when surfacing, boring, honing and grinding to monitor how much metal is being removed and where. Most machines will have some type of gauging to monitor what you are doing. But how accurate is the gauging and when was the last time you checked it? Machine tools and fixturing must also be leveled and adjusted properly BEFORE you start machining any metal. Mistakes here can be very costly.
For high end performance work, you should invest in a profilometer to check cylinder bore and surface finish perimeters such as roughness average (RA), average peak height (Rpk), average valley depth (RvK), and Rz, which is the average difference between the peak height (Rpk) and valley depth (Rvk). RA can have a wide variance across a given surface profile, so Rz gives a more accurate indication of the actual texture across the surface. Most gasket manufacturers now specify surface finish requirements in Rz because it is more accurate than Ra. Many shops assume that the boring or surfacing procedure and equipment they are using is delivering the desired results. But have you ever checked it? You may be surprised to discover that the finishes you thought you were achieving are not as good as they should be.
Crack detection equipment is also a “must have” for every shop. This requires magnetic particle inspection equipment for checking iron parts, and penetrating dye and UV light for checking aluminum castings. Porosity leaks in aluminum blocks and heads can be hard to see and require a pressure tester and/or water tank to reveal the leaks. Ultrasonic testers are also available for finding hidden flaws and defects inside many parts.
An ultrasonic tester sends sound waves into a part, then listens for return pings that would indicate a problem hidden below the surface. Ultrasonic equipment can also be used to measure wall thickness in castings, which is important if you are boring out a block and are uncertain how far you can safely go.
Valve and seat work requires an assortment of valve guide and seat tools including valve guide reamers, pullers and drivers, seat cutters and even a die grinder if you are doing any hand porting or blending work. Seat concentricity needs to be checked with a dial gauge.
Installed valve height is another dimension that also needs to be measured with a height gauge or valve spring height micrometer. A valve spring height micrometer is substituted for a valve spring, expanded until it takes up all the slack between the spring seat and valve retainer and fully seats the valve. The reading on the micrometer then shows you the actual height of the spring. You can then determine if the springs need to be shimmed to achieve the desired close seat pressure.
Clearances have to be measured prior to and during engine assembly. You don’t want to end up with a bearing that is too tight or too loose, or too much end play in the crankshaft or camshaft, or too much or too little gap between the ends of the piston rings, or too much or too little clearance between the pistons and cylinder walls, or too little clearance between the pistons and heads or valves. Everything has to fit together perfectly, and the only way to know that everything is fitting perfectly is to measure all critical dimensions and check clearances while you are assembling the engine.
Again, never assume a reground crankshaft journal is accurate, or the bearings are the correct size. Mistakes sometimes happen and parts may be mismarked or put into the wrong boxes.
For rotating the crankshaft during engine assembly, a “must have” tool is a crankshaft turning socket that fits on the crank snout.
If you are modifying pistons (grinding or smoothing valve recesses and/or lightening webbing under the piston), don’t use an ordinary vice to hold the piston. Use a piston vice that supports the piston via its wrist pin holes and holds the side of the piston so it doesn’t rock.
For adjusting the spacing of the piston ring end gaps, a manual or motorized piston ring filer is much faster and easier than trying to hand file or grind the ends of the rings.
For installing piston rings, a “must have” tool is a ring expander. Twisting rings into the grooves can deform the rings and cause sealing problems. You will also need a ring compressor to install the piston and ring assemblies into their respective bores. A tapered ring compressor is faster and easier to use than a clamp type ring compressor, and reduces the risk of ring breakage by allowing the rings to gradually compress as the pistons are pushed down into the bores. You will also need different sizes of tapered ring compressors for different bore diameters. Rod bolt protectors are also a good idea to prevent nicking the crankshaft journals during rod installation. A soft-faced piston installation tool for pushing the pistons into the cylinders is also a better choice than pounding them in with a hammer and block of wood.
Installing a stock cam in a pushrod engine is fairly simple and requires no special tools, but an installation handle that connects to the front of the cam makes it easier to maneuver through the cam bores. For performance work, however, a “must have” tool is a degree wheel and dial indicator for checking and adjusting cam timing. An adjustable pushrod may also be needed to determine the correct pushrod length for a modified engine with altered valve train geometry.
For overhead cam engines, you may also need special tools to position and hold the camshafts while the timing chains are installed and aligned. A cylinder head holding fixture can make assembly faster and easier, especially with multi-valve heads.
Valve lash adjustments on engines with solid lifter cams will require a feeler gauge, and certain roller lifters will require a valve lash adjuster tool to make the job go faster.
Absolutely essential for engine assembly work is an accurate torque wrench. An inexpensive beam style torque wrench is adequate for a do-it-yourselfer, but a professional engine builder should be using a click adjustable, dial gauge or digital electronic torque wrench. Adjustable torque wrenches must be calibrated periodically to make sure they are reading accurately. Adjustable torque wrenches that are used frequently should be recalibrated every six months. Dial gauges and electronic torque wrenches also need to be recalibrated, but typically provide more accurate readings (plus or minus 0.5 percent versus plus or minus 3 percent for a click style torque wrench).
Since many late model engines use torque-to-yield head bolts and rod bolts, an easy-to-read angle gauge is also required when tightening fasteners with a torque wrench. Using the proper thread lubricant is also important to achieve the specified load on a fastener. Ordinary motor oil is often specified for head bolts, but moly-based thread lubricant will usually give more consistent loading.
Once an engine has been assembled, other tools can come in handy for checking your work. This includes a leak down tester or vacuum tester to check ring and valve sealing.
A pressurized engine pre-oiler is another “must have” tool if you are going to fire up and break-in engines on a test stand. The last thing you want is a dry start that could damage the bearings, rings, cam or lifters in a newly assembled engine.
Controlling the engine break-in process yourself can eliminate comebacks and warranty issues that sometimes happen when a customer breaks-in an engine and doesn’t do it right.