How to rebuild an engine
by: 1931Steve, Alittle1, Augusto, Chevelle 502, Chevythunder, Cobalt327, Crashfarmer, Crosley, Eloc431962, HenryHighrise, Jamminredheadchixor, Jon, Kringold, Lonestar, Metzijndrie, Nightfire, Paulmeisel, Schnitz, Techinspector1, Topfuel, WakBordr7387
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You will need a basic set of hand tools, such as a good variety of boxed end wrenches, ratchet and socket set, screwdriver set, and a gasket scraper. This basic set of tools will get you through the majority of the disassembly steps.
You will need a few special tools when it comes time to build or reassemble the engine. A good torque wrench, Plastigauge, and a cam bearing installing tool (or have the machine shop install the cam bearings). Also, you may need a ridge reamer, a ring groove cleaner (a piece of a broken ring can be carefully used for this), a ring expander, a ring trimmer, a ring compressor, and a good cylinder hone. If cylinder head work is going to be done, a spring compressor will be needed.
Depending on how in-depth and involved you want to get with your rebuild(s) and how many engines you think you are going to rebuild, you may want to acquire some additional measuring equipment. Items such as a set of outside micrometers, an inside micrometer, vernier, dial or digital calipers and maybe a dial bore gauge can let you know precisely what your sizes are. A "snap gauge" set can be used for spring installed height, bore diameter, etc. Think of these tools as indispensable if you are planning to blueprint your engine or if this is going to become a routine thing. You will also need a decent engine stand. It will make your build easier to support the engine, keeping it from the ground, and also helps in tearing the engine down and keeping the engine clean at assembly time. An engine hoist is also a good addition if you plan on pulling and installing many engines.
 Selecting tools
For each tool needed to rebuild an engine, we'll need to know:
- Approximately how much do the tools cost?
- Is it better to buy a cheap version of this tool, or should you spend money to buy a high-quality version of this tool?
If you're starting a "project" or work on cars often it would be wise to spend the extra money on higher quality tools. Cornwell, SK, Starrett, Craftsman, MAC and Snap-On are commonly known to be the "best tools". Snap-On is a little better quality, but cost considerably more and can sometimes be a pain in the butt to exchange your broken tool since you would have to chase down one of their trucks. Craftsman is a good brand of tool too, and can be bought at almost any Sears department store as well as many K Mart stores since they connected with Sears ca. 2012. Look on the package when you buy hand tools; most have a lifetime warranty on them, even the cheapest ones.
For the most part your basic hand tools and a few impact tools will do the majority of the work but as listed there are several specialty tools to consider purchasing or renting:
- torque wrench
- ring compressor (ring expander is a huge plus)
- dial caliper or vernier caliper
- degree wheel (explained below)
- dial indicator and dial bore gauge
Eventually it will come time to install your camshaft as well. If you are planning on doing this yourself, you will need a degree wheel. You can buy these alone, or in comprehensive kits from somewhere like Jegs, Summit, or maybe even a local shop. They go for around $200. Just the wheels themselves can be purchased for as low as $10.00. You will also need a dial indicator, as well as a magnetic stand for it. These can also be purchased at Jegs, Summit or even your local Harbor Freight store. The larger the diameter of the degree wheel, the easier it is to be accurate.
 Purchasing tools
When purchasing tools, it is best to consider the application and frequency of use. If the tool is intended for infrequent to frequent hobby use, the purchase of cheaper brands of tools such as Craftsman may be appropriate. But if the tool is intended for daily use in harsh conditions, especially in the context of automotive repair, an investment in higher quality tools produced by companies such as Matco, Snap On, Mac and Cornwell should be considered.
 Borrowing tools
If you decide you need some specialized tools that you really don't want to invest money into right now, ask around in your circle of friends to find out if any of them have the tool(s) and will loan to you for the task at hand. It is common courtesy to return borrowed tools promptly and in better condition than they were lent; if a tool was dirty when it was borrowed, clean it before it is returned.
Be aware of the industry notion that a tool that has been borrowed more than twice should be considered for future purchase.
Also, Auto Zone will lend out tools for free, although they may require a deposit on the tool. Also, check with local rental stores, some of them carry items like torque wrenches and cam bearing installation tools, even engine stands, although I highly recommend you buying an engine stand because most of the times your engine will remain bolted to it longer than expected due to lack of time or money or availability of parts, and if you need to return the borrowed stand you'll get into some kind of trouble, a low cost stand will do fine for most small blocks, for a big block maybe you should install the accessories later when the engine is in the car.
 Renting tools
There are some tools you will want to rent instead of purchasing, such as a cherry picker to remove and replace the motor in the car.
 Work area
Most people who are going to rebuild their own engine will be tearing it apart before taking it to a machine shop, and then reassembling it when the machine work is done. When tearing it apart, try to work in an area that you can get dirty, and where bolts and other small items won't get lost.
When assembling an engine, your work area can't be too clean. A clean, well-organized space is safer to work in and makes project completion easier and faster while minimizing the loss of tools and parts due to misplacement and/or damage. Tool storage chests/carts, a label-maker, crafts carriers, magnetized trays and even muffin trays do a good job of keeping a workspace organized and tools/parts in their place. Plastic trash bags of various sizes can also serve in the shop by covering an engine on an engine stand, heads, and other items that need to be kept dust free.
In order to minimize the risk of sending dust up into the air and settling on work area surfaces, a floor sweeping compound, damp saw dust or damp cloth should be used. If the space is small and/or enclosed, an air filtration system may also provide aid in minimizing the presence of particulate matter.
 Skill level
The amount of skill necessary to rebuild an engine depends on what engine you are rebuilding and just how much of the work you plan on doing yourself. If you are rebuilding a standard pushrod V8 such as the small block Chevy with all the machine work being performed by a reputable shop, then the skills needed are basically nothing more than being good with your hands, the ability to take and read measurements, use tools properly, the patience to do things right the first time and the ability to read, understand, and follow a comprehensive manual on the subject. If you don't understand or are not certain of a procedure, ask an experienced professional!
If you are rebuilding something more exotic, such as a rotary engine or a turbo diesel, then you should take the time to research and familiarize yourself with them. Some engines require complicated computer-controlled management systems which may require extensive modifications, depending on how the engine is to be rebuilt, and will therefore also require a greater skill level.
The main thing to keep in mind is that there are close tolerances to check and a certain order of steps to follow. Just take the time to research your engine and above all, ask questions when necessary.
Today there is much information available on the internet. Be careful! Not all information is correct! Verify any information with several professional and/or reliable sources.
 Deciding on an engine
Factors in deciding on an engine/build are as follows:
Picking an engine is no small chore. It's a crucial step to building a hot rod, and one that affects the performance of the final product. It is entirely up to you which engine you want to run in your hot rod. Pretty much anything is possible, but not anything will be money and time efficient. Big Block Chevy's have been jammed into little Chevettes, and Chrysler Hemi's have been sandwiched into VW Bugs. With the right tools, mechanical skill, knowledge, money and time, any engine/vehicle combination can be achieved. But most people don't have unlimited amounts of money and most people don't own a fully equipped shop for massive chassis and body modifications to allow the engine to fit. So it would be recommended to pick an engine that's suitable for your application and your skill level.
 Stock build
A lot of people choose to run the stock motor that came in the car. This would be a good idea if it's your first hot rod, if the engine in your car is still in good condition (if it even came with an engine) or if your motor and mechanical skills aren't developed enough yet to undertake an engine swap. Depending on what kind of car you're working with, the stock engine will often suffice, if the car is meant to be a daily driver or a weekend cruiser.
If you're planning to build a wild custom car, strip racer, or weekend warrior, the stock engine probably won't be of any interest to you. There are many performance parts available these days for the older popular engines. Anything from the Ford Flathead, Chrysler Hemi, GM Stovebolt, Buick Nailhead, and Ford small blocks have a big variety of aftermarket parts available.
Taking the stock engine and hopping it up a bit to squeeze a little bit more performance out of it is a very common thing done by a lot of people building a first time hot rod. Just by changing the exhaust, intake and camshaft, a stock boring engine can often become a neat hot rod mill with plenty of power for daily driving and weekend cruising. If your plans for your hot rod include a loud nasty fire breathing monster motor, your stock motor probably won't do a lot for you.
Remember, almost every modification for performance will alter fuel consumption and/or reliability. Most competition engines are not built to perform on the street as a daily driver. The more radical the modifications, the more maintenance is usually required. Use common sense and make your modifications compatible (carb, heads, cam, etc.).
 Mild build
The next step up from a stock motor would be a mild engine. Often times stock motors cross into the mild engine category. The most popular engines used for a mild HP powerplant is the small block Chevy (SBC), big block Chevy (BBC), the small block Fords (SBF), and small block Mopars (LA engines). Any of these engines are used widely in the hotrodding hobby as well as race venues of all types and they all have a huge choice of aftermarket parts available. They all present a good platform for a first time rebuild or for somebody who needs more than stock. Again, which engine to pick is entirely up to you. Some people swear on the reliability and availability of parts of the SBC, while other people preach a Ford should go in a Ford. Many rodders consider it sacrilegious to put anything but a Mopar in a Dodge, Plymouth or Chrysler. But in the end, it all comes down to your choice. If you find a Mopar LA fitting better in your rod than a Ford or Chevy, and if you are able to get one cheap, who's to say you shouldn't use it? There are many books written on rebuilding these engines, and while the choice shouldn't merely be between these, they are the most popular.
 Wild build
A lot of rodders prefer their horsepower coming from big displacement high output engines. If this sounds like you, your engine rebuild might cost considerably more than a stock engine rebuild/hop-up. The most popular route for wild engines include the big three domestic car producers: GM, Ford, and MOPAR.
The 454 BBC is often considered the ultimate readily available hot rod powerplant. However, over time the Chrysler Hemi, Chevy W-motor, Pontiac, AMC and the Boss 429 Ford have all had a resurgence since Edelbrock (and in some cases other manufacturers) have made alumimun cylinder heads and in some cases new aftermarket blocks available, as well as all the other necessary parts and pieces.
 Locating an engine to rebuild
This section should cover the basics of where to find a potential candidate for an engine rebuilding project. How to search junkyards, classified ads, the internet, etc.
Locating an engine can be as easy as ordering a shortblock crate engine from Edelbrock on the phone, or removing an old rusty flathead from a totaled car in a junkyard.
Classifieds are probably the best way to go if you don't have an engine hoist, a cherry picker, or some device to lift the engine out of the car. Most newspapers have an Auto Parts section in the classifieds. Often the engines get a section for themselves as well. Usually, the engines sold in classifieds are either pulled already or the owner will pull it for you. This saves you quite a bit of work, time and money. Care should be taken however, to buy a fairly complete engine. The alternator, starter, A/C, wiring, intake, carb, fan, etc. will all add up to a very big sum of money if purchased separately. Consequently, it is advisable for you to buy an engine that comes with all the necessary accessories to make it run. The transmission is another important part when buying an engine from the classifieds.
Be sure to check if the engine comes with a transmission, unless you already have one or will be acquiring a different one. Before doing this, you should check to see if the tranny and engine you're buying can be adapted with the proper bellhousing.
Another good way of finding the perfect engine in the classifieds is by browsing through the car wrecking section. Often times, people will sell cars for parts, or as beaters, or for wrecking. These cars can be had as cheaply as $100. If you're lucky, the engine in them might be half decent. Often times these cars are no longer roadworthy because the body is literally falling apart due to rust, but they're mechanically sound. An advantage to buying a complete donor car is that you get to hear the engine run, the engine is already mated to a working transmission, you can use all the accessories and wiring of the existing car to make the engine run. And if you're lucky you might even find a good use for the rearend. Sell the interior and seats on eBay or your local classifieds and get a small portion back. The drawback to buying a donor car is that the engine has to be removed, and the car takes up space (which some just don't have). A disadvantage to buying from the classifieds: you often don't get to hear the engine run (as it's pulled already in a majority of cases).
 Auto salvage yards
An auto salvage yards (aka junkyard) can be a great resource for locating needed car parts or locating an engine for your hot rod. Many of the cars built during the past forty-plus years came equipped with a V8 engine, a relatively heavy duty transmission and rear end, and are rear wheel drive. Now that these vehicles are past their usefulness as transportation, many end up in the junkyards to be recycled into a project. Junkyards catering to the older iron may be full of cars from the 1980s and older, waiting to donate their mechanical heart. "Pick-a-part" junkyard shopping is often a good option in order to find the best prices. Some of these type 'yards will run specials on a certain day of the week or month that you can get a discount price on all you can haul out in a load, for example.
Many Chevy, Dodge and Ford cars and trucks from the '50s to the early to mid '80s came equipped with a carbureted (non-EFI) V8, perfectly usable to power a hot rod. However, care should be taken when selecting an engine. Engine size, width, and length should all be taken into account. Depending on which car the engine is destined for, measurements are crucial to determining the fit.
Junkyards can be rough places in which to work. Time is going to be needed to remove the engine, and all tools and equipment have to be brought from home. It might take several hours before the engine comes loose and out of its nest. Each car has different places where parts bolt onto and where the engine connects to the frame, and each bolt has to be removed. Most of these cars have been sitting there for a while, so be prepared to wrestle with rusted, stripped and broken bolts, layers of caked-on grease and dirt on the undercarriage and oil pan, and a lot of rusty sheetmetal. Some 'yards have an area that a vehicle can be placed up on supports so the engine and other large parts can be better accessed.
When choosing an engine, engines with thick amount of surface rust, critical missing parts or an obviously cracked block or heads should be completely avoided. If you can, pick an engine in a car that retains its hood. A car that has been sitting out in the 'yard without a hood will have rust built up inside the cylinders from the rain pouring into the engine. The more accessories and parts that are remaining on the engine, the better for future use. Testing the engine to see if it turns over by turning the crankshaft with a long breaker bar type wrench is a good way of determining whether the block is frozen up/rusted solid or not. If an engine doesn't turn over, leave it be. See: Freeing a stuck engine.
This might work well if you live in a more rural area where pickings in the classified ads are slim. Talk with anyone who gets out into the boonies on a regular basis and offer them a reward for information leading to an abandoned car or truck. Candidates would include police officers, letter carriers, rural newspaper delivery persons, repairmen who work on high-voltage lines, water/electric meter readers, surveyors and so forth. Place a wanted poster in the local hunting or fishing supply store to reach sportsmen.
How to safely and properly pull an engine.
Engine hoist -- A mechanical device used in the removal and installation of automotive engines.
- If you have a digital camera, Now would be a good time to take many good photos before you pull it down, for Installation reference,i.e. brackets and wiring. For more information on documenting your project, see: How to document your project.
- Disconnect the battery.
- WARNING: If the vehicle is equipped with a Supplemental Restraint System (SRS), or air bag system, wait 5-10 minutes after disconnecting the battery, then pull the fuse labeled "SRS" or "air bag," then wait another 5-10 minutes, turn the key on and make sure the air bag light stays on. This means the air bag system is disabled, and you will avoid serious injury or death by inadvertent air bag deployment or non-deployment during a crash.
- Make sure that the air conditioning system is discharged before you remove the A/C compressor.
- Use baggies for ALL your nuts and bolts, and label them. Items too large for baggies can be placed in plastic trash bags or cardboard boxes, but above all, label them! Also you can use a felt tip to mark parts, top, bottom, left, right, etc.
- Remove the hood. Don't do it alone... get a neighbor, a buddy, your wife.
- Be sure to drain any fluids beforehand, to keep from making a mess, and to be friendly to the environment.
- Remove the fan, fan shroud, and water hoses (drain and dispose of coolant properly; it's poisonous to humans and animals). You may also want to remove the radiator, but if you are careful, it is not necessary.
- Disconnect fuel lines, vacuum lines (mark termination and make a written list), wiring (mark termination and make a written list), belts, and pulleys that may be in the way. You can also draw pictures if a camera isn't handy.
- Place a jack under the transmission to keep it upright in the vehicle, unless you are removing it as well.
- If you plan on removing the transmission, don't forget any linkages, backup lamp switches, neutral safety switches (some are transmission-mounted), modulator valve vacuum lines, TCC control wiring, and the speedometer cable (or speed transducer and wires). Cover any holes with tape.
- Fit a plastic bag over the tailshaft, and duct tape it after you remove the driveshaft. This will keep residual oil in, and dirt out.
- Be sure that whatever you are using to lift the engine is strong enough to lift more than the weight of the engine safely, and is on a completely level surface. If outriggers are provided, use them. Be absolutely certain that the lift can not roll on its own, or become unbalanced side-to-side.
- Use some type of lift ring on the engine, such as a plate that bolts to where the carburetor was. For easier engine removal, the Engine Hoist Pivot Plate has been recommended.
- Be sure to use padded fender protectors; a strike from ring gear teeth can do serious body and fender damage.
- Never store an engine by keeping it in suspension in the hoist as this is an unsafe practice and poses the threat of damaging the hoist.
- Jack engine up slightly, and remove the bolts to the motor mounts and the transmission bellhousing (unless you are removing the transmission also).
Note: If you raise the vehicle, USE JACK STANDS SAFELY POSITIONED! For more safety tips, see: Health and safety in the shop or garage.
How to ship an engine through a third-party shipping service. And, how to safely load, secure, transport, and unload an engine.
An engine, because of the oil and gasoline residue it holds, is considered hazardous material in the United States and comes under special requirements for shipping documentation. If you do not already know how to do this, it isn't worth your while for one engine. Get somebody who does this regularly (maybe a friendly auto dealer or salvage yard) to do it for you. If you are going to transport the engine/transmission in your own truck, get one or two car tires to sit the item(s) on. It's non-skid, protects the item(s) being transported and allows stabilization when the item(s) are strapped down.
 Prior to disassembling
Before you start taking things off of your engine, there are a few items you want to have on hand so you can start and finish with few stops and starts.
You will need a 4-wheel engine stand (3-wheel engine stands have a wicked tendency to tip easily). Using a 4-wheel engine stand is the safest and fastest way to disassemble an engine. The only thing worse than dropping a greasy iron head on your foot is trying to catch an engine tipping over on a 3-wheel engine stand.
You will need baggies to put all of your nuts and bolts into so you do not lose any of them. Make sure to label the baggies. Some like to use a metal coffee can with some 1/8th inch holes poked in the bottom and sides, to clean parts with prior to putting them in the baggies. This will allow you to rinse the dirt and grime off all the fasteners very fast and you do not have to worry about any of them falling out into the solvent bath. A can of PB Blaster or something like it can be used on the rusted fasteners.
Before starting disassembly, it is best to clean the built up sludge off the motor, preferably well before the motor enters the bay (a clean work area ensures a clean build). Degreasing the engine with a heavy duty degreaser accompanied by power washing works very well. Be sure to plug all holes to prevent water getting inside the engine. Some motors have sludge so thick it hides bolts and prolongs disassembly
It is a good idea to have a bunch of clean rags. Some of these engines can be DIRTY and if you keep your tools clean as you go, you will not waste time washing your hands. If at all possible, roll the engine to a place where you can clean/degrease it from top to bottom. As a suggestion, revise to take a few pictures of the engine from all angles. Then, when you are putting things back together, you have a reference photo to figure out just where that bracket goes.
Disassembly is usually broken down into two parts. One is removal of external parts and accessories and the other is the actual disassembling of the engine block and its internal parts.
 External parts and accessories
The first items that come off of an engine that will be rebuilt are the exhaust manifolds. Then, take off all the brackets holding the A/C compressor, alternator, power steering pump, and smog pump. Then take the distributor out. Wrap a clean rag around the bottom end of the distributor, and then put it into a zip-lock plastic bag. This can be cleaned later.
Now for the carburetor or fuel injection or throttle body. Put the injectors into plastic bags. Again, when it comes time to put new O-rings on the injectors you can work on each, one at a time, without getting them dinged up by being knocked around in one of the fastener cans you will be using to hold nuts and bolts.
If the engine has a carburetor, do not turn it upside down unless you plan on installing a rebuild kit on it also. Any "crud" that has settled to the bottom of the carburetor fuel bowl will become lodged in places you do not want dirt or rust, so keep it right-side up and again wrap a clean rag around it and then pop it into a plastic bag. Store the carb, distributor and any other fragile parts carefully to avoid damage. If you are working on an engine with a throttle body just put the unit in a plastic bag for now. At a later time you can put in new O-rings. You just don't need all these parts in your way until you start to reassemble the engine.
For an engine with a carburetor now is the time for the fuel pump to be taken off. On the Small Block Chevy (SBC), there is a mounting plate that needs to be removed that has a fuel pump push rod behind it that needs to be removed as well. You can put this rod and the spacer plate in with the fasteners.
 Engine block and internal part disassembly
Disassembly of the engine starts with the removal of the valve covers.
The rocker arms should then be removed and placed in number sequence so that they can easily be identified from where they came.
Pushrods can be pulled and placed in a shallow pan for cleaning and possible reuse.
Head bolts should be removed and inserted in a cardboard template to make note of there location.
Prying up with a pry bar in the intake ports to cause separation of the head from the block, watch for coolant spills. Use a wide blade screwdriver to leverage the heads up off the block and dowel pins. Remove the heads to a solid work bench for inspection.
Before the cam can be removed, the damper and timing cover have to be removed. Use a puller to remove the damper and remove the oil pan before removing the timing cover to avoid bending it, if this is a SBC engine.
The SBC engines from the factory sometimes had a nylon covered cam gear. This nylon can- and did- come off when the gear wore out. The plastic pieces then fell into the oil pan to be sucked up in the oil pump screen. This has caused many failures in the past. If you see a gear missing the plastic on ANY engine, you know the pan and pump need to be inspected and cleaned of any plastic.
Remove lifters from their bores; use a hook or removal tool and carb cleaner spray to remove the hard ones. Keep the lifters in order if they are to be reused. Drain the oil then pull the crank pulley, timing cover and the oil pan. Remove the timing gears and chain. Pull the camshaft. Remove the oil pump and drive rod. Before loosening the rod caps, use an engraving tool to ID the rods and caps with the cylinder number they go to. This is preferred to using a number set or center punch, but if done carefully this is still OK to do. Be sure to use only as much force as needed to get a legible number or marking and no more.
Mark the caps in the same order as the firing order with a viberatory etcher. If you use a center punch or numbebered punch set, use a light touch so as to not distort anything.
Pull off the cap on ONE rod and using a hardwood block, tap out the piston, then return the cap to that rod. Then remove the rest of the rods.
Pull the flywheel or flex plate. After marking the main caps for location if needed (some will be marked for position from the factory), undo the main bearing bolts, pull the bearing shells, and with care lift the crank out of the bearing shells and place on the work bench. Make sure that you block the crank so it won't roll off the bench. Nothing worse than damaging a crank when it hits the floor. Wash down all the parts and block. Lightly coat the bearing surfaces with clean oil and coat the engine bores, etc. with ATF, etc. to keep rust to a minimum.
Depending on your budget, experience, and preferences, take block and crank to the machine shop for inspection for cracks/defects and for measurements of the bores, main saddles and decks, or inspect and mic the engine yourself using the proper specs. Reasonable care should be taken when moving the block and crank so that they do not become damaged in transportation. If moving them over a long distance it may be better to put the crank back in the engine and bolt it in for the ride, also put the pan on for extra protection. Heads should be secured safely.
 Deciding what machine work to do
What will the engine be used for? This will be the determining factor on how much you're going to spend. In any case, whether it's a stock replacement swap or a race engine, there are a few things that should be done.
- Have your block degreased and magnafluxed. If it passes the magnaflux test, proceed to the next step knowing it to be crack free.
- Have it sonic tested; this way you know if the engine block is even worth using.
- Have the block checked for core shift.
- Most reputable shops can check out the vitals of your engine castings and internal parts.
- Have your cylinder walls checked out for roundness and wear to determine the oversize needed.
- Have your machinists put a fresh hone on your cylinder walls, unless you plan on doing this step yourself.
- If over-boring an engine, use a "torque plate" if at all possible.
- Don't forget to have new cam bearings installed if the hot tank ruined them or if they were too worn to reuse.
 What to expect to pay for machining work
It really varies by where you get the work done and what you actually get done. An average machine shop charges around $90.00 per hour (ca. 2012). A simple head grinding could take as little as a half hour whereas a major bore and hone could take a few hours.
 How to select a machine shop
Cleanliness, experience, referral from trusted sources, knowledge, etc. Remember, anyone can purchase the machinery and equipment. Good equipment is necessary, but so is experience. No two shops do things the same way. Talk to the shop owner/manager and find one that you are comfortable with. Big names don't always assure top quality.
Your machine work is only as good as the machinist performing the work! Meet and talk to the machinist that will be working on your engine...establish a rapport...be his friend as the future life of your engine is in his hands!
Always interview the machine shop that is going to do the work on your engine. See that the shop has a complete line of rebuilding equipment to do the job that you want done. Check out the equipment that they have. Here's a page showing engine rebuilding tools. Beware of shops that just "front" the actual work for other specialty machine shops. Cut out the middle man, do your homework and take your heads directly to the shop that can grind and fit your valves, AND flow your heads on their flow bench to see the improvement and benefits of their head work. Do your homework!
Also, some machine shops specialize in certain engines (such as the AMC V8 if you want the "oil line mod" done), and it is advisable to seek out a shop that specializes in the engine you're rebuilding. Be sure while interviewing the machine shop to ask what engines they know a lot about. Don't ask "Do you know a lot about this engine?", as they can simply reply "yes". Ask them "What engines are you guys familiar with?"
- Always chase your threads with a thread chaser (not a tap) on all threaded holes, especially where torque values are critical, like head bolts holes, intake and exhaust holes, etc.
- Clean all bolt threads thoroughly: A wire wheel on a grinder works well for this.
- Clean and oil threads for a good torque reading but be sure that this is either what your manual instructs or is common practice for your engine/build. Take special care with soft metals like aluminum, as you may do irreparable damage.
- Be sure to check and verify before reusing existing head bolts as some engines use "TTY" (torque to yield) fasteners that should not be reused; new fasteners are required.
- Be sure to use anti-seize on the threads when using or replacing stainless steel fasteners, or when fasteners are threaded into aluminum.
- Always check the unit system and grade of replacement fasteners. Using metric instead of SAE threads, for example, is not in any way acceptable, nor is using ungraded or the wrong grade fasteners. Use caution if using a different fastener strength grade (i.e. using a Grade 8 instead of a Grade 5 fastener); "stronger" isn't necessarily "better". Always use the fastener designated appropriate for your application. Using the wrong fastener could compromise the engine, its parts and/or put one at risk. In some instances, using too "strong" of a fastener may do more harm than good because they were intended to break before serious engine damage could occur.
 Rod and caps
Remember to follow the manufacturer's cylinder numbering system unless they were numbered differently by you or someone else- not all engines had the rods numbered from the factory.
Even if the rods aren't numbered you can still orientate them correctly for what side they go on. This can be done several ways:
- If the pistons are on the rods, they'll have an arrow or notch. This faces forward.
- If you install a rod bearing into the rod and cap, you'll see that it is positioned with one side further away from the face of the rod/cap. That side faces the crank cheek.
- Usually the larger chamfer also faces the crank cheek; smaller chamfer faces the other rod on that journal.
- Numbers face the pan rail.
 Bearing tangs
Different engines have the rod and cap bearing tangs facing differently, so don't think they're always one way or the other for all engines.
On SBC and BBC, the bearing tang notch in the rod big end faces the pan rail of the engine.
Other engines like the Pontiac and small block Ford have the bearing tangs oriented to the inside.
 Testing and break-in
Oil formulations are being changed mainly due to pressure from the EPA and secondarily from the factories switching to roller lifters. Zinc and phosphorus tend to coat O2 sensors and plug catalytic converters resulting in warranty claims as well as contributing to dirty exhaust emissions, so they are being eliminated from motor oils as we speak. These elements were used in the oil to provide extreme pressure lubrication and protection from galling on heavily loaded engine components such as the cam lobe/lifter crown interface.
The loss of those high pressure lubricant supplements from the motor oil now available had less impact on newer engines because of the change to roller cams. With them, there is no special procedure for break-in. You just oil the lifters, drop them in and no other special break-in procedures are needed for the cam and lifters. Obviously the rings and other new components will still require a break in period, but with a roller cam the biggest problem associated with breaking in a rebuilt engine- flat tappet cam lobe/lifter failure- is a thing of the past. Be advised though, that there could be a problem with mechanical roller camshafts in a street motor. In many cases the best valve train for a street motor would begin with a hydraulic roller cam. Most hydraulic roller cams will have a rev limit of around 6,000 to 6,200 RPM due to the weight of the components, the design of the hydraulic lifter and the cam lobe design. If a higher powerband is wanted or needed, you've moved out of the street engine realm and are now into race engine territory, and should be looking into a solid roller valve train.
This is similar to how the current ignition systems came to be. Kettering invented the points-type ignition system early in the last century and it endured for some 70 years. When it came time to clean up the environment, the OEM's switched to electronic ignition and we never looked back. Points-type ignitions have been replaced by HEI-type ignition systems. Now we have moved to solid state ignition with a coil for each cylinder, controlled by computers and rare earth spark plug electrodes to provide good performance and acceptable emissions levels for as much as 100K-plus miles before servicing is required. Same with carburetors. Electronic fuel injection is light years ahead of the old technology, and it contributes to vastly improved fuel mileage and much cleaner emissions.
For those who insist on using flat tappet cams (more than likely due to the cost of roller units, particularly if building a pre roller cam type of block), here is the best way to do it:
1. Start with a matched and coordinated set of parts. Use the lifters and spring specs recommended by the cam grinder for your particular application and rpm limit. There is no point in using more valve spring pressure than needed, especially in a flat tappet street motor. To do so is asking for problems. Always consult with your favorite cam grinder for cam/lifter/spring recommendations for your particular application. Never rely solely on the recommendation of gearheads on auto forums. It's OK to ask and get general recommendations and suggestions from such sources, but before you lay down your hard-earned money, consult with the manufacturer's tech guy. He will want to know all the particulars of your combination including exact static compression ratio, so have all this written down so you can answer his questions intelligently.
2. You might want to research using special lifters or treatments that help prevent cam lobe/lifter failure. Some options are:
- Hard-faced lifters with a stellite face on the lifter crown that will resist scuffing.
- Comp Cams has an optional nitriding process that can be applied to any of their cams for around $100 over he cost of the cam.
- SM Composite lifters, ~$700/set.
- SM Tool Steel lifters, ~$485-$625.
3. There are specialty/racing motor oil that will give protection to your new cam and lifters. "Over the counter" motor oils are not up to the task, generally speaking and they are constantly changing formulations, it seems. Crane Cams has recommended Shell Rotella and an engine oil supplement containing extreme pressure lubricants. The other oil that is touted by engine builders is 15W-40 RPM Delo. GM has discontinued (and now have re-released) the EOS (Engine Oil Supplement) they used to offer. If you use a molybdenum disulfide-type cam and lifter break in lube applied to the foot of the lifter and cam lobes along with good quality oil and add 1-1/2 ounces of ZDDP additive per quart of oil for initial start-up , you've done as well as you can to prevent lifter/lobe scuff/wear/failure. With subsequent oil changes, one ounce per quart of oil should help to contribute to long engine life.
4. Assemble your heads with old, used, stock springs if they will give enough lift before coil bind. DO NOT ASSEMBLE WITH THE SPRINGS YOU WILL EVENTUALLY RUN if the springs are much higher than about 120-130 pounds on the seat at the installed height. Keep an old set on the shelf just for running in a new motor, then change them out at the 30 minute mark. Manley makes a lever-type tool for this procedure, to be used with compressed air to keep the valve seated. If you don't have a compressor you can feed thin rope/cord down the spark plug hole with the piston down away from TDC. After the rope is fed in, carefully rotate the engine so the piston is compressing the rope up against the valve head. Do this on the compression stroke. Or have a shop do it. Another way is to use a set of reduced-ratio rocker arms for break-in. Crower Cams may have 1.2:1 ratio for SBC and 1.5:1 for BBC, but this needs to be researched. They may be high-buck roller units though, something that might be out of the reach of the home builder who only does one or two builds a year. Somebody needs to step up and make some stamped steel rockers in a reduced ratio that would be affordable for everyone.
5. Checking for interference. Nothing will wipe a cam and lifters quicker than mechanical interference in the valvetrain. Check for piston to valve clearance, rocker arm to stud clearance at full lift, spring coil bind (stacking solid) and retainer to valve guide boss clearance at full lift. Also check for pushrod to guide clearance to insure the pushrods are not rubbing or binding. You might have one culprit that you didn't catch, such as a bent pushrod. Roll all pushrods on a piece of plate glass before assembly to insure straightness. See: Installing a Racing Camshaft and Valve train points to check.
6. Another problem that can occur if you are not diligent in checking tolerances is a too-tight lifter-to-bore clearance. Failure of the lifters to rotate in the lifter bore will gall the lifter crown/cam lobe in short order, and cam and lifter failure will soon follow. Always oil the lifter bores and lifters when doing mock-up and drop them through the lifter bores. With the lifter bores vertical on the engine stand, the lifters should drop through and fall into your hand with oil on them. If they don't, first inspect the oil gallery holes where they intersect the lifter bores for any raised burrs, etc. Then scrub the lifter bores with a shotgun brass bristle brush and acetone/lacquer thinner to remove all traces of shellac. Just running a rag through the bores is not enough. If the bores are still too tight, hone the lifter bores for additional clearance until they will fall through- only do this if all else fails; too much clearance can reduce oil pressure throughout the engine and is not needed in most cases. The cam grinders are beginning to manufacture their lifters with a shorter radius on the crown to assist in lifter rotation.
7. These suggestions are brought to you by John Callies of Callies Crankshaft fame:
- a. Visually inspect for tool chatter and mis-machining.
- b. Clean the shaft with mineral spirits and dry thoroughly.
- c. Use a hand held propane torch and heat the shaft to disperse any moisture.
- d. Spray the cam with graphite.
- e. Use quality high pressure lube on cam lobes and lifter crowns (molybdenum disulfide black goop that comes with most cam and lifters).
- f. Select a quality lifter since the market is being saturated with offshore lifters that are soft.
- g. Make sure on start-up the engine is ready to run at 2000-2500 rpm for 20 minutes. ZERO IDLING FOR 20 MINUTES.
8. Make sure the motor is timed and use a known good carb or other induction system as well as ignition system. The new cam and lifters will not tolerate any grinding on the starter to get the motor fired. They are lubed by splash off the crank at higher engine speeds. Have everything ready to go including having the carb primed with fuel and a fully charged battery.
9. Pre-oil the motor with a drill motor and oil pump primer tool such as this one from Jegs. Put a socket on the harmonic damper retaining bolt and rotate the motor through at least 2 full revolutions while priming.
 Related resources
- Chevrolet engine rebuild guide books and DVDs
- Camshaft install tips and tricks
- How to prep and start a rebuilt engine
- How to choose a camshaft
- Determining top dead center
- How to make a timing tape
- Adjust valves
- Engine inspection