How to Rebuild Pontiac V-8s - Updated Edition. Rocky Rotella
given time, and it doesn’t matter if it was purchased off a name-brand tool truck or from a reputable retailer. Snap-on, Mac Tools, and other brands make professional hand tools for working mechanics. These fine instruments are a pleasure to use and should last a lifetime or longer. However, the at-home mechanic can competently rebuild an engine with Craftsman, Husky, and other highquality consumer tools. But I don’t advocate using low-quality tools that can damage fasteners, round-off bolt heads, and generally make a mess of a basic job.
Before any engine can be rebuilt, it must be completely disassembled, and tearing it down before delivering it to a machine shop can often save you a few bucks. Fortunately for Pontiac hobbyists, V-8 disassembly doesn’t require much beyond basic hand tools for the majority of it. If you don’t presently own such equipment and future plans include additional engine rebuilds or repairs, then you might consider investing in them as they can be handy for most automotive repairs. A list of the tools you’ll need at this time includes:
•Standard 6-point socket set in 3/8- and 1/2-inch drive
•A 1/2-inch breaker bar
•Variety of combination wrenches
•Variety of flathead and Phillips screwdrivers
•Flared wrenches for fuel lines
•Small variety of pry bars
•Soft-faced hammer
•Various taps for thread cleaning
•Digital camera and notebook for documentation
Though generally not regarded as a tool, compressed air is great to have available for a myriad of reasons. An air blow gun can be used to remove decades of dust and grime, especially after being loosened with solvent and a wire brush. Though the use of eye protection is suggested throughout the entire rebuild process, it is mandatory when using compressed air.
Air-operated tools seem to make any job easier. While I often use such equipment for more common repairs, I prefer hand tools when rebuilding an engine. It allows me to feel just how much effort is required to remove or install a fastener, and that can be a telltale sign of thread or fastener damage. A pneumatic impact wrench can be used to remove high-torque harmonic balancer and main cap bolts.
Some specialized equipment, such as a valve spring compressor, engine hoist, and engine stand, are required. But keep in mind: The tools mentioned above are for disassembling and assembling your Pontiac V-8, as well as several other task-specific tools. You might look into renting or borrowing them from friends or parts stores for a single engine rebuild. If additional engine rebuilds are possible down the road, then now might be the best time to add them to your toolbox. However, they are usually more costly and can quickly deplete a budget. The list of those specialty tools includes:
•Engine stand (1,000-pound capacity)
•Engine hoist (cherry-picker type)
•Torque wrenches
•Micrometers and calipers
•Various dial indicators
•Feeler gauges
•Piston ring compressor
One of the most important resources to have on hand during your entire rebuild is a Pontiac service manual that’s specific to the year of your engine. You’re probably wondering why I’d make such a recommendation if you’re reading a book entitled How to Rebuild Pontiac V-8s. Well, there’s a simple answer for that. Though the Pontiac engine family is so closely related, most individual engine models contain at least a few characteristics that are unique to certain model years, and a Pontiac Service Manual should address an area if it varies from what’s shown in this book.
A Pontiac service manual is an excellent resource that can provide information about specific details for a particular model year. Costly reprints are commonly available from various sources, but worn, lower-priced originals are often available on popular internet classifieds or auction sites. A service manual for the model year of the engine being rebuilt is a musthave item for every enthusiast.
A digital camera is another excellent resource that can be used throughout the entire project. It’s beneficial when documenting the position of specific components during assembly. But it also allows you to provide your machinist with detailed pictures of any suspect areas you might have found in the disassembly process. With the relatively low cost of high-resolution point-and-shoot digital cameras and high-volume memory cards, it’s a wise investment for the project and one that can be used for personal use too.
A gasket scraper of some sort is an inexpensive tool that’s used to remove the gasket paper or sealant that’s generally left behind on mating surfaces during disassembly. This unit uses a conventional razor blade that can be changed as often as necessary.
Planning Your Rebuild
The owner of a 1967 GTO had complained that the car’s original 400 suffered from a number of operating issues. It had been rebuilt several years before by a reputable area shop. But the engine simply never lived up to the owner’s expectations in several ways.
The engine was rebuilt with dished pistons to reduce compression ratio, so the original 10.25:1 mill operated suitably on lower-octane fuel, which was ideal for the owner because he planned to frequently take it on long trips to various car shows across the country. After the rebuild, the engine’s coolant temperature sometimes soared; it audibly detonated on occasion and commonly ran-on after shutdown. Though the owner was told the engine could operate on 87- or 89-octane fuel, he found the issues seemed to worsen while using fuel under 91 octane. The engine appeared down on power, it struggled to operate past about 4,000 rpm, and it leaked and consumed oil regularly.
Over the course of several thousand miles operating in this condition, the owner received a number of suggested solutions from fellow hobbyists. Though each was tried with hopes of a miraculous result, none ever really improved the situation, and the owner’s frustration worsened. He approached me and asked for my opinion on the matter, and I agreed to assist.
The first step I took was an initial test drive to better understand the GTO’s operating condition and gather a basis to determine the effects of any adjustments I’d make. Keeping in mind that this particular GTO featured functional air-conditioning, a Turbo 400 automatic transmission, a stock-stall torque converter, and a 2.93:1 rear axle ratio, my initial test drive revealed the owner’s perception of lackluster performance was not exaggerated. This particular 400 ran about as well as a typical low-compression Pontiac 350!
A dial indicator is a useful tool that, when combined with the proper mounting base, can provide useful measurements when rebuilding an engine. This unit was purchased from a local discount tool retailer, and its accuracy is more than adequate for this task.
When torque is applied to a fastener, its overall length increases as it stretches a certain amount, and that stretch can be used to determine its clamping force. Comparing your measurements to the manufacturer’s predetermined values can tell you when a fastener has fatigued, which could otherwise result in failure. A stretch gauge is a valuable tool to measure the length of any bolt after tightening, and it’s most commonly used to measure connecting rod bolts.