How to Rebuild Pontiac V-8s - Updated Edition. Rocky Rotella

of various arrangements are available, I prefer a C-clamp style like this. It’s better to spend a few more bucks for a high-quality unit like this one from Snap-on that won’t flex under pressure.

       This valve spring micrometer and other similar units determine the installation height of a valve spring when combined with the particular length of valve and retainer that’s being used. Available within specific ranges, this Comp Cams unit measures from 1.4 to 1.8 inches.

      Most machine shops can assemble certain components you’re unable to handle yourself for whatever reason. For instance, cylinder head assembly includes measuring valve spring pressure and installing valve springs at the proper height. Allowing your machinist to assemble them is often a wise move. If you’re concerned with the critical measurements and minute clearances associated with the rotating assembly, or if correct rod and piston orientation is intimidating, your machinist may be able to assemble the short-block for you at a reasonable cost or suggest a certain engine assembler for you.

       Various telescoping gauges, calipers, and micrometers are essential tools when performing any engine rebuild. They can be used to verify the measurements of most components. Units like these can be purchased at a reasonable cost from a local discount tool retailer. They’re accurate for engine-build measurements.

       A dial-bore gauge can be used to measure areas of the block, such as the bore diameter, cylinder wall taper, and diameter of the camshaft tunnel and main caps. This unit was purchased from Summit Racing Equipment, cost less than $100, and has been very useful.

      No matter how much or how little of the engine rebuild you intend to perform yourself, you need to find a machine shop that can meet your machining requirements. You want to find a shop that has rebuilt and/or machined many Pontiac V-8 engines because you don’t want a shop to make mistakes. If they have to learn the specs and machining processes while working on your engine, the chances of making mistakes are much greater. If you don’t have one already in mind, finding the best choice for you can be as easy as asking around to gather opinions. This may be as simple as attending local car shows and asking fellow Pontiac owners who they’d recommend for an engine rebuild.

      After striking up a conversation with a Pontiac owner, clearly ask if the Pontiac’s engine has ever been rebuilt and if so, by which owner. Remember, you’re looking for first-hand experience with a machine shop. Here are some general questions to ask:

      •Why did you select this machine shop?

      •What was considered a complete engine rebuild?

      •Was any portion of it sent out to another shop?

      •How long did it take to complete your project?

      •How long were you told it would take?

      •How much work did you perform yourself?

      •Were you completely satisfied with the results?

      •Did the cost seem reasonable for what you received?

      •Have you had any issues with your engine since the rebuild?

      •Would you use this machine shop again?

      If you’re satisfied with the answers to these questions, simply consider that machine shop as a possibility and move on to the next Pontiac owner for another opinion. Remember, when dealing with the minute tolerances associated with an engine rebuild, one can go wrong from time to time. A quality machine shop stands behind its work, however. Once you’re completely confident in one shop’s ability, you’re ready to contact them to inquire about the services offered.

       A feeler gauge is used to measure the clearance between two perpendicular mating surfaces. And when combined with any precision straight edge, it can be used to measure cylinder head or deck surface warping. Units like this are available at any parts store and generally cost less than $20.

      The term “machine shop” is often interpreted as a business that can rebuild an engine for a customer, but there’s a major difference between the services offered by an actual machine shop and engine assembling and building shops.

      While modern machine shops often offer both machining and assembling services, some machine shops have no interest in assembling an engine after the machining portion a rebuild is complete. In these instances, it is your responsibility to completely assemble your engine or enlist the services of an engine assembler.

       With so many affordable aftermarket crankshafts for other makes available today, there aren’t many modern machine shops that grind crankshafts in-house anymore. If your rebuild requires this, and if the machine shop you select subcontracts the task, ask for the name of the company.

       A high-quality machine shop should possess the equipment required to properly machine a Pontiac block. That includes using a Pontiac-specific torque-plate for boring and honing cylinder walls and a line hone to restore main journal geometry.

       Balancing the reciprocating assembly involves attaching stationary weights to crankshaft journals, which replicates the effects of the piston-and-rod assemblies. The crankshaft is spun at low RPM and a strobe light is used to determine where counterweight mass should be added or removed to ensure smooth operation.

      An engine assembling shop in simplest terms is just that: a shop or a person that assembles engines for customers. Some or all of the component machining is outsourced and the entire combination is assembled with little regard toward maximizing performance. The engine is typically fully assembled and ready for installation into a vehicle, but it may or may not have been fired prior to customer delivery and usually does not include any form of tuning.

      An engine builder is best described as a person or a shop that designs and assembles a customer’s combination. It includes performing or arranging machining by one or more competent machine shops and selecting the proper combination of components to help a customer achieve his or her performance expectations. Engines are typically delivered to the customer completely assembled and fully tuned, and the output should be documented with the results of dyno testing.

      There are distinct markets for all three services, and that’s something to consider if you’re going to have a shop assemble any part of your engine for you. No matter which route is chosen, have a clear understanding of how your components are being machined and which machine shop is handling the task. It may be worthwhile to visit that machine shop before making a decision on moving forward.

      In my opinion, a good machine shop is one that can completely rebuild any engine in a timely manner with its own in-house equipment. I feel that outsourcing any part of a rebuild can compromise a project. The machinist tends to lose control of time and quality, and that can negatively affect the outcome. A quality machine shop to consider for your project should possess the following equipment:

      •Parts cleaning equipment

      •Cylinder honing equipment and a Pontiac-specific torque plate

      •Line-hone equipment

      •Vertical mill

      •Surfacing equipment for heads and block

      •Rod preparation equipment

      •Crank grinding