Specialty Tools for Performance Engine Building

Your ability to do an exceptional job, can sometimes be hampered by the quality of the tools you have available. This is true in most endeavors you undertake, including the assembly of a performance street or racing engine. I’m a real fan of high quality tools. I have a lot of them, and today I’d like to share with you some of the ones I use for every build.

These won’t be listed in any specific order, although I will comment on the ones that I consider to be absolutely necessary. Whenever possible, I’ll also list a lower cost alternative, as well as an explanation of why one is better than another.

  The purpose of this article is to provide a comprehensive list of the tools necessary to inspect and assemble a quality high performance engine. Detailed instructions on the methods for proper use will be the subject of several future articles. Let’s get started …..


Mag Light w/Adapter


The Mag Light with a flexible fiber optic adapter enables you to to inspect block passages that would otherwise be nearly impossible to see. The adapter has some rigidity to it, and can be shaped to conform around or between just about anything.

This is an invaluable tool in your search for any small amount of debris that may be hidden somewhere in the multitude of passages within your engine block. It’s also great for a closer look at anything during assembly that proves difficult to view with available room lighting, or a normal flashlight.



Bearing Micrometer

A big part of any successful engine build is to verify every possible dimension. In order to properly measure the O.D.(outside diameter) or thickness of any component requires the use of a good quality micrometer. For the most common performance engines, you’ll need a combination of four different mics:

  1. 0″-1″ : This will cover smaller components such as lifters.
  2. 2″-3″ : This will work for most crankshaft rod & main journal diameters
  3. 4″-5″ : This will measure common performance piston diameters.
  4. Bearing Micrometer : This is a special mic with a ball end on one measuring surface that allows you to verify the thickness of a bearing shell.

All micrometers except the 0″-1″ come with a precision ground checking standard. This will typically be the exact length of the lower end of the measuring range. While the supplied standard will verify the accuracy of the micrometer at the low end, it’s also necessary to check it at the high end. Besides high & low standards, I have precision ground gage blocks for the mid lengths of all of my mics as well. You must be sure the mic is accurate throughout the total range of measurement.


 Bore Gages


Similar to the micrometers, you’ll need a couple of bore gages minimum. This is one of those scenarios where the quantity and quality of the gages is driven by whether you plan on becoming a professional engine builder, or this is a once in a while endeavor. If you aspire to become a pro, here’s what you’ll need:

  1. Sunnen professional quality standard bore gage – to measure cylinder bores
  2. Sunnen professional quality long barrel bore gage – to measure main bores
  3. Sunnen micrometer style gage set-up fixture – to accurately set size of both above gages
  4. Sunnen “AG” style rod & pin bore gage – to measure the connecting rod bores
  5. Professional quality adjustable small bore gage – to measure smaller holes, such as lifter bores

If you’re building the occasional performance engine, you’ll want to purchase at least two quality adjustable bore gages. One to cover the range of the big end bore of the rods and the main housing bores in the block, and one for the cylinder bores in the block. With care, patience, and skill, you can use the same micrometers used to measure the journals & pistons for gage set-up.


Ring Compressor

There are a few styles of ring compressors available, with the most universal of these being the band style. The up side to this style is that they are relatively inexpensive, and will fit pistons ranging in diameter from 2″ to 8″ or more. The down side is that they tend to wedge between the piston and the bore during piston installation.

Because the body is made of a thin band and they are several inches tall, it’s awkward to tighten the compressor on the piston, and keep everything square with each other. Also due to the thinness of the band, it doesn’t sit very well on the deck of the block – causing the above mentioned wedging.

Next up is the plier handle band compressor. This style of ring compressor features interchangeable thick bands that compress by squeezing a large plier-like grip. The bands are short and made from a thicker material allowing easier installation than the previous type.

The third type is the one I use and recommend – the tapered sleeve. This doesn’t get any more simple or foolproof. These are made from aluminum tubing, with the inside diameter starting large at the top, and tapering down to a size slightly smaller than the bore. You can sit the sleeve on the deck of the block, and slide the piston assembly right through it into the bore.

The tapered style comes in a solid one piece design that requires an individual sleeve for every bore size, or a split type that is adjustable to fit an approximate .060″ bore range per sleeve.

Check back soon for part two of my continuing specialty engine building tool write-up. Please invite your friends to join us, and thanks for visiting …..

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