The world is an imperfect place. No matter how hard we try, the things we make are always going to be just a little bit different than we want them to be. Normally, it’s just something we have to live with – “good enough” usually is, and a few thousandths of an inch here and there doesn’t make a difference. When it comes to making horsepower, though, the tolerances that are just fine for a production engine leave precious power on the table. By “blueprinting”, or measuring and selecting components to bring those tolerances as close to the ideal dimensions shown on the engineering drawing as possible, engine builders can squeeze every last drop of performance out of an otherwise ordinary combination.
Blueprinting an engine requires specialized tools and precisely-made fixtures, because the measurements are only going to be as accurate as the measuring devices. Typically that meant that engine builders had to make their own custom rigs, or buy them piece by piece at great expense. Fortunately, T&D Machine Products has developed an inexpensive and very precise tool, the Engine Blueprinter Kit, that puts everything needed within reach of anyone serious about engine building. Phil Elliot of T&D Machine Products explains, “This set of tools allows an at-home builder to fully measure all aspects of an engine.” This convenient kit puts all the pieces needed to fully measure engine tolerances in one box, bringing the specialized capabilities of a dedicated machine shop’s gauges and fixtures home. “Every task can be done more inexpensively,” Elliot adds. “Very few DIYers have the array of tools necessary to blueprint an engine — the machine shops do.”
Included in T&D’s Engine Blueprinting Kit:
One Inch Dial Indicator
The heart of the kit is the one inch dial indicator. Used in conjunction with the included fixtures and gauges, the dial indicator not only measures fixed dimensions like deck height and pushrod length, but thanks to the ability to both zero the dial face and set the independent reference pointer, it makes it easy to gauge ‘travel’ in components like lifters or measure crankshaft runout.
There are six gauges included in this kit. Machined to very accurate overall lengths, these gauges are used separately or in combination depending on the components you are measuring in order to gain precise measurements.
• 2- 0.500
• 1- 3.500
• 1- 5.500
• 1- 7.500
• 1- 9.500
The Flat Calibration Bar
Anodized blue and precisely machined, this metal bar is used for zeroing in the dial indicator.
“L” Shaped Indicator Holder
One of the two included fixtures for use with the dial indicator, the L-shaped indicator holder makes offset measurement setups easy, and can be used by itself or in combination with the other components for more complex situations.
The bridge fixture is designed to hold the dial indicator across gaps for tasks like measuring piston depth or checking the flatness of surfaces like the block deck or cylinder head faces.
The Bridge Legs
These legs come in both long and short, with the long measuring 2.50” and the short measuring 1.00”. They are used along with the bridge top and the flat calibration bar.
The Slotted Bar Assembly
This tool has various functions including being used to measure deck height, connecting rod length, and pushrod length. The perpendicular round bar on the end is self-centering in main or rod journals, and several mounting points for the L-shaped indicator holder let the assembly adapt to measure practically any dimension shorter than the overall length of the bar.
The kit comes with an assortment of hardware to assemble the fixtures in various configurations, plus interchangeable tips for the dial indicator. T&D even supplies a hex key so you won’t have to raid your own tool box to put the pieces together.
• 1- Allen Wrench
• 2- ¼-20 x ¾ Allen Bolts
• 1- 7/16 x 1 ½ Bolt
• 1- 7/16 Washer
• 1- 0.300 Indicator Tip
• 1- 0.950 Extension
• 6- 1/4 -20 x 5/8 Allen Bolts
• 1- ½ x 1 ½ Bolt
• 1- ½ Washer
• 1- 0.820 Extension
• 1- 1.700 Extension.
So how does it all work?
T&D Machine Products’ Engine Blueprinting Kit can be used in ways that are limited only by your imagination. By combining various kit components, practically every critical dimension can be gauged. Per Elliot, “The Engine Blueprinter can be turned into an ever expanding plethora of measuring devices.” We’ll show you a few common measurements, but by no means are these the only dimensions you can check with the kit.
Some of the things you can easily measure with this kit are:
• Crankshaft Stroke
• Piston Deck Clearance
• Piston Compression Height
• Crank to Block Deck Height
• Pushrod Length
• Connecting Rod Length
• Cam Lift
Measuring the crankshaft stroke is done by using the bridge top, long bridge legs, the dial indicator, and an appropriate combination of indicator tips and gauges. Setup starts using the flat calibration bar and short gauges to zero the dial indicator. Then, the crankshaft stroke measurement is determined by placing the assembly on the crank with the legs on the mains and the indicator on the journal, and calculating the difference between the known length of the gauge used in the setup and the measurement off the crank.
Piston Deck Clearance
When using this kit to check the piston deck clearance, the dial indicator is mounted in the bridge top with the long or short legs attached, and zeroed in using the flat calibration bar. With the piston brought to top dead center, the piston deck clearance can be read directly off the dial.
Piston Compression Height
Compression height is measured by using the L-shaped indicator holder and the indicator equipped with the proper extension. Since piston compression height is the distance from the center of the piston pin to the top of the piston head, you’ll need to know the diameter of the pin, but that can be measured accurately using the kit as well.
Crank To Block Deck
Eight different slots at precise 1-inch intervals along the slotted bar assembly allow you to position the dial indicator holder at an appropriate distance from the cross-pin to measure the distance from the top of the main journals to the block deck. Using the included gauges to set up the indicator’s zero, the deck height can then be measured in comparison to that known dimension.
The slotted bar assembly comes into play again when measuring pushrod length; it’s easy to set up the dial indicator using the included gauges to determine a fixed starting point, then quickly go through a set of pushrods to make sure they’re all the correct size, and just as importantly, all the same as each other.
Connecting Rod Length
The same combination of slotted bar assembly, indicator holder, and dial indicator can be used to check con-rod length. Not only a handy measurement to make during a build, it’s also great for checking aluminum rods for stretch after running them, a key indicator of impending failure.
Checking the cam is done by removing the cylinder head and placing the indicator extension on the lifter with the holder square against the face of the block. Turning the cam while watching the dial will allow you to directly read lift at the cam straight off the gauge.
Measuring With Ease and Precision
The T&D Engine Blueprinting Kit puts all the measuring tools and fixtures engine builders typically gather over the course of years together in one convenient 8”x18” impact resistant and foam lined carrying case. Whether you’re assembling your own engines at home, or doing it for a living in a professional shop, the kit brings it all together affordably. Elliot even sees the benefit of pros demonstrating the tools to their customers. “We hope that during your engine builds, the Engine Blueprinter can be used and shown to the public,” he says. “When you find that the kit can be used to measure deck height, rod length, and a myriad other things, it will help your job become easier, faster, and more accurate. When you pass that info on to others, they will want and need one too.”