Best Tool For Cylinder Head Work
Article by Mark Trotta
Whether you're working with cast iron or aluminum, you need a strong, reliable grinding tool with speed control for porting or port matching cylinder heads.
Air vs Electric Powered
I'm a big fan of air-powered tools, and I'll probably be the last guy to switch over to electric. But an air-powered die grinder has very little torque at low speeds, which is where you need it for removing metal.
Air-powered grinders spin way too fast, and they tear up disposable's quicker than an electric powered grinder. They also make a lot more noise.
An electric rotary grinder gives you great torque at low RPMs, and for cylinder head porting gives the easiest, quickest results.
For those of you that regularly use air tools, an electric grinder will be a quiet relief. The only sound it makes is a low-pitched whir.
Rotary Tool with Flex Shaft
For motorcycle and automotive cylinder head work, my choice was a Foredom TX series. For those unfamiliar, Foredom is a U.S. owned and operated company, and offer a complete line of industrial-grade rotary tools, handpieces, and attachments.
Pendant Motor
The TX series has a separate, hanging motor, coupled to a speed control (floor or bench mounted) and a 39" flex hose.
When in use, I'll hang the motor on a hook on a workbench shelf.
The speed control can be either bench or floor mounted.
Mine is an earlier model that has a dial-type speed control. I keep it at the base of my bench-mounted drill press.
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Dremel vs Foredom
A Dremel is more suited for wood, glass, or jewelry than metal. They spin up to 35,000 RPM, while an electric motor runs between 15,000 and 18,000 RPM.
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Pocket Porting
Automotive head porting refers to modifying cylinder heads to achieve more volume or less restricted flow. At a minimum, this would be smoothing out the radius of the valve pockets.
CAUTION: A well-intentioned amateur can easily ruin a good cylinder by removing too much metal.
Port Matching
Port matching is correcting misalignments between intake manifold and cylinder head ports. A common way to port match is, take a felt-tip marker (or machinist dye) and trace the ports on the gaskets, then slowly remove the excess metal, just enough so it blends in. When done, air/fuel mixture will have a smoother transition from intake to heads.
For grinding and polishing cast iron, double-cut carbide burrs work best.
Removing Casting Flash
Most DIYers are comfortable with grinding off casting flash left from the manufacturing process. All you're doing is removing unwanted metal and smoothing rough surfaces.
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Other Uses
Whatever you originally purchase an electric rotary tool for, you will find other uses for it, such as cutting, deburring, grinding, and polishing. They also work well removing rust and corrosion from hard to get places.
Removing rust from manifold ports with a wire wheel attachment.
Switching attachments to remove rust from combustion chamber.
Electric rotary grinders also make quick work of grinding down weld repairs.
Smoothing down a weld on aluminum with an 80 grit sanding drum.
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Handpiece Options
Foredom handpieces are lightweight and come in many shapes and sizes. The one I have is a 44T Handpiece, which fits comfortably in my large (XL glove) hand.
When purchased, 3/32", 1/8" and 1/4" collets were included, but I only use the 1/4" collet. Also included were pin and wrench for changing accessories.
Changing Attachments
To loosen/tighten the collet to change bits, a pin is inserted into the hand piece, then the nut can be loosened/tightened with a small wrench.
Some people think this is too much trouble, but it's never bothered me any.
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Shop: Foredom TX Motor with Speed Control and Flexible Shaft
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Beware of Counterfeits
Counterfeit Foredom rotary motors have been offered on several online sites. They can be difficult to recognize, as they usually come with an authentic-looking label and a serial number on the motor. If the advertised price is much lower than everywhere else, beware!
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Notes and Misc
You MUST use a speed controller of some type. Full speed is dangerous.
Protect your hands from cuts and abrasions--wear gloves.
Wear a face shield or safety glasses with side-protectors.
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