The MGA With An Attitude
Engine Cylinder Hone -- TS-312

Any time you install new piston rings you need to hone the cylinder walls to break the glaze in order to allow the new rings to wear in and seat properly to minimize oil consumption. The hone has a flexible drive shaft and is typically driven with a 3/8" electric hand drill at speed under 1000 rpm. A pro shop might use a hone in a drill press to run it as straight as possible and to have better control over axial motion to produce a cross hatch pattern on the cylinder wall.

flex hone If the cylinder is fairly clean and not significantly scratched you could use a flex hone (often called a ball hone) to break the glaze and remove minimal material. These are quick and easy to use but need to have a fairly close match to the bore size. If it's smaller than the bore it won't work. If it's much larger than the bore it will be difficult to keep the balls inside the cylinder with close approach to the ends of the bore. If you have more than one bore size to work with you need multiple tools. If the cylinder wall is slightly scratched, and you need to remove a little more material to get it to clean up, then the flex hone is not the best tool. It can remove material more in the middle of the bore and less at the ends, therefore causing the bore to be less straight.

cylinder hone The articulated three stone hone is a more universal cylinder tool. This may have a much greater working range to work with small bore and large bore engines, so you only need one hone. It should also help to keep a more constant bore size (straighter cylinder) when removing a little more material to clean up a slightly scratched cylinder. An abrasive hone is subject to wear as it is used, so the abrasive may need to be replaced occasionally (maybe every 30 to 50 cylinders or so). The straight stones are cheaper to replace than buying a new flex hone. If you like to use various grit grades, the straight stones are also fairly easy to change, as opposed to buying multiple flex hones.

With any honing process some of the abrasive grit wears off of the tool at the same time that fine metal powder is bring removed from the cylinder bore. This stuff is VERY bad for an engine if it is left inside. So it is best to do this honing on a completely disassembled and bare engine block, and clean it thoroughly before assembly. It is possible to hone cylinders with an engine still in the car and partially assembled. If you do this, pay special attention to keeping the grit off of the camshaft and crankshaft as well as possible, and do your best to clean everything thoroughly before reassembly. It would also be a good idea to install a magnetic oil drain plug, and to drain and change the engine oil soon after initial run in.

These tools may cost $20 to $40, might be found at J.C.Whitney or discount tool supply stores or at any auto parts store. Being prone to a certain amount of wear, they may be less likely to be available through a tool lending program, but it doesn't hurt to ask.

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