How to Hone a Engine Cylinder | Dingle Ball Hone & Stone Hone
What is a Dingle Ball Hone and Can I Hone a Cylinder Myself
Engines depend on precise tolerances and careful assembly. So, it’s reasonable to wonder about how to hone an engine cylinder and if it really is okay to drop a drill-driven abrasive ball hone into a cylinder where the piston is about to be speeding by at several thousand feet per minute. We checked in with engine guru Lake Speed Jr. from Total Seal Piston Rings to get some answers.
When to Hone a Cylinder
Let’s start out by clarifying that there is not a hard and fast rule here. As Lake Speed points out, what’s acceptable for one engine will not be for another. It all comes down to desired level of performance and reliability. With that said, here are some things to look for when assessing the condition of your cylinder walls.
What is a cylinder hone? This is the last step to put the final finish on the cylinder walls in an engine. In For our purposes here, we’re talking about the “freshening up” cylinder walls without the aid of the expensive boring or CNC honing equipment that you might find at the machine shop.
Much ado is made of the cross hatch in the cylinder walls and why cylinder surface matters. This is critical because those scratches hold the oil that keeps the rings lubricated as they move up and down in the cylinder while also preserving the seal that holds compression. The desired condition of that cross hatch is critical, and we’ll keep coming back to it throughout this article. But first, let’s start out by answering the question that many of us are asking; “Can I hone a cylinder myself and when should I hone?” The answer is yes, and assuming you’re working on a mild street engine with ductile iron piston rings, the good old dingle ball hone can be an inexpensive and easy way to restore some crosshatch in the cylinders. However, if there is a step at the top of the cylinder, or grooves or other wear deep enough to catch your fingernail on, you’re going to need to consider a stone hone or a trip to the machine shop.
DIY Flex Hone vs Machine Shop Cylinder Hone
A DIY engine cylinder ball hone or stone hone will remove some material and restore a single-grit crosshatch in the cylinder surface. It will not be appropriate for a cylinder that has been damaged or has a step at the top. When the surface condition is such that substantial material needs to be removed, it’s time to take a trip to the machine shop. Many shops will have a modern CNC hone like a Rottler which will do several things that a hone at home will not do. First, bore geometry will be maintained or restored. The cylinder will be perfectly round, straight, centered, and ready for new rings or pistons. Second, a CNC hone can create the perfect crosshatch pattern and angle to hold the proper amount of oil.
This is also where the performance level of your engine starts to matter. Assuming there are no major issues, a DIY hone in the home garage can resurface the cylinder and get your mild street engine back on the road. However, a high performance, racing, or power adder engine will likely benefit from a more precise hone at the engine shop.
Why Do Piston Rings Matter When You Ball Hone an Engine?
Here’s where ring type and performance level really start to enter the conversation. Ductile moly piston rings are porous and hold some of their own oil. So, the crosshatch on the cylinder wall is less critical since there is oil on the ring as well as the cylinder. But as power levels and combustion temperatures increase, and especially when nitrous or boost enter the equation, cast moly rings can begin to fail. This is where you need to consider upgrading to a steel ring, which is harder and better suited to more extreme temperature and pressure. However, steel rings don’t hold oil like a ductile moly ring will, so the finish on the cylinder bore is far more critical. If you’re making enough power to warrant a steel ring, your best bet will also be to have a CNC hone done at the machine shop.
Cylinder Grit What Grit Should I use to Hone Each Cylinder
As Lake Speed spells out in the video, 400-grit on a stone or ball hone tool is fairly standard and will yield a “single grit” finish that will restore some roughness to the cylinder wall. This type of finish will work fine with a ductile iron piston ring that is also holding oil. The ultimate for a CNC hone in a high performance engine with steel rings is what Lake calls the “plateau” hone, which starts with a 170-grit diamond cutter that finishes the bore to size, then a 600-grit finish. This establishes deep grooves to hold the oil in addition to larger, semi-rough areas to carry the load.
Ultimately, single grit DIY cylinder hone tools will restore some roughness to a slightly worn cylinder wall. But they will not create the perfect surface for an ultimate high-performance engine or one that will use steel rings to hold boost or nitrous. More serious engines will need the precision of a CNC hone at the machine shop.
