ring gapping and basic piston ring info YOULL NEED

Discussion in 'Rotating Assemblies' started by grumpyvette, Oct 14, 2008.

  1. 87vette81big

    87vette81big Guest

    Building a 1984 Buick Grand National V6 engine today Grumpy.
    File fit tge rings.
    Forged CP Carillo pistons.
  2. Grumpy

    Grumpy The Grumpy Grease Monkey Staff Member




    a dremel tool comes in very handy, it takes a great deal of patience, and caution and a good understanding of what your trying too accomplish , plus constant checking, but a dremel tool can be used, to gap rings

    be damn sure you verify the rings are installed in the correct location , with the correct clearances, bore surface finish,with the correct part,and the correct side of the ring facing the top of the piston
    but like you stated I find its a bit odd that I find most machine shops are instantly able to quote the cost to "TORQUE PLATE HONE" several of the less popular engines like the pontiac, olds, AMC caddy, and early hemis etc. yet they don,t own the required TORQUE PLATE, and in some cases I don,t think they care or want to discuss that minor technicality
    (years ago the thinking was that because the second rings did not endure the same high temperatures as the top ring the second lower ring could have less gap as it would expand less from heat, modern thinking resulting from testing shows the second ring should have a slightly wider end gap to prevent the stop ring from loosing its seal pressure and developing RING FLUTTER at higher rpms, the problem is that "higher rpms" differ with every combo built)
    bores must be honed with a deck torque plate to simulate the stress of a installed cylinder head stress , the torqued bolts exert on the bore walls, the torque plate induces and duplicates that stress so that the bore walls will be pulled into the same relationship when you hone the walls concentric, rings won,t seal correctly in a non concentric bore
    gaps must be correct for the application
    RINGS MUST BE MEASURED WHILE SQUARE IN THE BORE< A RING SQUARE TOOL HELPS, I USUALLY PLACE THEM ABOUT 1" DOWN THE BORE THEN MEASURE END GAP, see later in the thread for how to make a good but dirt cheap ring square tool
    ring ends must be, correctly gaped, cut parallel and de-burred before installation



    these tools come in various ring sizes ,(but the various piston diameters are not as critical as ring width, it should be obvious that you MUST USE the tool that places the drilled gas port at the correct place in the upper ring groove roof and you damn sure better not drill deeper than the rear edge of the ring groove or youll destroy the piston

    while these professional ring filing tools ,(LINKED BELOW) would be great to have on hand,
    during your engine assembly
    , the price makes owning one as a hobbyist unlikely
    early in this thread theres pictures and links to the manual piston ring filers
    and if your very careful you can use a cut-off wheel on a dremel tool

    yes as always theres cheap,functional, and theres expensive precision ring filers

    http://www.abs-products.com/specialty-t ... nder.shtml


    Home » EN » How to Use a Cylinder Bore Gauge To Measure Cylinder Block

    How to Use a Cylinder Bore Gauge To Measure Cylinder Block

    Why engine can perform a rotation outpu ? it because the engine generating power from a combustion. The power of combustion pushing down the piston. But the movement of piston must produce a friction between the cylinder and the piston ring. In a long time, this friction will cause wear between the two components. That's why older engine have less power complaints with low compression pressure.
    If the cylinder is worn out, it means the power is also hampered. So it needs to be over size or replacing this one. But to know whether the engine cylinder is still feasible or not, we need to make measurements. It will calculating the size of the cylinders and engine block wear out. So how to step, consider how measure cylinder block using cylinder bore gauge below.
    Differences Tautness And Wear out
    Before we go any further, let's understand the meaning of these two words. Tranquility and innovation have different meanings.

    • Tautness, is a cylindrical wear when viewed from the side of the cylinder. This form of is tapered because there is a different size of the lower and upper cylinders. This difference will show a great tune.
    • Wear out, is a form of engine cylinder wear when viewed from the top. The normal cylinder, will definitely be a perfect circle when viewed from above. But when it form more oval, then it might be a signal that showing the cylinder wear out.
    How To Measure Cylinder Block Diameter ?
    To measure the diameter of engine block, we need a special tool called Cylinder Bore Gauge. This tool can measure the diameter of the cylinder with precision reaching 0.01 mm. But before making a measurement, we need to make some setting on this tool.
    cylinder bore gauge component and function

    • Dial gauge. This component will show the size scale with units of milli meters.
    • Lock position. This component serves to hold the dial gauge remain silent when bore gauge is used.
    • Grip. This component serves as a handle when applying a bore gauge.
    • Replacement rod. Component of a rod of varying length to measure many cylinders having different diameters.
    • Replacement washer. Similar to replacement rod, but replacement washer has a small thickness. Ranges 0.5 mm.
    • Measuring point. In the form of a bulge, when pressed it will move the needle of dial gauge.
    1. Steps to adjust the bore gauge cylinder.
    To make the adjustment, we need to know normal specification of cylinder diameter, you can find this specification on the service literarure each car or you need to measure directly using vernier caliper. But you need to know that this measurement is not a real measurement, because we just need a scale to set the right replacement rod.
    If you already know the diameter of cylinder then, continue to assemble the cylinder bore gauge. Start with installing the right replacement rod on the bore gauge. Suppose the diameter of the cylinder is 62.05 mm. Then we choose a replacement rod with a length of 60 mm plus replacement washer with a thickness of 3 mm. So a total length is 63.00 mm.
    Why is it higher?


    Because we will measure a wear. Components that experience wear and tear must have an enlarged diameter. If we choose the replacement rod of the same or smaller than the diameter of the cylinder, then the measuring point can not be depressed when taking the measurement.
    Once installed, set the dial gauge to zero using the micrometer. Position outer micrometer at size 62,05 mm, put the cylinder bore gauge (replacement rod parts) on timble micrometer. Then the measuring point will move and the dial gauge needle moves. Set the dial gauge scale to zero position on the dial gauge needle.
    2. Step to Measure Cylinder block diameter.
    Perform measurements inside the cylinder. There are three measurement positions of each cylinder that is on the X and Y axes of each upper, middle and lower positions. The X axis is the line that intersects the engine horizontally. While the Y axis is the line that cuts the machine vertically or elongated. So total, there are six measurement each cylinder.
    How to measure it ? input the cylinder bore gauge into the cylinder. Then, shake this tool left and right while watching the dial dial indicator. We need to pay attention to the farthest point of moving needles. Because this point will show the difference in diameter of the cylinder with a standard diameter. Perform this measurement at each position of each cylinder.
    To calculate wear out, we need to find the difference between the measurement of X axist and Y axis at each position. While the tautness, we can know by finding the difference in measurement of the top and bottom diameters on one axis.
    Another way of measuring the diameter of the cylinder.
    The step above is the correct procedure to measuring size of cylinder block. However, in its application sometimes encountered several constraints such as measurement results that are smaller than the standard. It could happen because each engine has a different diameter even made in the same factory. For that there is simple way that many technicians use to measure engine block diameter.
    The first step, we need to see the standar diameter on technical specification. Remember, we need to know the right specification and dont measure with vernier caliper. Why, bceause this data will be our benchmark to get the wear out. Once you see the right standar diameter then assembly the bore gauge and, make direct adjustments inside the cylinder.
    Like the above procedure, there is six position each cylinder but for first enter the cylinder bore gauge to the bottom position of cylinder to set the bore gauge. In this case, we are based that the bottom position is an area that does not experience friction with piston rings. So the diameter is still standard.
    Continue to move the bore gauge right and left. Notice the farthest point of the dial gauge needle. Position the dial gauge scale to zero position exactly on the needle moving to the furthest point.
    Furthermore, we directly conduct the measurement of the diameter of the cylinder in the six positions as described above. In this case, to know the cylinder diameter you should looking for the difference between standar diameter as benchmark and the result of measurement.
    Once you find the correct diameter, you can calculate the wear out and tautness of cylinder. From this data, you can conclude the condition of engine block.

    Similarly, guidance on how to use cylinder bore gauge to measure the diameter cylinder. Aside from the cylinder's sharpness and wear out, diseases of the engine can also be caused by non-standard pistons. Check how the piston check to be more clear. Hope can be useful.



    Last edited: Dec 24, 2017
  3. Loves302Chevy

    Loves302Chevy "One test is worth a thousand expert opinions."

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