Lap Valves - Valve Lapping

Discussion in 'Mazdaspeed 3 How-To' started by JohnnyTightlips, Jul 12, 2019.

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  1. JohnnyTightlips

    JohnnyTightlips Motorhead Silver Member

    May 12, 2016
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    Valve lapping is important to do when you are building your motor if it is higher miles. This will allow you to get a nice tight seal to the valve seats which is important to compression. Spent like 4+ hours lapping the valves. It took forever but I wanted this to be done right and I did not want to mess with it ever again "fingers crossed" I followed the video I posted before. Here are the steps I did.

    Tools Needed

    1. Clean Valve and head valve part
    2. Apply coarse grit valve compound , Lube valve stem with oil and few drops in head
    3. Grind until sound changes and starts to smooth, like 2-4 min "follow video"
    4. Clean Valve and head, Repeat the above process 3 times for Coarse and the 3 times for Fine, then clean and lube and check to squeaks "watch the video" PRO TIP if you put a tiny bit of oil on the suction for the lapping tool it will help it stick better, clean both surfaces before sticking it to the valve and press it down until it bottoms out on it.
    5. Before putting the head back together clean it all again with brake clean and make sure the valves go back to the spots they were mated with on the head, otherwise you did it all in vain. "check for leaks too" if leaking then do more work SON
    Valve on the left has been lapped. It looks like their are lines through it and there might be microscopic lines but it is smooth as butter and uniform.

    Left side is complete here too.

    All done, kill me now. Still need to clean and assemble but glad to be past that. If you are thinking of doing this yourself it is really just a giant time suck, not difficult at all. Take breaks so you don't fuck it up or miss something.
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