Engine break in on water brake dyno

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    I have always been fond of the acceleration then engine braking engine break in method but I am hoping to break in some motors on my water brake dyno. Since it has no inertia even if you pull the load off the motor it still won’t have much if any engine braking on decel. This engine braking is supposed to help allow oil to get into the hatching and help keep things lubricated as everything breaks in.
    Has anyone done engine break in on a non inertia dyno? Any tips on doing this?


    You can either add an inertia flywheel to your water brake dynamometer and/or switch to a stainless absorber rotor. Using a flywheel allows exactly designing in the inertia contribution you want.

    The more sophisticated solution is to add motoring to the dynamometer. We offer various size AC motor/generator and inverter packages, with or without resistive load banks or full regen capability. In smaller capacities, the cost is not too bad, but at higher power levels this is much more expensive than a water brake with a flywheel. Most of the OEM’s use such four-quadrant AC dynamometers, but they have big budgets too.


    Yes I know I am a year and a half late to the party, but I figured I would share my method just for future readers to consider.

    As far as ring break in goes, a big part of that is dependent on the rings and the cylinder machining. With some of the more modern rings and more precise machining I personally have seen the break in time become very short. What I do is fire the engine after making sure that coolant, fuel system and any other externals are ready and bring it up to temp while doing basic timing and fuel system checks. As long as I am not having to break in a flat tappet cam I will usually shut then engine down and get my ducks in a row to start making pulls. As long as I feel comfortable that everything on the engine is sound I fire it up and make a relatively short pull. If a street engine I will run it from 3000-4000 RPM’s. At that short of a pull if something is off it was so quick that it won’t hurt itself. I leave the engine running and look at the data. If all is good I make sure the temps are solid and make another pull. While doing this I am looking at the torque numbers. As the rings seat the power will increase until they are fully seated and the power will stop increasing.

    Now depending on the rings and machine work you may see as I and many others have seen that the power never changes. That is because the rings are seating so quickly on some of these packages. Many times I will make three short pulls and the numbers are within 1 HP of each other as they have seated and are already broken in by the first pull. As long as it has done that and all looks good we let it rip!

    Anyway, that is what I have seen and I learned this from others way more knowledgeable and experienced than I so I can’t take credit for it, but it has worked great for us. If you have any questions feel free to ask. I may not have answers, but you can always ask. LOL


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