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| techtalk:ref:engmech01v [2025/08/07 02:02] – [Solids vs Hydraulics and Pushrod Types] hippysmack | techtalk:ref:engmech01v [2025/08/07 02:52] (current) – [Solids vs Hydraulics and Pushrod Types] hippysmack | ||
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| === When are applications where you can't use a stock lifter? === | === When are applications where you can't use a stock lifter? === | ||
| When you run out of tappet anti-rotation pin clearance. Red Shift 585's have stock base circles and typically require an aftermarket tappet that has longer anti-rotation flats. SE 575's have almost as much lift, but they have a smaller than stock base circle, so they typically don't cause tappet pin clearance issues. ((https:// | When you run out of tappet anti-rotation pin clearance. Red Shift 585's have stock base circles and typically require an aftermarket tappet that has longer anti-rotation flats. SE 575's have almost as much lift, but they have a smaller than stock base circle, so they typically don't cause tappet pin clearance issues. ((https:// | ||
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| + | === What is the advantage of using non-adjustable pshrods? === | ||
| + | A non-adjustable pushrod is stronger at a given weight and also less likely to cause " | ||
| === When do you stop using fixed pushrods and switch to adjustables? | === When do you stop using fixed pushrods and switch to adjustables? | ||
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| === What is a proper argument for using hydraulic lifters? === | === What is a proper argument for using hydraulic lifters? === | ||
| + | A hydraulic lifter self-adjusts within a certain range. In other words, if your pushrods are too long, the lifter automatically shortens, and if the pushrods are too short, it automatically lengthens. The hydraulic lifters used in HD motors have about .200" of plunger travel. As long as it's preloaded between about .050 and .150, it adjusts itself properly. So in other words, there' | ||
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| + | If you preload it too far (i.e. pushrods that are too long), for example, the valves won't land on the seats when the lobes are in the full down position, and as such, you'll suffer loss of compression and/or " | ||
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| + | The whole idea of a hydraulic lifter is to self-adjust, | ||
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| This 2007 Sportster had it's factory stock hydraulic lifters, no travel limiting washers, and non-adjustable pushrods. \\ | This 2007 Sportster had it's factory stock hydraulic lifters, no travel limiting washers, and non-adjustable pushrods. \\ | ||
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| === What is a proper argument for using solid or travel limited lifters? === | === What is a proper argument for using solid or travel limited lifters? === | ||
| The one thing that a solid or travel-limited lifter brings to the party is easier starting, since they don't bleed down as the motor sits, thus shortening the intake duration which raises compression. They' | The one thing that a solid or travel-limited lifter brings to the party is easier starting, since they don't bleed down as the motor sits, thus shortening the intake duration which raises compression. They' | ||
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| + | You need to have a running clearance, which you set by adjusting pushrod length while using a feeler gauge positioned between the valve tip and rocker tip. Now it's true, you can slightly alter lift and timing by varying that running clearance, and racers sometimes do this. But you can't move it much without running into the aforementioned issues. Within the range you have to safely work with, it generally has very little effect on the dyno sheet. ((https:// | ||
| The Hydrosolid is a nice solution for someone who wants the valvetrain control of a solid (especially at high rpm) with the self-adjusting convenience of a hydraulic. They do require adjustable pushrods and collapsible covers, but they' | The Hydrosolid is a nice solution for someone who wants the valvetrain control of a solid (especially at high rpm) with the self-adjusting convenience of a hydraulic. They do require adjustable pushrods and collapsible covers, but they' | ||
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| + | The quickest and surest way to determine if you have travel limiters is to take them apart. There' | ||
| ====== Tappet Flats ====== | ====== Tappet Flats ====== | ||
| **This is in consideration of induced noise from the use of high lift cams**. \\ | **This is in consideration of induced noise from the use of high lift cams**. \\ | ||
