his Tech Tip, one in ongoing series we publish for Hurth and Borgwarner Velvet Drive marine transmission owners, is aimed at helping people understand their marine damper plates. This Tech Tip follows other Tech Tips that discuss Hurth marine transmisisons. See for example Tech Tip #11, Hurth Gears: Care and Maintenance, Tech Tip #39: Hurth Marine Transmissions: The Ins and Outs of Basic Service, and Tech Tip #48, ZF/Hurth Marine Transmissions: A Six Step Program. We also discuss Hurth and Borgwarner marine gears in our Shop Kinks. See for example, Shop Kink #1, Marine Transmission Fluid, Shop Kink #24, Avoiding Idling Gears, An Interview in National Fisherman, Shop Kink #26, Souping Up the Series 72 Borg Warner Gear, Shop Kink #30, ZF/Hurth Marine Coupler or Damper Plate 101, Shop Kink #51, Hurth Gear Shift Position: A Warning, and Hurth and ZF/Hurth Marine Transmissions: Old Wine in New Bottles?
Damper plates lead a tough life. They work in the dark, are often soaked in salt water, and are never checked, let alone maintained. They are the marine equivalent of a mushroom! The damper plate is bolted to the flywheel with a half dozen or so small metric allen bolts. Into this clutch like plate slides the splined input shaft of the Hurth or Borgwarner gear. The damper plate acts as coupler between the engine and the transmission and all torque is transmitted through it.
Noisey damper plate? Sometimes these hard working cluthes rebel and their springs loosen up and even fall out. Or one or more of the allen bolts back out and the plate become loose and moves around. Symtoms of this will be a rattling sound from the bellhousing area when in neutral. Engagiing gear is often difficult and the Hurth gear is hard to shift. Often loose or missing springs is the only problem. People often think that they need a new transmssion when all they need is to replace the damper plate.
What to look for? If you suspect that your damper plate springs are loose and rattling around and that you have damper plate problems here is what to look for. First check your linkage to ensure that everything is tight and working properly. Then check that the bolts holding the damper plate in place are present and installed correctly. Verify that the Hurth or Borwarner gear is not misaligned. Use a dial indicator to check for this. Finally, if the damper plate is worn and/or springs are missing, check to see that your Hurth or Borgwarner gear's front bearing hasn't failed. Worn damper plates can often cause the transmisison's input shaft to wear and result in front bearing failure.
If your damper plate is worn, not to worry. We stock damper plates for most applications and have them ready for same day shipment anywhere in the world. We also have ZF/Hurth and Borgwarner Workshop Manuals and our Foley Hurth Hytork Fluid that we can send. As you can see, if you own a Hurth or a Borgwarner, we've got you covered!
We hope that this Tech Tip has been helpful. Please email any comments or suggestions to our Dr Diesel at DrDiesel@FoleyEngines.com.
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