Westerbeke W40 Damper Plate


Replacing the Damper plate Westerbeke W40

An over due project

The damper plate softens the shock between the  engine and transmission when the it is engaged. It is basically two (2) plates connected by six (6) springs. One plate is bolted to the engine’s fly wheel and the other is connected to the transmission by the spline.

The springs absorb the shock while preventing the plates from rotating.

The first sign I had of a problem was when motoring at an ideal I heard a very clear rattling sound coming from the engine. Once I shifted to neutral the noise stopped. This sound was caused by springs that had lost their "spring".

The springs in the plate I removed were so loose that I can use it as tambourine (very musical).

Clearly a project way overdue….

The first step is to remove the drive shaft. Next the step is to remove the transmission (Paragon PM10L). The transmission oil cooler must be removed to get to the four (4) bolts holding the transmission to the engine.

The Damper Plate is attached to the fly wheel with 5 allen screws. To remove it you will need a 3/16 allen wrench. Most hardware stores carry allen wrench sockets (shown above the damper plate left). The socket provides a longer reach and more leverage than a standard allen wrench.. Second dropping the allen wrench into the bell housing would make for much more work.

At our local Ace Hardware a 3/16 allen wrench socket cost about $3.50.

The replacement plate cost about $222.00 and is available from most marine engine parts suppliers.

The damper plate design has changed little in the last 29 years since Sea Dragon's Westerbeke was mated to its Paragon PM10L transmission.


  Re-assembly is straight forward... The only caution is to coat the transmission input spline with an anti-seize lubricant. I have used Permatex products

Return to Projects Page 

Copyright © 2006 Garner Bennett. All Rights Reserved