This past spring my wife and I were sailing our 1984 O'Day 34 in the Bahamas
and a rattling noise
started coming from the engine
. Eventually we figured out the noise
was coming from the bell housing of the engine
(Universal M25 diesel), and not just a noise but we saw small metal shavings coming out of the timing port on the housing. With the help of the internet
and a couple invaluable (and much more knowledgeable) friends we figured out that the issue was likely the damper plate. There was some info that we couldn't find online, or found contradicting information for, so I wanted to fill in some of those gaps to help the next sailors in need (and pay forward some of the help I received!).
After getting to an anchorage and scouring the internet
for information we drained the coolant
, detached the raw water
hoses, removed the heat exchanger
, detached the transmission
linkage, detached the grounding wires, and detached the propeller
shaft from the engine coupling, good and rusty but we got there eventually. On the Universal M25 the transmission
is attached to the bell housing from the inside of the bell housing, so we had to remove the whole combo. There wasn't enough room between the shaft and the transmission to slide the transmission/bell housing back and off to expose damper plate and the flywheel, so we needed to lift
the aft side of the engine. The O'Day 34 engine room doesn't have vertical access, so we didn't have the option to hoist the engine, so we took a friends creative advice
. We outlined the engine mount locations, then removed the engine mount nuts, deflated a small fender
, shoved it in the 3" space between the transmission and the engine room floor and used a bike pump
to inflate the fender
. We placed 2x4's under the oil
pan to support the engine, deflated the small fender, replaced it with a larger deflated fender, and then inflated that too. The second bigger fender (which didn't fit under the engine initially) lifted the engine enough to clear the propeller
shaft. We stacked more 2x4s under the engine and then deflated the fender lowering the engine onto the wood
manifold came very close to needing to be removed to lift
the engine high enough but we were able to squeak by without taking it off. We tied lines to the engine hoist points to keep the engine from shifting backwards in case we got waked by a passing boat
, and then started working on detaching the bell housing from the engine body. There are nine bolts holding the bell housing in place, but embarrassingly I thought there were 10, and after some serious struggling and a short stint with a power
drill trying to drill out what I thought was a broken bolt, I realized the top center "bolt" was just a peg for holding the housing in place.
Once we got the bell housing/transmission off we found our damper plate in about 6 pieces. The springs and broken pieces of the damper plate had been rolling around in the bell housing shaving it from the inside causing the metal shavings we'd seen coming out of the timing port.
Now that we'd confirmed the issue we needed to replace the plate. Online there's a mix of what damper plate people say to use, for the Universal M25: Sachs 1866061001/3306316002 and/or Sachs 1866050002/3306316001. Amazingly someone in the anchorage had the first (3306316002) but it was clearly far too big for the flywheel on the M25. The correct model is the 3306316001, which we had flown in on Water
Maker Air from Fort Lauderdale
(only took 8hrs!!!).
With the new damper plate installed we put the bell housing and transmission back in place. We used a screw driver shaft to line up the holes and support the housing while installing the first bolts. Doing all this in the confined space of the O'Day 34's engine room was a real curse word inducing experience so that screw driver trick put an end to a lot of heart ache (again advice
from a friend). We borrowed some feelers from another neighbor for the alignment (have since bought our own) which was good since we did have to tweak the position of the engine a little even though we put it back where we'd marked the mounts. We got all the hoses, wires, and cables
reattached and our engine was back in action for the rest of our Bahamas cruise
. It wasn't fun, but it was a learning
experience. Hopefully this info along with the photos and the guidance already out there helps someone else in getting through the same problem.