Suspecting our marbles in a can noise (only in neutral) was the damper plate, I finally pulled the transmission today, only to be surprised that the damper plate was not the old spring type, but was the new polymer type. Either Westerbeke made a change over for our year 36, or the previous owner ( who was methodical about maintenance) had it replaced. The engine has 825 hours.
My question is, has anyone had a polymer damper plate develop a noise issue?
If not, are the Hurth transmissions noted for noise? The transmission fluid looks like new and is at the correct level. (I will be changing it). I have the unit out of the boat. When I spin the drive shaft by hand, there is a faint clicking sound. It's hard to believe that the faint clicking would get noisy when the engine is at idle.
Thanks for any thoughts. I'm tempted to just accept the rattling, return a brand new damper plate that I bought and reassemble everything.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
OK. I admit that I should have visited the Technical section of the C36 web site much earlier. I found a notification that Hurth transmissions tend to exhibit gear clatter-some more than others. They site all kinds of reasons for noise. Some seem more like excuses for some sloppy tolerances in the product. We will live with and ignore the clatter. There's always the volume knob on the cockpit speakers.
Assuming I can free up the last Allen Bolt from it's Loctite hold, I may as well replace the damper plate with the new one now that I have all the effort into pulling things apart.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
I also found my damper plate to already be the polymer version, and try as I might, I still could not get that final allen screw loosened. I would have had to remove the bell housing to extract the last screw. I put the darn thing back together and decided to live with it. I did get the tranny overhauled (it had about 2,500 hours on it) but there was no change whatsoever in the 'rattle'. It's just the nature of a Hurth transmission.
Larry Brandt
S/V High Flight #2109
Pacific Northwest, PDX-based
2002 C-36 mkII SR/FK M35B
Thanks Larry.
I haven't quite used up all my tricks to free up the last bolt- a soldering iron on the bolt head seems to be the preferred method to soften the loctite- I'll try that.
Also- I did some measurements. It appears that if I remove the propellor, I can push the shaft back into the hull towards the bell housing (with the transmission removed of course) and clear the strut by maybe 1.5 inches. With the shaft pushed out of the strut, I should have enough access to change the cutlass bearing. Hmmmm. I know the site has a loaner tool for this, and others have dropped the rudder. Maybe this is a third option.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
Paul,
watch this video I made, same as you I had a polymer one, the problem was the "teeth" in the damper plate. New one fitted tighter and made no noise as the one shown in the video.
Hope this helps
-Abraham
https://youtu.be/IQlc8v4STcs
Sailing from Norwalk, CT
2002 C36 MKII, "Cataluna", Hull#2077
Abraham-
Interesting. Seems from your video that there are two contributors to noise. When shaken (unmounted), the polymer damper plate rattles, indicating play in the assembly rivet heads, and when mounted, additional play from wear on the spline shaft and spline cavity on the damper plate. I was kind of guessing that those might be possibilities and your video confirms it. I will re-double my effort to remove the remaining bolt holding the old damper plate to the flywheel to see if my OEM unit exhibits the same wear and tear.
It would seem that anything but perfect alignment between the engine and transmission, might accelerate wear in these two areas. I noticed that my bell housing had a gouge of raised metal (maybe 1/32 of an inch tall on the bell housing mounting flange) that occurred prior to the factory assembling the tranny to the engine- that may have slightly cocked my transmission. I will sand that flat.
In any event, despite the annoying noise, it seems that the units can operate for many thousands of hours (per Larry's above input) and be totally functional.
I'm probably more hung up on the rattling than I should be....but it is such a beautiful boat, it shouldn't sound like a Sherman tank
Thanks.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
I used a hand impact driver with a snap-on hex/ 1/2 drive socket.With a big hammer. Locite recommends heat, something like 500 degrees. Don't use a cheap socket.
Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611
So I did the Damper Plate replacement over the winter. Obviously could not test it with a running engine. I'm still on land but I commissioned my engine. It seems the rattle that was there before is gone but there is considerably more vibration that can be felt on the floor around the engine than what I remember. Once I raised the RPM's it settled down. I couldn't observe what was going on for long since I had to keep filling a bucket to feed the cooling system but from what I saw there was no unusual amount of movement on the exterior of the engine or transmission. The whole system looked very solid.
Any ideas of a cause and how I can fix it. I don't want to trade a rattle for a vibration. I hope I don't have to dismantle the transmission again to get at the damper plate. I wasn't at first sure how to put it back but it only went in one way which seemed like the same as the pictures in our web sites article.
Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
Enrique-
Can't imagine pulling the transmission and replacing the damper would create vibration changes when reassembled. I would suspect something in the fuel supply.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
One other thought- are you sure the transmission was in neutral and the prop was not turning when you were running on the hard?
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
Good luck Paul!
BTW, there is another video on youtube of a Catalina 28 with the same issue on a polymer damper plate, might be a common issue with this.
Sailing from Norwalk, CT
2002 C36 MKII, "Cataluna", Hull#2077
I'm pretty sure tranny was in neutral. Shaft not spinning. Fuel can cause vibration? Engine seemed to run smoothly.
Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
Yes-
Clogged fuel lines or filters, an electric fuel pump beginning to fail, dirty injectors, bad motor mounts can all contribute to rough running. My engine at idle vibrates a fair amount-which is normal for our boat.
Paul
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
In the water with your rig tensioned is how an engine should be aligned, with one of the goals being even weight on the mounts that are athwartship from each other. A boat out of the water and with rigged loosened for winter storage can both contribute to a slight dimensional change in the beds, resulting in an uneven distribution of engine weight on the mounts. An engine with substantially uneven weight on the athwartship mounts is ripe for vibration. Cold engine mounts might also be a factor too.
If you did not loosen your mounts and the only thing you really touched was the transmission and bell housing to replace the damper plate, then consider waiting until after launch and static tune of the rig. If you did loosen the mounts, then this would certainly be a place to check, again when you're back afloat.
Nick Caballero
Retired C36/375IA Mk II Technical Editor
It may have something to do with being on the hard. My yard always does the final engine alignment in the water. Something to do with the stands and uneven pressure on hull.
Chuck Lennox
97 MKii Ventura Ca
Island Girl Hull #1611
Thanks folks. The things I changed were the removal of transmission, replacement of damper plate, replacement of water pump, change muffler/manifold hose to the blue bump hose, fuel filter holding bracket and regular maintenance (oil, filters, etc.). Didn't touch engine mounts. I have run the engine out of the water before and the vibration at low RPM's seemed excessive this time.
Enrique
Talisman
1998 36 MK2 Hull #1673
Tall Rig Wing Keel
M35BC engine
Old Saybrook, CT Summer
South Glastonbury, CT Winter
Finally was able to remove the last loctited Allen Head bolt so that the old polymer damper plate could be removed. Unfortunately, the bolt hole threads on the flywheel were damaged, so I had to re-drill, tap it, and use the next size up bolt. Not a big deal.
Similar to what others have found, I noted that the old damper plate does have a lot more free play on the transmission shaft than does the new one. Also, the old one had a large washer that had become loose on the engine side of the damper plate. The washer is fastened to the plate with a snap ring. It was loose enough to rattle-maybe another source of noise. WIth some effort, could spin the washer on the new damper plate, but it was tight and did not rattle. Still, I applied loctite to the new one to prevent it from loosening over time. There appeared to be no other loose items- the assembly rivets were tight.
Now we'll have to wait until a late May launch to see what impact all this work really has on noise reduction.
My cutlass bearing is good, and on a side note, it does appear that with transmission removed and propeller removed- the prop shaft can be pushed towards the engine and clear the strut to allow for cutlass bearing replacement.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
I recently had my 2003 Catalina 36 MKII pulled for some bottom paint and replaced the cutlass bearing at the recommendation of the yard. Once back in the water the high pitched rattling noise (tiny screws in a coffee can) was observed coming from under the helm. Based on what I have read in this forum, it sounds like it could be loose damper plate? Does it make sense that this could have happened as a result of the cutlass bearing being replaced? It pretty obnoxious noise and very distinct from the engine. It definitely was not there (or noticeable) until after the cutlass was replaced.
Any thoughts on this would be appreciated.
Thanks