Duane, in my experience, you need to have a back-up plan to remove the bell housing (alas!) IF one of the bolts holding the plate is so frozen that it cannot be budged. Before you tackle the job I suggest you contact your local SnapOn rep and get the very highest quality allen wrenches you can get, to have the greatest security that they will not break off in the bolt.

Also, are you sure that you need a new damper plate? The rattle coming from the transmission/engine may be caused by other things, and those are particularly addressed in the Hurth Gear Clatter Memo I posted in the Technical -Manuals archive of this website.

Hi Duane,

I just did this job as well this past winter, also following Sean McGuckin's article. I got my new damper plate from Discount Marine (part number JHW-044624, product: Westerbeke, Damper, Hbw, 044624, 44624). Looks like you're looking at the exact same part, so I can tell you that it does indeed fit.

I had a distinct rattle at idle, and from all descriptions it sounded like the problem was likely the damper plate. I used a ratchet with a hex bit to remove the bolts, rather than allen wrenches. Once I got the old plate out, it actually looked to be in fine condition, and none of the springs were noticeably loose, so I was pretty bummed that I had probably done all that work for nothing (but at least I now had a spare damper plate!).

However, once I got the boat back in the water, I was happy to find that the idle rattle is now a thing of the past, so it seems to have done the trick. Considering our C36's are similar vintage, and both with the M35B, I'd personally guess the damper plate replacement should also help you out.

Good luck!

Duane - if you have not pushed that botton yet, let me know. I purchased the new style plate last year for about $190 from a source in Seattle. I'm afraid to admit my aging mind can't think of the name right now but I can run down to the boat and get it if you need it.

David S. Power
Two If By Sea #1687
Punta Gorda, FL

Duane - it just came to me: PYI for $191, including shipping. If you need a part number, let me know and I will go down to the boat and get it. It came in a couple of days. If you have a dripless, it will be more of a project as there is very little room to get it apart.

David S. Power
Two If By Sea #1687
Punta Gorda, FL

Sounds like you are goimg on the hard. Do you want that part number or are you going ahead with your original plans?

David S. Power
Two If By Sea #1687
Punta Gorda, FL

Duane - actually it is AYI. guess the memory is not as good as I thought. The part #22B4. Before I ordered it, I asked the tech what they would recommend. I had the part number as Tom had replaced his on Cantagree. After asking several questions about the engine, transmission, etc., the tech recommended the same part number.

David S. Power
Two If By Sea #1687
Punta Gorda, FL

Duane
While the transmission rattle on my 2005 model boat with only about 200 hours on the motor is noticeable - its not too bad.
Nevertheless I have anticipated the possible need to change it at some time in the future and have done a bit of research on the cause and solution options.
There is a fair bit of information on the topic in this Forum but can I suggest, if you haven't already done so, to have a look at the Catalina 350 Association Forum where there is also a lot of discussion and some recommendations.

In particular there is a comparison of the Sachs and both low and high deflection PYI Dampers.

One recommendation in the following C350 Forum Post ([url]http://www.catalina350.net/phpBB3/viewtopic.php?f=11&t=486&start=20#p290...) recommends the high deflection PYI Damper. As follows:

[I]"To all who are plagued by the "Low speed Rattle"
It seems to me that the problem of chatter/rattle of the transmission seems to be two fold.
A light flywheel by the engine manufacturer for the entire family of engines and a poor choice of damper Universal/Westerbeke to absorb torsional variations this will cause at low speeds.
The quick fix given to us from Hansen Marine and Catalina is to raise the idle speed and or replace the damper.
My guess is that PYI in response to this, has developed a High Deflection Damper to replace the original.
I found that Bata Marine (based on the same Kobota blocks) sells similar marine engines with a critical modification. They install an extra flywheel weight (increases mass) that reduces torsional variations/vibrations. They claim very quiet and smooth operation over a wide range of engine RPM especially idle of 800-900.
Numerous postings on this and other pages have reported problems with low speed transmission rattle.
It seems to me that poor engineering/lack of testing by the original manufacturer is the cause.
I have installed the original PYI, a Sachs and a PYI HD damper. I have run them for about 10 Hours each and report that
the HD Damper is the best as far as reducing transmission rattle .
I can also wonder if the torsional stress is some how reducing the service life of the original dampers.
My experience with Damper life is limited to my 1980 Universal 5425 engine with a Sachs damper and a Hurth transmission that lasted over 4000 hours of cruising
My Catalina 350 engine with 125 hours was a rattle bucket which prompted me to seek the root cause of this problem. I now have about 350 hours and a quiet boat.
I also have two extra dampers PYI and Sachs hardly used".[/I]

Also the is an excellent article the C350 archives (complete with pictures) of a damper plate installation while in the water with a PSS Seal".

I'm sure many of us would be interesed to hear of your results.

Looks like my memory was better than what I thought. Where did I come up with AYI? NO MEMORY OF THAT!

David S. Power
Two If By Sea #1687
Punta Gorda, FL

Peter, your late model boat already has the polymer damper plate in it. I know that because my 2002 #2109 had it from the factory. I don't know what serial number CY began adding it to production boats.

Probably not the case, actually. I just replaced mine, and it was the spring version. Looks like the switch must have happened sometime between 2000 and 2002....

I posted on this a while ago... I had the rattle and was told by a diesel tech that it was just "transmission backlash". Like Larry, I have a 2002 with the polymer damper.

My point here though is that the rattle is not normal. I had mine go completely two year ago with low hours on the engine /transmission on the 4th of July in a narrow channel with boats all around me and no forward or aft control at all as I was maneuvering to pick up a mooring.

If you have this problem, I strongly suggest getting it taken care of asap. I was in Norwalk CT and I am ashamed I don't remember the marina but they were super in fixing it in 2 days after having the part shipped in. (They are the first marina when you come into the river). Cost me one boat buck and since then I have no rattle!

That's interesting Larry.
I guess the issue with me is that I'm not sure what is normal. There always had been s rattle but I simply adjust the revs to keep it to a minimum.
I don't have a C36 close by to compare it to. Anyway it will be interesting to see Duane's opinion after the fix.

Chuck and Peter, and others with the polymer damper, make sure you read the Hurst Gear Clatter Memo. Maybe the clatter is caused by, say, injectors, or some other culprit?

[QUOTE=pierview;18019]I posted on this a while ago... I had the rattle and was told by a diesel tech that it was just "transmission backlash". Like Larry, I have a 2002 with the polymer damper.

My point here though is that the rattle is not normal. I had mine go completely two year ago with low hours on the engine /transmission on the 4th of July in a narrow channel with boats all around me and no forward or aft control at all as I was maneuvering to pick up a mooring.

If you have this problem, I strongly suggest getting it taken care of asap. I was in Norwalk CT and I am ashamed I don't remember the marina but they were super in fixing it in 2 days after having the part shipped in. (They are the first marina when you come into the river). Cost me one boat buck and since then I have no rattle![/QUOTE]

Curious, just what did they do, or what did they replace?

Gary... you had to ask today.... I just deleted the picture I had posted of the plate. Looks like a steel plate with polymer between the two. If you check back in the files, I posted what happened to me with a picture about 3 years ago.

Hi all;

I just finished replacing my plate damper following the directions in Sean's excellent article. It went exactly as advertised, and really quite simple.

Of note, when I examined the old one, the "damping" portion, the teflon interface, was fine. The problem is that the splines in the plate were very severly worn, the teeth being about 50% worn off. This allowed play on the transmission shaft, resulting in the "chattle" at low rpm and load. The male transmission spline was fine, as apparently that is case hardened.

By the way, I'm from Canada, thus challenged by customs and shipping, etc. My source for all things Universal here in the north is Anthony Keats Marine, in Whitby Ontario. Ordered the plate on Monday, arrived Wednesday morning. 

Where can I find Sean McGuckin's article to download?

My M35B engine with 1700 hrs rattles in low RPM's but otherwise seems to work fine.  I can minimize and live with this rattle but am deathly afraid of a transmission failure to the magnitude described in this chain of posts.

Should I be replacing the plate?  I don't see a write up in the technical section. Is it elsewhere?

Enrique
Talisman '98 MK2 36' hull #1798
On the hard in South Glastonburry, CT

So am I at risk of transmission failure here?

I've owned the boat since 400 engine hours so I suspect it's the original damper plate

enrique

Duane-
It must be the season for damper plate replacement. I purchased a new polymer one from Discount Marine too and plan on performing the work during hopefully a mild day this winter. Our M35B has 825 hours and we experience a fair amount of rattling.