The old one is out, the new one is in ------ sort of

Hello to all,
The repowering of Jolie Brise is underway. The old Volvo came out yesterday and the new 3YM30 is in. I am now asking what are my options for motor mounts as the stock mounts on the new engine are not adjustable enough to align the shaft flange with the transmission flange. The transmission sits about 2’’ higher than the shaft flange.I have been looking at low profile mounts and think I have some solutions but would like to hear from anyone who could shed some light on this. Any pictures would be a plus.

Bob & Lois

BCC Jolie Brise

Hello Bob,

Though I just sold my BCC it is still at PAM. If you check with Kate at Roguewve maybe she will let you take a look at the 3YM30 motor mount brackets used in “Lightfoot”
This was repowered about three years ago by previous owner. Maybe you could get some photos.
Best to you
Mark

Hi Bob, I recently installed a yanmar same model, if you look under the forum “Building a BCC” there are some pics there and I have others if you would like. It really depends on the support for the engine, I fitted a standard fibre glass engine mount that was moulded to follow the complex curves of the hull profile. It just fits right in and then the rest of the alignment should follow. The pan has a ss plate in situ to bolt onto. Another plus. It is available from Cape George.

Stewart,
Our BCC is factory finished 1984. The same engine pan and ways are as yours. Since you had to fit yours it looks like it may sit a bit lower than the one we have that was factory installed. Did you use the rubber mounts that came with your 3YM30? I really don’t want to mess with altering the bed and am going to all ends to make something else work. If you could send more pictures I would appreciate it. By the way, your boat is looking great !!!

Bob & Lois

BCC Jolie Brise

Bob,
What is the model of the Volvo you are replacing? We replaced our Volvo MD11C with a Yanmar 3GM30F, and we only had to have some steel pieces welded up. I believe later Volvos had a shaft alignment that dropped below the level of the engine bed plane. This may have helped when installed in a bilge-less modern boat, but makes replacement a challenge.

I can take some pics, if it would help.
Dan

Dan,
The Volvo that we are replacing is an 18 hp mod 2000. The transmission has a downward offset. It is going to be a challenge as the 3YM30 must drop lower into the pan. We have plenty of room to go lower so its just a matter of getting the right mounts. Pictures would be helpful in getting more ideas. Thank you.

Bob & Lois

BCC Jolie Brise

Bob,
Here’s a photo and a sketch of Shaula’s modification for mounting the 3GM30F, using the standard Yanmar soft mounts. The modification was necessary because the glassed-in pan wasn’t long enough, fore and aft. In the early days, Sam suggested a very small engine, but I’ll bet he lengthened the pan before installing the 3GM30 as the standard. We made the forward pieces out of 3/8" mild steel plate, and the aft ones out of 3/4" plate.

Do the mount’s studs have to be perpendicular to the plane of the engine’s mounting brackets? It seems like if they are not, you’ll have problems when you tighten down on the nuts. Have you considered 2 long hardwood wedges that have the same angle as the downward offset?
Dan

Dan,
Thanks for the pictures. In our situation we must lower the entire engine to make the shaft and transmission flanges line up. I’m thinking that I may have to make new brackets to bolt onto the engine and use low profile mounts.

Bob & Lois

BCC Jolie Brise

Hi Bob I have some more pics for ya but alas they are large file size, send me an email at s.gillies@nl.rogers.com and I shall send by return. They are too large for the forum capacity.

Hi Bob & Lois, I did a similar swap on my BCC, hull # 72 , 1985, but with a 3GM30 , replacing a Volvo 2002.

I had asked all around about using different mounts, than what were supplied with the Yanmar, and all replies were to try everything I could to try to use the Yanmar mounts. The replier’s said that Yanmar did extensive mount testing and design to get the least vibration, ect., especially because these 3GM30’s were to be used for the charter fleet.

What I didn’t like about the Yanmar mounts, is Yanmar’s recomendation to remove and replace the mounts every few years, at least that is the recomendation in the manual.

The 3GM30 Yanmar mounts were so soft that I had trouble to aline the shaft flange to the trans flange, so I decided to use a Federal (edited) flexable coupling, to compensate for the expected excessive cutless bearing wear, due to the soft mounts.

That National flexable coupling, had an unexpected benefit, in that, it isolates the shaft and prop, from grounding to the engine, and thus to the batt negative.

So, I found a way, but be careful the fwd Yanmar mounts have a different degree of shore, than the aft mounts.

I have the same problem as Stewart with photo files too large to attach, here.

BTW , www.polyflex.com.au has some interesting mounts, too.

Douglas

Any pics of the flexible mount Douglas, could send them to s.gillies@nl.rogers.com if you like.

Hi Stewart, gosh, my mistake, about calling my flexable coupling, a “National” coupling.

I checked the internet and found my coupling to be a “Federal” flexable coupling, check this address for photo and more info :

http://www.henrysmith.com/couplingsfederal.htm

I will take a photo of the installed Federal Coupling, next weekend, and will forward that .

I had to use the standard bolt together flanged couplings to get the shaft alignment as close as I could, then removed it and installed the “Federal” flexable coupling.

There is a very interesting problem that cropped up on my boat, due to the Volvo 2002 and the standard flanged coupling.

For some unknown reason, the f/g shaft log, that holds the cutless bearing, broke it’s resin seal/mounting to the hole through the deadwood, and this allowed saltwater to go up the outter sides of the shaft log, then down into the deadwood below the shaft.
This always caused high moisture readings in the deadwood area.

It seems that during hull construction, the internal deadwood area was filled with glass fiber, (guessing that it was floor sweepings), then polyester resin was poured in to fill the voids.
Well, all the voids were not filled, and that is where the incoming saltwater collected, which intern, created the high moisture readings.

I think that a previous owner got something tangled in the prop, and instead of stopping and clearing it, drove on, and the shaft may have gotten bent, driving on with a bent shaft could have jarred the shaft log loose from it’s resin bond, while it was destroying the cutless bearing.

It was a long tedious proceedure to back pressure-remove the water from the dead wood area, and re-seal the shaft log, all of this could have been prevented in the first place, had a flexable coupling been installed, first, as it would have been able to absorb the bent shaft vibration loading on the cutless bearing and the shaft log.

Douglas

Douglas,
Interesting information on the Federal Flexible Coupling. Do you see any disadvantages of this type of set-up. Are there any other BCC owners using one of these? If you have pictures they would be most welcome.

Bob & Lois

BCC Jolie Brise

Hi Bob & Lois , so far, I have only seen advantages from installing this Federal flexable coupling.

If you really stop and think about reciprocating shaft movement, ie; a 3’ shaft rigidly bolted to the transmission flange, then add the vibration and movement of a diesel on the end of that shaft, mounted on soft engine mounts,

like wow,

what loading and wear that cutless bearing will be absorbing when that engine dances around underway, not to mention during fwd and reverse shifting, also, not to mention throttled up running for port, in a heavy seaway, that cutless bearing and it’s log holding it, will get extreemly abused.

Now if that shaft gets bent or bowed, and still is driven more, expect the trouble, I had to deal with .

I think that I read in the Yanmar installation manual that they reccomend a flexable shaft couple, too.

The advantages that I didn’t think of, but am greatful for is extended life on the prop zinc, and cutless bearing itself.

Douglas