Yanmar SD40 > SD60

[RI Sailor]

I had one Yanmar SD40 saildrive fail and decided to replace both replaced by the marina since the boat was out of the water (and that's not easy up here in Rhode Island). The installation included the SD50 to SD60 conv kit - I assume this is the same as for the SD40? It also included the DAMPER-FINE SPLINE.

When they installed them there was some water seeping in I assume around the rubber blatters.

Anyone familiar with this conversion from SD40 to SD60 that has any comments on how it worked for you is appreciated

Thanks
Dan

[skipperpete]

Hi RI Sailor
Was your SD60 supplied with the thick stainless steel mounting plate and the two spacers?
The problem you mention can be caused by irregularities in the Grp bed. The embedded metal threads in the bed get pulled upward by the SD 40 mounting bolts and this causes a 1mm or more dip between the individual bolt holes that the rubber gasket in the plate mounting kit cannot quite seal even though the bolts are drum tight. If you didn't get the mounting plate kit ,then the bed needed to be made perfectly level for the SD60 sitting directly on the Grp because the sealing edge is not as large and forgiving as the original Yanmar moulded sealing edge.
That adapter plate was supplied to avoid the wavy bed issue but it really works best if you ditch the thin rubber gasket and bed it on an approved sealant. No sealant on the saildrive diaphragm though.... never ever.

[RI Sailor]

Thanks for the reply. I will check to see if the spacers came with the adapter plate.

Can you tell me more about the sealant - which one and where?

Regards
Dan

[skipperpete]

Hi Dan
The sealant subject is a bit controversial but 3m 5200 between the adapter plate and the fiberglass base seems to work amazingly well but takes days and days to cure. The fast cure is good but you need to be pretty well organised if you use it. Some folks like Sikaflex.
The spacers go under the front engine mounts to match the thickness of the rear adapter. Without them you end up with the front mounts adjusted to the very end of their upper limit and thats not good.
The top surface of the adapter plate is very smooth and is the perfect surface for the saildrive diaphragm to seal against with no sealant of any type needed.

[RI Sailor]

Thanks so much for the update!

[Captain Bill]

I am four years post conversion from SD40s and on my second set of upper units. I was lucky enough to get two with the ramp angle defect the first time out. My adapter plate was put down with sealant and I've had no leaks around the plate. I'm on my 3rd set of prop shaft seals, and they were not replaced due to scheduled maintenance. I'm also on my second set of dampers. I find that there are serious vibration problems with the drive/engine combination, especially in the 1800 to 2100 rpm range. I think this is caused by the new damper, but can't really prove it. Under no load my 3jh3ce engines are as smooth as silk in that rpm range. The new damper is a spring type damper and contains two sets of springs which if I understand it correctly are designed such that each spring set absorbs power pulses in different RPM ranges. I think that one set is designed for lower rpms and one for higher,but their ranges fail to overlap. The old SD40 dampers were elastomeric type and I never had any vibration issues. This has been an issue since day one. New engine mounts, prop balancing, new upper units, and a new damper have done nothing to fix it. The prop shafts have been checked for straightness and were less than .001 from perfect. Note there was no vibration issue on day -1. My experience with Yanmar saildrives has not been pleasant. The SD40s had their own problems but these ZF built drives have been really special. Another member was told that the prop shaft service life is 1400 hours and you cannot buy a new one. The only way to get a new shaft is to buy a whole lower unit, which actually has a list price higher than a whole new drive unit. I have already had my prop shafts sleeved because of wear at prop shaft seals.


It's needless to say, I'm not happy with My SD60 sail drive experience. As far as I can tell from comparing parts lists and specs, the SD60 is just a re-labeled ZF SD10 and the ramp angle defect was a known issue with those since well before I bought my SD60s. That being said, I have been using these drives for full time cruising and that is not their target market. 1400 hours might be 25 years of use for the weekend sailor and that's their target market. For me 1400 hours is a little over 2 years.

[David B]

Originally Posted by Captain Bill

It's needless to say, I'm not happy with My SD60 sail drive experience. As far as I can tell from comparing parts lists and specs, the SD60 is just a re-labeled ZF SD10 and the ramp angle defect was a known issue with those since well before I bought my SD60s. That being said, I have been using these drives for full time cruising and that is not their target market. 1400 hours might be 25 years of use for the weekend sailor and that's their target market. For me 1400 hours is a little over 2 years.

We have the ZF SD10, and have just this year come across the issue of no output shaft or bearing kits available. From what I can see, they press the taper bearing cup into the back of the housing such that it would be very difficult to remove without really damaging the housing, so ZF don't make the kits available.
I understand there is now a ZF SD20, but don't have information on the changes - they just imply that you can now change the bearings etc.
In defence, I had a quick look at a Yanmar SD40 (I was told) stripped down, and it seemed there was only a bush bearing at the back. Obviously the taper roller bearing of the ZF version is much better, but …..