Yanmar SD40 & SD50 "slipping" Saildrive Upgrade

[Captain Bill]

Originally Posted by Bruce Beard

So the new unit is a ZF?
They are bright people and I’d bet that they will be just fine.
It is kind of interesting that they had issues out of the gate actually. I’d have bet that they had the design down pat. Who’d have thought?
Very interesting!!!

I looked at the parts diagram for the SD60 and SD10 and can't see any difference. The guy I mentioned in the previous post said he had been trained on the defect 2 years before the SD60 had been released by Yanmar. One has to wonder if ZF didn't dump a bunch of known defective units on Yanmar because they didn't want to own the problem themselves. But then again I'm a bit of a cynic at times. I should also tell you I looked at replacing the Yanmars with Beta Marines and had an extensive talk with them about saildrives and maintenance issues. They used to offer the SD10 with their engines, but no longer. They moved to the Technodrive Twindisk SP60 as their offering.

[Bruce Beard]

Originally Posted by fortyninegroup

I have an SD-50 with ~3000 hours on it. 200 of those are mine.

It started slipping and I ended up pulling the clutch - a beast of a job, as the shims had been spun outside the clutch housing on the upper shim. I ended up using a puller to remove the assembly, it did not just lift out, the way it does in the video referenced earlier - I followed that process however ( and have the Yanmar manual). The shims were wrinkled, so I measured where I could and replaced the cones, thrust washer, and shims. The stamp for the offset to calculate the shim thickness that is supposed to be on the base of the shifter is just not visible. There are signs where someone working on it previously has scraped the shifter base.
Today we went out and above 2,000 RPMs I can still detect that the prop speed is not increasing with the increase in engine RPM at above 2,0000 RPM. I'm also getting an occasional shrill sound that sounds like slipping. The SD-50 is pretty good up to 2,000 RPM. Reverse is also good. Looking for any advice, as this is the most thoughtful and informative thread I've seen on this SD-50 slippage issue. Thanks in advance.

All I can offer is that when we toasted our first drive at 500 plus hours, there was a lot of visible wear in not just the cone but in the mating parts too.
I had intended to rebuild it and keep it as a spare but that made little sense as the price of parts was beginning to approach the cost of the new unit. I do not believe that simply replacing the cone alone would have been a good long term repair.
I was friendly with a Yanmar dealer who sold me a new drive at nearly his cost and I believe in 2006 that was in the range of $3700...?

After replacing the unit and switching to a good GL-4 lube, I watched that unit like a hawk. I still used reverse to stop the propeller from rotating and we made no other changes to our habits other than switching the oil.

After another 500 hours, per Yanmars maintenance schedule, I replaced the cone. This time and every time I looked in the following 10 years, the cone and its mating parts came out looking new. I remember even panicking once when I placed the removed cone next to the new one and almost got them confused!

My guess is that you have suffered more damage than you knew to the mating surfaces and that you need to consider more parts or a replacement unit.

[Bruce Beard]

Originally Posted by Captain Bill

I looked at the parts diagram for the SD60 and SD10 and can't see any difference. The guy I mentioned in the previous post said he had been trained on the defect 2 years before the SD60 had been released by Yanmar. One has to wonder if ZF didn't dump a bunch of known defective units on Yanmar because they didn't want to own the problem themselves. But then again I'm a bit of a cynic at times. I should also tell you I looked at replacing the Yanmars with Beta Marines and had an extensive talk with them about saildrives and maintenance issues. They used to offer the SD10 with their engines, but no longer. They moved to the Technodrive Twindisk SP60 as their offering.

Interesting...
I can’t imagine ZF doing something like that intentionally though.
I thought that the SD-60 was a ZF unit. It is actually made by Twin Disc?
As I read this thread I look at the ZF marine gear bolted to the back of the engine in our American Tug and wonder what surprises it may hold...
The thing is huge compared to that little sail drive!

[fortyninegroup]

Thank you Bruce... I will open her up this week and see if there are any obvious indications. If it's spun another shim, that would say to me that the wear tolerances have been exceeded.

[Captain Bill]

Originally Posted by Bruce Beard

Interesting...
I can’t imagine ZF doing something like that intentionally though.
I thought that the SD-60 was a ZF unit. It is actually made by Twin Disc?
As I read this thread I look at the ZF marine gear bolted to the back of the engine in our American Tug and wonder what surprises it may hold...
The thing is huge compared to that little sail drive!

The Yanmar SD60 is a ZF drive that is very close to if not Identical to the ZF SD10. The Beta Marine saildrive is now the Twin Disk SP60 and has been their offering for several years now. Beta formerly offered the ZF SD10 but changed to the Twin Disk because of service issues with the SD10. Hopefully you will have no terrible issues with your gear. ZF generally has a good reputation and perhaps this issue with the SD10/SD60 series was a one-off failure on their part. I'm told they made Volvo sail drives which have a better reputation than the SD40/50s from Yanmar. Unfortunately for cruisers I don't believe the Yanmar or ZF target market is for cruisers, but for day sailors where 100 hours a year is considered heavy use and 50 is more like normal.

I note that you have replaced the cone clutches every 500 hours even though they show no appreciable wear with the GL4 oil. In my old SD40 service manual I noted that the rated service life of several components was 1500 hours. The roller bearings are the ones I specifically remember. To me that says that Yanmar is happy if the thing goes 1500 hours without an overhaul. In the recreational market that would be 15 to 30 years, in the cruising world, not so long. I don't think this is terribly unusual for the recreational sailing market where the motor is used to get one out of and back into the harbor/slip. A friend had a shaft drive transmission go out several years ago and was told his transmission was a dollar an hour transmission designed to sell for $1500 and last 1500 hours. As I said this was a while ago. In another thread a member said he was told that the prop shaft of a ZF SD10 was designed to last 1400-1500 hours. A Yanmar mechanic and a Beta mechanic both told me that the design life of the damper between the engine and transmission was 1500 hours. The Yanmar mechanic told me because he was selling me a new one and the Beta guy because he was telling me how superior the new design they were selling was to the old spring type on the yanmars.

This 1500 hour number seems to pop up a lot and from different manufacturers. The only drive I can find for sailboats that claims it is for the commercial market is the Twin Disk SP60. They claim their target market is the charter industry and their service intervals are much longer. Do they actually last longer in real life? I have no idea.

Since Power boat transmissions are meant to be used continuously, if they are designed for the same 15 to 30 year service life, hopefully you should get many years of service in your tug. A Engineer friend of mine was told by one of his professors, an engineer is not paid to design something perfect, they are paid to design something good enough. I believe in the recreational sailboat market the consensus in the industry is that 1500 hours is good enough.

[Bruce Beard]

Originally Posted by Captain Bill

The Yanmar SD60 is a ZF drive that is very close to if not Identical to the ZF SD10. The Beta Marine saildrive is now the Twin Disk SP60 and has been their offering for several years now. Beta formerly offered the ZF SD10 but changed to the Twin Disk because of service issues with the SD10. Hopefully you will have no terrible issues with your gear. ZF generally has a good reputation and perhaps this issue with the SD10/SD60 series was a one-off failure on their part. I'm told they made Volvo sail drives which have a better reputation than the SD40/50s from Yanmar. Unfortunately for cruisers I don't believe the Yanmar or ZF target market is for cruisers, but for day sailors where 100 hours a year is considered heavy use and 50 is more like normal.

I note that you have replaced the cone clutches every 500 hours even though they show no appreciable wear with the GL4 oil. In my old SD40 service manual I noted that the rated service life of several components was 1500 hours. The roller bearings are the ones I specifically remember. To me that says that Yanmar is happy if the thing goes 1500 hours without an overhaul. In the recreational market that would be 15 to 30 years, in the cruising world, not so long. I don't think this is terribly unusual for the recreational sailing market where the motor is used to get one out of and back into the harbor/slip. A friend had a shaft drive transmission go out several years ago and was told his transmission was a dollar an hour transmission designed to sell for $1500 and last 1500 hours. As I said this was a while ago. In another thread a member said he was told that the prop shaft of a ZF SD10 was designed to last 1400-1500 hours. A Yanmar mechanic and a Beta mechanic both told me that the design life of the damper between the engine and transmission was 1500 hours. The Yanmar mechanic told me because he was selling me a new one and the Beta guy because he was telling me how superior the new design they were selling was to the old spring type on the yanmars.

This 1500 hour number seems to pop up a lot and from different manufacturers. The only drive I can find for sailboats that claims it is for the commercial market is the Twin Disk SP60. They claim their target market is the charter industry and their service intervals are much longer. Do they actually last longer in real life? I have no idea.

Since Power boat transmissions are meant to be used continuously, if they are designed for the same 15 to 30 year service life, hopefully you should get many years of service in your tug. A Engineer friend of mine was told by one of his professors, an engineer is not paid to design something perfect, they are paid to design something good enough. I believe in the recreational sailboat market the consensus in the industry is that 1500 hours is good enough.

I am sure you are correct.
I remember the really awful little Briggs and Stratton lawn mower engines produced in the 70’s that didn’t seem to last but a few seasons. I heard once that the design was intended to last something like 20 hours! It was a price point thing...

[ChrisseH]

Back to the SD50 gear lube issue.

Am wondering why Yanmar changed the SD50 gear lube specification in 2009? And when doing so, why did they not at the same time start to use sintered cones also in new SD50 units? Or maybe the latest units do have sintered cones? OK, I recognize that now there is also GL4 rated Quicksilver available, but the rating is no longer mentioned in the spec.


It seems unlikely that the specification change was done to avoid the clutch cone slipping problem. Maybe it was beacuse of fear that the gears in the lower gear house would wear too fast? But I have not noticed too many complaints about problems with the lower gears.


So maybe the gears will be wear a bit faster with GL4, but I replace the gear oil once a year (after typically 100 - 130 hours) and the wear is also dependent on the power outtake. In my case (with 3JH4E + SD50) I use the engine typically at 2200 - 2400rpm, which means that the power outtake is perhaps only some 25hp.

[Spruijt]

I read with interest the solution offered by Brett/ Gideon. I am about to buy 2 sets of this kit for my Lagoon 400. I cruise a few months per year and easily make 200 hrs on the engines.
No I would like to know what the experience is of users of this kit with thrust bearings. I understood that 125 have been sold, that appears enough for some evaluation to assess the efficacy.
So can experienced users please inform us whether they had any slipping or not using this kit? Thanks Berry Spruijt

[kcj]

I have a cat with 4500hrs on each side.sd40s Last season I put one of Gideon 's kits in. I have nothing but good things to say about his kit and his support. It results in a much more positive engagement of the clutch.

Shortly thereafter I did a cone lapping on the other side. (lapped due to lack of access to parts at time, $$$ and curiosity....)

There has been no slipping on either side in the 200 hours since. I will report on which side slips first.. Hopefully neither [emoji16].

Btw, while Gideons kit takes longer to install due to some fitting and dremeling, the major pain was removing the top nut of the cone, which you have to do to lapp them as well. It's offensive that yanmar calls lapping routine maintenance as, imo, that nut was not designed to be removed...

[Spruijt]

Thanks appears positive, hope more will follow.

[foboss]

Hey. I have installed the ZF SD10 and the propeller of my left hand. So far, only 20 hours. Sticker 15w40.
Can I use the propeller of the right hand?
Really analog SD60?

[Panache5000]

The latest improvement to the existing Upgrade KIt is the replacement of the Lower Collar and split C Clips with a TAPERLOCK System to prevent rotation/wear between the Lower Collar, C Clips and Groove in the lower section of the Centre Shaft.
The split Taperlock Ring fits into the internal taper on the new Lower Collar, and "grips" the Grooved section of the Centre Shaft. The grip (Pinch action caused by the combined tapers) increases as the load increases, preventing rotation between these parts, and transferring the rotation to theTHRUST BEARING.
Both the Lower and Upper THRUST BEARINGS are part of the Upgrade Kit, and replace the standard Yanmar Copper Thrust Washers!


Contact me on; saildrives@yahoo.com if you need more info on the Upgrade Kit.

[ChrisseH]

Just a short notice about the experience I have using Mobilube GX 80W-90 (GL-4) in my SD50. Changed gear oil last week and the colour of the old Mobilube was no longer (as last fall) greenish - The one year old gear lube looked like new despite that I this summer got 182 more engine hours. Since lapping my cone in May 2017 I have now obtained 485 engine hours and there is still absolutely no sign of slipping. As I am not doing any long distance cruising I intend to use the old cone as long as I can without opening the clutch assy. It will be interesting to see how long the the clutch will work just by avoiding using GL-5 type of gear oil...

[AliaVita]

Originally Posted by ChrisseH

Just a short notice about the experience I have using Mobilube GX 80W-90 (GL-4) in my SD50. Changed gear oil last week and the colour of the old Mobilube was no longer (as last fall) greenish - The one year old gear lube looked like new despite that I this summer got 182 more engine hours. Since lapping my cone in May 2017 I have now obtained 485 engine hours and there is still absolutely no sign of slipping. As I am not doing any long distance cruising I intend to use the old cone as long as I can without opening the clutch assy. It will be interesting to see how long the the clutch will work just by avoiding using GL-5 type of gear oil...

Thanks for the update. Quick question if I may. What compound/paste did you use to lap the cones?

Thanks in advance

Rob

[ChrisseH]

I used lapping compound with the grain size 325. Purchased a kit for valve lapping that contained compounds for two different grain sizes and used the size that was closest to the grain size mentioned in the video about the SD50 cone lapping (280 GRIT).
It is important that the lapping compound only is used on the cone surfaces. If you get lapping compound in the bearings they will rapidly wear out. After the lapping all lapping compound must be carefully removed also from the cone surfaces. Watch the video a few times before you start to work on your cutch.