Need advice on my SD 50 saildrive

[impi]

Hi all ... Impi is up on the hard for new anti-foul and a general service which included new cones and changing seals and oil to the SD50 sail drive.

Horror of all horrors ... we got lifted and all seemed to be moving along splendidly ... the agents for Yanmar replaced the cones and just when the job was thought to be complete a few turns on the prop seemed great on Stbd side but not so on port side.

Port side makes a cluck, cluck, cluck noise when turned and even locks up if all end collar bolts are tightened up.

No bearings were removed and neither any shims.

The technician did install the cones having forgotten to place the gear in neutral, and when the throttle was pushed forward there was a noise which startled me and caused me to produce a 'glare' at the technician.

The guys decided to remove a shim from behind the bearing which loosened it up but too much ... in my opinion shims should be added to wearing parts not removed?

The SD50 leg was removed to facilitate the replacement of a leaking seal at the top of the SD50 between the engine and drive (top tip ... make sure you have the latest dip stick which is longer as the original dipstick resulted in over fill and blows the seal) ... another tip ... Yanmar agent here tells me it's not worth applying for warranty as Yanmar are not good at that anymore?

So, the leg has been removed and replaced several times and taken to their workshops and back ... still a tuk tuk noise and tightness ... the workshop manager wanted me to replace the lower shaft but I convinced him to rather remove and test by using the stbd shaft first which he did ... the problem was the same and fortunately my idea prevented a costly flight of a shaft that would have revealed no result.

The SD50 seems straight forward ... a vertical shaft and a horizontal shaft with bearings.

Can something have been done incorrectly to the cone replacement to cause this and does anyone have any idea as to where to look for the answers?

[Captain Bill]

It sounds to me like these guys are guessing at what they're doing rather than knowing what they are doing. I have SD40s and have had much experience in dealing with yanmar mechanics. What I've found is that there is not much quality control in the Yanmar support chain and you don't have to have much in the way of specific Yanmar knowledge to hang out a yanmar shingle. Secondly most yanmar mechanics actually deal with the innards of sail drives only rarely and really don't know much about them. I've found one pretty good shop in Cocoa Florida and when I asked them about replacing my cones they said that they've never had to replace the cones in a sail drive they just lapped them. Furthermore the biggest problem with failure and specifically serial failure was because the mechanics did not properly shim the parts after service. They stated that Yanmar sail drives are sensitive to shimming and that the the clearances had to be measured, not guessed at. I think I agree that it is unlikely that removing a shim from a worn part was the right thing to do, but unless they actually followed the proper shimming procedure there is no way to know. I have the SD40-SD50 service manual and there is a specific procedure for shimming the gears in the upper housing. My guess would be that it locks up when tighted because the gears are not meshing correctly There are also needle bearings in the upper housing, if one of those is out of position it might move while loose and lock up when tightened.

Good luck.

[perchance]

Shimming is used to set the preload on the tapered roller bearings, gear lash and pinion gear height. The clutch cone may have an up side similar to Volvo drives and may have been installed wrong way up. If the technician does not follow the specs in the manual I wouldn't guarantee your drive will last.

[impi]

I hope the Yanmar agents here in Tortola do this right ... at the end of the day! Gonna be a pain in the butt but I am going to insist they correct the problem. Came out of the water great apart from slippage on the clutch and now the problem seems 'monumental' at this stage of the game ... already an overcharge in hours on labour and can you believe they say an assistant to the technician is charged out at the same rate as the technician!

[Captain Bill]

Originally Posted by impi

I hope the Yanmar agents here in Tortola do this right ... at the end of the day! Gonna be a pain in the butt but I am going to insist they correct the problem. Came out of the water great apart from slippage on the clutch and now the problem seems 'monumental' at this stage of the game ... already an overcharge in hours on labour and can you believe they say an assistant to the technician is charged out at the same rate as the technician!

Unfortunately in the marine repair buisiness I often found that yards charge the same for appretices as they do for the master mechanic. It is also common for them to screw up and take much more time than needed, often on the customers dollar. Thats why in the automotive business in the US they use a flat rate manual. Change a clutch and it should take x hours of labor and they only charge for x hours of labor even if the tech takes ten times as long as the manual says.

[perchance]

The problem with flat rate is that if the tech goes over the time allotted they tend to slap it back together to get it out the door before they lose too much money and leave the customer in the lurch.

[Ex-Calif]

What a horrible story.

Gearboxes are rocket science and monkeys should not be poking around in them. Even though this is not a high speed gearbox (We have boxes that run 19k rpm) the tolerances are close and the stack ups are specific.

My first question to the mech is, "Do you have the overhaul manual."

If they don't they are crap shooting with your very expensive drive.

I am not saying a shop can't do this. But they definitely can't do it without the right tools and heaven forbid the right manual.

"Let's add/remove a shim and see what happens", is quite frankly a complete bullsh%t statement.

[sjobein]

Sorry to hear about your problem impi. Sadly yanmar's service manual are wrong when it comes to shimming, and has been so since the first manual came out in 2005 (M2215-04E140) to the last correction in 2008 (0BSDM-G00100).

I started with a total overhaul on my SD40's for 5 months ago, expected to use 2 weeks. Ended up with 2 months..
Yanmar refused that the manual is wrong, but after serving them the details with a teaspoon they finally admittet that the manual is way off (and i'm still waiting for the corrections). All of the yanmar technicians I've been in contact with say the same:

<<"Count the amount of shims you take out, put the same ones back in">>. That's not the way to go when I changed all the bearings in the saildrives (2 x 13). After calculating roughly the shim thickness, adding and removing shims (with 0,1mm thickness) was the way to go for me. I used paste on each gear so I could meassure where the teeth's are meeting before each correction. I had to assemble/disassemble each of the drives 4 times to make a perfect match.

A good place to start should be here:
"Port side makes a cluck, cluck, cluck noise when turned and even locks up if all end collar bolts are tightened up."

Which bolts do you refeer to as "collar bolts"?
The stud bolts from the pinion assembly or the top cover bolts?

Btw, dont blame the yanmar guy for removing shims. it makes perfectly sense several places in the drive.

[sjobein]

This is one (of many) missing links in the manual:
<Ch.4 Shim adjustments>
"4.2.2", "D" is originally 49mm.
"4.6.1", "M3" is originally 108.25mm.
"4.6.2", Calculation of shim thickness (S4) = (D + 60 - M3) --> S4 = 49mm + 60(constant) - 108,25mm
But wait, isn't "M3/108,25mm" supposed to fit inside "D/49mm"? The entire manual is a big oxymoron. And yes, for every meassurement that I found wrong, I checked if it could be missing digits, different meassurement units or different meassure points intended to be used. Example <Logic_Missing> but none of them made sense.

BTW. in the lower rigth side of <Ch.4 Shim adjustments>, you can see why removing shims (S4) after wear will bring the horisontal shaft in the lower gear house closer to the vertical shaft. NB. This can also be done with increasing the shim thickness on the top of the vertical shaft. And to my knowledge, the shimrings above the vertical shaft are the biggest bastards in the SD40/50 to make nasty sounds!

I believe there is o-rings (not seals) on the top of the leg, and these will not blow if you overfill with oil for 2 reasons:
1. Under your top cover it is a dump channel that (overfilled) oil will be let directly on the top of the pinion assembly.
2. The oil in your drive is travelling around due to heat convection (very low preassure)
But of course, this doesn't mean you should flood the entire drive

Please use the schema under (UGH) to clarify the nr of your collar bolts.
Lower gear house
Upper gear house

[perchance]

I am surprised that no gear lash spec is given unless I missed it as gear lash is an indicator of gear tooth engagement along with pinion gear height. Having these specs makes shimming a simple job of doing the lash readings and adjusting the shim stack to correct it.
I can only assume that the Japanese have their own way of doing things.
Moving the gear positions on well worn gears could be inviting failure as the worn area is usually lower than the original gear profile

[belizesailor]

Great case study for why my next boat won't have sail drives. I've had good luck with mine, but if you do have problems they are complicated, require specialized tools, skills, and proprietary parts which are crazy expensive. As in your case, even the "tech" is having a hard time getting it right.

[impi]

Thanks for all the comments guys ... we got scorched on this one I'm afraid to say!
We ended up with a bill in excess of $5500 where a brand new complete drive with gears and all costs $4900. Eventually we reached an arrangement which cost us $3500 and included new bearings all round, new seals etc. as well as a new lower drive casing which really was not the problem in the first instance but somewhere along the line someone cocked up and it cost us. None the less Impi is good to go and will be launched tomorrow without having compromised on quality in repairs which is what we need as we depart for Bahamas at the end of the month to be followed by the long passage down to Panama. Thanks for all the support ... Much appreciated

[jmpilot]

Hi there, I am also on a 440 over in PR getting ready to leave in a couple weeks for Cartagena then Panama and on. Spent a lot of time in Nanny. Sorry about all the problems, I worry about these SD's all the time. So far so good. If you need names of any workers (companies) over at Nanny let me know, I have dealt with most of them.
Perhaps we will see you in Panama
john and cyndi

[impi]

Originally Posted by jmpilot

Hi there, I am also on a 440 over in PR getting ready to leave in a couple weeks for Cartagena then Panama and on. Spent a lot of time in Nanny. Sorry about all the problems, I worry about these SD's all the time. So far so good. If you need names of any workers (companies) over at Nanny let me know, I have dealt with most of them.
Perhaps we will see you in Panama
john and cyndi

Hi John and Cyndi

Thanks for the message. We in fact were launched after spending almost a full 2 weeks in Tortola Yacht Services yard ... MAN!

Anyway, on the hook now at Deadman's Bay and I must say the sail drives are running nice and smooth. I hate that one has to sail with a constant concern about the sail drives and I hear through the 'grapevine' that there will soon be a replacement clutch pack instead that goes into it ... but this is 'hear say'.

Yeah ... will look out for you guys down at Panama ... actually meeting a few guys on the forum at sea now which is great. Had Stingo over for a pint or two before we were hauled and had a blast on board Impi.

Off to Bahamas at months end and then heading down ... please let us know when you are there ... also heading for Marquesas islands then?

Cheers for now.

[Panache5000]

I had engagement problems on the SD50 drive.
When selecting fwd, it would sometimes not engage immediately, and the throttle/gear selector had to be munipulated ("Blipped") a couple of times untill the drive engaged. Also with gear selector in fwd (Engine NOT running!) and manually turning the propeller, the propeller rotated about 1/2 revolution with a "spongy" feel before the drive engaged.
Checked cable adjustment on both Selector as well as gear & throttle lever assembly.
Also checked gear selector adjustment and shimming according to Yanmar manual.
Discovered that there was a lot of vertical up/down free-play on the upper vertical shaft, which was more than what the up/down rotation of the cone selector could accomodate to ensure engagement between the cone and the cup. The cone selector would dis-engage before the cone has mated sufficient with the cone cup to ensure positive drive. This partial engagement went unnoticed at low engine rpm/load, and the propeller would turn but not exert the full thrust.
The cone clutch and cup design eliminates slippage under load due to the helical spline on the vertical shaft and cone. The higher the load on the propeller, the tighter the grip between the cone and the cup. This however can only happen if there is good initial grip between the cone and the clutch upon selecting drive before the cone selector dis-engages.
The cone selector partially dis-engages (retracts) in the fully engaged position to prevent wear between the selector surfaces and the cone selector groove!

This is more than likely the original cause of the SD50 cone clutch slippage problems.
If the drive is allowed to operate with the cone in this (unnoticed partially or lightly engaged) situation, it WILL lead to cone wear. This is especially true in light motoring/motor sailing.

We fixed our engagement problem before it developed into a slippage situation, with the resulting cone clutch replacement and associated shimming problems.

The way we went about was to measure and replace the Trust Washers, Collar and Nut with the correct thickness Thrust washers to achieve the desired free play.
The Thrust Washers are prone to wear, and the problem may re-appear.

We are however in the process of developing an improved installation utilising Thrust Roller Bearings and reworked Collar and Nut to replace the Yanmar Thrust Washers etc.
Volvo uses the Thrust Bearings in their large capacity drives, and they do not have the problems that we experience with the Yanmar SD50.
NOTE; I had a VOLVO drive with Thrust Bearings in my previous boat, and NEVER had to re-adjust due to wear!