ZF SD10 Sail Drive Replacement

[mjamesw]

I live in Australia and after a lot of searching I have just purchased and had delivered the twin disk saildrives and nanni parts from Misco Marine Italy. I was working with Michele. Look them up. Very helpful, always kept me informed and great service. Next step is installing the drives in the first week in October.

[Sea Joy]

mjamesw--that's very helpful, thank you! Best of luck with your upcoming project. Would love to see pictures !

[Plumpton]

Originally Posted by Ostinato

The purpose of this string is to provide information to individuals who are considering replacing ZF SD10 sail drives either with identical drives or swapping them for something else. If .......

I am thinking of replacing a Selva leg with a Sea-Prop 60 -> so how did your saildrive last?

[Ostinato]

The sail drives have been essentially trouble free except for one issue I am trying figure out. My pressure plates have been wearing out after about 750 hrs. This is actually an issue with how the sail drive and fly wheel cover mate I think. Both drives are doing it but I haven’t figured out how it could happening.

One good thing about SP60s is that if there is wear on the shaft where the output shaft (prop shaft) exits the housing you change out a sleeve and not the shaft. But so far I haven’t had to do it.

[Bill Gibbs]

I have 2 Nanni 3.1s (21hp) with ZF SD10 saildrives in my cat. In comparing saildrives for a possible future repower, I find differences in listed weights.
Yanmar SD 20 - 66 lbs
ZF SD10 - 88 lbs.
Twin Disc SP60 - 111 lbs.
seems like quite a difference. The yanmar is only used up to 30hp, while the other 2 are good up to 60-70hp. Do these weights seem right?

[Ostinato]

Not sure but one person was able to put the SP60s in place by himself without a hoist. I have personally not tried to lift them.

[FPNC]

Seaprop 60 weighs 77 lbs dry.

ZF SD10 88 lbs dry

Yanmar SD20 66 lbs dry

[Parallaxcat]

Originally Posted by Ostinato

The purpose of this string is to provide information to individuals who are considering replacing ZF SD10 sail drives either with identical drives or swapping them for something else. If others have done this or something similar, I hope they will also share their experiences. One of the things that made deciding to do this difficult was that there seemed to be very little information posted by people who had done it.

Background: I had two Nanni 3.100HE engines with SD10 sail drives. The engines and drives had approximately 2400 hours on them and I was detecting saltwater intrusion in the sail drive oil.

When the prop seals were last changed, I noticed the shafts had grooves in them where the seals rubbed on them. Repairing shafts seemed to be limited to coating the grooved areas with chrome or ceramic material. In some cases double lipped seals have been used as a temporary solution. However, getting the shafts repaired in a foreign country (Italy) where transportation and language were a barrier did not seem practical nor did anyone know how to do it.

Through a dealer I contacted ZF which only wanted to sell me a complete leg at about €4,000 each. I eventually got them to agree to sell the shafts and some related parts for about €2,000 per engine. In the process of questioning why I needed a 10mm nut and plastic cone for €100, ZF said via email they no longer were going to answer my questions. I was able to find a better price for the parts in Malta but the cost of hauling there was out of sight.

I then went to a boat show in Cannes solely to talk directly to a ZF representative. By luck I met with the after sales service manager for the entire company. I asked him what I should expect in maintenance cycles. He shared the following:

Replace prop shaft seals every 700 hours
Replace prop shafts every 1400 hours
Replace clutches every 1200 or more hours depending how they are used (i.e. if it was a charter boat you would be lucky to get 1200 hours)

He later confirmed this information via email. I concluded my drives were toast.

Alternatives: I considered doing a complete rebuild of the drives but I have never had any luck with this approach when dealing with transmissions and quickly abandoned it.

I then explored replacing the drives and found SD10 drives would cost approximately €3700 each plus shipping and VAT (19-22%) etc. During this process, I discovered that Nanni was no longer using ZF drives and had switched to Twin Disc SP60s. I also learned Beta engines were using the SP60s as well as a Spanish engine company and that Nanni made a kit for facilitating the conversion. The SP60 drives cost about €2,400 each plus shipping and VAT.

However an engineer from a Nanni dealer told me that it was a straight forward job and only required a few new holes to be drilled and tapped in the embedded metal ring that holds the drives down on the engine base fiberglassed to the boat. This created a major dilemma. Purchase new SD10 drives and do a plug and play replacement or get involved with modifying the boat to accept SP60 drives and expect a much larger labor bill.

After seeing a disassembled SP60 it appeared to be bettered engineered with superior water seals and I later came to realize a much heftier dampening plate. Twin Disc also makes the complete parts list and service manual for the drive available on line; information not made public for the SD10.

Decision: I ultimately decided to replace the existing SD10 drives with SP60s. It turned out the holes lined up perfectly and no drilling or tapping was necessary. The information I had been given was wrong. It took only 11 hours of time to do the job versus the 40 hours I had budgeted.

The two brands of drives do sit differently on the engine base. With the SP60s the engine moves forward about 0.5” (12mm) and down about 0.75” (18mm). This is part of what the kit was designed to help achieve.

The installation had one complication. The Nanni kit did not anticipate a factory installed Balmar alternator option on both engines. This was accommodated by modifying an engine mount and a weight (from the kit) which is attached to the side of the engine.

One other point is to be sure the shift linkages are correctly adjusted for the SP60s. They shift differently than the SD10s and the linkages need to be set correctly to be sure forward and reverse are fully engaged.

The ratios on the two drives are also different. The SD10s are 2.52 and the SP60s are 2.38 meaning the SP60s spin the prop at a slightly higher speed for the same engine rpm. In some cases this may mean re-propping. In my case, it did not.

When the SD10s were pulled I discovered they were also leaking transmission oil into the bell housing. However only time will tell if the SP60s have a longer life than the SD10s.

If anyone wants to see my spreadsheets comparing costs and the sources I contacted. please pm me.

Hi I have sd 10s and they are indeed inferior. A few tricks.. Stainless shims under the seals can move the seal set so that the seal lips no longer ride in the grooves . Btw recoating the shafts is perfectly acceptable and can make the surface better more wear resistant than the original.

Pump as much oil out of the transmission as you can through the dipstick and then refill the case with diesel fuel, then work the transmission through 50 to 100 shift cycles with the engine running . This can clean up the gunk on the cones and return them to service.

Afterwards again pump as much fluid as you can out of the transmission and refill with transmission fluid. You can do this twice if your concerned about the remaining diesel mix. Of course if the boat is pulled you can change the fluid completely but I’m not sure but what a bit of diesel left in the mix may help

These tricks have cured slipping and poor shifting transmission and the seal trick is an old standard and can be used on practically any seal set

[gruffa]

Parallax Cat, thanks for your comment.
Which trick did you mean for the shaft? Sleeve or coating?

How thin are the sleeves and where are you likely to obtain them? ( I'm in Australia)
How is the coating done?

James

[skipperpete]

Hi Gruffa, the wear sleeves are called “Speedi sleeves” and almost all Australian bearing supply outlets have em ( Blackwoods, BSC), because they are very thin they are quite tricky to install on a saildrive propshaft, you need a length of pipe to extend over the spline so you can whack the sleeve into place with a hammer and for a first timer it might be easier to take the shafts to a precision engineer and get them fitted at his machine shop. Maybe The previous post was referring to the trick of slightly adjusting the seal position in the housing to move the lip off the worn groove.

[Iceblue]

Hi, Does anyone know where we can get the oil seals for the SD10 in US? Thanks

[Bill Gibbs]

I bought some from
Mila Baran

RDI MARINE * RDI SERVICE * RDI ENERGY
2225 W.Commodore Way
Seattle, WA
Tel: (206) 286-1230
Fax (206) 286-0992
parts@manengines.com

Back in 2016.

[FPNC]

Transmission Marine in Ft. Lauderdale.

Most ZF oil seals are standard metric seals and can be purchased generically. If the seals are any color but black , order Viton(R) seals. The size of the seal is normally printed on it in millimeters.

[Iceblue]

Thank you to both of you.

[gruffa]

It's worth trying to obtain some generic seals. At least in Australia.
My replacement set from the Nanni/ZF supplier were about $300 !
I took them to a seal place before I installed them and was able to obtain identical seals for a quarter of the price!
Similar with the o rings too.

Unfortunately the seals are on the boat in another State so I can't tell you the specs. I won't be back there for a few months.