ZF SD10 Sail Drive Replacement

[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.

[Ostinato]

Pictures of the installation.

[DotDun]

Thanks for the great information! Just rebuilt the lower unit on (2) Yanmar (assume ZF) SD20s. Will keep Twin Disc in mind if/when there is a next time.

[HarrisLoo]

Hi, i am searching for the parts catalog for ZF SD10. Can anyone spare a softcopy? My email = hlccmarine@gmail.com. Thanks

[FPNC]

[QUOTE=Ostinato;2454790] RE: The ZF Saildrive " 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."


Your new Seaprop 60 drive utilizes a separate stainless collar that fits around the shaft and contacts the lower lip seals. The inevitable wear from the lower seals is on this collar. Not the actual shaft. The collar is replaceable in lieu of replacing the entire shaft.

[thaisail]

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.

I have a SP60 leg that needs to be overhauled and I am looking for spare parts. I see from your report that your new SP60s were put in about 2 years ago. I am guessing by now you must have found a good supplier for spare parts. Please can you let me know who you have found to supply parts for your SP60's?

[Ostinato]

Sorry I’ve only had one problem with the drives which was an air vent at the top of the drive which leaked oil. Twin Disc replaced the vents with updated parts for no charge. So I have had no need to find a supplier.

How many hours on drives and what is the problem?

[thaisail]

That drive was operated for more than a year with out an anode and we have to change some major parts in the lower end.

Interesting that you have had issues with the vents. I have been working on some SP60s that have a similar problem. They are brand new and they are fitted in a catamaran and both are leaking oil from the vents. Can you explain more about how this problem was resolved?

[Ostinato]

There is a new replacement vent that is available that fixes the issue. A dealer in Genoa did the work under warranty.

He replaced the vent and also the entire top of the drive. When he did this he said they had problems with these too and had them in stock.

I read in Sailnet that you were headed for the UK soon. The dealer in Genoa spoke good English and should be able to help you get parts. I probably can find contact info if you want it.

[thaisail]

That would be great if you provide me some contact information for your dealer in Genoa. I was actually looking for a dealer in Italy because the factory is in Italy! If you have an email address, that would be best but any information will be helpful. If you are ever in Phuket, please contact me if you need anything from us. We are the Beta Marine distributor for 4 different countries in southeast Asia!

[thaisail]

I am not sure if you know about this but the problem you had with your earlier sail drive will not be the same for the lower shaft where the two seals ride. There is a clearance fit sleeve that the seals ride on and the one we are overhauling will need that sleeve to be replaced. To do this you have to cut the old sleeve off with a cutting disc and then heat up the new sleeve with a bearing heater and put the shaft in the freezer. You then quickly drop the hot new sleeve over the shaft and then hold it down on the shoulder of the shaft until it cools off and this way you will get a new surface for the seals to ride on. The part that I really need is the bearing holder that is attached with two bolts just in front of the anode. If I can get that part, the rest of the leg can be rebuilt with parts found locally in the shops in Bangkok.

[Ostinato]

Here is the info you requested.

[Ostinato]

Originally Posted by thaisail

I am not sure if you know about this but the problem you had with your earlier sail drive will not be the same for the lower shaft where the two seals ride. There is a clearance fit sleeve that the seals ride on and the one we are overhauling will need that sleeve to be replaced. To do this you have to cut the old sleeve off with a cutting disc and then heat up the new sleeve with a bearing heater and put the shaft in the freezer. You then quickly drop the hot new sleeve over the shaft and then hold it down on the shoulder of the shaft until it cools off and this way you will get a new surface for the seals to ride on. The part that I really need is the bearing holder that is attached with two bolts just in front of the anode. If I can get that part, the rest of the leg can be rebuilt with parts found locally in the shops in Bangkok.

Hope this finds you in good health. Do you know how frequently the seals and sleeve normally need to be replaced in terms of hours of usage? I now have over 800 hours on these drives. They are not showing any signs of water intrusion but if they were ZF drives with that many hours, I would be changing the seals as soon as I had the drives out of water (water intrusion or not) and I would be examining the shaft (sleeve for the SP60) for wear.

[sandymunro]

I have two SP 60’s with Vetus 3.29’s.....not really used often enough....

One gearshift became a bit more ‘Clunky’ on engagement than the other but reducing the engine idle speed has made it reasonably gentle and acceptable.

I have ‘Aussie’ Autostream Props set fairly fine pitch and the higher reduction gear option and all seems happy & smooth now with engine idle set at 700rpm which drops to 650rpm on engagement.

Experience otherwise all positive to date with the SP60 and Vetus 3.29’s but still interested to hear more feedback from others.

(Four Selva Saildrive Anodes available)

Sandy Portland UK

[Sea Joy]

Ostinato -- Can you provide more details about where to source the conversion kit for the Nanni diesel to be mated to the Twin Disc SP60 saildrives? I have searched the internet and called both Twin Disc and Nanni parts distributors here in the US but can't find anything. I need to get rid of my failing ZF SD10s as soon as possible and I think the Twin Disc saildrives are the perfect replacement given the information you provided in your post. Thank you!!!