Borg/Velvet questions

[mainstreetmark]

Hey guys -

Been a tough week for me and my new 43' sailboat. Was motoring up from Lauderdale to Saint Augustine when I lost, probably (and hopefully) the clutch on the thing. So, I'm stuck in Jupiter with no friendlies in the area, and am trying to get things moving forward again.

My limited access to the internet has revealed that the tranny, branded as a Borg-Warner, is actually now called a Velvet Drive? Is this true?

Additionally, I'm having trouble finding any particular identification, other than way up on the front, where there's a several digit serial number, which didn't yeild much on the google search.

Basically, how do I conclusively identify this tranny, so I can order a clutch rebuild kit, and who's a resonable source for such a kit?

Should I be getting a velvet drive kit or a "borg warner" kit?

(PS: yes, it would be nice if I had the manuals that came with the boat, or full time internet connection)

[hartley]

Mainstreetmark.....It is unfortunate that no one has replied to your queries,somewhere near you.I am a long way away,however all i can do is advise you in a very general sense .You appear to have a Borg Warner marine gear commonly known as a "velvet drive" ,the most common ones are 71c and 72c series ,they come in direct drive ,that is 1 to 1 ratio and various reduction ratios ,,the ones with reduction ratios ,have the reduction gears bolted to the end of the main housing ,these are a very popular marine gear ,and i would be very surprised if there was not someone in your vicinity that could supply the necessary parts .The good news is that these gears are relatively simple to rebuild (as opposed to some others).Some of the main problems that can be encounted are ....faulty input shaft seal,if that goes you lose oil therefore no drive ....faulty drive plate,sometimes called flex plate ,you will hear some strange noises .....and of course the clutch plates themselves ,usually from lack of oil .....hope you can solve your problem
cheers ...hartley

[mainstreetmark]

Thanks for the reply!

Yeah, I did a lot of googling around and discovered that I probably do have a 71C or a 72C (since it looks just like what I got, etc...). So, I ordered some parts and am having them delivered to my friendly local west marine (despite the prices, they are generally nice people in there)

Still dead in the water, but I can feel a pulse now.

[mainstreetmark]

Ok, so me and a local mechanic combined the parts from two borgs together with a new clutch pack.

Re-assembly was very tough, it took a lot of banging and wrestling to get the new pack into the clutch housing, but we finally did.

Six hours later, the transmission was installed back in the boat, but, it would only go forward. Neutral was still "forward", and reverse stalled the engine (a perkins diesel).

What did we screw up? Do you think it's just a case of "very tight" clutch plates that need to be worn down or something?

[Frosty]

[QUOTE=Ok, so me and a local mechanic combined the parts from two borgs together with a new clutch pack.

Re-assembly was very tough, it took a lot of banging and wrestling to get the new pack into the clutch housing, but we finally did.

And you ask --'Why doesnt it work"?

[mainstreetmark]

Yep, I sure did ask that.

The same number of plates went in, as came out, but obviously brand new ones aren't nearly as thin as the ones they replaced. We expected this, should we not have? Can I take one of the plates back out or something?!

[Frosty]

Clutches work by bieng in a relaxed state,-- bieing seperate and being able to spin loose from each other. When squeezed together by iether hydraulic pressure on pistons or cylinders they will bite and drive. A long time ago I used to build auto transmissions but not Borg Warner velvet drives. Cleanliness and and the utmost care in fitting of every part as it should was of the utmost importance or it would not work correctly.
It is not normal procedure to say Oh its a bit tight I will leave one out. The clutch package (if the correct one ) was made for that gearbox and should fit perfectly. If you leave 'one out' you will need to leave out 1 steel disc and 1 fibre plate,-- this could be more than the actuator can handle in the way of travel and might therefore be not able to completely compress the clutch pack.
I can not advise you to 'leave one out' to cure the problem,--banging and wrestling should not be part of assembly.

It is usuall in these circumstances to purchase a replacement gearbox that works and has a guarantee. I think you will find that you are now approaching that cost, and it still doesnt work.

It is likely that the parts you have wrestled with are no longer servicable.

[mainstreetmark]

Hmm... I bought a clutch rebuild kit for this transmission. All the included parts are identical to the ones I'm replacing, sans wear and discoloration from heat. I don't believe it's the wrong kit, and I also don't understand why they'd even sell them if they wouldn't work.

I just need to understand I guess. Perhaps the issue is that the steel discs had a bit of surface rust in spots (hooray crappy "new" parts) and that caused a 1/1000th of an inch interference.

We expected to be able to break it as soon as lubrication, or significant force (say, from a P-4108) hit it one time.

[Frosty]

Any rust on the clutch plates could have been cleaned off with 400 paper. I really dont mean to be doom and gloom but there are also hydraulic pressures involved in its operation. I have no idea why it doesnt work and I can not possible advise you further apart from locate a rebuild from a professional supplier.
If any one has anything to add to help mainstreetmark then please feel free to do so.

[alex fletcher]

velvet drive require particular ateintion to the stack hight if the clutch packs you can find rebuild info in mercruiser manuals did u change the out case of the pump if so the box may be indexed worng ie plate on the front of the box in the wrong position LH stand rotation the oil passage must be on portside lower
RH counter rotation the oil passage must be starboard top

[alex fletcher]

Borg-warner
theadrore rice blvd
hwe bedford ma 02745
ph
[508)9952616

[kapnD]

I am pretty much a mechanical klutz, and despite that have sucessfully rebuilt a velvet drive. Taking pictures and labeling parts as they are removed is the key to success. I also used gentle air pressure to move the clutches with the case open. This helped me understand how the darn thing works. As Alex mentioned, the most common mistake in re-assembly is the position of the pump. I was able to pre-test mine by coupling a 1/2" drill to the input shaft with a short rubber hose and hose clamps. This saved me a lot of time, as I had installed the pump incorrectly! Good luck, Don

[Black Swan]

The 71c and 72c are 2 of the most common trannys around. Borg Warner is the manufacturer, Velvet Drive is the product and 72c is the model. BW has gone through many changes of ownership, the most current "owner" of the Velvet Drive is Regal Benoit.

In order to do a "shade tree" overhaul, the first thing you need is a shop manual. May be availabvle online, but definitely from whatever dealer you got your parts from, it's just another "part".

Specifications change from time to time which require careful measurement of your components to determine if shimming or additional up-to-date parts are required. Feeler guages, a digital caliper, and the info as to where, when, and how to take the measurements are essential. Remember, these things have been around for about 50 years or more, and yes, there have been changes.

The second thing you need is an immaculately clean workspace. The Velvet drive doesn't tolerate contamination well. Both the forward and reverse actuator pistons must be dirt free in order to operate.

Third would be a good understanding of how the darn thing works, particularly the selector valve, pump, and bypass circuits. The condition and position of the rear shaft bushing and/or sealing rings, depending on the vintage of the unit, are critical.

Last is to understand that the whole thing should "slip" together, though at times it seems that it may need forceful persuasion, a bigger hammer is not the answer.

Good Luck!

[oktay Çemberci]

Originally Posted by mainstreetmark

Hey guys -

Been a tough week for me and my new 43' sailboat. Was motoring up from Lauderdale to Saint Augustine when I lost, probably (and hopefully) the clutch on the thing. So, I'm stuck in Jupiter with no friendlies in the area, and am trying to get things moving forward again.

My limited access to the internet has revealed that the tranny, branded as a Borg-Warner, is actually now called a Velvet Drive? Is this true?

Additionally, I'm having trouble finding any particular identification, other than way up on the front, where there's a several digit serial number, which didn't yeild much on the google search.

Basically, how do I conclusively identify this tranny, so I can order a clutch rebuild kit, and who's a resonable source for such a kit?
Should I be getting a velvet drive kit or a "borg warner" kit?

(PS: yes, it would be nice if I had the manuals that came with the boat, or full time internet connection)

Dear
Here is the site www.engine-cemberci.com
http://www.engine-cemberci.com/engin...VET/VELVET.HTM
you will find service manuals of Velvet Transmissions.
Oktay Çemberci
İstanbul/turkey