swan 411 perkins 4.108 transmission
I need to know model transmission,I don,t know if is borg warner 71  or borg warner 72.

In my 411/004 the transmission is a BW Velvet Drive, Mod. AS7-71C, Gear ratio 1.91:1, PN 24073. The difference between the 71 and 72 models is a small increase in size. I wonder why you needed such data.

Cheers
Daniel

hello Rikys

The gear-ratio on the BorgWarner 71 and 72 is written on the small brass-plate beside the controllerarm.

On my old Borgvarner, and yes I have a Perkins 4.108 to, the plate was gone so I had a friend to measure the ratio. A pice of "tape" was placed on the pulley i front of the engine and in idle he measured the engine rev.

Then a pice of "tape" was placed on the Bullflex flange on the propellar shaft and gear set to fwd. the rev, on the shaft was measured and the result in my case was gear ratio 1: 1,51.

It is not a big deal to have these measurements made, You just have to find somone who has the "tachometer".

Kaj 40/08 Ophelia

Rikys,
I need to correct myself because the data I gave regarded my previous boat which was not a Swan S&S 411. I am not able to be so precise for my present boat because I cannot find any written note in my files. Just recalling few particulars I can affirm that the transmission has a 2.10:1 reduction unit. The additional reduction unit is easily recognizable. I insist that if you explain your problem I may help; I have a service manual for several models of the Velvet Drive transmission.

Regards
Daniele, Luna Menguante, 411/004

Dear all

The records say that the B-W reduction ratio for Swan 411 was 2.91 to 1

Kind regards

Lars

Thank you Lars, your input is always greatly appreciated. The 2.91:1 ratio for forward and reverse narrows the possibilities to the following model: AS15-71CR. The R stands for reverse rotation which for sure applies to my 411. In fact there is another possibility: AS15-72CR but this would imply a 3.20:1 ratio in reverse. As far as you know, do 411s have a different ratio for forward and reverse?

Daniel, 411/004

Daniel, you are perfectly right, the full notation is Velvet Drive AS15-71CR

There is nothing mentioned about a different ratio in reverse, I would assume it is the same.

I have a notation AS13-72CR for a bigger reduction gear, used on larger Swans with 6-cylinder Perkins engines, and suitable for powers in excess of 100 hp

Kind regards

Lars

thank you all

I wiil buy a overhaul master kit in usa and that is why I want  to know the model,I also think that is model 71 but was not sure because lost the identification plate.I have to do this because sometimes not gear forward.

repeat thank to answer my doubt

I would be very interested in knowing where you found the overhaul kit. Regarding the malfunction of your transmission: is it only in forward or also in reverse? The most obvious cause could be low oil pressure or high temperature due to several different causes included too-much or too-little oil, dirty oil screen, regulator valve stuck, regulator spring weight low, defective cooling. The mentioned checks can be performed without removing the transmission.
Regards
Daniel

daniel thanks for your interest

the problem is only sometimes going forward and is not always the oil is hot,I,m go to change oil and chekc pressure .the kit bought to internet in usa.I want to make this reparation myself,I,m a mechanic  by hobby in antiques cars.

regards ricardo

I am sure that you will able to fix it. In case you do not have them, I just found the Velvet Drive manuals on internet in the following pages: http://www.marinepartsexpress.com/bw_sch_fs.html

http://mysite.verizon.net/vze6mxo8/downloads/Velvet_Drive_Serv_Manual.pdf

Regards_____________________
Daniel

I am not familiar with your particular Swan model but on the 43 model the Perkins engine has to be moved approximately 6 inches forward in order to remove the Borg Warner transmission with reduction gear casing separated from the transmission casing.  The transmission casing alone weighs approximately 80 pounds so have plenty of helpers when you do the overhaul.

Good luck.

Hiro

This is correct also for the 411. You need to push forward the engine after freeing the aft coupling from the propeller shaft, all the tubings and the electrical wiring. It is not an easy job but one person can do it with a small manual chain hoist and a strong wood beam across the hatch.

I would like to ask Riky to make pictures, a lot of them, so that they may be posted in the Maintenance section of this site.

Regards
Daniel

hello

I know that the higt weiht the velvet drive (66kg) and little space to work,my idea is remove the table to move the engine forward or make engine complet out the boat to work more comfortably.before doing this job I will replace oil(atf) by sae 30,also want to measure the oil press in cold and hot.

regards ricardo