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I've had a range of boats of various configurations over the last forty years - but this is my first experience with V-drives. The Velvet drives in the Riva Bertram 25 are unlike any I have seen, and I cannot find manuals or references. They are supposedly 71C's, but don't match Velvet drive service manuals. Even my usually quite competent wharf guys hadn't seen this variety before.
Perhaps some of you gurus would be kind enough to take me to school?





The configuration is unlike anything else I have seen. From the raw water intake, the hoses first go all the way to the front of the V-drive. The water passes through what looks like a cooler, before passing rearwards alongside the gearbox through a regular hydraulic gear oil cooler. There are two dipsticks on the gear box. One on the main body (the yellow round knob; regular gear oil, I assume), and one additional on this front assembly. Is there an separate oil reservoir for the V-secion of the drive? Looking at the dipstick it does not look like hydraulic oil, so I guess this is regular gear lube. Anyone know the oil spec I should be using here?

So my questions in short:

1: Am I correct in my interpretation that there are two oil reservoirs (one hydraulic for the main transfer and one gear lube for the V-section) and each circuit has a separate water cooler?
2: The gear boxes appear to be running well, but I am unfamiliar with symptoms to watch out for. What typically fails - if anything? With all the oil cooling going on, I assume overheating is a potential issue, but how do I monitor it?
3: How often do you change the hydraulic oil?
4: Anyone know the oil spec I should be using on the front reservoir?

Thanks for your patience with a V-drive rookie!
And, yes, the shaft seals are due for a clean-up. Shafts are going out for tidying and repacking as we speak.

I do not know...only taking a guess from what I see before someone with knowledge answers your question.

My guess is that unit with yellow cap is your transmission...looks like one anyway...that unit would get transmission fluid as there would be clutches in there.
Unit behind looks like a gear case to provide v-drive and angle...I'd expect to see gear lubricant in that unit.

Anytime you have surfaces rubbing...clutches, gears, bearings, seals the friction creates heat...so coolers are a good idea...two fluids...two coolers.

As to intervals between changes...I'd say now as it most likely hasne't been done in awhile and I'm going to say yearly thereafter to which I'd imagine few people do. What to look for...burnt and foul smelling fluid...metal particles would be a sign of a problem rearing its head.

One thing I know for certain...those drives make aligning and shaft changes a royal pain in the bumm...but as you already have yours out...I'd imagine you already know that.

Carl

Have you looked at this?

http://www.marinemechanic.com/books/man ... Manual.pdf

http://marinetransmissions.info/VelvetDrive.html

Mark,

Thanks, yes I did. That was the manual which confused me. If you compare to my pictures, you'll see that the V-section of my drive is quite different - even if the plate says 71C. The V-drive tranny in the manual only has one oil fill, and no internal cooler. I am wondering if it's only the base transmission which is Velvet drive, and the V-gear is something different altogether which they slapped onto the transmission. Anyone who knows?

Carl,

Yep. I can confirm with authority that I now know a lot more about contortionism than just a few week ago...

Front half is a Borg Warner, v-drive looks to be a thermo electron, aka crusader.

The US 25 v-drives used BW/Walters.

In my 25 I have Paragon drives.

Joseph Fikentscher wrote:In my 25 I have Paragon drives.

OK. So the Riva Bertram is not using the same setup as regular B25. Oh well..

Joseph,
The only other paragon setup I saw in a 25 was a paragon gear with a walther vdrive.
You must have a real early model, whats the year.

1968