BW Velvet drive question

How do you fellow Velvet Drive owners check the fluid?
Reason I ask is that I just changed my fluid, the drain plug is plumbed with a hose to an electric pump makes it a simple process. Pretty sure it was totally empty because the pump was sucking air for a bit
I refilled with 2 qts per spec ran for a few minutes and checked the level it showed too high?
Not sure how the cooler plays into this equation but one would think it would need some more fluid to fill it up as well? Manual clearly warns NOT to over fill so I’m concerned.
Thanks
Tbtapper

Per the manual the oil level must be checked immediately after shutdown because oil in the cooler lines will run back and give a falsely high reading. I have verified myself that this does in fact happen. Took less than a minute after my first check immediately after shutdown for the level to show more than 1/2" higher on the dipstick.

What you *can* do is after setting the oil level using the correct method, allow the transmission to sit undisturbed for a while and then see what level the dipstick shows. Make a small mark on the dipstick at that spot and that will be the "at rest" oil level.

FWI - depending on exactly which BW transmission you have, you may be able to get most or not more than 1/2 the total oil out during a drain.

Ken

kchace said:

Per the manual the oil level must be checked immediately after shutdown because oil in the cooler lines will run back

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Yes, you need to be fast; ATF is thin. My direct drive VD took 2 qts, but my VD with reduction took 3 qts, including the oil cooler. I drained using vacuum and the fairly large dia. dipstick hole.

kchace said:

... What you *can* do is after setting the oil level using the correct method, allow the transmission to sit undisturbed for a while and then see what level the dipstick shows. Make a small mark on the dipstick at that spot and that will be the "at rest" oil level.
Ken

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That’s what we’ve done and are doing. I no longer have to check the level in a hot engine room.

So...............from a cold start, can I run the engine for a minute or so, in neutral, to get the fluid into the cooler then shut it down and check the oil?

Your oil cooler must be mounted so the in/out is pointing up; otherwise you will always get a false high reading no matter how quickly you check it after shutdown and you will always be low on oil when running.

We have the Borg Warner 10-17. The manual says 3 quarts. When we first bought Hobo, we’d shut her down and imediatley checked the fluid level. After 1/2 hour we checked again and noted the level. I did this for probably the first year and the marks never changed. When we do fluid changes, we take out 2.5 quarts and add 2.5 quarts. We had the transmission rebuilt last winter after 8400 hours just for pm and it looked great according to the rebuilder. I haven’t checked it hot or right after shut down in over 9 years.

Here’s a picture with out cooler alignment. It’s been pretty much the same for the last 10 years and at least 4 cooler changes.

Well, you are 1/2 right having your outlets horizontal.
You can't check your fluid fast enough to catch hot (or cold for that matter) fluid while it is still in the cooler and hoses so no wonder you don't see a difference. If you were to turn your cooler so the outlets were up, start it, top it, start it, check it; you would see a difference = 1/2 your cooler volume. If your outlets were down, you would see a difference = your cooler volume give or take a hose or two full. That you extract 2.5 and add 2.5 changes nothing IMHO
BTW: Often transmission coolers are mistakenly not counterflowing as they should be for maximum efficiency. Meaning that the hottest oil (from the top of a BW) should enter the end of the cooler with the coolest water.
BBTW: Beautiful engine room...

The manual says to check it right after engine shutdown.

When cold, the fluid level sits about 1/8 inch over the full mark on my boat. Now I just maintain it to that point when cold.

But u would be 1/2 wrong if this discussion takes a turn and contemplates oil changes.[emoji848]

Since I was restoring/renovating my boat and repowering from twin gasolines to one diesel engine, I had to read BW gearbox installation manual many times before going into the process and this is my experience from reading and work done:

1. Cooler can be angled from horizontal to vertical position, but if not horizontal, yes, as someone mentioned, it is important that oil input line to cooler is coming from one side, since I do not have manual with me now, I do not remember if it is upper or lower part of cooler, but I know that is important for purging air from cooler easier so that it really does cool efficiently (water is cooling better than trapped air)

2. Direction of oil and water inside cooler must be opposite, again for better efficiency of cooling.

3. About the oil measuring, the oil level is not the same immediately after engine shutdown and when sitting for longer period if the cooler and its lines are mounted higher than the gearbox since when stationary, oil drops from cooler and its lines to gearbox.

Therefore, since I was installer on my boat, I have chosen to mount the gearbox cooler below the gearbox in horizontal position and in easily reachable place in engine room. And really, I do have same oil level now, no matter if it is being immediately shutdown or not and I can use top level mark on dipstick always.

One more tip though, when newly installed, it will "consume" a bit of oil in about first 50-70 hours and it has to be regularly filled up to the top (it consumed amount shown with 2 little marks on dipstick below the top). After that it will stop and never change level. At first, I was worried, but it seems that since it was new, it needed some time to fill all the gaps inside gearbox, hoses and the cooler and I presume that it is the same reason why it is not possible to really empty all oil from gearbox when you need to change it (it is not possible to ideally take out the oil from all those gaps internally).

Nidza said:

Therefore, since I was installer on my boat, I have chosen to mount the gearbox cooler below the gearbox in horizontal position and in easily reachable place in engine room. And really, I do have same oil level now, no matter if it is being immediately shutdown or not and I can use top level mark on dipstick always.
Chrysler marine had an engine with the coolers mounted very low also. Certainly solves the level issue, but does keep raw water in the cooler at shutdown, and the low old oil contaminates a bit during oil changes

One more tip though, when newly installed, it will "consume" a bit of oil in about first 50-70 hours and it has to be regularly filled up to the top.

Now that is interesting. It's like the clutch plates somehow absorb fluid for a while. Maybe, I've done several clutch pack jobs on BW and never noticed it.

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b/r

diver dave said:

Chrysler marine had an engine with the coolers mounted very low also. Certainly solves the level issue, but does keep raw water in the cooler at shutdown, and the low old oil contaminates a bit during oil changes

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You are right about the oil change - that it would not be emptied, therefore I have put it in very accessible location so when I change gearbox oil, I also disconnect cooler and empty it, too, not only the gearbox.

Well you are right about the raw water, there is always some compromise, one more thing to be thought of. Thank you for this experienced notice. I presume that even if the cooler is mounted above the gearbox, all raw water from cooler is extracted only if it is not horizontally mounted, if it is, some water will always stay there.

Design aspects are always interesting and even when it seems perfect it can be done in better way. If only one could design and build so much boats, it is very interesting, fun and brain challenging. Hmm, note to myself for future boat - gearbox and cooler above waterline, cooler under the gearbox, cooler leveled to empty all the water after shutdown, of course the hull must also comply. Isn't it a challenge, that is why design is always fun. Then again, sailing is fun, too. Of all the compromises in life, the one related to time is the worst.

For sure. Boats are a floating compromise. Hopefully floating, that one is not negotiable[emoji108]