Gearboxes, Help Please

[PeterCharleston]

Hi All, your experiences with Gearboxes please, Borg Warner, PRM, ZF, ?? any disasters ? kit to avoid ? mistakes/tricks to apply ? Paul gave me some fab tips to have sensors to avoid his traumatic experience, as you can guess, i don't have a clue, Charleston needs gearboxes , Sean Brackstone at Marine Enterprises, has found some Perkins M265Ti engines for me, but gearboxes are evading my clutches, there are number of options, the best thus far is Lancing marine from Mr Bellamy, but new at lots of thousands !! many thanks in advance.

[Folly Reach]

Borg Warner getting a bit long in the tooth and you will need a reduction box. Very heavy.
Try and go down the road of handed boxes and propellors. Yes its gonna cost but I think it will be money well spent.
Ben is going through this angst at the moment I believe with his Bulldog.

[fushion julz]

I have a Borg Warner Velvet Drive in Hermes....

Last year, after only a few months of ownership, the 'box pee'd out all it's fluid and needed a rebuild/replacement.

I decided to replace like with like...partly as it was the easiest and partly the cheapest route. The original 'box was removed and taken to Lancing Marine. However, their list of parts plus labour and, effectively, no warranty was more expensive than a fully reconditioned unit with a 12mth warranty from Mermaid Marine.

As units go, they seem to be pretty robust and the later versions have some improvements to stop (as in my case) the seals popping out!
I concur, though...Heavy and awkward to install in-situ!

I have since discovered that a full rebuild kit with clutch packs, plates and gaskets along with a new pump costs around £250 and the task (as shown in the workshop manual) seems very simple.
The old unit is now in bits on my bench awaiting weather more conducive to spending a few hours fiddling in the garage!

[Folly Reach]

Half as heavy again with a reduction box tacked on the back. Being a Swordsman it will need a reduction as the set up swings a much bigger pair of propellers.

[IanW]

the 'box pee'd out all it's fluid and needed a rebuild/replacement

May be an opportunity for all BW owners to benefit !!
Have you discovered yet why the seal failed causing such a disaster ?
If it is obvious I would be interested in your findings and attributing factors, if any ?
Years ago a reverse clutch failed and from memory A R Peachment Ltd Brundal effected the repair. However, I also remember at the time being warned that there were few repairers with a setting jig for satisfactory results. Not paying it didn't worry me, so there was no need to check out the claim.

[Ben]

As Ian says the Velvetdrives are getting old, as are all parts of Fairies!

I've not got any real knowledge, club member Geoff Allchorn runs a transmission company and he can rebuild the Velvetdrive.

My Bulldog has PRM, I had to read about them, they can run full power both ahead and astern at exactly the same ratio, which is nice for handed props, they also have a mechanical lock to get you home in case of clutch pack failure. I spent a lot of time reading about the PRM boxes as mine need repair or replacement, you might find the PRM 750C works in a Swordsman. Careful research needed!

ZF do a range, but the number scheme defeats me!

[Phil62]

When I was debating about the way forward, I bought 2x BW 1.5:1 thinking I would be buying used Sabres or similar, so when I bought the new 220 FPTs I was still going to use them.
Nope!
A very learned person on here who had worked for Cummins development on these NEF family engines explained that they were torque monsters and would rip the old BW's to bits, so I started looking for ZFs, but couldn't find any 1.5s at a sensible price.
I then found a pair of NOS 1.2:1 ZF63 (down angle) at a good price so bought them, I also found a pair of new 4 blade props 18" dia which I had re-pitched to 17" having played with numerous prop calculators and even created an excel spreadsheet with a few formulas in to try and decide which pitch was best.
The result was a setup that leaps out of the water straight up to max RPM at about 24/25 knots, and cruises lovely at about 20kts, but you can feel she is well underpropped so either a new pair of props or a re-pitch is in order (tbh I fancy slight larger ones)

I'd guess a pair of newer style Perkins 265's might also be too torquey for BW's but others may know better.
P

[PeterCharleston]

Hi, lots of superb info, the Fisherman in our area are not too keen on the Borg Warner, they seem to vaguely favour PRM's, go into a cold spasm and reach for their wallets if ZF's are mentioned ! also quite interesting the amount of largish fishing boats with twin outboards , i guess they may not be commercial. The down angle and contra rotating is very appealing, has anyone had issues with gearbox to shaft alignment, we've replaced a lot of timber , does not seem much of a gap from the bottom of the shaft coupling to the hull. also where do we go to service/replace the AVB bearing and the rubber gaiter ?

[Folly Reach]

Peter. AVB stern glands are easy.
Each gland assembly will have two seals. One in the engine bay side and one in the stern tube side exposed to seawater.
Prize out the seals and give them a wipe. From memory there will on the seal be six numbers arranged thus.

72 09 42

Please note this is merely an example of numbers. It's not the sort code for my Swiss bank account... Or indeed the size of your particular seals.

The 72 is the outside diameter.
The 09 is the depth of the seal (thickness)
The 42 is the inside diameter.

You can source the seals either on the Internet or if shopping local try a bearing supplier. In Poole for example there used to be a company called Ashley Bearing Co.

Specify that the spring inside is stainless steel (I think they usually are)
Having given the whole assembly a clean up reassemble. The seals should be an interference fit in the body and can be carefully pushed in with a man sized vice if you don't have access to a press.

In terms of the rubber between the gland and the stern tube this could set up a debate.
The last one I did I used a silicon hose with a bellows built into it for help with vibration. My learned friend and former Commodore Ben Curtis didn't think it was man enough and suggested some heavy hose available from I think Portmere rubber in Southampton. At the time the surveyor was happy with the silicon as it was amply reinforced with winding in the lay up of the silicon. The silicon hoses are widely available on the Internet just Google silicon car hoses.

For cooling to the jacket I had hoses in and out made up by my local hydraulic hose man. Much neater than plastic or rubber with jubilee clips.

You will need new clamps or jubilee clips to secure the rubber to the gland and stern tube.

Refit with lots of fresh grease and connect to a remote greaser for ease of routine topping up of grease. Don't overgrease it though..

[fushion julz]

the 'box pee'd out all it's fluid and needed a rebuild/replacement

May be an opportunity for all BW owners to benefit !!
Have you discovered yet why the seal failed causing such a disaster ?
If it is obvious I would be interested in your findings and attributing factors, if any ?
Years ago a reverse clutch failed and from memory A R Peachment Ltd Brundal effected the repair. However, I also remember at the time being warned that there were few repairers with a setting jig for satisfactory results. Not paying it didn't worry me, so there was no need to check out the claim.

As with all thing mechanical, depending on who you ask (or believe) there are several explanations:

Either: the clutches were badly worn causing an increase in pump pressure that forced the seal out
Or:
The lack of a lip on the old style of input housing was a point of impending failure/weakness
Or:
The input shaft was badly worn enough to allow fluid to seep out and the fluid pressure forced the seal out.

Having inspected the parts, I suspect the last one is the most likely as the input shaft is quite noticeably pitted.

I have a Borg Warner factory service manual for the 72C and there are no special jigs or equipment required, past what any reasonable mechanically minded person would probably have already.

All the (service) parts would appear to be available...clutch plates/packs, seals, speedy sleeves, gaskets, etc and are not terribly expensive.
The only real downside to this transmission is the weight. Certainly removing/installing in a Huntress whilst it is still afloat gives minimal clearances as the shaft is prevented from sliding too far back by the rudder and the gland!

It is possible, but doing it out of the water would be a lot easier!

[tjsb]

It is good that the prop and shaft hit the rudder as this stops any flange failure resulting in the shaft falling our of the back leaving a big hole.

As to gearboxes, if money was no object, I would go for down angle to flatten the angle of the engines. This should also mean lower height. Of course any change may require shifting engine mounts which appears less than simple in order to ge excellent alignment.

Toby

[fushion julz]

I'm guessing that if you change the angle of the engine installation then some adjustment to the oil pan and/or pickup will be needed.
Beats me why no one uses a dry-sump system on boat engines...Would appear to solve many issues...Height of the install, ease of oil change and a guaranteed oil flow in all sea states.
I was wondering how the oil pickups behave in a marginal sea state...Dread to think of oil starvation out at sea if the going gets rough!

[Ben]

Portmere rubber in Southampton to sell stern gland hose, its laid up with fabric wrapped radially, to give it torsional strength, its what AVB used.

A long time back I used the ASAP Supplies 'Driveforce' brand of overhaul kit for a pair of Velvetdrive 1:1, all the gaskets, seals and clutch packs. I recall getting the pistons out of the clutch cylinders is a bit tricky. The boxes worked fine, no slip, no leaks, but one of them did turn the shaft very slowly when in neutral.

When I needed to do it again on another boat I used Geoff Allchorn http://www.autogearboxes.co.uk/marine.html

Regarding down angle boxes, I see the attraction, but, all those I have seen are drop centre too, which means while the engine maybe installed closer to level its also higher up. We don't have the luxury of know what AVB would say about that.

[tjsb]

Referring to engine alignment in this thread, I have got a way of doing laser alignment. It is suitable for out of the water alignment and BW72 gearboxes with 2 inch cutlass bearings. The cutlass bearing tool can be easily made up, if you have a different size. I will draft an article for FN, but if anyone needs to align engines with BW boxes before then, get in touch. T

[tjsb]

And I didn't need a crane.