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Dashwood

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Ok so I spent 3 hours yesterday cracking off the gearbox and drive plate. First thing, a couple of pints of oil had accumulated in the bell housing, my hands look a right state as a result as the bottom two bolts had to be eased off as they are trapped behind the gearbox with oil dripping on to my hands. I had to chop away part of a bulkhead as the boat has been built around the engine. Thankfully all of the bolts associated came off easily. The drive plate is an RandD special it seems, having spoken to them they are very helpful I must say. I have sent pictures and they will get back to me with there assessment and price for a replacement. I have explored the PRM gearbox and from what I have been told by the guy at Calcutt it wont be up to the job and the Hurth  HBW2502R I have is apparently a better box than the run of the mill Hurth zf boxes. So assuming its only the drive plats at fault I will get a direct or more robust replacement and bolt back together.

 

Beta marine are near me so I may see if they will have a look at my box and check it over

 

 

update soon.

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So Beta also helpful but cant really assess the box any better than I can, lift and rotate check bearings on input and output shafts check for grinding etc, so it seems I will have to check it over myself and bolt it back together with the new drive plats and hope.

P9210121.JPG

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53 minutes ago, Dashwood said:

Ok so I spent 3 hours yesterday cracking off the gearbox and drive plate. First thing, a couple of pints of oil had accumulated in the bell housing, my hands look a right state as a result as the bottom two bolts had to be eased off as they are trapped behind the gearbox with oil dripping on to my hands. I had to chop away part of a bulkhead as the boat has been built around the engine. Thankfully all of the bolts associated came off easily. The drive plate is an RandD special it seems, having spoken to them they are very helpful I must say. I have sent pictures and they will get back to me with there assessment and price for a replacement. I have explored the PRM gearbox and from what I have been told by the guy at Calcutt it wont be up to the job and the Hurth  HBW2502R I have is apparently a better box than the run of the mill Hurth zf boxes. So assuming its only the drive plats at fault I will get a direct or more robust replacement and bolt back together.

 

Beta marine are near me so I may see if they will have a look at my box and check it over

 

 

update soon.

 

I'm surprised. I think your engine is 22 or maybe 30Hp so the PRM260 (280) should be fine, its very common on boats with slow revving engines and is reputed to be very reliable. Mine has now done 18,000 hours.

 

...................Dave

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Hi. With the alternator issue, I have a simple 12v system with a lucas alternator and my battery charging light flickers when the battery is fully charged after a few days cruising , it has since installed. The Hurth to PRM swap might not be straight forward. I looked into it. I have a Hurth HBW 250 and couldn't find a PRM equivalent with as much of a drop between the input and output shafts.  

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Hi Fitter Kieron thanks, I have now heard back from R&D and they think that my drive plate is ok but they are quoting for a replacement anyway. So Im exploring if its the gearbox which is sitting on my bench. Rotating it by hand all and going ahead and astern all seems ok so tomorrow I'm going to spin the output shaft with an electric drill and see if there are any untoward noises.I'l also drain the ATF and see if there are any metal elements in there. If its not either the gearbox or drive plate then I'm wondering if the prop' has been bent or damaged if I hit something underwater when I went astern and maybe catching on something or thrown out of balance, in which case its a dry docking job. With hindsight I should have run the engine up and tested the gearbox with the prop shaft disconnected, there would have been no load but I might perhaps given me some more clues. I maybe also should have opened the weed hatch and had a feel around the prop'. Ahh well, what else would I be doing?

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So... I have had the gearbox on my bench and set it up to be driven with an electric drill through the output shaft and all seems well. I have had a quote to for new clutch plates and a general overhaul so I will probably have this done any way as the box has been on there for 30 years, hopefully thats all it will be.

 

 I have asked a friend to lift my weed hatch and have a feel around as I cant get to the boat for a while, just to determine if this after all was the problem.

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Looks a simple one to get over the blade.

 

I've had one wind into a figure of 8 with both coils wound tight on the blade, that was a bugger to cut off.

 

If its a fabric cross ply, save it for making fender protectors, a lot easier than cutting steel radials.

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  • 1 month later...

Quite! any way as it turned out it was useful to crack off the gearbox, clean out the bell housing and fit a drain plug, greas all of the universal joints on the propshaft and of course remove the offending tyre. To be fair the vibration fooled a couple of the geezers at my mooring as it apperaed to be coming from the gearbox, but hey lesson learned and all back together and well greased!

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  • 8 months later...

So almost a year on from the gearbox debacle and after bloody lockdown I am now tackling the alternator. I have fitted the new unit and tried to establish the wiring. The main leads to the + and - sides of the battery bank are straight forward as is the lead to the ignition warning lamp (WL). However I am left with a few wires that were connected to the old unit in the following way that I do not have any idea yet where they ft he new unit if at all, See the attached photo. The old unit is an A133 Lucas that has been 'marinised'. A spade terminal has been fixed inside the casing to the point in the picture. and a wire was also attached to the S terminal that i cant fond any reference to anywhere on the threads. Any advise gratefully received as to what these terminals might be?

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P7260026.JPG

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If the spade terminal is the one down the square hole it is, as  told you by email, the terminal for a radio suppressor and it is normal on those alternators. it is fixed to the main positive diode plate.

 

Your photo also shows a red eye terminal on a brush connection, it is for an external alternator controller like a Kestrel or Adverc.

 

For others on  the forum. I found a reference that said the S terminal is the sensing terminal for battery sensing. This is likely to indicate the boat has or had a passive split charge diode, and that will require altering if the OP gets a machine sensed alternator.

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So almost a year on from the gearbox debacle and after bloody lockdown I am now tackling the alternator. I have fitted the new unit and tried to establish the wiring. The main leads to the + and - sides of the battery bank are straight forward as is the lead to the ignition warning lamp (WL). However I am left with a few wires that were connected to the old unit in the following way that I do not have any idea yet where they ft he new unit if at all, See the attached photo. The old unit is an A133 Lucas that has been 'marinised'. A spade terminal has been fixed inside the casing to the point in the picture. and a wire was also attached to the S terminal that i cant fond any reference to anywhere on the threads. Any advise gratefully received as to what these terminals might be?

thanks Tony

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8 hours ago, Dashwood said:

So almost a year on from the gearbox debacle and after bloody lockdown I am now tackling the alternator. I have fitted the new unit and tried to establish the wiring. The main leads to the + and - sides of the battery bank are straight forward as is the lead to the ignition warning lamp (WL). However I am left with a few wires that were connected to the old unit in the following way that I do not have any idea yet where they ft he new unit if at all, See the attached photo. The old unit is an A133 Lucas that has been 'marinised'. A spade terminal has been fixed inside the casing to the point in the picture. and a wire was also attached to the S terminal that i cant fond any reference to anywhere on the threads. Any advise gratefully received as to what these terminals might be?

thanks Tony

 

I am sure the spade terminal down the small hole is for a radio suppressor, so for most boats is redundant. Find an image of an A133  on the net and you will see a small rectangular box connected to it, that box is the suppressor.

 

Again, as I have told you in separate emails, the S terminal appears to be a battery sense terminal that is used to "hide" the volt drop caused by a passive split charge diode system. It is normally connected directly to the battery positive so the alternator knows the charging voltage at the battery rather than its output terminal that is the usual way.

 

Any other cables are either redundant or are using the alternator as a junction box. Usually its the B+ terminal that is used as a junction box.

 

So:

 

Thickish cable, often brown, to the B+

Thickish cable, often black to B-

Thin cable of unknown colour from warning lamp to W/L or D+ terminal

Thin cable from a battery positive point to the S terminal.

 

That should be enough to get the alternator charging.

 

My advice is to fit a higher output A127 (about 70 amps) and change the charge splitting to a VSR but that will require the B+ lead altering to feed the domestic bank  and a pair of heavy cables fitting from VSR to each battery bank positive. Throw the diode away.

 

 

 

 

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