Help!! What control cable do I need?? Volvo Penta MD1 RB Gear box

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paul1084

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Hi all,

I have an old MD1 with the RB type gear box (I think).... I use a 33c type control cable for the throttle which works fine. I am trying to attach a control cable for the gear shift (F/N/R). On top of the gearbox there is a short stainless steel horizontal bar with a threaded hole in the side at the end. pushing the bar forwards or backwards selects forward, neutral and reverse. I purchased a new 33c Control cable, fabricated a bracket at the right height/distance to mount the cable, attached the end to the bar... the threads match, and then mounted/connected the other end to a lever. Now the lever pushes/pulls the bar, but no where near enough to engage the forward or reverse gears.... its clear that I need more than 3" of travel on the control rod.... I think it could also do with being a bit stronger, as the gear lever is quite "clunky" and requires some force to push into gear.

Does anyone know what control cable I should be using for this engine? I assume the threaded hole in the gear lever is standard and has not been added as an addition, so it must have been designed with a control cable in mind. I have trawled the internet, and can find no conclusive information, the RB gear box seems to be quite rare, most appear to have a different setup altogether.

Please help!! any help will be much appreciated before I aimlessly plummet more money into this old engine (Which runs beautifully by the way :)

Thanks

Paul
 
Paul,

I have an MD1 and used a Morse 66c cable when I replaced the throttle control cable - I think I got it from T.Norris? - will look out the details tonight and come back to you

I don't have quite the same arrangement at the gear box as you, but I think the cables will be the same


Gavin
 
gavin400 said:
Paul,

I have an MD1 and used a Morse 66c cable when I replaced the throttle control cable - I think I got it from T.Norris? - will look out the details tonight and come back to you

I don't have quite the same arrangement at the gear box as you, but I think the cables will be the same


Gavin
Click to expand...

Thanks, 66c would be 6" of travel which sounds about right... although I've done a quick search, and can't find said product :ambivalence:
 
The two controls most used were the morse MJ? And teleflex D4
The morse unit used a 64C which is much beefier version of the 33C and uses clamps to secure and has 4" stroke
The teleflex unit used a UD617 which has a spiral core bulkhead securing (25mm hole in bracket) and has 6" stroke
Various other cables have been adapted to suit
Contact cabletec or Hindle controls who will help you
Any photos of gearbox with brackets and control will help I assume as you tried a 33c you do not have old cable
 
gavin400 said:
Paul,

I have an MD1 and used a Morse 66c cable when I replaced the throttle control cable - I think I got it from T.Norris? - will look out the details tonight and come back to you

I don't have quite the same arrangement at the gear box as you, but I think the cables will be the same


Gavin
Click to expand...

66c would not be fitted to throttle could be gear?
 
scottie said:
66c would not be fitted to throttle could be gear?
Click to expand...

I think 66c might be what I need... I don't think 4" stroke would do it so that's 64c out, but 6" should be enough. however it can't be the UD617 cable, as that has 5/16 UNF threaded ends, and the threaded hole on the lever is 3/16 UNF (same as 33c cable) However if I search for 66c cable on the internet, nothing comes up... does this cable even exist?

Unfortunately I don't have any decent photos.... wish I'd taken some, as I was at the boat yesterday. I won't get down to take any more until next weekend now, when I was hoping to go back armed with a solution.

No, unfortunately I don't have the original control cable.
 
The throw or travel of the cable is governed by the control unit NOT the type of cable. Many control units have a limited range of adjustment by moving the cable connector to a different hole in the arm. If your old control unit worked the throw is correct. By adding something to the length of the gearbox actuating arm you reduce the radial movement and as you found out fail to engage the gears.
 
cliff said:
The throw or travel of the cable is governed by the control unit NOT the type of cable. Many control units have a limited range of adjustment by moving the cable connector to a different hole in the arm. If your old control unit worked the throw is correct. By adding something to the length of the gearbox actuating arm you reduce the radial movement and as you found out fail to engage the gears.
Click to expand...

True, so as the actuating arm on the gearbox is fixed, and has not been altered... there is only one hole... (and I think if the hole was moved nearer the gearbox, then there would not be enough leverage, and to much force would be required to operate the lever) then I think I require a cable with 6" travel, and a thread size of 3/16 UNF... but I cannot find such a cable.... I have never used a control cable on this engine, I purchased the refurbished engine second hand, and have installed it myself... this is the final hurdle (not much fun pushing my hand into the dark engine bay looking for the lever to switch to reverse as I'm heading for the pontoon :S)
 
paul1084 said:
I like that idea... I may give it a go if I can't get a suitable cable... Do they still connect the ends of the rope to a control lever?
Click to expand...

apparently not

on the cat boats they just pulled the red for forward and blue for reverse - or is that the other wy round?

small blocks and dinghy halyard are the right size.

of course a liver is better though

but I confess I sailed the slug fro two seasons using this method
 
are you using a single lever control? Since 1976 "Eden" had one fitted on a velvet drive, Ahead ok, astern give 1/2hour notice in writing.
Found even at max movement the astern valve hole was only 1/4 open, so changed to a two lever Jobby from ASAP. all chromed, cured fault and has revolutionised control and boat handling as the revs no longer increase when engaging drive. might be the answer to your movement problem.
 
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paul1084 said:
Hi all,

I have an old MD1 with the RB type gear box (I think).... I use a 33c type control cable for the throttle which works fine. I am trying to attach a control cable for the gear shift (F/N/R). On top of the gearbox there is a short stainless steel horizontal bar with a threaded hole in the side at the end. pushing the bar forwards or backwards selects forward, neutral and reverse. I purchased a new 33c Control cable, fabricated a bracket at the right height/distance to mount the cable, attached the end to the bar... the threads match, and then mounted/connected the other end to a lever. Now the lever pushes/pulls the bar, but no where near enough to engage the forward or reverse gears.... its clear that I need more than 3" of travel on the control rod.... I think it could also do with being a bit stronger, as the gear lever is quite "clunky" and requires some force to push into gear.

Does anyone know what control cable I should be using for this engine? I assume the threaded hole in the gear lever is standard and has not been added as an addition, so it must have been designed with a control cable in mind. I have trawled the internet, and can find no conclusive information, the RB gear box seems to be quite rare, most appear to have a different setup altogether.

Please help!! any help will be much appreciated before I aimlessly plummet more money into this old engine (Which runs beautifully by the way :)

Thanks

Paul
Click to expand...


Is the gear linkage connected to the correct holes to give a longer stroke. The amount of stroke delivered is determined by the levers and the cable must have
the ability to cope with this. Is the lever on the gear box correct. Is there another hole nearer the operating shaft which would give the lever more throw?
 
Bilgediver said:
Is the gear linkage connected to the correct holes to give a longer stroke. The amount of stroke delivered is determined by the levers and the cable must have
the ability to cope with this. Is the lever on the gear box correct. Is there another hole nearer the operating shaft which would give the lever more throw?
Click to expand...

There is only one hole on the lever which is located towards the end.... as for the lever itself, it looks original... it fits onto a keyed shaft, and looks of similar age.... also has the same red paint at the shaft end, and the engine paint looks original.... all in all I think the lever and its threaded hole are standard, and therefore there must have been a standard control cable for this engine... approx. 6" travel, and 3/16 UNF thread....

looking on the internet, UD617 cable is the closest cable I have found... it seems heavy duty, and the travel is 6".... but the thread is 5/16 UNF which won't fit.
 
2014-03-01 13.43.43.jpg2014-05-21 19.14.26.jpg

Ok so I have found a couple of images taken earlier this year of the lever attached to the gearbox... the close up also shows the threaded hole in which the control cable should attach.. but please note in this photo the lever had been removed, and replaced upside down, so the hole was facing the wrong way. The lever is the stainless bar positioned towards the back of the engine on the left side (behind the old water intake which has been removed now)
 
scottie said:
66c would not be fitted to throttle could be gear?
Click to expand...

My two Morse cables, for throttle and gearchange are exactly the same. I bought two replacements when the throttle one broke coming out of Cobh in July 1992.
I fitted the other in Kos marina on 17/07/2014.

I think the combined gear/throttle control fixtures are the more significant item as that determines the amount of throw the cable transmits, additionally there is a plastic holder, an ABS collett and a spring clip which fit on my Vetus unit. The engine is almost irrelevant as each boatbuilder fitted the control of his choice. The ABS collett was left out of the gearchange when the boatyard fitted the new engine and it took me 2 years and 3 losses of forward/reverse to find out there was a missing ABS collett (about 8mmx5mm). Most of those ancillaries appear to be unobtainable, I had 5 colletts machined specially. Now I have lots of spares which I'll never need.
There will have been a mounting point on the engine, to fix the end of the cable, the shaft of which goes into your gear-selector lever.
 
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Mine had a bracket below the dynastart and bolted to the engine block, which clamped the outer cable sleeve. The inner cable continued to the change lever, a fork and eye connection with clevis pin. Travel was nowhere near 6" tho', more like 1 1/2" neutral to fwd, and the same neutral to reverse. I think my gear change lever was a good deal shorter than yours.
 
[
Sorry for the confusion - checked my invoices and it appears that it was a 33c that replaced the gear selector cable (it is larger than the throttle cable)

My set up sounds the same as Ardenfours - probably because my boat was an Arden 4!




QUOTE=gavin400;4889235]Paul,

I have an MD1 and used a Morse 66c cable when I replaced the throttle control cable - I think I got it from T.Norris? - will look out the
details tonight and come back to you

I don't have quite the same arrangement at the gear box as you, but I think the cables will be the same


Gavin[/QUOTE]
 
God save us from bodgers. That bar is way too long and is designed for manual operation. measure the angle it moves through forward to reverse, measure cable travel (eg 3"?) work out where along the bar the travel is, eg3" and that is where the cable should be attached. It would surprise you how much force the control levers can produce
 
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