Dynastart repair or replacement

[seaesta]

I have just returned from a nice long cruise in my Westerley 25 which has an old Volvo MD1 complete with Dynastart. The engine runs great but the Dynastart is getting very low on cranking power /speed forcing me to assist it with the starting handle and also the red no-charge light stays on. Does anyone know of
- a more modern replacement
- a firm that can properly service them
- an old spare Dynastart and associated bits
A mate said they can be wombled from an invalid carriage (and I suppose owner would'nt be likely to catch me) but I canot find one round here!!
All help and advice greatfully recieved

 

[oldharry]

You need either a Bosch main outlet, (unless its one of the old and rare Lucas ones) or a good Auto Electrical specialist. The Auto people will quickly be able to tell you whether the unit is repairable. Bear in mind that quite commonly the fault is in the control box rather than the Dynastart unit itself. However if cranking speed is down, and the charge light is staying on, this would tend to suggest a problem in the unit itself. Have you checked the brushes? Bosch should be able to advise the minimum service length, and supply new.

Be ready for a hefty repair bill too - Dynastarts are expensive when they go wrong!

I would not have though raiding the local old peoples home would produce a Dynastart - motorised wheelchairs only have heavy DC electric motors. I suppoose the advice you were given reflects the fact that most DC motors can double as generators too - which is how the Dynastart does what it does. However they are generally even less efficient at generating than the Dynastart, which has its coils specially wound for this function.

 

[tr7v8]

No, not a wheelchair, an Invalid Carriage. As in small single seater 3 wheeled blue box made by AC and driven by disabled people and roundly condemned by people such as Graham Hill. These things had Villiers 9E 200cc 2 strokes and used Siba Dynastarts to start and charge the batteries. Most of them have been pensioned off by now, bl*&dy good thing as they are slow and unreliable.
They've been replaced by Motability where by people get converted proper cars instead.

Jim
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[halcyon]

If you need a new control box, it may be cheaper to buy a new boat, Bosch are talking £400 or more.

If the control box has gone, a good auto elec can adapt a dynamo reg to do the job, it then needs a relay fitting to control the starting..

Any Lucas or similar place can check out actual Dynostart for operation, then decide on action.

Our yacht has had a alternator fitted, running from flywheel, to replace Dynostart charging, which appears do have died years ago.

Brian

 

[charles_reed]

Dynastarts are inefficient and unreliable, luckily most designers have recognised the practical problems outweigh the theoretical elegance.

I'd suggest you do the following:
Take out the Dynastart.
Using Yellow Pages find all the independent auto-electricians in your area and start telephoning them.
Discard all those (usually 65%) who won't touch a dynastart with a bargepole.
Take the Dynastart along to the one who appears, over the telephone, to be the most knowlegeable (and hurry before he retires).
Get his advice of the cost/feasibility of re-build.
If you can get the Dynastart working, use the time productively to plan its replacement - usually the dc motor section can be used, it's the method of mounting and wiring the replacement alternator which bears the most thinking about.

 

[oldharry]

Inclined to agree with you Charles - its rare for the starter side to fail - although 'cranking speed is down' on this one. Poor contacts somewhere in the starter circuit may be the culprit. Its not usually difficult to arrange a separate mount and belt for an alternator.

 

[chippie]

I have one on top of a Sachs Wankel engine that was once in my boat.I thought the output of the dynamo part was straight DC which could be regulated by an automotive regulator such as was used when cars had generators instead of alternators. Am I wrong? I am not taking you to task, I really want to know.
I think fitting an alternator is probably the best solution for charging ,but what about starting? Is there an alternative for that?

 

[halcyon]

The Dynostart reg has a relay to operate as a starter.
To us a automotive one you need to fit a seperate relay, and minor mods may be required to the reg.
Any motor rewind people can repair the starter function as it's only a dc motor, and must be kept as it's mounting are unique.
Our yacht has had an alternator hung on the side of the engine bay, running on the flat of the flywheel. May look wrong, but it's ran like it for years, including two trans-atlantic runs.

Brian

 

[Mirelle]

Two ways to go

One is to retain the Dynastart as a starter motor (which is what many of us, including me, have done) and fit a separate alternator. My MD2 acquired a second pulley bolted to the outer end of the flywheel for the alternator.

The other is to scout around for dead MD1s (rare) and MD1Bs (more common) and shift the flywheel starter and alternator over.

I dont know if the parts are common to the MD1 and MD2 - quite possible. Does someone know?

The MD1 and MD2 (which I've got) will last at least 35 years but the uprated B version does not seem to do as well, so you can often pick up younger bits for an older engine!

 

[seaesta]

Re: Two ways to go

Wish you hand'nt said the MD1s last 35 years as mine was made in 1966!!!

More Seriously thanks to everyone who has contributed - any more anyone can add would also be appreciated

 

[barryg]

contact Norris of Isleworth near Richmond Surrey
They overhauled my dynastart some years ago it was like new when finished cost at that time about £120.00. they needed the regulator so make a note of the connections!

 

[onenyala]

Re: Two ways to go

Try Russel Auto Electrics in Watford Tel 01923 235601 They checked out my dynastart and my voltage regulator which was condememed by another auto electric dealer. Russels showed it working on a test bed coupled up with the reconditioned dynastart.
There was a n article in PBO which shows you how to replace some of the circuitry in the voltage regulator if you cant get a new one - I got a new regulator about 2 years ago for about £200 plus.
Stuart Jones

 

[scottie]

check with your volvo dealer
std replacement is now two units 1 regulator other relay / solenoid

 

[tr7v8]

Just found this on Ad Trade web site!

Boats For Sale


FOR SALE
Dynastart 12 volt, as new, £35, Gillingham (seadt-35-4229) Tel: (07092) 502106
Price: £35.00
Town: Gillingham
Postcode: ME87


Jim
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[GarryA]

Just obtained an old second-hand Siba DS3111 dynastart for my Petter PE2. (I think it is a DS3111. At least that is what I think it says on the Siba Plate riveted to the body. The plate is somewhat damaged - see image) It has all three terminals on the endplate, none on the body at all. The three terminals are, one stud and nut terminal about three eighths inch Dia. (which I assume is the starter side) and two small spade terminals, the standard size terminals you would expect to find on the back of 12V switches and instruments. Both terminals are the same size which I am assuming are the dynamo and field windings. As an aside, I would have expected the D+ terminal, if one of the terminals was the D+ that is, to be larger than the F terminal. Am I right in this assumption?

Before I strip the thing right down and start again, does anyone know the readings I should have on an AVO meter between each of the terminals and/or earth so I can determine which is which? i.e. which is DF and which is D+ for example.
At the moment, a 12V battery (- to earth and + to the gert* big terminal) produces a very weak spark but nothing else. No rotation of pulley). Spinning the pulley by hand, albeit very slow, produces nothing on an AVO meter from either of the small spade terminals, neither when connected to earth nor to each other.
Spinning by hand gives a free rotation that continues after you stop spinning it. A slight sound of brushes against commutator but no rough bearing sound though.

The seller claimed that it had been rewired and then stored. Rewired by whom, when, or why, he did not say.

Only one more thing to say....... HELP! PLEASE!

(*Translation( Gert = Sussex language for Very big))

 

[VicS]

You might get more responses if you started your own new thread instead of resurrecting and hijacking an 18 year old one.

Cannot answer your questions exactly but the diagrams from the Fairways Marine instructions for fitting the new type regulator and relay in place of the old type control box might help

 

[Dan Tribe]

No, not a wheelchair, an Invalid Carriage. As in small single seater 3 wheeled blue box made by AC and driven by disabled people and roundly condemned by people such as Graham Hill. These things had Villiers 9E 200cc 2 strokes and used Siba Dynastarts to start and charge the batteries. Most of them have been pensioned off by now, bl*&dy good thing as they are slow and unreliable.
They've been replaced by Motability where by people get converted proper cars instead.

Jim
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I had quite forgotten those things. Often seen parked around the perimeter at football matches.