| Author |
Message |
    
thomas johnson
Member
Username: capt_tom
Post Number: 4
Registered: 04-2006
| | Posted on Monday, March 31, 2008 - 12:32 pm: | 
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I am looking for a source for a new tach. cable complete and water pump impeller kit. Also want info on converting to 12 v neg. grd. and last is there a resonable replacement for the old 3 brush gen. like a way to attach a alternator.
Tom |
miro forest
Senior Member
Username: miro
Post Number: 318
Registered: 11-2001
| | Posted on Monday, March 31, 2008 - 05:17 pm: |
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I was able to mount a small Honda car Alternator into the space for a 3 brush generator in a 6 cylinder Buchanan. These engines are mid-1950's based on a Hercules block - Chris Craft used them too.
It is more of a mechanical adapation problem than an electrical problem.
The big thing was to machine a shaft extension for the Honda alternator. It was bit tricky and I ended making 2 of them - one to learn and the second for the good one ( ain't that always the case)
Although not marinized, the alternator has been giving good service for 12 years and keeps the battery well charged.
While it IS possible to convert the 3 brush 6 V to 12V the outputs are usually not worth the effort and cost. Better approach is to mount the alternator.
Most 1950's era engine systems as NEG ground - rare to fnd a positive ground. Use common sense to reverse the polarity.
miro |
Lawrence T Wolfe
Senior Member
Username: larry_from_maryland
Post Number: 283
Registered: 07-2003
| | Posted on Monday, March 31, 2008 - 06:03 pm: |
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Miro i think you reversed you typing and the polarity in your last sentence.Most 50's era generators are positive ground. There are exceptions,cattiplar used neg ground. |
Richard A. Day Jr.
Senior Member
Username: richardday
Post Number: 577
Registered: 11-2003
| | Posted on Monday, March 31, 2008 - 08:10 pm: |
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I think most responsible boat and engine builders would have used negative ground once it became clear positive ground leaks could eat out thru hull fittings, hull nails etc. We had a neighbor whose 40 foot boat sank at the dock when his friend installed the battery positive ground running the automatic bilge pump and the bronze throuh hull turned to jelley in almost one night. |
Lawrence T Wolfe
Senior Member
Username: larry_from_maryland
Post Number: 284
Registered: 07-2003
| | Posted on Tuesday, April 01, 2008 - 06:30 pm: |
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Oops working on too many tractors i guess. Hey dick have you seen the large one cylinder engine on the side of the road on rt 236? It has about a 6 foot tall flywheel and the engine bed is about 12 foot long.The guys comeing to calvert might want to make a side trip to see it. I have not talked to the owners yet. |
thomas johnson
Member
Username: capt_tom
Post Number: 5
Registered: 04-2006
| | Posted on Wednesday, April 02, 2008 - 12:11 am: |
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most marine and farm aplacations that were 6 volt were pos. grd. apparently someone deduced that 12 volt needed to be neg. grd. to ans. the statementabout pos. grd leakedge, it makes no diff. +/-. there can and will be some corroseve acction from electrolis. the purpose of zincs on modern equipment in marine aplacation, its a sacrificle metal.I need tech. advice on what changes I need to make to change from + grd, to - grd. Is the gen. internally grded. Is the distributer grded. Or can I simply reverse the battery conn. What happens with guages, amp meter etc. sorry guys, I can't type or spell worth a tot. |
J.B. Castagnos
Senior Member
Username: jb_castagnos
Post Number: 354
Registered: 07-2002
| | Posted on Wednesday, April 02, 2008 - 08:39 am: |
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Your ignition should work, it would be best to reverse the leads on the coil, you'll have a spark jumping from the ground electrode to the center of the plug if you don't. The mixture doesn't care, it will ignite anyway. The amp meter leads will have to be reversed, generator repolarized and if you have a fuel gauge you may have to reverse the leads on it. The coil will have to be replaced or a resistor installed in the line if going from ignition switch if going to 12 volt, also a resistor on the fuel gauge to drop it back to 6 volts. |
