how is this saildrive insulated

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djrussell0

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fitted my newly refurbed sail drive today and because I have not been near the insulation break on bell housing have not give it any thought.

any how during fitting I noticed I had studs with metal washers securing bell housing to engine. the sail drive is 30m years old and I would consider good for age but defiantly can not be insulated

it all looks original and has a isolator switch from the battery's when not in use, however I believe the earth side is the issue.

anyone else have this set up on a 2001/120sb unit



View attachment 47934



View attachment 47935
 
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djrussell0 said:
fitted my newly refurbed sail drive today and because I have not been near the insulation break on bell housing have not give it any thought.

any how during fitting I noticed I had studs with metal washers securing bell housing to engine. the sail drive is 30m years old and I would consider good for age but defiantly can not be insulated

it all looks original and has a isolator switch from the battery's when not in use, however I believe the earth side is the issue.

anyone else have this set up on a 2001/120sb unit
Click to expand...

I think it probably is not insulated. I have not looked thoroughly but I dont see any insulating components in the parts diagrams.

IIRC the insulation thing was introduced during the MD 2010/20/30/40 production.

Sometimes the engine block is not used as the negative return when the sail drive is not insulated leading to the use of two-wire sensors, insuatred alternators and earthing relays etc. The wiring diagram in your owners manual will show you if this applies .. or you may know whether or not is has an earthing solenoid etc

The owners manual also usually draws attention to the isolation of the saildrive where that applies. I have not checked... you can do that!
 
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Look on your wiring diagram for a relay that connects the engine to ground via a fuse. If you have one, there is no insulation.

As an example, go to the Download section in the Bavaria Yacht Forum site in my signature, download Volvo Penta 22 Series Instrument Panel & Engine Wiring Diagram DIY Manual.pdf

Relay is #5, fuse is #6.
 
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hi Nigel different wiring for mine but same for the delux version, but I did notice a isolator switch for both earth and live!

so as far as I can make out its manual 2 isolator switching for budget version and relays for delux pack for 2001 engines 1984-91

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will check next week when I go to boat, what is the difference between a 2 and 1 wire system apart from the obvious that the one wire is getting earth from engine

thanks Dave
 
djrussell0 said:
will check next week when I go to boat, what is the difference between a 2 and 1 wire system apart from the obvious that the one wire is getting earth from engine

thanks Dave
Click to expand...

The difference is that a 1 wire system uses the engine block as the common negative connection for sensors , alternator and starter and, where applicable, the glowplugs and stop solenoid

In a two 2 wire system the block is not used, the sensors and alternator have insulated negative connections. The starter motor may however still use the block as the negative return, which is when a heavy duty earthing solenoid is used to connect the block to negative during cranking.
Even when a two wire starter is used the glowplugs and stop solenoid may still use the block. In these cases an earthing relay is required to connect block to negative during preheating and starting and stopping .

Variations obviously possible!
 
djrussell0 said:
right so after starting it looks like my engine/saildrive would be completely isolated from the negative pole.

Dave
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So be careful that any work you may do, accessories added, work around bodge solutions to problems. incorrect parts fitted etc do not compromise this.

Also be aware that a short between the wiring and the block may not be noticed until one day when you discover severe/catastrophic corrosion of the sail drive!
 
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VicS said:
So be careful that any work you may do, accessories added, work around bodge solutions to problems. incorrect parts fitted etc do not compromise this.
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In my case it was a compressed insulating washer on the starter solenoid. I tightened up the nut, not noticing that the ground wire was now touching the case. It didn't even occur to me that this was a problem at the time.
 
unfortunately I will have to wait to do any running tests as I have winterised the engine, I suspect I have nothing to worry about as I have said the sail drive seems in reasonable condition for age.

many thanks for all the input, it has given me a good insight to some thing else new to boating

Merry Xmas Dave
 
VicS said:
The difference is that a 1 wire system uses the engine block as the common negative connection for sensors , alternator and starter and, where applicable, the glowplugs and stop solenoid

In a two 2 wire system the block is not used, the sensors and alternator have insulated negative connections. The starter motor may however still use the block as the negative return, which is when a heavy duty earthing solenoid is used to connect the block to negative during cranking.
Even when a two wire starter is used the glowplugs and stop solenoid may still use the block. In these cases an earthing relay is required to connect block to negative during preheating and starting and stopping .

Variations obviously possible!
Click to expand...

View attachment 48202
getting more confused now, I have a single wire warning system with my battery grounded to the bell housing! so defiantly grounding saildrive this could have been added later , no extra grounding solenoids . I have found various different wire diagrams for this base engine. The one for my engine ref the serial number from Volvo does show a 2 wire system. Wire loom on mine looks OE and as old as the engine. the above wire image is as close to what I have less my ground goes to back of bell housing. ground wire from the Paris Rhone 50amp alt also bolts to side of block, again looks OE. Is it possible that my engine/sail drive had no isolation from new in 1985 and in subsequent years they learnt from their mistakes. not going to loose to much sleep just yet as I know the history from the last 8 years and its has been on a swinging mooring all of that time and no adverse corrosion.

any thoughts welcome

don't understand why the earth signal wire for the temp and oil is on the alternator ground side in this version though
 
djrussell0 said:
View attachment 48202
getting more confused now, I have a single wire warning system with my battery grounded to the bell housing! so defiantly grounding saildrive this could have been added later , no extra grounding solenoids . I have found various different wire diagrams for this base engine. The one for my engine ref the serial number from Volvo does show a 2 wire system. Wire loom on mine looks OE and as old as the engine. the above wire image is as close to what I have less my ground goes to back of bell housing. ground wire from the Paris Rhone 50amp alt also bolts to side of block, again looks OE. Is it possible that my engine/sail drive had no isolation from new in 1985 and in subsequent years they learnt from their mistakes. not going to loose to much sleep just yet as I know the history from the last 8 years and its has been on a swinging mooring all of that time and no adverse corrosion.

any thoughts welcome

don't understand why the earth signal wire for the temp and oil is on the alternator ground side in this version though
Click to expand...

At a bit of a of a disadvantage now. New computer for Xmas but all my knowledge, files and links are on the old one!

Lots of variations in the way these have been wired I think and not necessarily reflected in the wiring diagrams you can now find on-line
Not noticed that double pole isolation switch before... but then not studied the battery isolation in depth ...... maybe that is what they fitted on some rather than the earthing solenoid before sail-drive insulation. I don't remember for sure when the sail drive insulation was introduced. IIRC there is a brochure that describes it on VP website.


The negative connection for the sensors in the diagram you've now posted is OK . It just goes back to battery negative via B- on the alternator, 31 on the starter and the isolation switch. The negative connection for the control panel is the SB wire in extreme top right connected to 85 on the relay which is connected to battery negative via the same route.
 
Hi Vics,

looking at that diagram would you say the this is a insulated style starter? I,m bit slow on wiring but I cant see how the warning lamp senders are not put on all the time as they would be earthed switched.

Dave
 
djrussell0 said:
Hi Vics,

looking at that diagram would you say the this is a insulated style starter? I,m bit slow on wiring but I cant see how the warning lamp senders are not put on all the time as they would be earthed switched.

Dave
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From what I can see in that diagram I'd say it was a fully isolated negative system, starter motor included.


Bad diagram.
Should show two terminals on the sensors if its a two wire ( ie insulated system) One connection to battery negative as already described the other to the warning light


More usually, like on your car, or a single wire system , the body of the sensor is the negative connection and is connected to negative via the engine block.


A bit unhappy about that diagram!
 
that's what I thought, back to drawing board as I defiantly have the single wire system with the body of sensors forming the earth, looks like I will be looking for a way of retro fitting a insulating spacer between engine and saildrive. perhaps I have one between block and bell housing, will move battery earth to engine block instead of bell housing and test. as I said the alternator is already earthed via B- on to the back of block via a short original lead so this would suggest block has never been earthed via any type of solenoid. got paris rhone alternator off at moment and looks very old, also only 50amp which I believe is original so likely not fiddled with. the only signs of modification I can see is a 0-1 1+2-2 battery switching system.

Dave
 
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