Solenoid on negative

[pvb]

The Volvo part number is 872242, but it's likely to be a rebadged Valeo CEY-113 type relay. Alternative Valeo part numbers are 594045, 182560, 99845.

You can get lots of standard relays which would do the job - ask a motor factor to cross reference the part number. The mounting is likely to be different, so you'd just need to modify the bracket.

 

[Elemental]

I think Id get it off and clean up those manky terminals to give it another try.

You may find a clue to its real identity under the yellow label!

I dont see anything on the page that opens from Nolex's link that looks like an easy substitute although one of the other pages on the site has some that look hopeful.
I guess anything with a suitable current rating and an isolated negative will enable something to be cobbled together

Ideally it needs to fit the existing bracket as below but you may have to make up an alternative to #10 which is the link to the engine block.

Am I right in thinking that the mounting and body of the relay is also the neg. connection to the block as there's only one switched pole on the relay?

 

[pvb]

Am I right in thinking that the mounting and body of the relay is also the neg. connection to the block as there's only one switched pole on the relay?

The negative connection to the block is via the strap (item 10 in the diagram). This is only activated when the starter is operated, it then provides the negative connection to the starter, via the engine.

 

[Elemental]

The negative connection to the block is via the strap (item 10 in the diagram). This is only activated when the starter is operated, it then provides the negative connection to the starter, via the engine.

Thanks, I didn't see the strap (#10) as an electrical connection, and I've only managed to capture the battery leads in the photo (mind you, I can't remember why there are two neg. cables on the solenoid - unless one goes off to the domestic bank - there is a bus tie breaker).

I must say, thanks very much to all of you for your input, it's a great example of how valuable these boards are.

 

[VicS]

The relay case must be isolated !

I not expect the 2nd battery neg to be conected at that point but that may be the second heavy wire.
If would be better if the batteries had a common negative bus bar in the battery compartment.
As it is it will only be connected when the negative battery isolator is closed

Wiring diagram below taken from the on line owners manual

 

[noelex]

The second large negative wire may be the alternator – output.

The relay does not need to mounted on the engine and often mounting it on the wall of the engine bay gets it way from any water and can result in a neater installation. If you do this the negative connection to the engine block (10 in the diagram) needs to be replaced with a flexible battery cable.Mke sure all the wires have enough play to allow for movement of the engine on its mouning blocks.
If you want to leave it in its existing position the mounting holes on the relay are extended slots so they will accommodated a range of bolt spacings, its rare that they don’t physically fi with similar sized relays. If negative conection 10 will not fit with the new relay once again a flexible battery cable may still be the easiest solution.

 

[VicS]

The second large negative wire may be the alternator – output.

The alternator negative connection you mean!
According to the wiring diagram that's only 10 mm². It looks heavier than that!

The alternator neg is more likely to be the one painted Volvo green tight up against the starter motor

The small green painted one will be the neg connection to the coil. The red yellow one is the positive to the coil

 

[Elemental]

Resolution

Just for completion, I thought I'd provide an update on what I did.

I bought a SRB325 solenoid for £8.25 from ebay. As the case of this solenoid must be earthed and the engine block must not, I mounted it on a bracket made of polyethylene and then earthed the solenoid case to the battery via the earth cable. The 12v from the start button relay is fed to the solenoid 12v input.

Considerably cheaper that the £100+ that a new Volvo solenoid costs. Works like a champ.

 

[VicS]

Thanks for reporting back.

 

[Elemental]

Just for completion, I thought I'd provide an update on what I did.

I bought a SRB325 solenoid for £8.25 from ebay. As the case of this solenoid must be earthed and the engine block must not, I mounted it on a bracket made of polyethylene and then earthed the solenoid case to the battery via the earth cable. The 12v from the start button relay is fed to the solenoid 12v input.

Considerably cheaper that the £100+ that a new Volvo solenoid costs. Works like a champ.

Hmmm, I may have been a bit hasty. I am now somewhat puzzled. I installed the solution as described above. All seemed well, and the engine cranked briskly on demand. However, yesterday I ended up motoring for three hours. We stopped for lunch and after a couple of hours went to set off and the engine refused to crank. The solenoid is not operating. A quick check with the meter confirms the following

1. 12V (well, 12.6v) actuating voltage is being delivered to the solenoid when the start button is pressed
2. the solenoid chassis is isolated from the engine
3. the solenoid chassis is connected to the battery negative

One thing I'm curious about is that my ohm meter buzzes (indicating short circuit) when measuring the resistance from the actuating +ve to the batt. negative. I'm guessing that this is probably correct for the inductive operating mechanism?

Shorting the poles with a screwdriver allows the engine to start as normal.

So, I'm surmising that one of two unlikely situations exists

1. My new solenoid is defective
2. The start relay (which is new) isn't delivering sufficient current to operate the solenoid.

Does anyone know what the actuating current of a solenoid is likely to be?

Is there some other scenario I've missed, bearing in mind that this set-up was working for a while?

 

[noelex]

Does anyone know what the actuating current of a solenoid is likely to be?
?

Sorry to hear about your problems.
The activating current is only very small a couple of amps or so from memory, but starter switches or small activating relays for the main solonoid, seem the most common failure mode. I am not sure why a 10a relay is over rated in this application, but they do fail.

However I think the most likely explanation in your case is a failure of the main solenoid. It needs to rated for the full starting current and the eBay relay you got is designed for small petrol engines and it's from Lucas. They are not known for for reliable electrical parts.
I cannot find any specs for current capicity on the Lucas eBay relay.
On my 54 HP Yanmar the earh relay is a simple isolated case 100a relay of unknown manufacture. It was the best I could get in a small Greek town when I fitted a new engine, about 20 euros from memory, but it is still going strong 3 years later. I have the old very similar relay as a spare. I would prefer to get a higher rated relay with silver plated contacts when I can get one.

 

[Elemental]

Update

Hmmm, I may have been a bit hasty. I am now somewhat puzzled.

.....

So, I'm surmising that one of two unlikely situations exists

1. My new solenoid is defective
2. The start relay (which is new) isn't delivering sufficient current to operate the solenoid.

I took the new solenoid off and checked its operation with a 12v battery - very intermittent functioning. So, I contacted the ebay vendor (southernspares) who immediately sent a new one - no quibble. It's fitted and now seems to work just fine. It seems likely I had a dud. I'll be keeping the big screwdriver handy for a few trips though...