Starter Solenoid - too much choice!

[JJDraper]

I am pretty sure I have a failed starter solenoid, they are pretty cheap but the choice of units out there is confusing. Any ideas for a 'correct' one, or are they all the same? My ignition circuit has the ballast resistor, if that makes a difference. I have seen Lucas SRB 335, SRB 325, and ones that just say suitable for Triumph/Mini etc. Wide variety of prices from 10 to 40 quid.

On the same subject, if you put 12v across the small terminals, should the unit actuate? Mine are dead...

Any help appreciated.

Jeremy

[Higs]

Hi

See this previous topic:

https://lotuselan.net/forums/viewtopic.php?f=38&t=18576&start=

If you have a ballast resistor then you need the one in the second picture (with the extra connector). The wiring is in the post below it.

To answer your second question, if you put 12V across the white/red connector and the mounting bracket, then the relay will activate and there will be continuity between the two big terminals posts and also between the battery terminal post and the blue/white connector i.e. it activates the starter and also send 12v to the directly to the coil (and not through the ballast resistor).

Richard

[mbell]

The starter solenoid are quiet easy to repair yourself. Drill out the four rivets and unsolder the wires. You can then clean it up and but back together with a few small bolts.

I did this recently after mine stuck on (a not a fun experience). Probably quicker and easier than finding and ordering a new one.

'Chrispy' did a great thread on how to do this:
viewtopic.php?t=44932&p=320232

[Frogelan]

As always, there are some very accurate replies here. Thank you for those.

Whilst we are on this subject, if I fit a modern starter motor with what I believe to be an integrated solenoid, would I be right in thinking that the solenoid is no longer required (and that a starter relay will organise everything)?

Many thanks

Andrew

[mbell]

Whilst we are on this subject, if I fit a modern starter motor with what I believe to be an integrated solenoid, would I be right in thinking that the solenoid is no longer required (and that a starter relay will organise everything)?

Yes. If you have a ballest ignition system you'll need to make sure there is a power source for the coil when turning the engine over, e.g. direct connect from relay output to the coil.

My car I've kept the original solenoid, as it means there isn't an always live unfused wire in the engine bay.

[Higs]

My car I've kept the original solenoid, as it means there isn't an always live unfused wire in the engine bay.

Apart from that large cable coming from the battery to the solenoid post, and the brown wire from there that runs around the engine bay to the ignition switch.......

[mbell]

Apart from that large cable coming from the battery to the solenoid post, and the brown wire from there that runs around the engine bay to the ignition switch.......

The difference for me is the start motor connection is exposed and surrounded by lots of bits of earthed metal (engine/chasis) that would be easy to short against when working on the car by accident. The solenoid connections are more out of the way and there a lot less earthed things around it. The cables are of course insulated so much less a concern.

[Frogelan]

Thank you both for those comments re: live feed.

The project is a GTS car and avoidance of unprotected terminals leading to sparks is important in any fibreglass car.

I will be placing the coil well away from the Webers (under the cold air flexible hose next to the radiator) and will invest in sealing "boots" for the starter.

[Andy8421]

Thank you both for those comments re: live feed.

The project is a GTS car and avoidance of unprotected terminals leading to sparks is important in any fibreglass car.

I will be placing the coil well away from the Webers (under the cold air flexible hose next to the radiator) and will invest in sealing "boots" for the starter.

Unless you plan on shorting out something across them, correctly made terminals don't spark. The same is true of the coil, which shouldn't be sparking either.
If you are looking for a source of ignition near the Webers, then you don't need to look any further than the distributor - conveniently mounted where fuel can drip onto it. Even when working properly, the distributor has sparks at the points, and between the rotor arm and distributor cap contacts. While it wont hurt to do as you suggest if fire is a major concern, the distributor is definitely an area to focus on.

[Frogelan]

Thanks Andy. I'll see what I can come up with.

Some GTS cars have "drip" trays!

[Higs]

The difference for me is the start motor connection is exposed and surrounded by lots of bits of earthed metal (engine/chasis) that would be easy to short against when working on the car by accident. The solenoid connections are more out of the way and there a lot less earthed things around it. The cables are of course insulated so much less a concern.

That is a good point - I guess a large boot and disconnecting the battery whenever disconnecting the starter is necessary practice (sorry for my initial flippant comment - but I could not resist).