Trouble replacing solenoid

[Tigger]

Right...!

 

I'm halfway through replacing the solenoid on my k-series and I've come up against a problem.

 

The solenoid is off and I have shiny new one from Wood Auto to go back in. However I see that the piston (for want of a better description) is slightly different. The old one has a flat end inside the solenoid but the new one has a conical indent. OK, a simple question of removing the old piston me thinks, but oh no, not that simple.

 

What I need to know is what technique do I need to use to get the old piston out. Obviously the square spade connection with a hole it it hoops over something but I just can't get it to work loose. What do I do.....?

 

Pics of the new and old solenoid here

 

Thanks

 

Tim

 

[Jason Plato]

the square section hoops over the lever arm that is inside the main body of the starter motor.

 

it makes no differecne whats inside the solenoid as long as the hoop is positioned over the lver arm in the main starter motor body.

[Tigger]

The only reason I thought that there might be an issue is because their seems to be a stubby metal switch at the head end of the new solenoid which I wasn't sure was relevant in some way....?

 

When fully depressed the piston depresses the switch.... Also the new piston seems to be slightly shorter.

 

If irrelevant it certainly will make my life easier.

 

Tim

 

PS Thanks for the lightening response time

 

Edited by - Tigger on 4 Mar 2011 13:14:07

[irrotational]

My new solenoid has arrived today - i might have a pop at it tonight!

 

Just hope this square bit at the end fits wherever it's meant to fit....

 

i just remember spending a loooong time getting the old starter motor off - think i had alan keys and sockets arranged to make some kind of giant arm....

 

which way is it to undo bolts again!? 😬

[Tigger]

Okey dokey...... after a long afternoon bending both arms and fingers in to positions they really are not meant to be in I'm back to where I started.

 

I fitted the new solenoid wired it all up tried to fire it up and 'click', OK, try again, this time a different sound and the engine started leaking smoke. After quickly finding my smoke re-charge kit I managed to get it back into the engine and set about putting the old solenoid back on. Back in place I have a car which fires up without leaking smoke albeit after a couple of clicks.

 

I may try the next mod of a direct connection to the battery next.

 

It also seems that the correct piston is important when fitting the solenoid.

 

When I have the engine our next time I may try and re-fit the new solenoid but with the right piston.

 

One other thing to be aware of with the Woods Auto Solenoid is that if you have a 4-2-1 exhaust manifold you'll need to shorten the negative terminal to it doesn't touch the exhaust. It will also be considerably easier to attach the wire to the negative terminal BEFORE bolting the solenoid on to the starter motor.

 

We live and learn...

 

Tim

[LazerBrain]

It's been a while since I took my solenoid apart, so my memory may have faded... Please have a look at your starter and solenoid to compare against my comments.

 

When the solenoid is energised it pulls the piston in. The back of the piston pushes on the switch which joins the main battery cable to the starter motor supply, thus starting the starter motor spinning. Meanwhile the piston moving in pulls the lever which engages the starter motor pinion with the teeth on the flywheel. When the power to the solenoid is cut (by releasing the ignition key back to the 'running' position) the spring pulls the piston back out. This cuts the power to the spinning starter motor and the pinion returns to its rest position.

 

If the piston from your previous solenoid is not long enough to engage the switch then I would imagine you would hear the click of the solenoid and the pinion being pushed out, but no starter motor spinning noises.

 

I recall testing my starter motor before bolting it into position. I held the casing against the block to earth it and used a spanner to short the solenoid connection to the live main battery cable. Not the safest of tests, and the starter gives a big kick when it starts up! It did demonstrate the action though.

[Tigger]

Lazerbrain,

 

Many thanks. Things are a bit clearer now I know how the mechanism actually works. and also explains why it didn't.....

 

Is it actually possible to remove the 'pinion' (thanks for the correct description) without removing the starter motor?

 

Tim

[LazerBrain]

Ooops - I may have confused you... The pinion is the small gearwheel that is on the end of the starter motor. It slides up and down its shaft to engage with the flywheel (when extended) or park in its rest position so it's doesn't get spun round when the engine is running.

 

The piston on the end of the solenoid hooks over the lever that moves the pinion. (This is starting to sound like a bizarre nursery rhyme!) I can't remember, but I think you'll need the starter removed from the engine to remove the solenoid before you can try to unhook the business end of the piston from the lever. Let me check for some pics from my attempts - will try to post again later.

[Tigger]

For future reference, A German chap I know has a very comprehensive website on the workings of k-series MGF's. He has a section on starter motors and solenoids.

 

here

 

Tim

[MADMALC]

Cheers Tim, at last I know how to get the thing appart without ruining it.

'De solder' is the missing key. Knowledge is power.

 

🥰

[Tigger]

you see.., I knew someone would find that interesting. SWMBO was not convinced....

[MADMALC]

Mine calls you 'my invisible friends' and I love you all. 🥰

 

Sad is good.

[Tigger]

Quoting MADMALC: 

Mine calls you 'my invisible friends'

 

😬

 

 

[irrotational]

Sorry, just to annoy the original poster, mine is fitted and works! The solenoid piston looked the same length and my old solenoid had a post too no spade connection... maybe your old solenoid is a slightly different model.

 

To fit it, I had to take the starter off the engine (a pig with 4 2 1 exhaust) and pull the starter cog out, this made the lever ARM fall back so the solenoid piston could be hooked on...

 

Wish I had done this years ago!

[Tigger]

Irrotational.

 

Hurrumph....!

 

But glad yours worked. I was put off removing the whole starter motor because of the whole exhaust issue although, in a strange way knowing that the new solenoid hadn't cured the click makes me feel just a little better.

 

Out of interest what does the little wire which connects the solenoid to the starter motor do? Is it a ground connection?

 

Tim

 

 

[LazerBrain]

Out of interest what does the little wire which connects the solenoid to the starter motor do?

That's the 12v feed to the starter motor. When the solenoid is energised, the switch joins the main battery feed to the starter.

 

A few pics from my refurb...

 

http://www.lazerbrain.com/7img/starter/P1060389.JPG

On mine there's a dry joint where the central terminal (power to the solenoid) has been tightened and cracked.

 

http://www.lazerbrain.com/7img/starter/P1060392.JPG

Here you can see the spring that brings the piston out when the solenoid has no power, also the bit that attaches to the lever in the starter.

 

http://www.lazerbrain.com/7img/starter/P1060393.JPG

The rear of the piston - this bit pushes on the switch.

 

http://www.lazerbrain.com/7img/starter/P1060394.JPG

The switch inside the solenoid

 

http://www.lazerbrain.com/7img/starter/P1060395.JPG

This is the lever at the bottom of where the solenoid is mounted. Pushing down the lever returns the starter pinion to the rest position (ie when the engine is not being started.)

 

http://www.lazerbrain.com/7img/starter/P1060398.JPG

Checking the solenoid works by directly connecting across the car battery. Not the safest method...

 

http://www.lazerbrain.com/7img/starter/P1060400.JPG

Testing the starter. You can visualise when the solenoid is energised it will pull the piston towards the battery in this picture. The lever from the other picture is pulled towards the battery causing the other end to push the pinion away from the battery. You can see the pinion and the area that it can move to along its shaft.

[irrotational]

Tigger - sorry again! - how did you manage to hook the end of the solenoid piston over the lever arm whilst the starter was still on the car!?

 

I couldnt even get the old one un-hooked when it was like that!

 

The starter is a pain - i have a long allen key which just reaches the "tricky" bolt and the short end just sticks out by the larger gap in the middle of all the exhausts....then have to put some sockets and extensions on it to make this bit long enough to undo the bolt....

 

so it takes 30 seconds of fiddling and cursing per 1/4 turn of bolt!!

[Tigger]

Quoting irrotational: 

Tigger - sorry again! - how did you manage to hook the end of the solenoid piston over the lever arm whilst the starter was still on the car!?

 

I couldnt even get the old one un-hooked when it was like that!!

 

Nor could I. I just reverted to using the old solenoid.

 

Quoting irrotational: 

The starter is a pain - i have a long allen key which just reaches the "tricky" bolt and the short end just sticks out by the larger gap in the middle of all the exhausts....then have to put some sockets and extensions on it to make this bit long enough to undo the bolt....

 

so it takes 30 seconds of fiddling and cursing per 1/4 turn of bolt!!

I ran out of patience after fitting and 'un-fitting' the new/old solenoids too many times. I also think I would have struggled to get to the tricky starter motor bolt with my hex socket. How long are your allen keys? Anything like these?

 

Tim

 

Edited by - Tigger on 6 Mar 2011 07:25:01

[Tony Whitley]

Youngsters Never cranked a car over on a starting handle and so have no appreciation of the forces involved when a starter motor, er, starts. When I tested mine off the car it was on the floor with my foot firmly on top of it - and then I was a bit wary. Holding it by hand in the engine bay...

 

Anyway, the tricky bolt on the starter - I have a hex head on mine which I could only turn half a flat but then I put a few washers under the head and that gave a lot more access and I can manage a whole flat at a time.

 

And: after fitting the relay mod, a second relay direct from the battery to the solenoid, a new solenoid and eventually a new starter mine still stopped working properly after a year or so. The latest cure was to rewire the starter feed direct to the battery, the rest of the electrics take the long route to the battery isolator switch and back. May not pass a careful scrutineer but perfectly adequate for non-racing use. That is currently (geddit?) working.

[Tigger]

Tony,

 

I hope I haven't missed much by not cranking a car by hand.

 

If I follow you correctly you've added a additional BIG red wire between the solenoid and the battery. I don't suppose you have any pics of the wiring?

 

Thanks for the currently pun

 

Tim

 

Edited by - Tigger on 6 Mar 2011 10:29:53

[Tony Whitley]

Yes and no. Final mod was a BIG red wire from Halfords direct from the battery to the main starter feed. No pictures but if I recall it amounted to simply changing the feed which goes from the alternator via the starter to the isolator to go direct. I bolted the two ends together and insulated it well! So now I have a main battery feed to the whole car as before plus a feed direct to the starter.

 

The earlier mod was to fit a smaller (but still chunky - 17A) wire from the battery through a relay to the solenoid (activated by the existing solenoid feed), the idea being to maximise the voltage on the solenoid (minimise the resistance).

 

Edited by - Tony Whitley on 6 Mar 2011 11:00:34

[Tigger]

Tony,

 

 

I was going to try this but wasn't too sure about

 

point 3.

Detach the smaller wire (i.e. NOT the big red one) from the rear of the solenoid on the starter. It may be stiff, but should just pull off.

 

On my solenoid there are three wires. a Big red one, the little spade connector one and the short wire connecting the solenoid to the starter motor. I imagine it's the spade connector.. Is that right?

 

Or use your 'Final solution' and make a direct connection between the alternator and solenoid.

 

Thanks for your patience.... I'm a slow learner.

 

Tim

 

[LazerBrain]

Yes. The mod on that page affects the feed that triggers the solenoid (which is the small wire.)

 

Before you start making mods it would be better to determine the actual problem that you are experiencing. For example, if the solenoid has a poor connection then beefing up the supply to it is not really the fix.

[Tigger]

Lazerbrain,

 

Good point.

 

So far by process of elimination:

Solenoid is not the problem. Both new an old suffered from the same 'Click'

By-passing the MFRU doesn't cut the mustard either. Relay fitter ' Click'

 

Next:

1. by-pass the FIA switch....?

2. Fused connection direct between solenoid and battery

 

Tim

 

[irrotational]

Sorry - last OT post from me - the allen keys were halfords "pro" set from a little while ago - the 8mm allen key is about 15-16 cm from the long end to the short end....

 

Out of curiosity - how did you get your starter off if you didnt use a hex key and/or a hex bit socket?

 

Sorry if i'm missing something - but presumably you managed to get the new solenoidd piston hooked onto the starter lever!? It's just in one post you said you hadn't taken the starter off but in another you said you couldn't get the old one unhooked without removing the starter!?

 

I can't remember the whole trail but i think the acid test (battery pun!?) for dodgy wiring is to just get a bit of spare 30 amp wire and touch one end to the battery and the other to the solenoid - this bypasses everything except the solenoid and the feed from the solenoid to the starter motor....

 

Have you worked out what all 4 of the connections are on your old solenoid? It looks like someone has replaced the original post with a soldered in spade connector...but im not sure what the little spade connector at the bottom is for?

 

 

I am talking about this pic:-

 

here

 

...and silly question but how old is your battery - whats the voltage on it when nothings happening and whats the voltage when starting? It's in the archives but I think these should be 12.7 and 12.1 or something...

 

There were some comments that if it drops below 12 when cranking then the battery may be a bit old - BUT check I have made these up from memory after doing a lot of searching many moons ago