Zel's Motoring Adventures...Volvo, Renault, Rover, Trabant, Invacar & A Sinclair C5 - Updated 16/07.

[PhilA]

The brake pedal assembly is the same as mine. Don't forget to grease the fulcrum pin. 

Horns of that type don't care which way around they are wired. Most likely the points are corroded and/or badly adjusted.

Phil

[Zelandeth]

15 hours ago, PhilA said:

The brake pedal assembly is the same as mine. Don't forget to grease the fulcrum pin. 

Horns of that type don't care which way around they are wired. Most likely the points are corroded and/or badly adjusted.

Phil

Cheers, good to know.  I'll pull them off shortly and see if I can convince them to live again.  

Does anyone have a good 110 wiring diagram?  The one in the manual I have is tiny and bloody hard to read.  Colour would be even better, but I'll take what I can get.  Trying to search on Google just gets me about 50,000 Land Rover 110 results.  The wiring in the 110 is quite fundamentally different to the other P4s so it really does need to be the right one.  It's not the end of the world, and I could probably just spend an evening redrawing the one in the manual in a more user friendly form if it came to it.

Reason I ask is that I'm starting to get stuck into what's actually going on with the headlight circuit.  

The way the lights *should* work on a P4 is that this switch on the dash when flipped to the right turns on the parking lights, and to the left turns on the panel illumination, side & tail lights.

Flicking the rearmost stalk on the right hand side of the steering wheel should then energise the dip/main circuit.

The one nearer the steering wheel is the indicators.

Main/dip is toggled by the foot switch to the left of the clutch.

The instrument panel illumination can be adjusted using a rheostat that looks just like a switch on the other side of the instrument panel.

There has at some point obviously been an issue in this car.  While the park/side switch works normally, the dip switch has been disconnected and replaced by this one down by the choke.

However looking closer at things I don't think they have just interrupted the feed to that switch, as if you look closely when you turn that switch on, both main and dip filaments are lighting at the same time when on dip.  

The wires to the dip switch should be red/blue and blue.  A little digging behind the instrument panel, sure enough I found these.

At which point I got more confused.  The switch tests absolutely fine.  Less than 0.1 ohm when closed, and no fault to ground.

There definitely has been some hacking going on in here.

That brown wire taped in is one of the ones that goes to the added switch, the other is jumping power from the park/side switch.

I'm 99% sure that the three connections in question are the connections to the disconnected switch and the missing one which should hook up where the brown one is on the park/side switch.  It's actually easier to see the colours there than in person.

I just want to get a better diagram so I can see what exactly they have done (and document it!) before I go and change anything.  It wouldn't be the first time I've gone and reversed mods like these and things have *just worked* afterwards, leaving me completely at a loss as to why things had been hacked around, and questioning what was going on for ever more.  

It's also possible that the dip/main issue is entirely at the headlights themselves as well, they have been replaced - they could just be wired wrong and it's nothing to do with what's going on behind the dash.

The torrential rain this morning has also identified that there's some water getting in on the driver's side of the windscreen.

Hopefully a bit of Cpt. Tolley's will improve that.  I'd rather not have to faff around replacing screen seals.  The rear windscreen doesn't seem to leak though as far as I can tell, which is definitely better than was the case on the previous one I had.

[SiC]

22 minutes ago, Zelandeth said:

It wouldn't be the first time I've gone and reversed mods like these and things have *just worked* afterwards, leaving me completely at a loss as to why things had been hacked around, and questioning what was going on for ever more.  

If reversing bodges does fix it then I wouldn't be surprised on a P4. They have by far the most complicated light switch selection procedure of any car I've ever driven! I really wouldn't be surprised if the bodges are from someone not understanding how they work. 

[MorrisItalSLX]

I thought I would be able to help with the wiring diagram, but the manual I have is a pre-110 edition.

But I’m sure if you sent Rover a Telex they would be able to organise a wiring diagram for you.

[LightBulbFun]

22 minutes ago, Zelandeth said:

The one in the manual I have is tiny and bloody hard to read.

if the manual you have is an original physical copy, could you stick the wiring diagram page(s) through scanner at All of the DPI and then print it out larger?  

[PhilA]

Hackery probably because the seperate switches were simply misunderstood.

[High Jetter]

58 minutes ago, Zelandeth said:

Does anyone have a good 110 wiring diagram? 

Maybe parts cat has the answer. 

[Zelandeth]

49 minutes ago, LightBulbFun said:

if the manual you have is an original physical copy, could you stick the wiring diagram page(s) through scanner at All of the DPI and then print it out larger?  

That's probably what I'll do - but may as well colour code the lines while I have it in the digital domain anyway.  It's obviously a scaled copy of another diagram though as the pin markers on switches are nearly invisible.

1 hour ago, SiC said:

If reversing bodges does fix it then I wouldn't be surprised on a P4. They have by far the most complicated light switch selection procedure of any car I've ever driven! I really wouldn't be surprised if the bodges are from someone not understanding how they work. 

That's not impossible to be honest.  You'd think they'd have tried to figure out where the wires they've disconnected originally went though...or am I applying too much logic there I wonder...

We'll get there, just might take a bit of time.

[Zelandeth]

Before:

Not exactly user friendly.

After:

Still needs a bit of tidying up, but isn't that several orders of magnitude easier to follow now?  Even with the compression applied by the forum software, you can actually SEE the respective circuits at a glance rather than having to spend five minute squinting at it and inevitably losing your place.  The original scan was at 1200dpi, so the original is something like 7000 pixels wide.

Key to Item Numbers on the diagram - in a format you can actually scan through rather than a totally unformatted wall of text.  Especially helpful as the sequence of numbering isn't exactly easy to follow in some areas.

1  Generator

2  Voltage Regulator

3  Ammeter

4  Battery

5  Starter Solenoid

6  Ignition Warning Light (Red)

7  Ignition Switch

8  Starter Motor

9  Clock Illumination

10  Speedometer Illumination

11  Grouped Instrument Illumination

12  Number Plate Light

13  Number Plate Light

14  LH Tail Light

15  LH Side Light

16  RH Side/Park Light

17  RH Tail/Park Light

18  Main Beam Warning Light

19  RH Head Lamp Main Beam

20  LH Head Lamp Main Beam

21  RH Head Lamp Dip Beam

22  LH Head Lamp Dip Beam

23  Heater Motor

24  Horns

25  Horn Push Switch

26  Parking/Side Light Switch

27  Boot Light Switch

28  Boot Light

29  Dash Illumination Rheostat

30  Panel Illumination Fuse (3A)

31  Side/Dip Head Lamp Switch

32  Side/Main Beam Foot Switch

33  Heater Motor Rheostat

34  Horn Relay

35  Fog/Spot Lamps – Where Fitted

36  Clock

37  Front Interior Light & Switch (combined unit)

38  Front LH Door Switch

39  Front RH Door Switch

40  Rear LH Door Switch

41  Rear Interior Light

42  Interior Light Switch LH

43  Rear RH Door Switch

44  Rear Interior Light

45  Interior Light Switch RH

46  Windscreen Washer Pump Motor

47  Windscreen Wiper and Washer Switch

48  Windscreen Wiper Motor

49  Fuses A2 and A4

50  Ignition Coil

51  Brake Light Switch

52  Reversing Light Switch

53  RH Indicator Tell Tale

54  Indicator Flasher Unit

55  Indicator Stalk

56  LH Indicator Tell Tale

57  Instrument Panel 10V Voltage Stabiliser

58  Coolant Temperature Gauge

59  Fuel Gauge

60  Fuel/Oil Level Selector Switch

61  N/A

62  Distributor

63  RH Brake Light

64  LH Brake Light

65  Reversing Light

66  LH Rear Indicator

67  LH Front Indicator

68  RH Front Indicator

69  RH Rear Indicator

70  Coolant Temperature Sender

71  Oil Level Sender

72  Fuel Level Sender

73  Oil Pressure Warning Light (Green)

74  Choke Warning Light (Amber)

75  Brake Fluid Level Float Switch

76  Fuel Main/Reserve Pump Selector Switch

77  Overdrive Fuse (35A)

78  Overdrive Solenoid

79  Overdrive Column Switch

80  Overdrive Throttle “Kickdown” Switch

81  Oil Pressure Switch

82  Choke Warning Light Thermoswitch

83  Brake Fluid Level and Handbrake Combined Warning Light

84  Handbrake Switch

85  Fuel Pump (Main)

86  Fuel Pump (Reserve)

87  Gearbox Overdrive Inhibitor Switch

88  Overdrive Relay

I think this was worth spending a couple of hours on as it will make continuing the detective work on what's been meddled with massively easier.  Yes I probably could have found one if I kept digging long enough, but I definitely learned a lot more about the car's electrical system doing it this way.

[Zelandeth]

Did a quick and dirty test today and have confirmed the head will need to come off the Rover.

Definitely have combustion gases getting into the coolant.  That starts inflating the moment the engine starts, even from stone cold.

Not the end of the world.  I want to change the water pump O-ring anyway, and the inlet manifold gasket is suspect, changing that will be orders of magnitude easier with the head off the car.  At least I won't need to disturb the exhaust which is usually the thing I'd dread most when pulling a cylinder head.

Everything I should need is already in stock.

Gasket is a little simpler than on modern engines...

[GlenAnderson]

Found this today, while looking for something else. If it’s any good to you then PM me your address and I’ll get it in the post to you. 
 

[Zelandeth]

On 10/07/2025 at 20:43, GlenAnderson said:

Found this today, while looking for something else. If it’s any good to you then PM me your address and I’ll get it in the post to you. 
 

Sorry, completely missed this post.  Can't be a bad thing to have a spare of.  I'll ping you a PM.

Finally got a chance to (very briefly before it started tipping it down) look at the car today.  I can confirm that the head bolts are indeed tight.  Guess it's coming off then!

It does look nice and clean in there though - at least up top where it's easy to clean.  What's under the exhaust valve cover may tell a totally different story!

[Zelandeth]

Had a very quick look under the exhaust rocker cover this evening (I was literally just taking some stuff to the garage, wasn't even specifically looking to do anything car related).

Not as clean as things on the inlet side as you'd expect, but still very clean for the age of engine I think.

Definitely not a horrible sludgy mess anyway.

I still love the valve gear on this engine.  It's just one of those bits of engineering that I find very pleasing to look at, and think it's a shame it's hidden away behind a cover all the time.

I was pretty sure the valve clearances needed setting given it's far more tappy than my last P4.  Testing purely with my eyes says I'm right.

The clearances are meant to be 6 thou on the inlet and 10 on the exhaust, and they're all at more like 50 I'd say.  Inlet should be set hot too, so are probably even further out!  Not going to worry about that until after the head gasket has been changed obviously, but I reckon that will quieten the engine down a lot.