A few questions

[Finn]

I've had the car (early Mk2) a week now and I'm rather enjoying it, with fuel consumption to reflect

The car is an older restoration (8-9 years ago). The interior is condition 1 but the paint work is letting the exterior down. It's polished up well and looks great from 5 paces, but has numerous cracks and chips. The plan is to have it painted later in the year.

The electrics are a little errr "uninspiring". The presence of spilcing blocks, pre-insulated connectors and unconnected wires never inspire confidence.

The overdrive failed to engage a few miles from home which I assume is an electrical issue. I had a look through the holes in the transmission tunnel (cut, I assume to access the top bolts on the OD) and can't see the wiring to the solenoid. Where would I find these?
I am being a bit lazy as I don't fancy wriggling about under there in this wether.

The temp gauge reads low when the bulb is plugged in & off the scale (high) with the bulb removed. The previous owner replaced the sensor in an effort of fix the problem to no avail. I bought a new gauge, but ordered an oil temp instead of water temp gauge. My research suggests they may be the same internally. When I plug the new gauge into the water temp wires it performs in a similar manner so the problem may be elsewhere. Any thoughts?

The instruments are a mix of Jaeger, Smiths with a Lucas ammeter thrown in the mix. Where all the dials originally Jaeger?

Is the process for removing the dash top the same as the MK3 (mentioned elsewhere)? I would start by removing the vents?

Which brings me nicely around to the heater…. The heater box gets warm, but little of the warmth is transferred to the cabin. A reasonable amount of cold air comes though the vents in the dash fascia, but little to the screen vents. The cables to the heater box are disconnected but I managed to partially dis assemble the box and free up the flap at the front. The flap in the larger duct (screen?) is held open with cable ties.

So it appears the the fascia vents are controlled at the fascia while the screen vents are controlled by the flap in the larger duct?

What does the flap in front of the heater matrix do?On/Off? There doesn't seem to be a temp control (water valve) in the system. Is this normal? In the current configuration it appears all the air supplied to the cabin comes via the heater matrix and there is no means of suppling cold air to the cabin. Kind of, dispite the heater box getting warm the air is still cold.

The larger duct is squashed to clear the rear end of the RH rocker cover and getting the duct on is almost impossible. Surely this is not the norm?

I had new tyres fitted today - 175/70's in place of the 195's and the difference is remarkable.

Many thanks,
Finn.

[Tony Hayward]

Hello Finn

Can't help with the heater issues, Mk3 heaters are different. The overdrive solenoid is in the base of the gearbox (one wire, accessed from underneath; the wires on top are for the inhibitor/ reverse light switch).

The gauge problem sounds like a wiring issue - bad or lack of earth? Also check the voltage stabilizer.
The instruments could be a mixture - my Mk3 has Jaeger and Smiths from new.

Tony

[Finn]

Thank you Tony.

I was rummaging through the papers that came with the car (technical bulliten from November 1977 anyone?) and found a diagram for the fuse boxes. So I checked and the OD fuse was blown. Hopefully that is now sorted.

Finn.

[Admin]

The overdrive failed to engage a few miles from home which I assume is an electrical issue. I had a look through the holes in the transmission tunnel (cut, I assume to access the top bolts on the OD) and can't see the wiring to the solenoid. Where would I find these?
I am being a bit lazy as I don't fancy wriggling about under there in this wether.
The overdrive inhibitor/reversing light switch (an irreplaceable item) is on top of the gearbox, at the base of the bellhousing. With a single wire running from the switch to the solenoid, in the base of the overdrive (drivers side). This wire is prone to chaff where it runs over the machined edge of the gearbox top plate and short, causing the overdrive to dropout and maybe blow the fuse, so check that. Also check the gearbox oil level. Even if the level is OK, it may have sludged up and blocked the gauze filter, accessed via the six bolt alloy plate on the base of the overdrive. Drain the oil remove the bolts and plate, the gauze filter is on top of it but be careful with paper gasket. The solenoid rarely goes wrong but if you are tempted to remove it, watch out for the ball bearing that sits on the tip. It will be held by the oil until the solenoid is just cleared, then drop and bounce across the floor !

The temp gauge reads low when the bulb is plugged in & off the scale (high) with the bulb removed. The previous owner replaced the sensor in an effort of fix the problem to no avail. I bought a new gauge, but ordered an oil temp instead of water temp gauge. My research suggests they may be the same internally. When I plug the new gauge into the water temp wires it performs in a similar manner so the problem may be elsewhere. Any thoughts?
The most common reason for the temp reading out, is a miss match between gauge and sender. The gauges are/were all Jaguar items (what ever the manufacturer) and the sender must match the gauge and not the engine manufacturer i.e. Ford


The instruments are a mix of Jaeger, Smiths with a Lucas ammeter thrown in the mix. Where all the dials originally Jaeger?

As a Mk3 man I can't help with the heater - Err Grahame, it is a Mk2

regards
Paul

[Finn]

Thanks Paul.
I got the car on the ramps today and managed to fix the OD. There were 5 wires running down to the gearbox/OD. I ended up pulling the whole lot out to find 4 of them where 2 wires runing down to the back of the gearbox/OD and then turning around and comming back and through the bulkhead again, with, of course, a number of connections in between. I discarded the bulk of it and ran a new wire to the solenoid, encased in some washer pipe then the conduit for extra chaff protection. The OD now works.

There are now 4 unconnected wired comming through the bulkhead into the engine bay, but everything seems to work. Well, except the FRH indicator, but that was acting up before I pulled that lot out.

After further investigation on the heater, I now understand how the system works, but not why it doesn't.

Finn.

[Admin]

Finn, The washer tubing sleeve is as I did (just slides over the bullet connector). Not quite sure why there were five wires but it sounds as though you have taken the inhibitor switch out of circuit, a dangerous move. Without the inhibitor switch you can engage reverse, while in overdrive and wreck it. The usual is four connectors under the bonnet (near the bulkhead drivers side). I have sent a diagram by direct email.

[Finn]

Paul,

Thank you for the wiring diagram.

The presence of the extra wires now makes sense. It appears (in light of the wiring diagram) that the inhibitor was bypassed prior to my involvement with the O/D as the wires were all plugged into themselves when I withdrew them.



The section between the red arrows seems to be spliced in to bypass the inhibitor.
Purple was a loose end of wire
Green is a male blade that was not plugged in.
Orange was plugged into O/D solenoid.

Is the O/D inhibitor is difficult to access on top of the gearbox? I'm guessing its in the area between the dash fascia & bulkhead, with a transmission tunnel between me & it?

How does the switch engage? The indicative drawing shows a lever exiting a box, where others I've see are simply and on/off via depressed ball. Does the lever interact with the shift box (for want of a better description - where the remote connects to the selector) on top of the gearbox?

And, when you say "irreplaceable" is this because it is physically not possible to replace it or the part is unobtainable? Or both.

Thanks again,

Finn.

[Greybags]

Ah, the joys of Gilbern wiring, many a mystery from the land of the Dragon..

The inhibitor switch should be located on the top of the gearbox, with a long lever that clips into a quadrant operated by a selector rod.

Hopefully you can see it in the photo's ..

I believe they are as rare as hen's teeth, but do appear on Ebay every so often, but usually at a high price... But if anyone will know where they are, stores man Gavin is the chap to talk to...




Grahame

[Finn]

Thanks Grahame,

Why does the word "afterthought" come to mind?

I'm not really sure of the way forward here. However, the way backwards (excuse the pun) appears to be to engage reverse with the O/D engaged. Does the O/D expire when it is engaged in reverse or when the clutch is released and power applied?

Finn

[Gavin McArdle]

Just noticed this thread.
The original inhibitor switches are no longer available, have not been for some time.
Reliant Scimitar spares sell a copy which is total rubbish, I have supplied a few most of which have fallen apart during fitting.
As they cost around £70.00 it is an expensive exercise!
There is a way of bodging them to make them last ( as long as cable ties last!) I will take a pic later to day and send to Greybags for him to post. (Please Graham?)

If you start to move in reverse with overdrive engaged the o/d gears get very upset at being moved backwards and stop working completely. There is a technical term for this beginning with F

I can supply an inhibitor switch suitably bodged ( I have 2 left ) but with no warranty. In future I shall be directing members to Scimitar parts suppliers and let them carry the warranty.

I can supply a gasket set for the o/d including a rear oil seal for £25.00

I will try and answer the heater questions later on after I have refreshed my memory by looking at mine.
Gavin

[Finn]

Thank you Gavin.

I'm guessing the inhibitor switch is fairly difficult to access?

I'll look at what the various shift rods do and see if it is possible to use a different style (perhaps classic motorbike) brake light switch with a circuit switching relay for the O/D side to deal with the issue using a cheap propriety switch.

Finn

[Greybags]

Gavin ..

Email them down and I will post them for you, no problem ..

Finn .....
Now putting my historian hat on ...

Could you let me know your and the cars details so that I can add them to the files .. Details, pictures, copies of docs and any info at all so that I can keep things up to date, and of course if I have anything in the files to share, they will be passed on..

Look forward to hearing from you..

Grahame

[Gavin McArdle]

I have sent a pic of the bodged inhibitor switch to Greybags for posting on here, the base of the switch is hard plastic held in place by crimping the metal cover, the problem is the plastic just shatters the more the cover is crimped!
It can be held together by cable ties.
Unless your car has an inspection panel cut into the top of the transmission tunnel it is very difficult to reach the switch, you may be able to do it with the car on a hoist and standing underneath, work with your arms around either side of the 'box

As to the heater, I have not had time for an in depth investigation so this is from memory, no doubt someone will correct me where I am wrong.

The facia vents are turned on and off at the vents, they have a direct cold air feed.
The water tap is at the rear of the inlet manifold, you should have a heater hose conected there.
The flap in the heater box both controls temperature (after a fashion) and hot and cold air to the car.
It is not a very efficient system as air is not directed through the matrix but rather into the front and out of the side.
There should be a flap in the rear outlet of the heater box which closes the air off completely or can be used to restrict the flow.
Air is directed to car or screen demister or a mixture of the two via a chamber mounted behind the dash to the left of the steering column.
It is worth checking that the plumbing for the heater is the correct way round, also from memory the top outlet for the heater box is the highest point in the system and so may need 'bleeding' here.

There have been more than a few different mods to improve the heating over the years, Paul Clarks CD will go someway to showing you how some were done.
It would seem that some previous owner has enjoyed messing with the wiring!!!
In it's day Gilbern wiring was no worse than any other car of the time but many have been 'improved' over the years by 'experts'!
New looms are available if yours has been 'imrpoved' too much
Gavin

[Admin]

Finn,
Before getting too far down the replace it road. Do check out the condition of your switch?

Just because someone wired it out does not mean they knew anything. You can see in Grahame's lower pic. the ends of two connector blades, same on the other side. With the switch in either direction one of each pair makes a circuit.
Simple to test with wire battery and bulb or buzzer.

First rule with any old machinery is, make sure you under stand what should be, before looking for the problem and changing things.

As you point out, other's have already had their mitts in there!

[Finn]

Thanks Gavin.
The heater system I have is largely as you described, especially on the efficiency front. There isn't a vavle where the heater hose returns to the manifold. It is plumbed in the correct way, but the lack of flow through the matrix seems tombe the crux of the issue.
I have a DVD entitled Printed Archive 1969 - 2006. Is that the disc in question?
I'll deal with the inhibitor at some stage. I will check the functionality of whats there prior to any surgery.
I tend to go through the 'box then engage O/D on 4th only, then disengage O/D and change back down the 'box, so I don't see it as a pressing issue...until......
Thanks again,
Finn.