Zel's Fleet Blog - BX, Jag XJ-S, Sinclair C5, Mercedes 208D & 230TE, AC Model 70.

[Zelandeth]

All things for me to check.

The exhaust is a nearly new stainless system so still has that odd tinny sound to it. The mic on my phone always seems to pick up a bit too much high frequency stuff as well, so that may also be a factor.

Beyond checking fluids before the run home the bonnet hasn't been opened again yet! Shall resolve that at the weekend.

[Zelandeth]

Figured it was time to stop cowering in fear and actually open the bonnet again.

No huge surprises to be honest. Hasn't used any detectable amount of oil or coolant on the trip home which is nice to see.

Quite a lot of surface corrosion on everything which fits given that the car has barely been used for a not insignificant number of years.





Slightly intrigued by the little red anodised cylinder by the nearside brace.



In the absence of anything to suggest the contrary I'm guessing this is either a filter/silencer or a check valve attached to a vent line of some description as there doesn't seem to be anything nearby which could connect to it. Guessing the original unit died of old age. At the very least this one will get painted black as it currently looks daft.

Looks like the distributor cap will be "fun" to change.



The HT leads at least seem to be relatively recent - based on how supple they feel anyway. Even though it will be an utter pig to get to, I'll probably change the cap sooner than later as it's the sort of thing I usually do as a matter of course on any new car.

The throttles definitely need balancing I reckon. Just based on how much air it feels like is being pulled through each of the air intakes it feels like the left bank is doing far more work than the right.

The raspy noise when the throttle is blipped all sounds to be exhaust. It's hard to tell from a video, but in person that noise is very definitely all coming from the rear of the car.

One fault I had noticed was that I only had one functioning reversing light and that looked very dim. Quick examination revealed a dead 21W lamp in one side and a 5W one in the working light...explains why it was so feeble. Nice easy fix.



Helped by Jaguar having used stainless steel fasteners on the light clusters...oh how I wish Saab did...

While in the area of the rear of the car, I'd noticed that the courtesy lights in the boot didn't work. Turned out they were both disconnected. Reconnecting them restored full functionality.



Confirmed they're switching off (and staying off) by sticking my phone in there and recording video while I closed and then generally messed around with the bootlid. The photo makes them look brighter than they really are though, they're a bit feeble to be honest. For practical reasons these lights may have warm white LEDs fitted in due course to increase their output to useful levels.

The oil pressure gauge sender was investigated while I had the bonnet open (I still love the opening/closing action and the way the latches pull the bonnet closed when you reset the handle). No part numbers I can see on it.



According to the former keepers this was ordered correctly based on the chassis number...and they're reasonably confident that the issue is with the instrument panel.

The other issue which has come up (electrical, no surprises there!) is that yesterday afternoon the previously dead illumination for the tape slot on the stereo suddenly sprang back to life. However it then resolutely refused to go out again, being totally unaffected by anything else. I gave it the benefit of the doubt and decided to see if it would go out after a while on its own. Did it?



That will be a no then. The red LED is fine, that's the immobiliser fob detector and is allowed to be blinking away. So for tonight I've pulled one of the battery leads. On the plus side this takes five seconds to do because it's in the boot. I'll try to investigate that tomorrow. Hopefully it's not a serious problem with the head unit (which otherwise seems to function perfectly) and can be easily resolved.

[white exec]

Mike is the expert here, I wonder if Haynes produced a worthwhile manual for the car? It does date back to when they wrote them rather well.

Those under-bonnet photos explain why you prefer the bonnet shut! And I thought P6B and 2.5XM were cluttered enough. Looks like Jag designers just went for function, and to hell with how it all looked. V6 Citroen a model of tidiness by comparison!

[Zelandeth]

Do have a Haynes manual at least. This lot was in the boot.



The worst thing about that engine bay is that it's pretty much that packed all the way down...not just the top layer.

[xantia_v6]

Slightly intrigued by the little red anodised cylinder by the nearside brace.



In the absence of anything to suggest the contrary I'm guessing this is either a filter/silencer or a check valve attached to a vent line of some description as there doesn't seem to be anything nearby which could connect to it. Guessing the original unit died of old age. At the very least this one will get painted black as it currently looks daft.

That is the distributor breather filter. Earlier cars with the V12 engine had a tendency to collect fuel vapour inside the distributor cap, resulting in the distributor exploding and showering pieces of cap around the engine bay. It has never happened to one of mine, and I think that there was probably an upstream problem causing the crankcase fumes to have lots of petrol in them.

So Lucas, when redesigning the distributor for the HE version of the engine, added a "flash shield" below the distributor rotor and a ventilation system that sucks fresh air through the distributor, the thing you see there is an after-market replacement for the filter, which is usually a clear plastic fuel filter with the open end of the hose tucked away under the bracket that the big diagonal brace bolts to.

Looks like the distributor cap will be "fun" to change.



The HT leads at least seem to be relatively recent - based on how supple they feel anyway. Even though it will be an utter pig to get to, I'll probably change the cap sooner than later as it's the sort of thing I usually do as a matter of course on any new car.

The distributor caps don't give trouble (other than the exploding ones).

I strongly recommend that you remove the distributor (I can give some tips on making that task vaguely possible), so that you can wash the original grease (if still present) out of the advance mechanism and lubricate it properly with some oil. You also need to check that the vacuum advance capsule is still working. Ignition timing is crucial to fuel economy on these engines, and unfortunately they were designed before electronic control of timing advance was a thing. Electronic timing was fitted from 1988½, with a Magneti Marelli system, but it is also flawed and not really practical to retrofit.

The throttles definitely need balancing I reckon. Just based on how much air it feels like is being pulled through each of the air intakes it feels like the left bank is doing far more work than the right.

The idle air is all taken from the LH intake which gives a very misleading impression of the throttle balance. The official procedure for balancing is also misleading and usually produces the wrong results.

If you have an exhaust gas analyser, the best way to get the idle balance correct is to adjust the throttle stop screws to get the same CO reading on each exhaust (as the inject fuel quantity is always identical on both banks).

I use a simple manometer tube for balancing the throttles above idle.

The oil pressure gauge sender was investigated while I had the bonnet open (I still love the opening/closing action and the way the latches pull the bonnet closed when you reset the handle). No part numbers I can see on it.



According to the former keepers this was ordered correctly based on the chassis number...and they're reasonably confident that the issue is with the instrument panel.

That looks like the correct one, although there were at least 2 similar looking devices.

I have a complete spare instrument cluster here (currently NZ) that should fit your car, although it is from a TWR car with JaguarSport legend on the speedo and tacho dials.

Do have a Haynes manual at least. This lot was in the boot.

I don't think that Haynes updated the manual after 1973, so it is not much use for any electrical or fuel related work on the tater cars. The JDHT CD-ROMS are a necessary investment.

The worst thing about that engine bay is that it's pretty much that packed all the way down...not just the top layer.

Removing the air filters gives fair access to anything down the sides for the engine, but access to the front for say changing the water pump is just about impossible without removing the radiator, which is not a small job in itself.

[xantia_v6]

I just had a look at a couple of oil pressure senders, and on the top face next to the terminal, you should find faintly stamped:

PTP
1001/10/EC
700 kN/m²

It occurs to me that on the back of the gauge there are 3 connections made by self tapping screws that hold the gauge into the cluster, and if one of these is loose or dirty, it can cause the gauge to dramatically over-read.

[Zelandeth]

Ah ha! Every day's a school day. Did wonder if something like that was going on. Didn't immediately see any link between the two manifolds at a glance though - looking at the photos I assume the idle air supply is what the pipework running off the rear of the LH inlet plenum is for then?

The digital gas analyser is still a work in progress but I've got an old analogue CO meter which should do fine for this. The handbook states that the idle CO level should be in the range of 1-2%, does that sound reasonable to you?

Hopefully I won't need to remove the radiator in the near future given it was just rebuilt and refitted.

There's quite a bit of slack in the throttle cable too, so adjusting that and checking how far out of balance things are or aren't will be tomorrow's task I think. Aside from anything else I'll be happier knowing it's done, and it should be a pleasant enough job to start to get to know the engine bay.

I'll stick a standard fuel type filter on that hose and route the end somewhere safe, that will look far more in keeping with the engine bay...the red thing on there just now is just wrong for a Jag engine bay.

Was really just looking for anything obviously drastically amiss today like oil, water or fuel leaks (or obvious bodgery), so probably missed a lot of details.

[xantia_v6]

The shafts aft of the throttle spindles have (or a supposed to have) nylon bushings at the brackets next to the cranks. These bushings often disintegrate, giving lots of slop in the shaft and make it impossible to balance the throttles. If those are OK, adjust the rods that join the central throttle pedestal to each bank to take out any obvious slop, while still allowing the throttles to rest on their stop screws. Later you should adjust a bit more slop back into one or the other to get the throttles balanced a light throttle cruising (say at 30 or 40 MPH).

In the absence of a gas analyser, I balance the throttles by fitting a 1.8m length of clear plastic hose between the PCV ports on each manifold (the T pipe that uns across the engine above the fuel rails) I arrange the plastic tube on some pieces of dowel (or similar) so that it forms an 'M' shape with a decent dip in the middle, then fill the middle section of tube with coloured liquid (e.g. antifreeze), and use that to balance the vacuum on each bank, starting at idle, and working up through the throttle range. You must do this with the engine at normal operating temperature.

[Zelandeth]

Read this after I had a fiddle with things, but seems I was on the right track.

The throttle actuation rods were waaaay out of whack, meaning that the throttle pulley was resting a good 1/2" off the closed throttle stop. This was due to the left one. The right one is currently seized in its bushing but has been left soaking in Plusgas so I'll give it another poke in the future. At least with my foot off the throttle the throttle position sensor will be seeing that the throttle is actually closed now.

When I checked everything at rest after that was adjusted, we had 4% CO on the left bank and 0.5% CO on the right.

After adjusting the stop screws I was able to get things stable at 1% on the right and 1.2% on the left. I was kind of hoping I could aim for 1.5% (smack in the middle of the 1-2% quoted in the handbook), but I couldn't open the driver's side up any further without opening the throttle itself because I couldn't adjust the actuating rod on that side.

Right:



Left:


It's a lot closer to correct than it was. The car smelled very obviously rich before, it doesn't now so it seems I've done something right. Idle is very obviously smoother too.

Next up was some detective work to figure out why the lighting in the stereo was refusing to go out.

Pulling it out of the dash revealed clear evidence that someone has been in here before.



Have to wonder if this was more recently when the speakers were changed or if it was back when the head unit was replaced back in 1988.



Helpfully the handbook for the head unit contains a clear wiring diagram which made the detective work a lot easier.



Didn't take more than a couple of minutes to track down that someone had connected what should be the permanent live for the memory backup to the line which should be connected to the dash lighting circuit. That will be why it was always lit up then. Goodness only knows how long it's been like that.

At first I couldn't actually find the wire for this, but after groping around blindly for several minutes I found this.



...Which when tested turned out to have 12V present on it when the headlights were turned on. That will be the illumination feed then.

Having connected this to the appropriate terminal, tested it and stuffed it back into the dash it initially didn't work. Well it did but I couldn't receive anything because the terminal for the power antenna had been pulled out. Second time round, having more carefully routed the wiring bundle we had better luck.

Headlights off:



Headlights on:



It's hard to tell from the photo, but the display is dimmed when the lights are on. Sadly the bulbs which should provide lighting to the buttons on the stereo have burned out, so I'll need to conduct some microsurgery to sort that at some point in the future. For now though it has solved the problem with it refusing to switch fully off. Do wonder how long this has been causing issues with battery drain...

The four screws which were meant to secure the cage for the head unit to the dash were also missing...so someone didn't take much care when they were in here last.

Feels like a reasonably productive afternoon.

[Hell Razor5543]

She is a lovely looking beast, and almost certainly has landed squarely on all four paws/wheels when she joined your family. Give it a month or so and she will be performing as her designers envisaged, and not how she actually was when she rolled out of the factory.

[Zelandeth]

Having a rummage through the pile of receipts, invoices etc (which is about an inch and a half thick).

Front tyres date from 2015...and were £40 apiece.
Rears date from 2007 and were £60 apiece.

Hmm...methinks some new tyres might be high on the priority list. Probably explains the willingness to go sideways when the road is anything resembling wet though!

Cheap tyres on a car like this is just A Bad Idea I reckon.

The game will be finding 205/70 R15 tyres which are not intended for overweight SUVs and therefore have ridiculously stuff sidewalls...or van tyres.

[xantia_v6]

I think that your car is on 6.5" rims and should have 215/65x15 tyres. I have Falken ziex on mine which seem to be ok as a mid price tyre.

[Zelandeth]

According to the handbook it should have 215/70 R15s on. Which at a very quick glance are quite a bit more pricey than the 205/70s currently fitted. Realistically it's not likely that they'll be changed this month, but I'll keep it in mind and do a bit of proper digging next time I'm at an actual computer rather than my phone as it's really not well suited to tasks like that.

[Zelandeth]

Drives so much better with the right amount of air in the tyres.

The brake vibration is definitely up front as it is by far the most obvious through the steering. Nothing through the handbrake if applying some braking to the rear end only through that, so I think the rear discs are okay. Well... they're flat anyway!

Think the next job I'll be investigating will be the kickdown system as currently it basically doesn't. If you nail it she will hold second to 65-ish, but that's barely into the power band...not that this hinders progress given the torque available. However it became apparent quite how much pace I'm missing this way by taking manual control today and giving it a bootful in 2nd from 60mph.

Observations: Yeah...that is rapid. Also: Oh my word, that noise...

[xantia_v6]

As you may have worked out, the kickdown is operated by a micro switch at the engine end of the throttle cable, sits above the fuel rail. (you can't complain about the access!). The switch is triggered by tension in the outer cable, so if the cable is adjusted wrongly it won't work. It is not unknown for the switches to break with previous rough handling.

I have previously thought of building a more intelligent kickdown trigger, that takes rate of throttle movement into account to give part-throttle kickdown.