1974 Jaguar XJ12

Thanks for that.
Still got the TR6?

Suspect you can get a replacement cap off something with a nice new float switch included ?
Almost certainly a non Jag one will fit and not have a Jag tax applied...
James

Mini maybe?

www.ebay.co.uk/itm/195856448553?hash=item2d99f43c29:g:-zoAAOSwT4lWTKxm&amdata=enc%3AAQAIAAAA8JzAHvcNakvfBQSGkaPMkZNGr7rqJeAdnEfDwIYZkOxZGQc%2FGlDydd5Sthag0ux45Tpq%2FLkg0EgbHvvvPak%2BPU9zBhhPnEktANhMF2zjZ2s1qZ4hww1%2FWmW5zCUBgMrqzMesHBn4M6wjb2%2FTFAvFiW7bz3c%2FzRtP%2FYCwSqPuTTR3FhXsA3iwM2kN6pXHSAGb5JY%2B%2FJq%2B02nIE0Jq2CB8e1j7x2ZOEynyhzbRQ7URaZeHEPkCgfn8EhON2t1HzDIxc9hlLZFN4681AU5G9kULWiScPWMMrpasjUyNvHMkqnkgfp4Da8ED8Ny0nL5aw24tHQ%3D%3D%7Ctkp%3ABk9SR47E8J6pYg

Thanks fellas.
I’m going to have a play with this. If I can get it apart I should be able to put some sort of a float in it. A cork would work I think.

At last the tank is sealed. Followed the directions to the letter.
Hopefully it will work and be forgotten.
Very time consuming though.

Also flushed the brake lines with metho and compressed air. Discovered that the front brake hoses I'd been sent were incorrect. Apparently there was a change to metric/Jaguar complications/whatever but the correct ones are on the way.

Put the new vee belts on, can only imagine what a cow of a job that'd be with the rad in place.
Also got the coolant cross pipe installed.







That’s the only photo I took all day.
Thanks.

Finished the other side exhaust. Hopefully it will be rattle free, but it is close in places. We'll see.

Got the rad back from the man. Actually not my rad, but one I was given. The rad man said mine was not much good - evidence of pressure leaks. He said you fix one and another would likely appear nearby.
So I said recore it. No point in paying him to do a temporary fix, and then having to recore it a few months down the track.
That was on a Friday about a fortnight ago. He said he'd get it organised on the Monday.
But over that weekend I was at a car club thing and a guy offered me a radiator he didn’t want.
I took it to the rad man on the Monday morning and he said it looked good.
Ended up he removed the tanks, found it was good, cleaned it out and I kept my original, probably as scrap.
So I took a carton of beer to the chap that gave me the replacement - he saved me much more than that!

Anyway the rad is now in place and the system full of a light coolant mix. Hopefully it will still be full tomorrow…
Plan is to run it up to temp a few times and then do a flush.






Really not too bad a job remove/replace radiator in these cars.
Bonnet is easy to remove, and considering it’s got the grille and lights, reasonably easy to handle.
And once you know the couple of tricks, it’s not too bad to get the rad out and back in.
I took care to line up the hose clamps to make it easier to get at them in future.
Hoses are always busterds to get off, on just about anything.
You need a bionic arm/hand. There’s never enough room to get any strength into the twist/pull motion needed to get them to move. I really, really hate hoses.

Also had a bit of a play with some T Cut.
Fantastic stuff. Dad and I had a gallon tin of it years ago, long gone now.
I haven’t seen it available for ages. Original that is.
Bought a couple of 500ml bottles of original, not the coloured stuff that’s readily available, after a bit of a search.
The paint, where it’s original, comes up very well. There have been some horrific repairs though and they’re the bits that are going to spoil it.
But the chrome and glass clean is a joy to behold.
Too bad it’s only one door so far.
And I can’t wait to get stuck into the interior. It’ll be hard to leave this car to work on that Triumph!

Thanks.

The small holes in the outer shroud are supposed to damp the response but they only damp sudden changes, our minor is missing the shroud and I look on it as confirmation the level warning is working.

Thanks Kevin.
Yep Mark, I had thought about a sleeve of plastic or ally, really doesn’t make much difference. Ta.



Received the correct brake hoses in the mail today. Installed them and so now the brake system is ready to fill with fluid and bleed.

And blocked off all the vacuum points where I'd removed various hoses. Quite a few of those, the engine is looking much less cluttered.

With fuel in one tank and no apparent leaks, it was time to have a go at starting the beast.
No luck. It turns over just fine, but won’t fire.

Pulled the plugs and they’re wet, so it’s getting fuel.

Grounded a plug and spun the engine to see if it’s got spark. It has, but not what I'd call healthy.
Cleaned the plugs and checked the gaps. They have a vee cut into the electrode, never seen that before, no filing these.

Put them back in and still no fire, just a very occasional kick.
These things have ( 50 year old ) electronic ignition. And I’m not very good with any type of ignition really.

Found a thread on Jag Lovers with a reply that included a short troubleshooting guide.
And with it I worked out that voltage at the coil was low.
I couldn’t find a reason for that. I checked the battery to body connection. But I can’t find an earth strap to the engine to check.
So I ran a wire from the battery + to the coil + and woohoo. It’s a goer!
Didn’t run it for more than about 10 seconds as I need to reread the instructions on bleeding the coolant system. There are dire warnings in the manual about the consequences of getting that wrong.
As I typed, I realised that if running a positive wire cured it, it’s not an earth problem. Is that right?
If that’s right, what do I look for? A bad connection on the back of the key?

Anyway, it doesn’t matter.
I’ve had it running, so I’m having a beer to celebrate!
Then I might go and put some tools away and have a tidy up. God knows it’s needed.

Cheers!

Sounds like a poor connection somewhere on the coil feed?
No ballast resistor wire in the circuit?

Check Ign barrel connections for tightness.

Great news that it runs, for the ignition I am assuming you have a OPUS system, this link explains how it works.

www.jagweb.com/aj6eng/ignition.php

Putting 12 V directly to the coil will give a bigger spark but I'm not sure this is a good idea.

I would start by checking you have 12 V at the White wire at the ballast and are getting 12V during crank at the white/blue wire, then check the resistances across the terminals of the ballast resister.

ie

1 ohm wu to wg
0 ohm w to br
0.8 ohm wu to w

you can ignore the tacho side for now.

Next I would check it has the right low impedance coil and it's connected the right way round.

it's not shown on the diagram but the amp will need an earth to work (it's switching the -ve side of the coil to earth), this must be through it's case so check this is cleanly earthed.