Here's an odd one....Plug gaps

Steve,
I'm pretty sure its not the transmission, the box was rebuilt a while back (it is an auto, I'd like a 5 speed too but not sure if my feet would fit!!) and it seems pretty tight.
Also the 'smoke' seems to come from the area in front of the first carb (nearest the front of the engine). Its hard to see where as the manifold has that shroud cover and it stops quite quickly when the engine is not running hard.
Now whether its water or oil is another thing, I think oil, the smell is quite 'burnt' and there seems to be a little oil around the top of the engine. The smoke I get out the exhaust could be either, the water level was low when I got it so I guess it could be water, the temp on the engine is low all the time so it seems to run fairly cool. I'm starting to think I'll have to strip that side of the engine down so that I can see the area where the smoke is coming from. It may be rocker cover (most likely I would guess) or possibly head gasket on that side and that may account for the oil leak. Trouble is whilst its stripped that is the time to get the head reworked but then both sides....Where do you stop!
Maybe I'll see if its the rocker cover leaking oil. If not I'll take the head off and check the gasket (replace it anyway)
I'm pretty handy on the mechanics (restoring a 1929 Model A ford at the moment as well) but have you ever done anything like head removal before? With all those cylinders the timing reset must be a little more complicated that Henry Fords 4 pot A series !!!
On the misfire, I've yet to check the advance / retard but have checked all the vacuum hoses and they seem fine. I also doubt inlet manifold leaks as it only happened when I disturbed the plugs but I'll check as well
Cheers
Shaun

Shaun,

Do you have an automatic or manual? I have an automatic transmission in mine (I'd love to swap for a 5 spd, but that's another story). When I first got the car, I had a similar problem with smoke from under the bonnet and smell like oil burning. Further investigation showed something was dripping onto the exhaust pipes at the back of the engine. Thought it was the main rear seal on the engine. Turned out it was the tranny leaking. I ignored the leak until the box needed to be rebuilt. After rebuild, no more leaks, and no more smoke. But you should check this out. If you're getting that much smoke and smell that it is noticeable, you should trace down the source and, if possible, fix it.

Even more important than dealing with leaking oil, if it is leaking coolant, you could end up with a major problem if you overheat -- dropped valve seat(s). Then you're talking at a minimum rebuilding the heads, if not an entire engine overhaul or even a whole new engine. Overheating is the biggest danger with the Jaguar V-12's. Check all hoses and connections carefully and make sure that the "smoke" is not coolant leaking from the system. Plus, your nose should tell you whether it is oil burning or coolant. They are two very different odors.

Steve Weinstein, JTC-NJ
'72 E-type 2+2
'89 XJS Coupe

I'll check the points raised, thanks. My only thought that it was plug based was that prior to re-gapping it ran fine. I may have disturbed something when I took the plugs out, I did notice that the breather pipe into the distributor cap was off (that is the one supply air to the cap from the filtered hose). I've since put that back on but no differance.
The cap appears fine (its only a few miles old) but I'll check anyway, I have run the engine in the dark to see any external arcing.
I've tried pulling plug leads as well but there are so many pots on the beast it is ver hard to see if it makes it better or worse.
The smoke at idle from the exhaust is fine, it blows smoke on hard acceleration or over-run but that I'm trying to find out if it is oil or water, the smoke is neither blue or white (not that I can see from the driving seat). The smoke I mention in this post comes off the engine and up through the bonner louvre. I guess its oil coming from the top half of the engine (rocker cover?) and onto the manifold. I may have to strip that side down to see where the problem lies...Mind you I'm then only a short step away from a top end rebuild
Will keep you posted and must get that picture done!!

Cheers
Shaun

Shaun,

Forget the plug gap -- have you checked your distributor? Is the mechanical advance frozen? How about the vacuum unit, is it working? Have you traced down all the vacuum lines and checked the carbs and manifolds for vacuum leaks? Gulp valve connected and working properly? Are your carbs balanced, mixture adjusted properly? Did you check the distributor cap carefully to be sure there is not a hairline crack in it?

What you are describing doesn't sound like a plug gap issue. You can get the spark a little hotter by opening the gap a bit, but I wouldn't go beyond .035. Like I said on the other thread, I gapped my new Champions to .025 and they work just fine. (Are these old or new plugs. If they are very old or of indeterminent age, try putting new ones in.)

Also, while it is not unusual for these engines to blow a little blue smoke after start-up (a little oil works its way down throught the valve guides when the engine is sitting, but burns right off after starting), if you are putting out significant smoke at idle, there is something more serious wrong here. I'd make checking that out as much if not more of a priority than clearing up the rough idle.

Steve Weinstein, JTC-NJ
'72 E-type 2+2
'89 XJS Coupe