Looking to get some guidance on spark plug changing. I've read the guide online and it was very helpful, but I'm having trouble with the back 6.

Crows feet were suggested, but i can't find the sizes required. Would a standard 10-19mm set be ok, or do I need larger?

Will be posting more later, discovered petrol in the oil last night...

 

Petrol in the oil means no spark or an injector stuck open. Don't run the engine, use an oil suction gadget with the tube going down the dip stick tube. Ignore it at your peril (pronounced bearing knock)!

I use a simple universal joint for undoing / tightening the plugs. I have a semicircle rod at the end of a 10cm rod sitting on a flex rod to extract the plug leads.

I use a fuel hose fitting tightly on the connector on top of the plug to fit the plug in the hole and to turn the first few rounds.

 

Thanks for the tips. Do you have to remove the throttle plate if you use a universal joint?

I think I'll make a new thread for my engine issues, to keep everything on topic.

 

Another approach to plug changing is "clearing the Vee".

Most everything comes out: dist cap and wires, cruise control servo, throttle pedestal and linkages. The vee is cleaned of debris, vacuum hoses renewed, brittle/short circuited wires repaired....the whole nine yards. Of course the spark plugs are easy to change with everything out of the way. And....the distributor advance mechanisms can be checked and repaired.

You may find the cause of your gross over-fueling as well.

On reassembly the throttle gaps are reset and the linkages synchronized.

Lots of work but you'll be addressing lots of issues that need addressing on virtually all old Jag V12s.

Just a thought

Cheers
DD

 

If it is umpteen years since it was done yes. Otherwise, no, you don't have to remove anything and in fact I usually do not.

 

BTW, if the no 1 plug is difficult to access with the tool you have (It should be a s slim as possible, none of the cheap bulky ones) You can put a special socket of the pass thru type where the ratched sits outside on a hex. Then use a normal open spanner on the pipe to loosen and tighten the plug.

 

I'm currently in the process of changing my plugs too. The "A" labeled and "B" labeled wires were found on both sides so i have a silly question here... Which side is bank A and which is bank B? I'm guessing A bank is the drivers side?

 

"A" bank is the right side; that is, passenger side in USA

Cheers
DD

 

thanks doug. you're the best

 

Doug, don't want to sound to weird but what is the VEE? and other abbrevated terms? Im new to dealing with my 1984 xjs v12.

 

The "Vee" is also known as Death Valley, and it's the space between the two banks of cylinders where the distributor is. Lots of heat there.