Tony,

Wait for a helper.

Rotate that engine by hand, not the starter motor, as that starter motor will move it way too far, and we are talking 30deg between strokes here.

Access to do it by hand it terrible, but it is doable, take your time. Forget that timing mark for now on that pulley, it may have slipped, but can be sorted later.

Get 1A on TDC Comp stroke, look at the rotor, and it should be as Greg has described. If that distributor has never been out or moved, than common sense dicatates it is as made.

Please do not mess with moving that distributor at this time, That will screw up things seriously if it is done wrong.

Have you replaced that rotor????. My reason for asking is simple. When the old rotor is removed, you must pull UP, and most V12's are in this group, that OLD rotor is stuck solid on the centre shaft, and by pulling UP as hard as is neede, the centre shaft becomes disengaged with the lower workings, and when it is pushed back down, is out of phase, and I have done it, so it is a very simple blunder trap to fall into.

I will read the whole thread again later tonight when I get home, maybe the answer is in here somewhere.

 

Hi Grant

Just for future reference in case I have to change mine one day, if you can't pull the Rotor Up, how do you get it off to change it?

Do you have to break it, by hitting it with a hammer on both sides? or something?

 

OB.

Maybe 2 FBHammers.

What is needed is to look at the star wheel, down below the rotor. Use a screwdriver, or whatever is suitable, and PUSH DOWN on that star wheel whilst pulling UP on the rotor.

That rotor shaft is held in place by a PLASTIC ring on the "tip" on the inner shaft, and is just visible when the rotor is off.

It WILL NOT take much upward pull to break it, and then the shaft will rise up suddenly, stretching the 2 springs down below, and unmeshing the weights etc, and generally just ruins your day.

I have had to cut a few rotors off with the Dremel over the years, and Anti Seize helps a tad with the new rotor, but the "push down" is standard operating procedure for me no matter what.

 

OB you have a Marelli car the rotor is held in by screws. I think Grant is referring to Lucas dissy as the OP has

 

Warren,

OB got plenty of XJ-S's, and I think a Lucas among them, then he goes to the dark side with a Benz, oops.

 

Hi Grant

Yes there is a Lucas in the Fleet, so thanks for pre-warning what can happen when doing the Dizzy on that.

I'm going to Whisper this quietly but I love that Merc to bits and while I am a member of that Forum, its a little bit like a 'Ghost Town' over there, as

these Cars don't seem to go wrong.

Also took your advice and got some Contact Cleaner for the Relay and now the Car is running like a Bird.

Warrjon well spotted, most of my Fleet are Marelli.

 

up date have cranked eng by pulley, no 1 on A bank is in line with 5b on order of firing order on distributor, going to remove all plugs 2mw and see where TDC is on all cylinders, to see what firing order it is, i some how think the firing order was changed before i got car,

 

Tony, please be clearer.


What EXACTLY do you mean by "no 1 on A bank is in line with 5b on order of firing order on distributor"?
Are you talking about which HT lead post the dizzy rotor is pointing at in the cap; or are you talking about which CYLINDER the rotor is pointing at, or what?


Please try to be specific and exact in your reply. This is a link to a simulation of the firing order when correct. It shows both the dizzy rotor against the dizzy cap HT post, AND the cylinder being fired by the spark. A clever guy on the forum did this for us all, and I am ashamed to say I have forgotten who it was.
http://cimg8.ibsrv.net/gimg/www.jagu...df9e9b7e93.gif
The firing ORDER cannot be changed, all that CAN happen is that the dizzy rotor is pointing at the wrong HT lead when the spark comes. And THIS can only happen if the leads are on wrongly, OR if the dizzy has been removed from its drive gear and rotated and replaced in the wrong position. Your car may had this done, and the HT lead order changed to compensate, and when you replaced the leads CORRECTLY they were incorrect because you did not know the dizzy had been rotated to a non- OEM position.


SO:

• get A1 piston to TDC on the compression stroke for sure.
• then fit the rotor arm to the dizzy
• TELL US EXACTLY which CYLINDER the rotor arm is pointing at. (Remember it should NOT point at cylinder A1 if correct, it points at the correct dizzy cap post, see diagram)

 

Number 1 A cylinder on compression stroke, rotor arm is pointing to 5 B on HT lead post on distributor,

 

let me get this right siting in car A bank is on right, B bank is on left, firing order is 1a 6b 5a 2b 3a 4b 6a 1b 2a 5b 4a 3b, Right,,, but all books and web sites say on all car number 1 cylinder is closest to rad, on strait 4cyl 6cyl, and on v engines, same v6, v8, v10, v12, yet when u look from the front of my car first cylinder closest to rad is number 1 on B bank,?????????

 

Tony,

You are partly correct with the #1 cyl relation, but Jaguar are different, as the 6cyl XK engine has #1 at the rear, no idea why, better things to think about.

Your V12 firing order is SPOT ON.

I would tke `A lead, plug it into the cap WHRE THE ROTOR IS NOW, as you have confirmed 1A comp stroke TDC. Then contunue around the cap in an Anti-Clockwise direction with the othe rleads, then carnk the engine and see what happens.

Greg has probably sleuthed it, as to some lazy mechanic long before you owned the car doing something with the distributor, got it wrongly position, but timed OK, so shuffling the leads in the cap is the simplest way for him to cover up his stuff up. The engine ran, the owner paid the bill, job done. Let some poor bugga sort it out later in life.

 

Just to clarify exactly Tony. When grant said
"I would take `A lead, plug it into the cap WHRE THE ROTOR IS NOW, as you have confirmed 1A comp stroke TDC. Then continue around the cap in an Anti-Clockwise direction with the other leads, then crank the engine and see what happens."
He means connect plug A1 lead to the dizzy cap post at which the rotor is now pointing, in your case the dizzy post that should be for 5B but it seems is not in your case. To be 100% sure you understand, 5B is the cylinder second nearest the cabin on the LHS (UK passenger side).
THEN, attach the leads in an anti-clockwise direction, in the correct firing order that you listed above, that is the next dizzy post will have the lead for 6b, then 5a 2b 3a 4b 6a 1b 2a 5b 4a 3b.

 

UP DATE on car have rechecked every think on car, spark, fuel compression. all o/k. i don,t no what is happening, on compression stroke on any cylinder, spark is 180 deg on other side of compression stroke, but if i crank car over 3 or 4 times it all changes, so its not 180 deg out some think is changing firing order.

 

Tony
Are you are saying that the timing is actually changing as you crank the engine? How do you know this is happening, please describe carefully what happened to give you the idea the timing is changing as you crank over the engine.


If it really is changing then either:

• the distributor is NOT properly engaged in it's drive from the jackshaft.
• or the jackshaft cog which is driven by the timing chain (as are the cams) has stripped some teeth,
• or something similar has happened with the timing chain and its various sprockets and drive teeth.
• or the rotor arm is slipping on the dizzy rotor shaft

This is all possible, but the most likely is the dizzy not engaged properly.

 

Greg, rotor arm is not slipping, can feel resistant when trying to stop it when cranking, distributor has not been unbolted, when i get tdc on any cylinder the rotor arm is pointing to the opposite side. on spark of distributor, when i crank eng over a couple of times it changes to another point.

 

Tony, if the rotor is 180 degrees out, it seems unlikely that the compression stroke is properly identified. BUT what I want to know is HOW you know the cylinder IS on TDC of the compression stroke when the rotor is pointing at the wrong dizzy post. IF you are relying upon the crank pulley mark not being aligned as it should, you may be being misled, as if the crank damper has failed, I THINK the pulley can move without the crank itself (and thus the cylinders) moving. SO, test again with the A1 plug out and see when the piston really is at TDC on the compression stroke, wher the dizzy rotor is pointing, and report back


Finally if this test proves the rotor position really does change after you crank it over, so that the rotor is moving out of phase with the cylinders in a random manner, UNDOUBTEDLY the drive between the crankshaft and the rotor is somehow slipping. Finding out why is a large engine disassembly job.


So let's be 100% sure before worrying. Do the test I outline and let us know.

 

Mmmmmm.

I reckon the distributor shaft has disengaged from the lower shaft drive pins when teh rotor was changed.

What I understand so far:

Car ran fine.
You parked it for Winter, as you have done many times in 12 years.
Car did not start in the Spring wake up.
Lots of things done, replaced, tested etc.
Distributor cap and rotor replaced.
Distributor has NOT been unbolted, loosened, moved etc.
The rotor "appears" to be randomly "floating around". This would occur, as Greg has said, by the distributor not being engaged/meshed correctly, BUT, you have NOT removed the distributor, so not that.

The top rotor shaft is SO EASY to pull out of its mesh with the lower shaft, at rotor removal time, that this is still high on my suspect list, and that rotor shaft will "float around" exactly as you are describing if that has happened.

The timing "ring" on the crankshaft pulley can delamenate, and that ring will move around, making timing via that plate and marks useless.
That is why, when there are so many unknowns at play, I suggest the physical timing with the Comp stroke and the wire down the plug hole, to feel the piston rise to the top, A helper and hand turning the engine is mandatory for this procedure.

ANY plug can be used for this, and since you have that HUGE a/c compressor blocking #1 plugs, use #2 or #3, and just ensure that the rotor POINTS AT THE RELATED CAP POST for the cylinder you are using when it at TDC Comp Stroke.

 

Car is now running have changed all leads to dis around firing order now is from no 1 mark on dic cap= 3A 4B 6A 5B 2A 4A 3B 1A 1B 6B 5A 2B, slightly missing but i think the 2A 4A and 1B 6B may be wrong, will have a play with it tmw, THANKS TO ALL ON SITE.

 

Well done Tony!

Glad you got her running, was it just the Timing after all?

 

orangeblossom, yes leads from dis don't now how the firing order came about, cant under stand it i have changed plugs three time in past 12 years and changed dis cap 6 years ago i all ways fixed leads as in book I THINK, i don't have any record of this firing order, try 2mw to sort misfire , will post it on form.