Since I've received great advice from this forum, let me pick your brains once again!

I've been going through top to bottom maintenance on my 86 Vanden Plas. She only has 44K miles in meticulous condition, so it's more about age issues. I've done fluids, belts, rebuilt front end rubber components, misc vacuum lines, etc.

The rotor, cap, wires, and plugs were done 4K miles and approx 13 years ago. is this something that's good to replace due to age or do you feel that's no necessary due to mileage? Saw minor oxidation inside cap during a quick look.

Note: I do have a slight XK 4.2L "lumpy idle" and have read countless posts regarding solving, or shall I say chasing it.

Option 1 - leave alone

Option 2 - Cap, Rotor, Plugs (Champion), and wires

Option 3 - Try out the Pertronix distributor, coil, wires, and plugs

The reason I would consider Option 3 was such glowing reviews and potential to reduction in my slightly lumpy idle. The cost is so reasonable. I also read that early V12 coils help a bit too.

Thanks again!!

 

I would lean towards Option 1, or maybe just change the spark plugs if you want to do something.

Oil the distributor advance mechanism per the manual and check the timing too .

Good luck!

 

Those things are not really subject to 'age' problems....providing they live in a reasonably dry and rodent free environment.

However, were I in your shoes chasing the infamous idle tremble, I'd go with option 3. Hope springs eternal.

Or, an easier first/next step, option 1 but with a Lucas DLB170 coil

Don't forget to have your injectors professionally cleaned, and new injector seals, too

Cheers
DD

 

I'd go with "tuning up" what is there.


1. Starting with running the engine at night, in the dark. A "Tesla coil like" light show? indicative of leaky HT wires.


2. Remove each of the 7 HT leads and clean the ends and the sockets.


3. Remove the spark plugs. Do not sand clean them. Unless they are really "goopy", which they probably are not, just check the gap and adjust if necessary.


4. If a ballast resistor is present, verify it's need. If no need, dump it. ^v coil in a 12 v system???


5. Clean the underside of the distributor cap. Note the condition of the center button. The contacts will show erosion. Usually not an issue, unless it is extreme.


6. Remove and clean the low tension wires between the distributor, amplifier sand coil. These may be dry and brittle. Replace f excessively so.


Enjoy!!


Carl

 

This is all really good stuff.

Doug, you've posted luck with that Lucas DLB170. I was actually thinking the same thing and have been keeping my eye out for one with limited success.

Carl, you mention "If a ballast resistor is present, verify its need". It is there, but what do you mean by "verify its need"?

Regards,
Doug

 

Doug:


The ballast resistor dates back to point and condenser cars.


Some EFI cars with electronic ignition had them. Why? a couple of reasons.
Using 6 v coils in a 12 v. system. Or, just a remainder from earlier days.


If not needed, why have it ? A waste of v's and a creator of unneeded heat!


EFI car and 12 v coil? dump it. Not needed


Carl

 

Well, all the advice is excellent, but curiosity got the best of me!!

From a cost perspective, I reviewed everything and ended up ordering the Pertronix system to try out. A cap and rotor costs around $50 shipped from SNG Barrett, the Pertronix distributor, cap, coil and rotor was $200 and if I like it I can technically sell the used but functional parts INCLUDING the now, not needed amplifier.

Is swapping out the distributor as easy as it seems or will I be cursing profusely like most projects I tackle :-)?

 

Why, I dunno. victory was within your grasp!!


Not that Pertonix is a bad choice. It isn't. Beats points and condenser by miles/kilometers. But, if in good shape, the Jag system is fine.


No cussing. just proceed in increments.


Carl

 

Notes, pictures and drawings before any changes.


I get it. son says I always do things the hard way. Guilty as charged.


But, I challenge myself to use verbage other than expletives to let off steam.
Enhances my phraseology!! Exercises my grey matter. I hear that is good for we octogenarians!!!


Carl

 

Well, so far I did the plugs, coil, and ballast delete. Plugs looked way rougher than I thought, but that might have been from excessive short distance drives.

Figured I'd do one by one and judge differences, if any.

Ballast Removal - No differences at idle or driving
ADD New Coil - No difference at idle, felt more responsive driving.
ADD New Plugs - Drives great, if you can believe seems like lumpier idle. Replaced with new identical Champion

Up next Magnecor wires.

I think I'm chickening out on doing the distributor myself. With all the projects I tackle, I don't know why I'm avoiding timing. Keep getting this vision of a disabled car and me begging my mechanic to do a house visit. Feel free to talk me into/out of it!

 

I still don't understand changing out a low mileage Jaguar
distributor for the Pertronix????


But, if you must....
1. Crank the engine ignition off to TDC. Note the rotation of the rotor. CW or CCW.
2. Remove the cap and note the position of the rotor.
draw a picture. Take a photo.
3. Track each wire to the spark plug. Mark on your drawing.


4. Remove the Jaguar cap, wires in place. Center one not so important as the others.


5. Remove the Jaguar distributor.


6. Insert the Pertronix with rotor in place. Make it point to the same place as the
Jaguar unit. Clock hand position reference handy. 6,12 etc.


7. Attach the Pertronix cap. With the Jaguar cap as a reference, replicate each lead the same way,


8. Now. to the Pertronix instructions. The Jaguar amplifier is out out. Just + an - Lt leads to deal with!!!


9. Review your work carefully while the engine ids on TDC!!!


It should run just dandy. Caveat: Major difference is replacing a worn out distributor with a fresh unit. Minor if any change when replacing a good unit with a new Pertronix.


If you get in trouble, come here. Better Jag mechanics than I on stand by...


Carl

 

Quick question. If the plan is to line up everything identical to the old distributor, then what's the necessity of insuring you're at TDC?

 

As in many endeavours, a base line. A known point to go back to in the event of issues.

 

My last S3 XJ6 had a bad idle, and the only part of the system that was fine was the ignition.

Blocked fuel filter, blocked injectors, vacuum leaks, faulty air injection system, EGR valve rusted partially open.

I deleted the air injection setup, plugged the threaded holes in the head with 1/8th BSP plugs.

Fitted a blanking plate on the inlet manifold after removing the EGR setup, and fitting a blanking plug into the exhaust manifold where the EGR pipe originated.

Drained the fuel tanks, cleaned out any rust particles, ran two filters prior to the EFI fuel pump from each tank feed line, replaced the Ei filter as well, removed and cleaned all the injectors too.

Then it came to sorting out the rest of the vacuum lines, having delted the air injection and EGR, i removed two vacuum lines, replaced the ignition advance vacuum line, but after bypassing the faulty temp sensor, direct line for the fuel pressure regulator (which I also tested out for correct pressure)

Having had the inlet manifold off for all of this, I cleaned the manifold up at the same time, removed all the carbon deposits, thortoughly cleaned the idle control setup, cleaned and reset the throttle body to specs.

I did all this as the car had ran on gas for ages and never used the EFI setup so it was all seized or just hard from heat and no use.

Ran infinitely better than it ever did when on gas, and made the engine bay a lot nicer thing to look at with everything removed and tidied up.

After all that, the ignition system just needed new plugs and the timing to be set, I would have definitely gone to a modern distributor setup like Petronix if something went wrong with the distributor or the amplifier.

I'm considering something extreme like the MegaJolt system which is basically an ECU for ignition only, (usually when running a carb setup for fuel) which allows the use of a modern coil on plug ignition setup, does away with the distributor completely, allows much more tunability over a dizzy setup, but is way overkill for the average setup

 

Carl, thanks again for your help. I went ahead and installed the Pertronix unit. Took my time and it was definitely easier than I had anticipated. Your advise to take plenty of pictures made it a snap.

The install went well, however, I still need to confirm the timing is right. My dampener has surface rust on it such that I can't see any markings. In the meantime, I drove the car noticed a touch of pinging, so I retarded the timing a bit and all is good (about 1mm CCW).

The car definitely started quicker and is more responsive throughout the rev range. Idle was initially up about 200 rpms (not sure why), so I backed it off a bit. I still have a rumble at idle, but it's much better and more isolated if that makes any sense. The blips still occur but are more distinctive and not lumpy all over as it was before.

I'm glad I did it and like the Pertronix, however, more because it's inexpensive and eliminates the external amplifier and ballast...and is 30 years newer!

I'm thinking of having the fuel injectors serviced next.

 

Well, did the injectors now too. No change even though they looked awful.

This idle is now officially worse than ever!! I know I have to get the timing sorted out. My timing marks are simply MIA. Any tips on timing with no markings??

Pretty bummed as I thought perhaps the injectors were the final straw. In hindsight, the idle mostly worsened with the ignition update.