Oh, I see…you can replace the rings on that engine without removing the rods from the crank…sorta like lifting a 2-stroke’s cylinder(barrel) off the crankcase…that’s why you have talked about removing the liners. In that case , my advice would be of little value since others here have already addressed this and/or have the appropriate experience to render better opinions than myself.
Dear Tom,
Don’t even think about trying replace the piston rings by replacing the liners over them instead. It isn’t going to work as you mostly won’t be able to see what you are doing and you’ll need to reseat the liners back into the block as the primary task once you have removed them, rather play with piston rings at the same time.
With any luck, the liners are still nicely fixed in position by all of the rusty crud and sediment in the bottom of the block. Clear all of that out and fit liner clamps if you have them. Once the sump is off, undo the rods one by one and pop them out through the top. You’ll see what bearings you need for the crank as the correct number is written on the back of the shells. Use an ordinary piston ring tool to put the new rings back on from the top. If you dislodge the liners then you’ll simply have to do all of the above (as planned) but also refit the liners aswell and there is no point creating work for yourself.
Just do it according to the manual.
kind regards
Marek
Hi Marek,
Thx for your input, so you would advise to open the rods at the crank and get piston and rod out (as originally planned) replacing the bearings when reassembling. Well Nigel and the Kirby suggest to draw the liners (which I am a bit afraid) as one way of doing also to be able to have them checked probably.
In above statement i better wrote “from downwards”, i did not mean to take the pistons out through the bottom. I have my engine lifter now and the oil sump is accessible. I plan to remove that tomorrow and will provide pictures of what I find.
But all of you would advise me to change the rings or can I visibly check if they are worn or not ?
So I am supposed to use the same bearings as currently installed not an oversize ?
Manual ? I have Kirbys PDF pages and your assistance here which s very valuable for me.
Best Regards
Tom
The need to grind the C’shaft will depend on the amount of wear that has happened (if any) to the journals. Are they grooved through the bearings picking up foreign particles?
The bearings will have a -10 or -20 on the bearing to conrod surface if they have been replaced after the crank has been reground. Same applies for the main bearings and journals. If the bearings do not look as though they have lost too much of the white metal coating you could try plastigauge to determine what the current clearances are. They should be .0015"-.0034 for the big ends and .0015 to .003 for the mains. Big ends can be under ground to -40thou (.040")
As far rings are concerned much cheaper to replace now than once the engine is back together.
Dear Tom,
I’m suggesting that you don’t simply add to the work by doing things that may not be necessary as the project you have taken on is big enough already…
Without the manual for your car, how will you know what size something is and therefore whether it is the wrong size now? Whilst Kirby’s “Book” is a useful supplement and interesting reading, he hasn’t owned an XJS for a long time and has simply collated stories relayed to him by others, which well intentioned though they are, may reflect personal bias and the fact that many cars have been poorly maintained. Useful as it is, it isn’t a substitute for the shop manual.
For example, an “A” piston and liner is not the same as a “B” piston and liner and “A” and “B” mean different things in different contexts. If you don’t use exactly the same language as Jaguar did in your descriptions, then it’ll be easy to get conflicting responses from respondents.
Do remember to keep all of the disassembled parts together with what they have been taken apart from and scribe them or carefully box them separately from each other. They mostly do not go back together the same way if you mix them up even though they look the same.
kind regards
Marek
Hi Marek,
Neither my English nor my mechanical knowledge are at a high level and there are things that I can definitely do better than repairing a V12, fixing the interior of an E-Type or reassembling the car 
But up to now i did not miss any valuable information from the workshop manual and information on the internet seems to be comprehensive and more up to date than a WS manual from the 70’s. Vacuum blasting or plastigauge did not even exist that time and sometimes youtube video is more helpful than 3 lines in a workshop manual.
My pistons and liners are of Type A but i guess piston rings are the same for both of them. For the critical parts of course I marked and stored them in the precise order and almost every step of disassembly is being documented.
I’m not planning to exchange every single part of my two engines and believe some shops just do because cleaning and measuring parts can become more expensive than new ones @ their rates and they don’t have to pay for them.
But I also raised myself the question:
With a standard/not tuned engine what would a good mechanics do different from a bad one and how can someone ask 20.000€ and more for a complete engine overhaul ?
Best Regards
Tom
That figure for an overhaul would probably include a lot that you might not need to do! like crank grind, pistons and liners, valve guides, valves and seats, new tappet blocks, tappets valve springs etc etc.This type of replacement is expensive,hence the £20,000 Euro price tag.
Hi Jag-Lovers !
Due to many reasons my V12 project was delayed for quite a while but now I’m back on track 
My “training-engine” (not the matching number engine yet) is now growing together again. I stayed with the old liners and pistons as i tried to rebuild this first engine as cheap as possible with only the most necessary parts. I used new piston rings and big end bearings though but did not remove the crankshaft. The heads were cleaned with high pressure water, skimmed slightly (showing some corrosion at some water contacted areas) and equipped with new valves, springs and valve stems of course. Only one valve guide had to be exchanged and the valve seats were reworked by a shop. I have now refitted the heads and valve housing using few silicon sealing as recommended.
Before i removed the camshafts i marked their position both on the camshaft wheel and the timing chain so I hope i will not need the Camshaft tool/TDC method to have a correct valve timing.
I will keep you updated - thanks for you support so far !
p.s: if there exists a thread of things “never to do” i have a nice story
As the liners showed some slight corrosion i had the idea to use an old piston with compression rings to “clean” the liners by inserting the piston upside down. this was quite effective but once i pushed the piston to far in … guess what ? the upper compression ring extruded at the bottom of the liner and the “piston tool” was stuck. Took me about 1 hour of thinking and trying until i could finally crack the ring and remove the piston again. In my fears i would have had to remove the crankshaft … but thanks god this story turned out well 
But no other problems up to now
Hi jagies,
My XJS engine is now completed and i mounted it on kind of a test stand.
I did not rework the carbs and I think I will have to do it ?
With my first test one carburetor drowned and two were dry so I cleaned the valves and this seems to be ok now. But when I crank the engine (with choke fully activated) the engine fires only once in a while and only when I operate the throttle almost fully the engine will run a little smoother (but still very rough imo). I did these first tests without air filters on and only the 3 in 2 exhaust pipes on one and 3 in 2 in 1 on the other side.
I verified the look of 4 spark plugs (A1,B1, A6, B6) and only three of them smell a little from gasoline but B6 seems completely dry as it has never seen gas.
What next ? I have carburetor seal sets and the adjustment tool here. The diaphragms seem to be ok and I used ATF oil for the dampers.
p.s: I do not know about the history of this engine, When rebuilding I did not touch the crankshaft, timing chain or timing wheel (not even removed the cover) and placed the distributor head the only reasonable way. New spark plugs of course and the fuel pump pumps until the pressure relief valve opens.
Please give advises !
well i have to ask?? how well does it run?
ron
Hi Ron,
I will try to make a video tomorrow which will surely help remote diagnosing …
I’m almost sure something is wrong with the carbs and not the engine/ignition but hope you will “see” more with the video and sound
I have the carbs/inlet manifolds from the XKE engine but these have also been lying around for years now and I don’t know if I should give them a try.
Thx for now, Tom
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If you have a carburettor problem then it affects three cylinders at a time and will either be fuel, vacuum or linkage problems.
Ignition problems can either affect all twelve cylinders, or be down to individual plugs and leads.
Throttle linkage problems will be split into threes or sixes.
kind regards
Marek
Hello Marek,
Of course yes - that’s why I inspected only 4 of the 12 spark plugs but even with one carburetor completely failing (whatever could be the reason for that) I was thinking the engine would run on idle and a little bit smoother overall. I did not tear down the carbs yet and did not check the ignition timing with a stroboscope lamp and all individual sparks but the distributor looks optically fine and so do the ignition cables. By the way what does the “start” wire to the ballast resistor network affect ? Higher spark energy while cranking ?
Kind Regards, Tom
Yes
The coil gets charged from full battery voltage during cranking but only ballasted alternator voltage in normal running.
kind regards
Marek
One of the vacuum attachments one the B4-6 manifold was not properly sealed and the engine runs a bit “smoother” now. But as you can see it does not respond to the throttle …
Once the engine is supposed to be ok I want to convert it for my E-Type (oilpan, cooler etc.) and put it in the car. I plan to keep the matching engine completely unassembled (although I have all parts available) until this XJS engine fails or I have got too much time
Please have a look at the short video and tell me your opinions.
p.s: This was one of the first tests - i will try without choke later …
p.p.s: with less choke it revs up a little more, way too fat i suppose ?
hmm, after some time of cranking (2 mins) the balance resistor and coil become really hot (90°C) 
Kind Regards
Tom
No ideas ? I guess I will tear the carbs down, clean all parts and try to adjust them as described on other sites.
Thank you !
Sorry, I’d can’t usually see pictures or videos. If you had one carburettor from which no fuel came out, then it is likely that no fuel went in. I’d look at the jet which closes off when the float rises when the float bowl is full of fuel. I’d suspect it is jammed shut and no fuel ever got in.
kind regards
Marek
Hi Marek - Oh that’s a pitty because sure from the video you would have an idea on how it behaves
But on my test-stand without coolant I can’t do major adjustments I think.
Thank you !
Overhauled my Carbs during the last days basically cleaning and fitting new gaskets. The Choke output pipe was not properly repaired by PO and I will have to redo this with some “liquid metal”.
I hope the engine will run a bit smoother after installation.
