Citroen XM Forum

Thanks. I fully understand this was my error, but have noticed a mix of metric and UNC on both engines, (iirc, 1985 and 1989). I didn't expect Jaguar to have gone from British Standard, to American Standard, before switching to Metric.
The Uk went Metric for engineering applications in 1965.

I find it hard to believe Jaguar couldn't afford a few new Metric threading tools. They must have been replacing tooling on a regular basis, just pick a change over date and go for it.
I guess Jaguar were just being stubborn, which unfortunately typified the British car industry and in particular British Leyland.

Now that I think of it, the crankshaft pulley bolt is 7/8 BSF, a hold over from the pre-war design/tooling which was bought from Standard when they ceased production of 6 cylinder engines.

Jaguar always struggled to get any tooling expenditure approved by BL. The 1992 facelift of the XJS was designed in about 1980 iirc but only tooled up after Ford took over. The 5 speed manual transmission for the XJS was designed and 20 prototypes made in about 1973 but the tooling was never approved for production.

This is my 1975 XJ-S, which is 98% original, but rather tatty. It is still running Lucas OPUS ignition and Bosch/Lucas d-jetronic injection. D-jetronic was technically obsolete before the XJ-S was launched, but no replacement had been developed for 12 cylinder engines.

Thanks for the crankshaft bolt info, it makes me feel slightly better...

I do like the first series Xjs.

I have drilled and Heli-coiled all the threads for the sandwich plate to fit to the crank-case, apart from the one where the bolt broke inside the thread and with a central point, meaning it was difficult to make a centre punch mark for a drill to accurately drill down.
I used a small burr to flatten that bolt, which caused a little damage to the aluminium, so as I was at a neighbours I asked him for a bit of 12mm aluminium bar, which I made into an aluminium insert for that thread.
If I had the engine support beam in advance I would have dropped the subframe at the start and could have probably removed all the bolts with some heat, but with the subframe in, access was impossible.

I had noticed the Alternator trigger wire was disconnected, so while I still had good access I tested it was indeed the Ign feed, then connected it. I tested it to both Gnd and the alternator contact, which should be Gnd until the Alt starts charging, at which point it goes open circuit, putting the charge lamp out. The charge lamp doesn't currently illuminate...

Note just how good access is with the subframe removed...
The exhaust is a very tight fit by the subframe mounts, especially on the left side. On checking the manifold to downpipe nuts I found they were finger tight only, so loosened the downpipe to exhaust pipe clamp and tightened the manifold nuts, hoping to gain additional clearance. This hasn't really been successful, even though the engine mounts appear in good condition. I suspect the downpipe is a replacement part.
I scraped the old gasket paper off the oil pump ports, lightly sanded and degreased before fitting new gaskets with a smear of Hylomar blue, installed new O rings, slid the pipes into the elbows, then installed each elbow, suction/output pipe as a unit. I changed the original suction pipe which was designed for the relief flow oil cooler system for the one designed for the full flow oil cooler. The size difference is noticeable: the relief flow pipe o/d is approx. 7/8", the full flow one is approx. 1 3/8".

You don't see this in the pic, because the smaller one is closer. I had fully rebuilt the sandwich plate before taking the picture.
I fitted the sump baffle, remembering to apply gasket sealant to all the side bolts, as these are open threads which lead from inside the sump to outside the crank-case. These are known to wick oil up the threads, causing leaks, if sealant isn't applied. After installing the sump, new rubber hose onto the pressure relief return, new O ring and bolt down the filter housing/return unit, I filled with oil and with the filter not installed, cranked the engine.

Never has a large oil leak been such a welcoming sight...
Filter on and start the engine. The oil pressure isn't particularly high, but this engine is currently filled with 5W-30 oil and rapid flow, coupled with the oil reaching it's operating temperature, is more important than high pressure, as plain bearings and sliding surfaces create their own oil wedge when moving. Talking of oil, I noticed that simply using the fresh oil and a paper towel was sufficient to remove significant quantities of the baked on carbon from the engine components; oil and small brush for the breather flame trap.

Subframe re-installed along with damper top mounts, Abs sensors, front brakes re-connected and gravity bled. I forgot the Arb links, so had to do those later, with the wheels fitted, which was a bit fiddley, but possible.
Using a smear of copper-slip really helped with installation and should prevent any further seizing of fastenings. If you want a fastening/part to move either now, or later...grease it.

As the Magneti Marelli ignition system uses a coolant temperature sensor mounted into the R/h water rail I either had to swap that, or drill the casting. I opted to swap the rail so removed the R/h air filter housing and disconnected the electrical connections, etc.
I intended to swap the complete rail, but the very rear-most bolt, under the wiring loom and vacuum pipes, wasn't coming out, so rather than risk a broken bolt I fitted only the front casting and metal pipe.
New gaskets and 82°C thermostats both sides were installed. Remember to position the jiggle pin uppermost for air bleeding.

All good progress.

I think that at the build date of your car, the exhaust down pipes were made from mild steel, so the stainless examples you have would be replacements. They are always a tight fit against something.

A pic showing how a thermostat jiggle pin is orientated. Using a scissor jack, I "adjusted" the oil cooler pipes so brackets could be mounted to the engine, added two Gnd braids, as the original looking one would only reach the power steering pump pivot bolt.

Having previously looked at the alternator alignment and believing it was going to be driven by the Vee belt pulley, yet to be added, I looked again and noticed it was actually in alignment with the 4pk, Magnetti Marelli, crank pulley. The alternator and support bracket needed to be changed.

Having already fitted the viscous fan unit, it had to come off again to give access to change the alternator and bracket. Access is still poor, but fortunately the radiator wasn't installed. Remove the viscous fan, the A/c belt idler pulley bracket, slack off the alternator belt and unbolt the alternator clamp and pivot bolts. I needed to block the gearbox Atf cooler pipes down to be able to withdraw the pivot bolt, rotate the alternator forwards to access the electrical connections, then lift it out.

Due to a position change and the pivot bolt diameter increasing to 10mm, I changed the alternator support bracket mounted on the engine, then installed the new alternator in the reverse of removal.

I added the triple Vee pulley onto the front of the crank pulley, noting the bolts are now 8mm. Note: If it's Magneti Marelli the alternator pivot and crank pulley use metric bolts, if Lucas they are imperial.
When reinstalling the viscous fan I noticed the studs were not fully tight, so used double nuts to tighten them before fitting the fan unit, then fitted the remaining belts.
I had a new power steering return pipe made , installed the rack and pipes, then connected the steering column to the pinion valve. There are a number of fine splines, but only one recess for the pinch bolt to pass through. Rise the front wheels, turn them slightly left of straight ahead, and turn the steering wheel about 30 degrees left and the coupling can be jiggled enough to make the bolt pass through the recess.
This bolt is important but was missing, so I used a high tensile 8mm bolt and thread-locked the nut on. I ensured the bolt was facing downward at straight ahead, so even if the nut came off the bolt would be held in by gravity.
I had installed the viscous fan, so had to remove it again when installing the radiator and fan cowl. You can't slide the fan cowl in with the viscous fan installed.
I installed the water pipes and upper radiator support panel, filled with water until it ran out of the air bleed, then re-installed it, connected the electric fan thermo-switch and electrical connections, re-installed the fan, filled the power steering pump, ah, yes, refitted the viscous fan for the 4th time. I then fitted a new track rod end boot, which revealed a freshly split rack gaiter and then fitted the vacuum pipes properly, checked fluid levels and fired the engine up For the first time in over eight years the engine could run long enough to be able to warm to full operating temperature. It was smoky at first, but that cleared and it ran very well. Video...

https://go.screenpal.com/player/cOnuQEn ... bed=1&cl=1

As it warmed fully the oil pressure did drop to about 20psi at idle, but that's not unusual. The oil pressure warning lamp stayed continuously out. I noted the auxiliary cooling fan cut in and about 3 seconds later the engine dropped/spun a big end bearing. I suspect the expansion of the aluminium connection rod "big end" allowed the bearing shell to come free.

This is the end of this project for me.

Wow, that is incredibly unlucky. Are you sure that it is a big end knock? - although few knocking noises would be easy for fix.

I suspect that this would have been caused by some sort of lubrication failure (past or present). The connecting rods are EN 16T manganese molybdenum forged steel, and the original rods were generally considered strong enough for engines modified up to about 650 HP.

The noise was a sudden loud rhythmic clanking and it sounds like a big end is very loose. It really needs the bottom end off the engine for the bearings to be checked.

I have now been made aware that when the engine was originally swapped and not able to be made run, it was cranked over a lot and we now know the oil pump wasn't circulating any oil at all at until I sorted the oil pickup system.

When taking parts off the original 55,000 mile engine I noticed the crank bearings have already been replaced. It was then swapped due to being over-heated.
Of course the con-rods are steel, I wasn't thinking when I wrote my previous post.

Did you watch the video I posted the link to? After initial smoke and slightly uneven running, the engine had settled down to being very smooth, quiet and responsive.
The video was taken about two minutes before the engine went clunk.

Video link again. https://go.screenpal.com/player/cOnuQEn ... bed=1&cl=1

One final thought from me:

Could it be a torque converter bolt was left loose and is hitting the block?