My engine’s out for a re-spray.
While it’s out, my brother has suggested that I (1) check crank seals (2) Replace the oil pump and (3) crack a bearing and check for ovality and scoring.
Does anyone have any other suggestions for “while it’s out you may as well…”?
Incidentally, stangely for a 1983 4.2, it doesn’t actually currently drip any oil. Who votes for changing the crankshaft seals anyway, who votes for leaving them if they’re not leaking? It’s got 70,000 miles on it.
As always, thanks in advance for the immense amount of knowledge I tap into on this forum, and thanks for your suggestions.
Your car is averaging about 2,000 miles per year. Is this your present usage - or do you expect more in future? If it has been maintained well, performs well and you have no counter indications I would be inclined to leave well alone. How’s the oil pressure, oil consumption, pot compressions etc? Before any spanner work you could have an oil sample assessed to help thinking on bearings etc, perhaps. Our car did significantly more than double your present mileage before overhaul. Having said all that my knowledge relates to earlier carb engines - not later units like yours. Paul
Tough call. I’m leaning towards the ‘leave well enough alone’ philosophy in this case. But, there are good arguments on both sides.
I’ve had many project cars in my life and, in review, I’ve spent lots of money and time on ‘mission creep’ repairs/replacements which were really not required.
I’ve taken a different tack on my present project—turning and XJ6 into an XJ12. To the largest extent that I can muster…I have to grit my teeth a bit at times… any part or sub-system that is presently functioning well and doesn’t visibly appear about to fail, is being left as-is. This is primarily motivated by a strict budget. Habits are hard to break but economic realities are an excellent impetus
I’m saving lots of time and money at the moment but only time will tell if some of my decisions were wise.
I agree with Doug and suggest that you should” let sleeping dogs lie” with regards to major things like work on the crank seals, oil pump and main bearings especially if you have no reason to suspect them. Particularly since this is a low mileage car. I find that it takes me a lot longer to redo things that I undo, particularly since I clean, polish, measure, paint or otherwise fiddle with whatever I take apart “as long as I am there”. It is not unusual for these projects to stretch out over many months (or even years).
A few years ago I swapped an engine out of a 1986 XJ6 parts car and put it in my 1987 XJ6 VdP after that engine had a ring failure in the #6 cylinder. While I was preparing the parts car engine to put into the 1987 I had it on a very robust engine test stand and did a major engine cleanup and refurbishment (not a rebuild) where I cleaned all the grease off from front to rear, swapped out belts and hoses, adjusted valve clearances, and painted/polished/replaced lots of bits and pieces. These were are all reasonable and suitable for ne to do since the engine was out and most everything is easily accessible. One thing that I highly recommend that you do is remove the block core plugs, clean out as much of the debris that you can inside the water jacket, inspect the head studs for corrosion (replace them if they are bad), and then install new core plugs. I was amazed at the amount of debris inside the water jacket when I did this, and I even discovered that one of the core plugs was just about rusted through and was likely to fail sometime in the future.
Many thanks for your thoughtful replies.
Interesting that you suggest taking out the core plugs to inspect the studs Paul - Ken Jenkins (technical director at the UK Jaguar Enthusiasts’ Club) suggests doing exactly the same thing. With two votes for that one, it looks l’ll be doing that for sure.
Am I correct in thinking that if you do them one at a time, you can replace corroded studs in any particular order without fear of disturbing or distorting the head or its gasket?
Once again, thank you very much for the replies - as always, measured and knowledgeable.
Niel
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I fully support ‘leaving sleeping dogs lie’, Niel…
In this case, low mileage and no symptoms relating to oil pressure, leaks or bearings; odds are that you may do more harm than good - and waste time and money, with no actual improvement. ‘Might as well relates’ to the ‘shipwrights disease’; once started it is difficult to stop. Having already removed the engine ‘just for a respray’ - you are already showing the symptoms…
As Doug says, the wisdom of decisions can only be assessed in the future, but apart from a complete rebuild; there will always be something you omitted - unavoidably. Paul is right; do inspect the core plugs; any suspicion warrants replacement, a straight forward job with the engine out…
I think you are better off without tinkering with an engine that shows no distress as is. Using time, energy and money for things that obviously require attention when they appear - you’ll be nervous wreck if you constantly try to divine and prevent vague possibilities’…
So there is definitely a unanimous theme emerging here. Like Paul, I am a compulsive degreaser/polisher. Just too good a chance to miss!
Ok - message received and understood.
I will take out the core plugs and inspect +/- replace the head studs one at a time. I will leave the crankshaft alone.
With regards to “mission creep” - your collective intuition is frighteningly accurate. The car’s current state of disassembly began with an MOT failure for rear subframe mounts, binding rear caliper pistons and a couple of ball joint gaiters on the front. Live and learn. Still, she’s going to be very beautiful when I’m (finally) done.
Still tempted to replace that oil pump though. The thought of it giving up the ghost six months after I put the newly powder-coated front subframe back on is too awful to contemplate…
Once again, thank you vey much indeed for taking the time to reply, and best wishes to all on the forum
Niel
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Leave the head studs alone, Niel - unless core plug inspection indicates stud replacement is required…
…in which case you have a legitimate ‘mission creep’. If a stud breaks you need to remove the head to extract it - which actually is easier with the engine in the car, but not done unless specific symptoms so indicate. With the head out, a valve job is recommended - and a look in the cylinder bores may encourage a rebore…
The xk bottom end is rock solid - and the oil pump, running in oil is very unlikely to fail in a foreseeable future.
Of course, my priority is always to get a car back on the road ASAP, with faults cured - but that is not the only reasonable approach…
You’re lucky, you know what the engine was like before you started.
Unless it is way down on power, and/or has been making bicycle in a Moulinex type noises I would say:
Core plugs out, remove crud, inspect studs, clean plug bore, install new core plugs.
If you found a lot of crud, or the studs look sad but not iffy, change the WaPu (someone has been running plain water).
Clean it.
Polish the shiny bits you like.
Paint the non shiny bits.
Spend your time or money helping the painter.
