Maybe it was the cocaine.
Ok seriously, pour Kano Kroil or ATF/acetone 50/50 down the spark plug holes, half a cup in each, then leave it for a month. Yes, I said a month. Then try the 5 foot pipe on the pulley bolt.
Yes…and if it doesnt turn then…TAKE THE bleepin’ thing apart!
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A large enough bar will snap the bolt if the engine does not yield, Wiggles - the starter may not turn the engine either, but it’s harmless to try…
Of course, if turning the engine is of no interest, there is no problem to be solved…
Frank
xj6 85 Sov Europe (UK/NZ)
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Hi guys. As mentioned above am stripping un-seized HE as a practise run before doing my carb engine.
Anyway, thinking ahead, was wondering how I’m going to reach all 4 bolts on each cam-sprocket if I can’t turn the engine. Someone suggested splitting the chain but then I remembered the sprockets are two-piece. That is the central part separates from the toothed part. They are held together with a circlip.
Had a look at the factory manual and it talks about moving them in relation to each other to get bolt holes to align.
There is also an old thread on here where the topic was discussed in great detail.
Thing I don’t understand is why was the sprocket designed that way in first place? I thought the timing was done on the cam with the plate/notch arrangement.
In simple terms - why the need for a finer adjustment?
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Without a finer adjustment, the cam timing would be restricted to one chain link/sprocket tooth, Foxy - which is insufficient for necessary precision…
That said; with virtually all work on an engine the workshop manuals prescribes some engine turning for access. During dismantling, non-standard procedures may be invented - a stuck engine is not covered…
With the cams; if the chain tensioner is fully released, it may be possible to lift the chain off the sprockets? In any case, with the chains disconnected no attempts must be made to turn the engine - unless the cams are fully released or removed. Or the heads removed of course…
All of which is why attempts to get the engine turning before dismantling has some merit…
Frank
xj6 85 Sov Europe (UK/NZ)
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Why is this not a feature on all engines?
This goes against the advice of other contributors, who say if you can’t turn the engine dismantle it
That’s not possible. However with the central part of the sprocket unbolted from the toothed part the cams are no longer connected to the timing mechanism and you can therefore proceed with dismantling the engine
Foxy (do you have a real name?)
Are you trying to do this without a manual?
Here are some pictures that may be helpful.
Of course I have a manual, and parts lists. I think I’ve mentioned that in my posts.
But thanks for the links
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Certainly, Foxy - the trouble is non-destructive dismantling with a non-turning engine. My point is that some attempts to turn the engine is worth while - just to ensure it cannot be budged with ‘conventional’ means…
There are a variety of reasons for a stuck engine, mentioned earlier - but two of them are almost impossible to overcome by forced turning. Serious overheating causing pistons to seize in the bores is one - and liner and piston must be removed as a unit, as indeed you have mentioned. Another is debris in a cylinder, not uncommonly a dropped valve seat (overheating) or broken valve - which can be assessed and repaired by a head removal. In this latter case; the engine can be turned ‘backwards’ 360 degrees before locking up again…
That said; freeing a seized engine by brute force may or may not still require extensive dismantling and work - which is more easy with a moving engine. But likely feasible with the engine in-car - in your situation aI would certainly have fitted the starter for a try…
Frank
xj6 95 Sov Europe (UK/NZ)
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Fair enough, Foxy - but do not(!) turn the cams individually with the chain/sprockets removed. High risk of bending valves…
Frank
xj6 85 Sov Europe (UK/NZ)
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Search me, Foxy - Jaguar developed the xk as a racing engine, and their experience may have carried over to the V12…?
In principle the chain (or cam belt) locks the crankshaft to the cams - and aligned the valve timing should be spot on without further adjustments…
Frank
xj6 85 Sov Europe (UK/NZ)
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Hi guys. Am going to move my efforts onto a new thread as the title of this one is sort of dead in the water now.
Will post the updates in the V12 engine section
Hi again guys. My stripdown thread isn’t attracting any interest at all. Perhaps you guys only like it when you can disagree
Anyway just to say that the HE is fully stripped and the carb-engine is still at head-removal stage.
The heads wouldn’t lift with light tapping so I’ve decided to remove the studs instead.
Interestingly I used Coca Cola on the 7/16" studs and it definitely seems to have gotten down between the head and the studs
Coke did this
same stud cleaned
this stud didn’t get the Coke treatment
both are in similar condition but non-coke one needed a lot more torque to remove
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The general state of the studs indicates that they should be replaced, Foxy - somewhat unusual on a V12…
The main reason for ‘no comments’ on your stripdown, at least on my side, is that there have been no feedbacks from you - until now. The original problem was that the impossibility of turning the engine - and you decided to strip down the engine.
What we/I were/was waiting for is further reports on what you found - which you may have posted elsewhere since I haven’t seen it, and no other information has reached me. I assume that no reason for the original problem has been found so far? Hence no comments has seemed relevant…
The choice of head removal with or without studs is somewhat depending on circumstances. There is always some corrosion binding the studs to the head - on ‘long’ studs xk engines this is sometimes a major problem. Removing the head with the studs in place may require both brute force and cunning - removing the studs first may cause studs to snap, but without studs the head comes off ‘easily’…
The V12 is less prone to such stud difficulties and either will usually succeed either way. The use of solvents, like Coca Cola, is likely ‘indifferent’ - if it penetrates, there is room for it, and bolts will turn. If not, not - but anything is better than doing nothing…
With a successful stripdown (kudos!); what have you found so far, apart from the studs? Any reason for the engine failing to turn…?
As an aside; as the engine was stripped down without the recommended prior positioning - some care must be taken in reassembly…
Frank
xj6 85 Sov Europe (UK/NZ)
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Hi Frank. Am not sure where you get the info that it’s unusual for the studs of the V12 to be problematic.
A quick search on the www will throw up countless stories of V12 heads which won’t come off due the the fact that 10 of the studs on each head run inside the water jacket
Blockquote The main reason for ‘no comments’ on your stripdown, at least on my side, is that there have been no feedbacks from you - until now.
I think you’ve misunderstood (again) Frank. No feedbacks from me? I created a new thread 22 days ago I think, regarding the stripdown. I wouldn’t call that feedback. Input perhaps
The general state of the studs indicates that they should be replaced
Yes. That’s my intention. I have a full set of studs in better condition from the HE
With a successful stripdown (kudos!); what have you found so far, apart from the studs? Any reason for the engine failing to turn…?
Perhaps better if you read the other thread. You will see that the heads aren’t off yet