Long time sitting, now crank and no start condition Series 3

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Since the compression is lost on both #1 and #2 cylinder, Ariel - it high odds it is ‘only’ a blown (non-standard) head gasket…

While old/bad fuel may cause running problems or bad starting, there is little evidence that it in itself will cause serious engine damage. A ‘wet’ compression test should be carried out - if the compression does not come up, it is either the gasket or valves…and the latter is ‘unlikely’.

After a head gasket change, the head should be retorqued after 500 - 1000 miles, but the car is not expected to be running that little.

In your previous posts you mentioned that you had some starting/running problems. The engine should of course start easily and run on 4 cylinders, though not well - if the engine management is up to scratch. Which obviously is not the case recalling you previous difficulties, and advise given in that respect.

With two cylinders dead, the engine will pump out raw fuel out the exhaust - in addition to effects of other malfunction mentioned earlier. Which gives you something simple to do while musing on the head gasket problem…

Short term; disable the #1 and #2 injectors by pulling the electric plug - those two cylinders does no work anyway, and just contaminates. You may rectify the AAV and sort out the ignition timing, to ensure good starting and as good running that may be expected - though driving the car in this state is not recommended…

It would also allow for some further testing - encourage you to go ahead with the head…

Frank
xj6 85 Sov Europe (UK/NZ)
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The head must of course be removed, most likely only a head gasket change is required. If the head has been skimmed to the extent of requiring a thicker gasket is required - so be it, but it is unusual to skim to that extent…

Of course, with the head is removed other issues may appear, but I doubt it…

Ariel,

Do you trust your mechanic ?
Was the head job done properly ?
Where you present at the compression check?
Did you see the fuel contaminated oil ?

From your videos it doesn’t sound like an engine that runs in only four cylinders… and I see no reason why an engine would go bad just by siting, unless it’s open and out in the rain…

As Frank said, a wet compression test is needed.

Maybe stuck rings ? they will probably get unstuck with running.
A blown gasket might be, but my logic says that if it has a hole big enough to have zero compression you would have other visible signs as well, and most probably overheating and bubbles in your coolant.
(a friend of mine had a constant stream of gases in his coolant and went to a 1.000 mile trip and made it…)

A car with only four of six cylinders should be anemic but drivable,
And, as Frank said, gas should be flowing through the exhaust, did you notice that ?
Also if you remove the spark plugs of the offending cylinders does it make a difference ?

Before you take on the head try to make the car work, it sounds like a fueling issue to me.
Did you check your air and coolant sensors ?
Is your ECU adjusted properly ?

I am not familiar with the 6 as I have a V12, I might be wrong, but these are my two cents…

Best
Aristides

Frank, first of all thanks for the answer.

As long as the car has been poor running last weeks it throw raw fuel through the exhaust, but nothing alarming.

The other symptom i saw was, after the car won’t run since my last “trying to fix timing” time, the coolant went almost empty, the oil went slightly light brown recent no compression on cal 1 & 2 gives me a poorly head gasket or something related to that.

The stuck valve is not a probability for me also, the car runned till it stopped and you saw the video in N and no RPM climb problem.

Also Frank, when i tried to start the car, engine stone cold, 20/30 seconds of crank, no start but some kind of wired combustion i could check lot of compression on the coolant system, i mean if i remove the head tank cap i feel lot of pressure coming from there, like a whistling kettle for 2/3 seconds.

Maybe those symptoms also confirm a worn head gasket.

I will make the head gasket, but really i can’t remember how much the machine shop took off the block to allow me to use the original head gasket and thus eliminating that problem in the future, of course i don’t want a valve to piston head touch, can i measure some way to check proper valve clearance?

Also i forgot to mention, the piston heads and ring were new when i did the engine overhaul using +.020" 9:1 ones.

Aristides, those videos where prior to my electrical touch and all this problems appearing (coolant empty, no compression), that’s why the running was almost ok when idling and in Neutral. But the around the block drive was awful, no power and thus going through a new engine timing.

Also, i will try a wet compression test, i found some instructions on the internet, but if there are more recommended i’ll use those.

Thanks,

Ariel

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The head gasket may fail at various points, Ariel - giving slightly different symptoms…

Failing between two cylinders it will cause compression faults in both. It’s a sort of accepted rule of thumb that it’s a prime sign of such a head gasket fault. Sort ogf more likely than valves on two neighbouring cylinders have failed…

Head gasket may fail between cylinder(s) and coolant and oil channels in any combination with the aforementioned. Giving relevant symptoms; coolant in cylinder(s), oil in coolant, coolant in oil, loss of coolant and/or rising and dirty oil levels…you name it…

Exhaust symptoms may include black smoke and fuel smell due to excess fuel, grey smoke due to oil burning in cylinder(s) and white ‘smoke’ due to coolant ingress.

Only removal of the cylinder head will tell if it is a plain gasket problem - or something else. With a clearly defective gasket it’s unlikely to be something more, but a cursory examination of valves and cylinders should routinely be carried out with the head off. And valve lapping is standard with a long running engine…

As Aristides mention; if a head gasket fail only between cylinders, the car is drivable as such - but injectors on the involved cylinders should be disabled as described to avoid unnecessary fuel into the engine. With other suspicious symptoms, like loss of coolant etc, driving the car should be restricted…

With two cylinders out the behaviour f the engine will vary a bit depending on which cylinders are out. Certainly, there will be loss of power and response, but the xk may still be fairly smooth in some combinations…

I’m not sure about the head gasket thickness - skimming is always kept at a minimum to rectify excessive distortion. No limits on skimming are set, and there are no practical way of measuring for certain if a thicker gasket is required. Unrecorded repeated skimmings add further uncertainty - but a thicker gasket would be unusual to be required. However…

Frank
xj6 85 Sov Europe (UK/NZ)
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Hi guys, long time, but had no time to remove the head gasket. Today i have removed the head and found another problem, the head bolts and the modified studs where way too loose. Maybe that was the main symptom and the long time sitting along the bad adjusted bolts causes the water to oil contamination.

Here are some pics of the block and head:

What do you think?

There are lots of copper painted parts because the head gasket was all
Bathed in copper gasket spray.

Also, don’t know if I mentioned that the last mechanic (8 years ago), removed a the studs and made some inserts in all of the middle head studs holes instead of using new longer studs. I know, this is not an elegant solution for an xk engine, but i have to deal with it, it worked fine prior to gearbox damage but maybe that’s the origin of the head loose condition. I fear if i have to re replace those bolts with new studs, and it’s a costly work I will have to end the project as I can’t get another block here.

Well. This is how i am now, plan to replace head gasket and use the same blots.

They are like this:

Need some advice.

Thanks a lot,

Ariel

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One of the differences between the short and long stud engines was likely that the short studs required retorquing every 12000 miles, Ariel…

If this was not done, or if the head was not retorqued after initial 1000 miles running - it may indeed explain the ‘loose’ head and possible gasket leaks. Nor am I sure that use of sealant of any kind on the head gasket is innocent…

I don’t know why the mechanic went for the wholesale change to short bolts, it’s unlikely that all the long studs could not be easily replaced. However, a ‘proper’ repair could be fiddly and time consuming, and thus a fair DIY proposition - but the short bolt solution is really unprofessional, unless accepted/urged by the owner…:slight_smile:

The short bolt and long stud blocks are slightly different - so your first step is to verify that there is no visible damage caused to the block - like cracks. Then to clean up the mating surfaces of the block and head, and verify, with a straight edge, that there is no deformations. The head may have to be straightened, and if there are mating surface anomalies, to consider head skimming…

All that OK you may consider refitting the long studs - which likely would require checking and cleaning the block threads. Point being that if Jaguar considered the short bolt/long stud solutions equivalent there would be no point in using the more complicated long stud solution…

All that said; your plan of just changing the gasket and reuse the short bolts is not entirely without merit - providing you find nothing else amiss with block and head…

And then adhere to the retorque regime…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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As always, thanks for the big help Frank.

I have to clean and check for no cracks, but what do you mean with refitting long studs? you mean remove the inserts and go back to the original long studs?

Or discard this bolts and buy a new set of studs (like below image) that fit this “unprofessional and unapproved owner on that time but noticed yesterday” short scheme?

Thanks!!!

Ariel

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Your mechanic may have had valid reasons of his own for his actions, Ariel - labour cost may be one of them…

The problem with ‘retrofitting’ the long studs may be the same for you as for the mechanic - one or more studs failed to engage properly with the block threads. Which may be dirt - to be cleaned out through the expansion plugs. Or rusted away requiring use of Helicoil - laborious. And the removal of the inserts for the short bolt solution would add labour - unless the long studs fits within the inserts…

The ‘long’ process is of course the ‘correct’ one. On the other hand, the ‘short’ is quick and easy - and may work well enough. You having driven 8 years with it with no visible damage except for the loosened head bolts - proper attention to retorqueing may solve that…

You may be equally satisfied either way…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)
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Ariel,

There was a debate about long vs short studs not long ago (search the archives).
IIRC, the consensus was that short studs, even though not being the best solution, could work just fine.
If I was you I would definitely change the bolts with studs though.

Best,
Aristides

Frank, thanks hands down, as always.

As Aristides1 say, will try to find replacement studs in the local market instead of the used bolts, just to help my search, any ideal mm to go inside the block and overall length of the stud? 164mm maybe?

Thanks,

Ariel