Welcome to hell(long w/ photos) Series 1 xj6 core plugs corrosion head studs

Demian · July 8, 2018, 10:09am

$400. That’s a steal.

Yes, I was truly surprised…and relieved.

Upon discovering that corroded inlet passage on the head and congealed green goop with sand in it, i expected the worst.

Surprisingly that was only corrosion.

But again, i just had a good feeling about the car.

I have a backup s1 xj6 head, complete, so i have a backup plan.

No corrosion at all however there are a couple clogged port passages on the head.

Everything looks good otherwise. Expected carbon build up on pistons and valves…too much on valves.

Everythingvto be surgically ckeaned of course and analyzed in more detail.

Ignorance is bliss, but now, should i ever purchase another old Jaguar, i will always do this as a matter of course learning what I have about block gunk.

That said, only hope i can get the studs out now…sigh.

Demian · July 8, 2018, 10:16am

Yep.
I won’t be turning it with head off now.
Popped the cork out on #6 so i know it was,at correct stroke.

One concern i have and wished to ask and considered creating a new thread…

Lined up mark on damper precisely, yet surprisingly #6 cylinder top not flush with block face as one would anticipate.

There is roughly 1/2inch remaining until reaching block face.

Is this correct?
Concerned damper or marker misaligned or something.
That would screw everything up .

Thank you!

awg · July 8, 2018, 11:04am

a close visual check of the way the valves are seated, and the seats themselves, will give you a strong indication if valve seat recession is present, an expensive issue

depends how you measure it, a dial gauge will ensure that,

harmonic balancer rubber can “slip”

Robin_O_Connor · July 8, 2018, 12:49pm

Definitely not correct, best thing to do is beg, borrow or steal a dial gauge and choose a measurement before TDC and lightly mark the harmonic damper, take the crank over TDC and then come back up to the same measurement ‘on the other side’ now mark that position and then mark the mid point, this is true TDC.

Robert_and_Darlene_S · July 8, 2018, 6:57pm

Good explanation! This is the set up that I’ve used for many years. The indicator is a federal that reads from .001 to 1.00 with a 1.00 extension mounted in an old spark plug base.

Demian · July 9, 2018, 4:50am

Yes, hoping valve seats are ok…
Need to learn again what would determine a bad valve seat.

Anyway, excuse me, I’m an idiot.
It wasn’t at TDC…it was late
Nevertheless, each cylinder rises to the same height, which is more like 3/8 to the top of the bore…so it must be correct.

Funny, i though pistons rose to the block surface.

Anyway. Gotta say…

…doing all today and looking it all over, cleaning it up, it is …perfect…

Not one bit of corrosion anywhere. The surfaces are perfect.
No cracks of any sort, nor strange signs of wear within cylinders miraculously.

No lips at block surface, nor receding liners…flawless.
Gasket in great shape too.

A couple plugged little coolant passages was all.
Everything looks and more importantly, feels pristine

No scored bores, miraculoisly…no lips or ridges, etc

May measure later for myself, however i expect nothing honestly meritng a full rebuild.

Compression was good on all cylindets but the 2 with intake valve leaks.
Leak down test revealed nothing discernable or worrying out the dipstick tube, etc.

As a note to those doing for first time.
Don’t touch anything. Any debri that may be within cylinders, etc.

Attach a rubber tube to your shop vac and suck it all up.

Then use grease to seal periphery of piston tops to guard against anything getting in there.
Smear the bore walls too.

Clean the block surface…i used rags and electrical contact spray, and duct tape the surface.
Stuff wrags at front where chains are and cover with garbahe pag piece and tape as well.

Anyway, i couldn’t be more pleased.
No ridges at bore tops at block surface, no recessions caused by sleeves possibly dropping, etc…just perfect.

Many of the studs move within their holes which is a good sign.
But they will require some careful attention and massaging to remove.

Funds are light for head work.
Everything appears normal, but i of course need time with it.

Anyway, with what i do have i will restore engine bay, sand, repaint, detail, replace and properly update hoses and wiring, prepare them for those hot temps, etc…replace studs of course…
Clean all meticulously.

…then figure out the cylinder head.
Springs and valve seals are certain.
De-carbon everything and polish all.

Should guide clearances be ok, I’m debating whether to upgrade to bronze alloy?

Anyway, yes, very pleased and relieved.
Could not have hoped for better.

Kind regards

![P_20180708_203913|281x500]

As a note, those coolant passages were cleaned out and surface cleaned more prior to sealing.
That was only some carbon buildup of some sort around studs at block surface.
Cleaned right up!

After cleaning debris off pistons, oiling, etc…i hand cranked allowing a full cycle of each to inspect and measure cylinder bores. No scoring and no ovals…all within spec remarkably showing hardly any wear differentials. Amazing.

awg · July 9, 2018, 7:00am

post some real close ups of the valve edge, closed…if the valve is sitting slightly “proud” it is ok,
a recessed valve/seat allows the valve to sit deeper in the head

an experienced engine guy can yay or nay visually ( I am not experienced enough)

Frank_Andersen · July 9, 2018, 7:32am

**
That’s about the difference in stroke between the 9:1 and 8:1, Demian - so it figures…?

It’s prudent at some time to verify, with the dial gauge, that the piston is a max ‘high’ - true TDC. In which case; verify that the pointer is then at ‘0’ - adjusting it as necessary. It’s rather important for correct ignition timing…

The integrity of the damper should be checked - no slack with force applied in any direction. Any movement of the damper indicates defect - which will may interfere with engine smoothness, and ign timing setting…

Frank
xj6 85 Sov Europe (UK/NZ)
**

Demian · July 9, 2018, 8:43am

Understood…thanks tony.
Will do.
Those i noticed sat a bit proud, perhaps 1mm.

There are many great machine shops around me, and a couple that know old jags that hve been recommended…so may eventually go that route.

Will take some close up images soon fwiw.

Thank you (all) for taking time.

Demian · July 9, 2018, 8:49am

OH yes…i know its importance which is why it worried me.whew.
Am aware of possible damper issues and this appears and felt fine while using it to rotate motor by hand.

As a note, once again the error was mine as i set it quite a bit btdc…i was tired, and blind.

It is precisely equal with the others at tdc at about 5/16-3/8 below block surface, so not an anomally as originally thought.
Apologies…been paranoid.

PS…will do! Thank you Frank

Demian · July 9, 2018, 9:13am

Is it correct that the head gasket and cylinder bores are offset? Incorrect gasket?

Anyway, this car must have been stored a very long time without running.
Thankfully.

Breen60 · July 9, 2018, 9:54am

Hi Demian, have attached a cropped picture of my 4.2 litre block. I was led to believe that my original 9:1 pistons had been changed on favour of 8:1 pistons to help with then poorly understood unleaded fuel. They are close to the top of the block. Might be worth a second look and check. Paul

Breen60 · July 9, 2018, 9:59am

Yes, this is correct. Jaguar spaced the bores on the 4.2 differently to the 3.8 (were equally spaced). Required different crank spacing, off course, as well. Head remained equally spaced. So we get an offset! Please theing are progressing for you. Paul

Robin_O_Connor · July 9, 2018, 10:06am

My understanding is that the compression ratio is determined by the piston crown, not by a different stroke, stroke is used to determine the capacity of the engine along with the bore size.

Demian · July 9, 2018, 10:07am

That’s right, i recall that now. Excuse me…

Edit: Yes, excuse me, the error was mine.
Pushed myself quite hard, hot and exhausted.

Want to measure bores again too…

Main concern now are valve seats.
May be the issue regarding compression loss due to intake not closing…zzzzzz

How relative everything is.
I’ve almost entirely overlooked concern removing studs! …which was point of this thread.

I suppose you kick me in the knee it helps me forget about my sore foot!

Thank you for your input and well wishes.
Genuinely appreciate.

Breen60 · July 9, 2018, 10:20am

That’s my recollection. The profile on the dome for the 9:1 is higher and more pronounced. Paul

davidsxj6 · July 9, 2018, 10:23am

Robin_O_Connor · July 9, 2018, 10:30am

I’d forgotten i’d posted that

awg · July 9, 2018, 11:10am

fill the combustion chambers with kerosine, and see how quick it leaks out thru the closed valves,
subjective, but any that leak out very quick are suspect

Demian · July 9, 2018, 6:17pm

Sure, I’m aware of that test.
My concern isn’t sealing, per se, but seat wear causing recessed valves.

This makes adjusting valve lash impossible, and why you read of people unable to adjust valves with shim sizes available and others discovering ground valve stems.

Again, i have not investigated much on the head yet, but this may be why i have no clearance on those.

Need to await funds for head work.
Will turn my attention to engine bay for now, replacing and restoring using what I’ve already purchased.

Thanks