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Been lurking, Wife bought an 2001 XK8 a few years back, I replaced all the leaking hoses under the manifold, finally repainted the peeling clearcoat, then the engine overheated...Wife added two drink cups of water and limped home, it was running like crap, figured it was the timing, replaced coils, plugs, as she just had a poor idle (HA!) found the radiator plastic has a hairline crack under high pressure only, (lesson replace ALL plastic items when doing the hoses, I upgraded to aluminum parts earlier, but not the $175 radiator)
Started pulling it apart after buying the timing tensioner kit for around $700 in parts/tools, Once I pulled the valve covers and noticed 3rd Gen tensioners, I paused to check compression. #1 came out at 190, then battery died...-Curse of the Jag-...charged it and found most were 190, one was 210, BOTH rears were ZERO. borescoped the cylinders and saw the valves not closing on those two, minor indentions on piston....further reading (this forum) indicates it's likely the seats pulled out when it overheated and micro welded the valves to the seats.
This beast ran at a steady 6000RPM like a sewing machine with two dead rear cylinders, I do not know how, but it revved just fine above 1500rpm...
So after figuring out the heads have to be removed, buying two used L/R heads and L/R gaskets, then exhaust gaskets (L/R) , and further investigating (here) that the exhaust manifolds have to stay on the heads when pulled as there's no access to the bolt heads (really brilliant engineering) buying two manifold to cat gaskets and a full set of exhaust manifold and head bolts...then Oh Yeah, the head bolts need the RIB tool instead of TORX bit for removal...so might as well replace the valve stem seals (32) on the new set of used heads, and lap the valves while they are apart for good measure..(Add a different valve spring compressor for that design) So about another $1500 for a total of $2200 or so and I've yet to pull the heads, so it should be fine, then re-assembly. Glad I have space and a lift for this job.
LS4 swap would have been nice, but I'm either original or let it go. Perhaps after it runs (correctly) I'll let her drive it for the Spring at $4+ a gallon and sell it off as Summer comes assuming I do get it together properly.
Need head bolt torque, I'll find it here somewhere. And if I lock in the crank for timing, I won't be able to move pistons up and down to clean them off, so something else to ponder.
V/R W. Winget
I am not familiar with the XK8, but on the ones I am familiar with, the trans, and steer fluids are "cooled" via the radiator fluid. Overheat the radiator fluid, the other 2 also suffer. I would take a look see in my opinion.
An overheat on the Jaguar V8 is frequently terminal. There must be times during this issue you wished it had been!
The torque specifications are listed in JTIS under Powertrain/Engine/Specifications. Here's the Cylinder Head bolt settings:
I'm sure you've you've already found your way to the XK8/XKR forum so there's no need for a link to it from me. The 'HOW TO' thread at the top is a good place to start for information on regular issues. You can also use the US Mid Atlantic Region forum by following this link https://www.jaguarforums.com/forum/us-mid-atlantic-65/ to find other members in your region.
Hello,
You have had an adventure, haven't you! Good Job on your work so far. I hope it goes better in future.
Welcome to the forums from ElinorB.
(';')
@Jhooah, if the engine has been overheated, it may be best to find a replacement engine as the aluminium block and heads warp and cannot be successfully be repaired.
Thank You all for the replies and guidance, the heads are now removed and indeed 0ne "higher" intake valve on each side had their seats pulled out and now pinched by the closing valves. Figuring the higher Intake ones had less coolant to them, they went, while the lower Exhaust valves still had some coolant around them. Replacement heads were a good call, as the machine work on rebuilding the seat, machining and then inserting a seat, cutting the valve angle, etc. would very likely exceed the $365 (including shipping) per head I paid.
The old seats may make a nice set of ear rings for my Wife, nice and shiny, still round, unlike the ovaled out seat bases.
Now to clean up the new (used) heads, insert new stem seals, check valve clearances then clean the piston tops (means unbolting the flywheel lock) and the slow process of reassembly.
Couple of thoughts, who designed a Crank Sensor with 1" clearance for the torx screw driver to remove the screw...(used a pair of vise grips on a bare torx bit sideways...)
And "locking" the crank in place becomes pointless if you're going to be raising and lowering pistons for cleaning, so that step means just ensure the crank returns to TDC before timing chain reinsertion.
Still awaiting RIB tool bit set, so a great Thanksgiving break in store. Figure to buy another car for my Wife to drive to work and back, save this girl for weekend or fine weather trips, it may be the only way to live with an XK8...
V/R W. Winget
Carrollton, Va.
2001 XK8
Many Military Vehicle Restorations
I hear your pain about tool access!!
This little guy has worked where no others would. Pretty tough and I have not broke it yet and it has seen some torque for a 1/4" drive tool!
VIM (Made in Taiwan) HBR4 1/4" Reversible Ratchet. A little over 4" long.
All the normal hex bits fit thru the head instead of adding to the length. I have even cut bits down to just above the tips for even tighter access.
Only about $14 too!
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...And "locking" the crank in place becomes pointless if you're going to be raising and lowering pistons for cleaning, so that step means just ensure the crank returns to TDC before timing chain reinsertion...
@Jhooah, the correct valve timing is 45 degrees ATDC, not TDC. That is the reason for using the crankshaft locking tool whilst setting the camshaft timing.
If you rotate the crankshaft with the heads removed, remember to rotate the crankshaft in a clock direction only when viewed from the front of the vehicle, otherwise damage to the rod and main bearings is the result.
"If you rotate the crankshaft with the heads removed, remember to rotate the crankshaft in a clock direction only when viewed from the front of the vehicle, otherwise damage to the rod and main bearings is the result."
I have no doubt you are correct, I've heard of the timing chains being potentially damaged, but never the mains and rods, mechanically I cannot see why the direction would matter to them....Oil pump perhaps, but mains and rods puzzles me.
Thank You for the tip.
V/R W Winget
Thank You for the engine Course, I think it's similar or the same as the extensive manual set I purchased, and those found linked on the forum over the past searches.
I understand the 45 ATDC, as I'm not really timing her, it's where it 'gets assembled'. I have the cam lock set, and will ensure the larger flats are locked down prior to reassembly, and the gears are offset, etc.
Still pondering how the crank or rod mains would be harmed, having worked on multiple engines from Flywheel single cylinder era, WWI, WWII, 60's and up engines, I've never heard of a warning of potential damage, but when in doubt...heed the warning...
Thank You again, looking forward to getting parts cleaned and installed, then onto other on hold projects.
V/R W. Winget
11-16-2021, 08:07 PM
Dead 01 XK8 heat killed rear cylinders
