Unfortunately for me I managed to lose a secondary tensioner and bent 2 exhaust valves of #6 cylinder. Just turned a bit over 65,000 miles and had not noises at all by way of warning.

My question is a 2 part query.


First, are the cylinder head bolts of the stretch type where you torque them to spec and then do a couple of 1/4 turns more is succession like a Chevy block for example or are they a single torque and leave.

The second one is are the torque #'s in the svc. manual really accurate as the 35nm called for converts to something on the order of 25 ft. lbs. in our system which seems pretty low.

Oops, forgot....should I replace the bolts with new ones as they are pretty damn expensive and the lowest price I've found for 10 is $125 a set. I would think that since the motors never been run hot and there's no damage beyond 2 valves having been bent enough to lower compression to 70lbs. with no damage to the piston that the old bolts would be fine. especially true if they're not of the 'stretch' kind.

 

Stretch bolts. The manual calls for torque, then 90 degrees and then another 90 degrees *I recall* double check those facts before proceeding.

As for reusing the bolts I weighed the risk/reward and decided I didn't want to buy a new head gasket and redo the job if one of them snapped while tightening down so I opted for new bolts. Check Land Rover or Lincoln LS bolts for a cheaper alternative.

 

There's a whole load of conflicting information on this one. You'll see in other threads that it is reported that Jaguar say they can be re-used once. Then when you look at some parts of the Jaguar documentation, they say use new bolts, and in other documentation that they can be re-used. I'm about to re-use mine, so we'll see...

 

Advance Auto Parts Felpro head bolts for a Lincoln LS are $57 at the moment per head with a current 30% discount promo and free shipping.

That is about $80 plus tax.

 

Yesterday I purchased 3 individual head bolt sets front rock auto for $20 each head. It was a close out special and I got all they had on sale. They do have a DNJ complete set, both heads for $47.79.
Search for 2000 Lincoln LS. 3.9L

 

[QUOTE=dsnyder586;1498029]Stretch bolts. The manual calls for torque, then 90 degrees and then another 90 degrees *I recall* double check those facts before proceeding.

That's why I'm confused, as the 1999 XK8 svc. manual (pages 816 -817) I have shows the torque values as being 35nm which converts to only 26 lbs. ft. and shows no additional twists. That's for the 10mm head bolts and the 8mm ones are torqued to just 17-20 lbs. ft.

It does indicate an 80 degree twist (odd twist at just 80) for the crankshaft damper bolt if has no locking ring but no extra twist if it has a locking ring but MUCH higher torque specs. The only other bolts listed that require an additional twist are the "variable camshaft timing oil control unit to intake camshaft and they require 30lbs + a 90 degree twist.

I don't want to have a re-do for any reason but given the specs in the manual I'm also loathe to throw away $125-130 for something that isn't necessary as I'm already some $900-1000 in parts alone on this bit of misfortune.

 

Go to Gus's site Jagrepair.com
Download engine repair course 168.
It shows the six step procedure and torque sequence.

 

That's the ticket. I downloaded the whole think for future reference. It does specify the 'use once' but a couple of engine builders I've talked with comment that if the engine has no history of having been run HOT that would have caused head or block distortion and with relatively low mileage there's no reason to not use them an additional time.

That said the head bolts from the 3.9 V8 in a Lincoln LS are the very same ones since the engines are identical and built by Jaguar and at Parts Geek only cost $38 and change for all 10 big ones and the 2 smaller 8mm bolts so why risk re-using one and having it break while torqueing.

 

Don't use Lincoln LS headgaskets. The ports for the water passages are too small. Get 4.2L jaguar headgaskets. They are multi layer steel and less issues than the 4.0L headgaskets. I just ordered a set for about $100 a pair.

 

I am about to replace the head gaskets and prefer MLS type gaskets, will the 4.2L head gaskets work on a 1997 XK8 ?

 

I'm 95% sure thar they will work on the 97 heads. I have used them on a 99 and 2000 4.0L and they worked. Maybe somebody who has done the 97 will chime in.

 

Thank you

 

If you can use AJ27 heads on an AJ26 block (which I have more than once) those gaskets should work fine.

 

Thank you for the information