XJ8 Pulled Head bolt Threads
#1
XJ8 Pulled Head bolt Threads
Have an XJ8 that was overheated and both heads were bent about .010. Had them cut and when torquing the second head, two of the head bolts pulled the treads out of the block. These threads are down at the bottom of a four inch bolt hole and will be very hard to timesert. In order to trust this engine I think they should all be done. Anybody ever hear of repairing these threads and are there special tools for the repair?
#2
Guest
Posts: n/a
Pulled Thread
Gearjam, I had your problem with my 1998 XJR, but with one pulled thread on rebuild after overheat. My delema was similar - should I replace all of the theads or maybe the 8 central ones, as these were most likely to have suffered the worst heat damage (anealing?). I could not get suitable 'timeserts' so went for normal screw inserts. I also had to procure a special 'long series' drill and needed to make a special extension to attach to the insert tap.
In the end, I descided to go with just replacing the one pulled as I figured I would still have options if any others failed. Luckily it was successful and I now have a great running car.
However, I had at least one dropped valve insert in each head and I was advised that 0.010" was too much to regrind and so opted to replace the cylinder heads. I would advise that you check your inserts at the least.
Incedentally, I fitted new heads for a 1999 3.2 bought on e-bay for a bargin price. These required that the camshafts, etc be replaced with my own and of course, all of the valve clearances were set correctly. Also, as they were new, the oil gallery inserts were still in place and so suitable for my supercharged engine.
In the end, I descided to go with just replacing the one pulled as I figured I would still have options if any others failed. Luckily it was successful and I now have a great running car.
However, I had at least one dropped valve insert in each head and I was advised that 0.010" was too much to regrind and so opted to replace the cylinder heads. I would advise that you check your inserts at the least.
Incedentally, I fitted new heads for a 1999 3.2 bought on e-bay for a bargin price. These required that the camshafts, etc be replaced with my own and of course, all of the valve clearances were set correctly. Also, as they were new, the oil gallery inserts were still in place and so suitable for my supercharged engine.
#4
Join Date: Sep 2008
Location: Damon /Houston, Texas
Posts: 7,254
Received 2,192 Likes
on
1,358 Posts
#6
Guest
Posts: n/a
Thanks for the warm welcome, I may know my mechanical stuff, but the electronics on these jags scares me. I also should have mentioned to gearjam that he should (and probably has) check the cylinder block faces carefully for any distortion, mine was out by around 0.010" and was 'decked' in addition to a check for porocity.
I have to wonder if there is an approved way of ensuring that the inserts are tight. Maybe the surrounding alloy could be compressed/centre-popped? Does anyone know? I still have the old heads and some of the tools ind inserts for the thread repair - whereabouts are you gearjam?
I have to wonder if there is an approved way of ensuring that the inserts are tight. Maybe the surrounding alloy could be compressed/centre-popped? Does anyone know? I still have the old heads and some of the tools ind inserts for the thread repair - whereabouts are you gearjam?
Thread
Thread Starter
Forum
Replies
Last Post
al_roethlisberger
XJ XJ6 / XJR6 ( X300 )
7
09-11-2015 10:04 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)