So while working toward the 2nd cam tensioners to change them with the zip tie method, I have been reading all that I can on the forum to make sure I do the job correctly.
Last night I came across "camshaft woes" from 2011. The forum member relates that he had broken the cam while tightening up the bearing caps after changing the tensioners.
What can I do to make sure this does not happen to me? Cam position, or other safeguard?
Thanks,
Dennis

 

Rotate the engine clockwise from the front until the lobes of the exhaust cam are making the the least contact with the valve shims. Then loosen the screws beginning at the ends and tighten from the center.

 

RJ'
Thanks for the info. I'm sure I will have more questions as Time and work go on.
Thanks,
Dennis

 

put like 4 zip ties on it. make sure the cam cap slips on easy

it is almost impossible to screw up this job

 

Xalty,
Thanks for the response. I thought this job was pretty straightforward, but then this old thread showed that there were awful things that can happen. The original poster who broke his cam shaft never really explained how it happened. I made the assumption that the cam was not sitting appropriately aligned in the cam bearings and then an attempt to seat it by force resulted in the cam being stressed and broken. So I will rotate the engine until I have the fewest and least contact between cam and cam followers and make sure the cam caps are seated appropriately. Is there a cam position defined( top dead center on #1 or flats in alignment on the cam, etc.) or is this an eyeball the cam exercise?
Oh, when you say put 4 zip ties on it, do you mean on the sprocket and chain?

Regards,
Dennis

 

Dennis,

Probably the best Money you will ever spend is the Money you pay the Jaguar Trained Mechanic to do this job for you.....I had to Pay for a Piston, Rod and several Valves and all the Gaskets.....If you are planning to Zip-Tie the Tensioners....? Come-on! Fix it right or don't do it at all.............

Billy Clyde @ Cinco Ranch

 

Billy,
What caused this catastrophe?
Dennis

 

Dennis,

This was a long time ago and happened with my First XK8 Coupe (1998)....One morning on the way to the Office; I stopped for a Cup of Coffee.....When I came back and Started it up.....All Hell came apart and the Motor died right there! Hauled it to a Jaguar Shop that I had heard about....What He found was that the Tensioners on the Right Bank had Broken (Plastic)....It was my first XK (bought Used up in Louisville, KY)...At that time, I had never heard about the Plastic Tensioners....That cost me something like $4,500.00 as I recall! This was back in 1999 or 2000...Just wish I had known about the Plastic Tensioners at the time but it was my first XK....The Guys up in Louisville sure didn't mention it and they sure didn't want to help! I guess I was lucky to get back to Houston.....Valve opened at the wrong time and broke a Piston and Bent those Valves and a couple others. Had to replace the Rod , Piston, Valves and all the Gaskets on the Right Bank and Replace the Tensioners on the Left Bank...Lucky that I didn't have to remove the Left Head...only replaced the Tensioners on that side.....

About 6 Months later, a Guy caught me at a Gas Station and just had to have it! A couple Days later....It was his......That lead to me getting a Black 2000 XKR Coupe...That's a Story for another time, Dennis!

Billy Clyde @ Cinco Ranch -- Katy

 

....I didn't do the zip tie method, but did replace the tensioners after someone else had started the process. Since you have to remove the camshaft (or camshafts)....I discovered the cam blocks are numbered and must or should be placed back in the same position. The previous mechanic did not... Also, the bolts that hold them in place are very delicate and must be torqued carefully. I don't know if I stripped one because of the previous guy - or gal - had helped it along, but I did so it's on me. Heli-coil has held for the past five years, but it's not something you want to deal with.

 

If the caps are not installed correctly AND they are not pulled down EVENLY (each cap tightened a little at a time) until all the caps are touching the head, the cam can be stressed until is SNAPS. The cam is HARDENED and BRITTLE. It will NOT bend, it will BREAK.

 

Truck Graphics, & Motorcarman,
Working with Aluminum Engines and Overhead Cam Heads made of Aluminum is not the same as our old Iron Block Engines.....Never heard of Heli-Coils until about a year ago...That's when 3 of my Head Bolts pulled out of the Block and started pushing water back into the Cooling System...Blew the Radiator and most of the Hoses...plus almost every thing else....New Head Bolts and a bunch of Heli-Coils, plus all the other stuff....Never had that problem with an Iron Block!

New Radiator is about $550.00 and all the Hoses on an XKR cost around $600.00...not to mention all the Heli-Coils and other Gaskets and such!...Plus Labor! Cost almost as much as I have seen some of the older XK8's sell for........You've got to love'em to even fix'em....Beginning to think about Electricity...Wonder if I could put an Electric Motor in my XKR?

Billy Clyde @ Cinco Ranch

 

Motorcarman,
Thanks for the info. Where or how far is Wise county from
Brazos county? May call on you for some hands on info in the future!!!
Thanks,
Dennis

 

Billy,
I feel your pain! I have bought cars against all better judgement from the internet sight unseen. Five years ago a 1957 Corvette that was an internet queen and that I have had to rebuild literally every major system of the mechanical build in order to enjoy. Don't get me wrong, for some masochistic reason I enjoy this. I will be happy to replace the 2nd tensioners and know that i made the difference in saving this auto marque. The XK8 is such a beautiful car that even with the mechanical challenges, I would buy another!
Best wishes, and a hope that you never experience a catastrophe again!

Thanks,
Dennis

 

Keep in mind that the primary tensioners are also plastic and the plastic face of the primary guides degrades and breaks up, sometimes blocking the oil pump pickup screen. Eventually, you should address that issue.

 

RJ,
I luv ya, but you're bringin' me down man! If you've been following my posts, you will realize that I hope to be dead looooong before I need to crack open the front end of this motor again! Maybe even leaving this car to my God son so he will have the frustration and joy of remembering me for many years!!!
However, if I am blessed with a long, long life, I do realize that the primaries will need to be done. Maybe sooner rather than later if I find a lot of debris or cracking when I look down into the timing cover with a boroscope(see my previous post re boroscope use!).
Best wishes '
Dennis