First, thanks for all the help with the '01 XK8. I removed the right valve cover and discovered one of the bolts for the tensioner was almost completely unscrewed.

Here's a picture of the length of the bolt. I received several messages asking me to make sure it's the right length since the newest tensioners require a different bolt.

Please let me know if this is correct OR if the previous owner/mechanic/whoever used the wrong sized bolts when upgrading the secondary timing chain tensioner.

Thanks!

 

See above from Steve in your other thread, assuming that's right, and he's not often wrong, that bolt looks very short.

Hopefully someone will have the correct dimension.

 

I gave the measurement from the very top of the cap of the bolt. I think your bolt is OK, but not 100% sure.

Can you redo the picture in this position since I am away this week and do not have a bolt to check again.

 

That makes more sense Steve, but bolts would normally be measured from below the head.

 

I'm at my desk now. I'd much rather be elbow deep in the engine! ha ha.

I'll measure from the top of the bolt to the bottom. I'm guessing it'll be right at 46.5, but I'll post a picture this evening.

I really appreciate the help!

 

You are right Norri, unless an electrical engineer measures it.

 

Bolt length is conventionally measured from the base contact surface of the head to the tip.

Using that convention, I believe that the two numbers mentioned have been 35mm for metal tensioners and 40mm for plastic tensionsers.

JEPC lists both for the X308 which used both styles, and only 35mm for the X350 which only used the metal tensioners.

So .. 35mm for metal tensioners.

The ones in the picture would be 35mm. Should be a M6.

When installing make sure the holes are cleaned out to avoid hydraulic lock cracking the head and test install by running them down to the full depth by hand with the tensioner in place.

 

Thanks Plums! Appreciate the help!

 

I always forget to order the shorter bolts so I just use a cut-off wheel and remove about 1/4" from the end of the old bolts, clean up the threads and reinstall them.

You can always steal 4 of the front timing cover bolts as the short bolts (THEY ARE THE SHORT BOLTS) and replace them later (or cut the long bolts off and use them in the front cover or used thick spacers).

There are many way to get the job done.

bob gauff