Jaguar Repair: Stakedown kit install #2 1984 XJ6, haynes manual, scrap aluminum

Question

Driving the valve guid   QUESTION: Howard,

  Do you have a torque spec for the bolts that hold the timing sprocket to the camshaft ?  I couldn't find it in my Haynes manual.  Maybe it's not too important since they have the locking plate underneath...  I took a lot of fiddling to get the first bolts started, used a screwdriver and block of wood to lift the sprocket into place.  I managed to drive down the valve guides with my bearing driver after I removed the caps that go over the valves see photo.  I took lots of measurements with the depth end of my calipers but it was tough to get consistency since the top of the head is rough. I do think I drove them in a dozen thou or more.  The cam went into place no problem, thanks for the great tip about using a vice grip on it to hold it in position.  The Haynes manual said the bearing caps are torqued to 9 foot lbs.

  Thanks again,

  Steve

ANSWER: Hi Steve, I have a Jaguar factory manual on the Series III and it does not quote a torque spec on those bolts either. (probably why Haynes don't have it) The bolts are a high grade bolt and can be pulled down pretty tight with even a long box end wrench and the tab plates are a little soft so as long as you pull them down tight and bend the lock tabs over you will not have a problem. I have never torqued those bolts and never had one come loose. They use to be drilled and safety wired on the older jags.

Thanks for the photo, That is what I should have had instead of my scrap aluminum blocks I use ha! Don't forget to check the upper chain tension when finished.

I have installed a lot of those hold down plates and on later valve clearance checks I always check the screws that hold down the plates and only found one screw that could be tightened a little after long use. Not sure that it was me that put it in or not as every one in the dealership put them in.

In 1960 when I started in Jaguar they showed me how to drill and tap the head and put set screws in to hold the lifter sleeves in place. A very difficult job. There were no hold down plates available in those days.

Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,

  I have a torque chart, for 3/8 fine the spec is 35 ft/lbs for grade 5, I tightened them to 30 since I don't really trust my torque wrench !  I used some blue lock tite on the hold down screws, but I did it in the dark and the next day I noticed they weren't all the way down so I tightened them some more.  So maybe that broke the lock tite bond but I'm not going to worry about it.  The chain probably isn't as tight as it could be, like I said I did have to fiddle a bit with a screwdriver to get the bolt in, if you have the instructions for tightening it, please pass them on to me and I'll do that job at a later time.  I'm surprised to hear the sleeve problem goes all the way back to 1960 !  I thought it was only in the 80's with emissions tuning that increased the engine temp.   Incredible Jaguar didn't redesign the head back then, but at least it's not as bad as Ford's decision with the location of the Pinto gas tank !

Thanks again Howard,

Steve.

Answer
Some of the hold down kits I have installed came with star lock washers for the screws and others didn't so I would put star lock washers on all of them. A lot of mechanics use Lock-Tight and I never heard of them having a problem.

The cam bolts are grade 8 or even better and 30 ft lbs should do ok with the lock tabs.

The cam chain adjuster is located inside under the breather cover. A single nut holds the adjusting wheel tight but even when you loosen it (whitworth size) (but a metric comes close to a good fit.) If you notice the outer edge of the adjuster wheel is splined and a spring loaded plunger holds it in place. The nut only locks it. To rotate the wheel there are two holes in it and a tool with two pins that fit into the two holes also has an flat ear that depresses the spring loaded plunger to release the wheel. A handle on the tool is rotated to adjust the tension on the chain. The tool is hollow so a socket and short extension can be inserted through the tool to tighten the nut once the chain is tight.

I believe I seen the tool for sale from Moss Motors or one of those parts suppliers. If not you can get one from Engel Imports on line.

The bottom chain is oil pressure and spring pressure adjusted automatically.

Jag didn't make that bad a design as the Pinto, but they had several dumb design items in the series III cars.

Howard