Jaguar Repair: Howard M. Fitzcharles III, jaguar engines, cam chain

Question
Howard
The procedure you explained on 10.30.08 regarding tappet shim changing, does that apply to all 6 cylinder Jaguar engines i.e. to my XK 140 from 1955?

Expert: Howard M. Fitzcharles III - 10/30/2008
Question
QUESTION: pulled head and had valves done. put back together shim and  tappets back same order came out. now got no compression.


Answer
Hi Florian,
Of course you have no compression. You should have adjusted the valves (changed pads (shims)before you installed the head. Hopefully you have not bent any valves.

If you have not bent any valves you can do the adjustment now. Since you have rotated the engine you can not do any more harm so turn the crank so that the notch (cam timing notch) is facing the head and stuff a shop rag into the cam chain area (so you don't drop anything down inside the chain area. Now remove the available sprocket to cam bolt. Find or make a thin nut to fit the end of the shaft that sticks through the guide in the chain area. (5/16" NF nut as I remember) Start the nut but DON'T tighten it.
Install the rag on the other cam chain area and do the same.
Remove the rag and rotate the engine until the cams are in time. (both notches pointing 90 deg from the cam cover surfaces, and the timing mark on the front pulley is lined up with TDC.

Now reinstall the rag again and remove the other cam sprocket bolts. Now pry the sprocket off of the cam and snug up the 5/16" nuts.

DO NOT ROTATE THE CRANK NOR EITHER CAM AT THIS TIME. Remove both cams being sure not to mix them. BE sure not to get the cam bearing caps mixed (most are numbered)

Remove all of the lifters keeping them in order. Remove all the adjustment pads keeping them in order and measure each with a micrometer and write down the thickness.

Now rotate the crank so that all pistons are off of TDC. (It only takes a small amount.)

Locate some thinner pads or pick the 6 thinnest and put them on one cam (keeping track of which went where) install that came and cam bearings and use a feeler gauge to see what the clearance is on each valve and write it down. If any valve does not have clearance you can not proceed until you have clearance in all 6 valves.

Write down the clearance and remove the came and change the pad to what ever pad will give you the correct clearance (according to the specs for your engine) It sometimes takes two or more tries to get it correct.

When you have ONE cam finished remove that cam because you can NOT have both cams on the head when doing this or you will for sure bend valves. When the second cam is finished remove it and turn the crank so that the pulley is set at exactly TDC. Then you can install the cams but be sure you are installing them in time. You must not bolt a cam down and turn it to get it aligned. As soon as the cams are bolted down stuff the rag in the chain area again and install the accessible bolt on each cam and confirm the timing. Remove the rag and rotate the crank so you can gain access to the other sprocket bolts. (don't forget to remove the 5/16" nuts as you bolt the cam sprockets up) Be sure to safety wire the bolts again.
NEVER USE ANYTHING EXCEPT THE JAGUAR CAM SPROCKET BOLTS. They can be easily recognized by the hole drilled in the head and the shoulder at the threads.

If all of this is too much for you, you need to find a Jaguar mechanic or you will for sure destroy your engine.
Howard