Setting up the XK Engine Cylinder Head on the Block
By Dick Maury
This article is aimed at the person who has a rebuilt cylinder head and is going to install it back on the block. I will assume that the head has been properly rebuilt and the cams are set at TDC (top dead center) using the proper cam timing gauge.
First thing to do is to make sure the top of the block is clean without any oil, old gasket material or dirt. I would recommend at least wire brushing the studs off using a circular wire brush on a drill to make sure they are clean. It is also a good idea to chase the threads on the studs with a die or thread chaser. The size is 7/16 x 20. Wipe everything down with lacquer thinner or a suitable solvent that does not leave a residue. Do likewise for the the surface of the cylinder head. Tie the cams sprockets together using a rubber band, o-ring or a piece of wire. This will make it a lot easier to install the head later.
If you have the distributor cap off, fine. If not remove it and check to see that the rotor is pointing to the front cylinder (the one nearest the radiator). Some call this #6 and some refer to it as #1. It really does not matter as long as it is the front one that the ignition rotor is pointing at. This cylinder should be at or near the top of the cylinder. If it is not, then turn the engine until it is there. The front nut is a 1 5/16" and the engine should be easy to turn at this point. Do not use the starter. Once there, using a depth micrometer or a screwdriver with your fingers, check the height of the #2 and #3 cylinders. As one is going down and the other is rising when the front cylinder is at TDC, this will help get the timing right on the money. Turn the engine until they are at equal height. Once there, do not turn the engine. Check the timing mark to see if the indicator is pointing to exactly TDC. You will notice that the indicator plates are slightly adjustable.
Now that the engine is at TDC and the head is at TDC, it is time to install. Take the head gasket and carefully slide it over the studs into place. It should be marked "TOP" on one side. If it is a later gasket, the water holes are larger on the exhaust side. I won't get into the logistics of putting the head in place but do get some help and be careful not to let the studs scratch the surface of the head.
Now that the head is in place, install the appropriate washers. Take a tap and chase out the threads in the acorn nuts. Use some anti-sieze on the threads and screw them down finger tight. Follow the torque sequence in the shop manual starting in the center and alternating out to the edges. I don't try for full torque at first but go up in 20 lb/ft increments. There are two size acorn nuts as far as height is concerned. The longer ones are for the later XK engines that use the long studs. They will work fine for the earlier engines. The earlier shorter nuts can bottom out onto the studs on the later engines. This will cause the head gasket not to be properly compressed yet the torque wrench will read the proper results. Always check the standing height of the threads after installing the washers compared to the amount of thread in the nuts. There should be a good bit of room for stretch without the nut reaching the end of the thread.
Note that you have not been instructed to turn the engine or cams at this point so hopefully you haven't. Take off the rubber band or wire off of the cam retainers so the sprockets will fall free to the side. Put them onto the cams and check for looseness in the chain once installed. If the chain is not tight, rotate the front chain tensioner until all of the slack is out of the chain. Hopefully the sprockets have stayed in place on the cams. Only if you are very lucky will the bolt holes line up with the holes in the cams. Earlier cars had two holes and the later had 4. You can put a 4 hole sprocket onto a 2 hole cam and vice versa without any problem. If the holes are not lined up, locate the circular retaining ring inside the sprocket and remove it using a sharp pic. Still keeping the sprocket on the cam, slide the inside piece of the sprocket towards the front of the engine and turn the inside piece so that the holes line up. You will notice that there are a lot of serrations so fine adjustment is possible. Gently push it back into place and check to see if the hole is aligned. If not, repeat until it lines up. If you have to turn the inside piece 180 degrees to line up with other holes, that will work. Once the inside piece is in place and the holes lined up, start one of the bolts with your fingers. They should screw into place without a lot of effort. If they will not start of go in all of the way, then the alignment is not correct. Once the bolt is in place, repeat process for the other camshaft. Install the circular rings to hold it all together at this time. Now that there is at least one bolt in each cam with the timing set, it is safe to turn the engine over to install the other bolts. If you are using 4 bolt retainers, install the next two bolts with the lock plate and then go back to install the plate on the first bolt and last bolt after the other two are in place. This will insure that the timing is not lost. On the two bolt cams, once both are in place on a cam and tight, safety wire tie them together.
From here on , it is just a matter of cam covers and hooking up the various accessories that vary depending on the year of the car.