Valve Train Assembly Sept/Oct 2007


Now that we have cleaned and checked the valve train parts and purchased whatever didn't pass muster, we can start putting it all together.

The block should have all of the machine work finished. This should include drilling and deburring the lifter bores if adjustable lifters are being used.  Check each lifter bore with a lifter to make sure it is free in the bore.  Do what you need to for the lifter to move freely. These holes should be located low on the lifter bosses;  we use a 5/32 inch drill bit. Using an Allen wrench through the hole to engage the slots in the lifter is far easier that trying to get two wrenches in the same space where there is barely room for one.

Why an Allen wrench? Because they are tough, less likely than a drill bit to break or bend, and they have a built in handle.

The block should be cleaned for assembly. No dirt, honing residue, machining chips or any other contaminants should be allowed. Cleanliness is next to Fordliness, especially here.  If you have to drill the gallery plugs to get them out, do that.

Support the block so it is secure and at a comfortable height to work on. If you support a '48 and earlier block by the bellhousing bolt holes, cut a piece of wood the correct length to support the front also. More than one block has been lost by breaking the bellhousing off.

Install the cam bearings. Be careful to line up the oil holes between the bearings and the block. The rear upper hole also has to allow the fuel pump pushrod to pass through. Check that before proceeding. Install the gallery plugs now, before you cover up the holes. Lube the cam lobes and eccentric with assembly lube, and the journals and bearings with engine oil. A couple of 6 inch long bolts in the front of cams that use a bolt on gear make a handle to aid in the insertion. Be careful, don't cut cam bearing material out with the edge of a lobe.

When the cam is all the way in, make sure it turns freely. If not, find out why and fix it now while the block is otherwise empty. You did verify cam journal size and get the correct bearings, right?  They are available in STD, -.010 and -.020, as well as +.015 and +.080 on the OD.

If you have a cam with a press on gear it should already be on the cam. If a bolt on, put it on now with a new cam bolt lock plate. You can use Loctite for added insurance. Use only the correct, shouldered bolts here.

We install the crankshaft next. It is the safest, easiest way to turn the cam with the valve train in place. The rod and piston assemblies are installed after all valve train work is finished.  Don't turn the cam with a lever between two cam gear bolts; it is easy to crack the flange from a bolt hole to the OD.

If you are using the 49-53 valve train, install the valve guide seals on the intake guides. I oil the seal and "wind" it on with a small screwdriver.

Lubricate the guides and valve stems with oil and assemble. Insure that they move smoothly on each other. Install the spring with the more tightly wound end against the guide, it is the heaver end, so it should be the stationary end.

If the same forked tool used for teardown is supported on a 6x6 inch block on one end, the other end can be used on the bench with hand force to assemble spring retainers and split locks, if used.

The lifters get assembly lube on the bottom and engine oil on the sides. They should slide freely into the lifter bores.

The valve sub-assemblies should slide, not so freely, into their bores. Use enough oil on bores and guide seals, where used, to eliminate shearing any rubber. Sometimes some persuasion with a Popsicle stick through the intake port will help. Genuine Ford valves, and a few aftermarket valves, have a "bump" on the stem to help push the guide down into its bores.

Remember that the split line on 32-48 guides should be transverse to the block center line so that you can pull both halves of the guides down together to install the guide retainers. The gap in the forked tool must fit the guide properly for this to work. Sometimes it helps to pull the guide down one spring coil at a time.

When all of the guide retainers are installed, you may set the valve lash. The recipes given in the manuals are fine for stock grinds, but not for performance grinds. A recipe that works on all grinds is: set the intake lash when its exhaust just starts to open, set the exhaust lash when its intake just closes.

If you are setting lash by grinding, don't lubricate anything but the cam journals until all the grinding is done. It is critical that you maintain ID on each lifter and valve for its position in the block. Pull the cam back out to check cleanliness, then reassemble, lubricating as noted above.

Now that was kind of fun and you have a real sense of accomplishment.