Rebuilding an F-head Engine

Page 3: Installing the Valves and Camshaft

by Eric Lawson

Return to the Engine Rebuild Table of Contents.

Camshaft and valve parts
Except for the tappets, all of the parts in thispicture are new. Because this is a new cam, the tappets had to be reground. If the old cam is being reused and the tappets are still useable make sure the tappets go back into their original positions in the engine.

These are the ends of the camshaft. At left is the timing gear end of the shaft.

The oil holes in the bearing journals should be checked to be sure they are open. The oil hole shown at left allows oil to flow between the camshaft thrust plate and the face of the camshaft. The hole shown at right allows oil to flow out the port to which the cylinder head oil tube connects.

Valve parts
From left to right: the woodruff key that goes into the slot on the camshaft, the timing gear spacer, the camshaft thrust plate.

The spacer washer should be about .006 inch thicker than the camshaft thrust plate. On engines that have been rebuilt several times, the camshaft thrust plate becomes worn. If the difference in the thickness of the spacer and the plate is correct, but the end play of the camshaft is too small, try placing the other surface of the thrust plate against the camshaft.

Valve parts
This picture shows the valve spring, the valve, the "Roto-Cap" valve spring retainer (bottom row, left) and the valve locks (bottom row, right).

When the valve spring is properly installed, the two coils that areclosest together, toward the left in this picture, should be againstthe block.

The valve locks are tapered. The narrow end of the taper should beclosest to the head of the valve. The Roto-Cap fits over the lockand holds the locks against the valve stem. The ridge in the locksengages in the grove in the end of the valve stem. The taper in thevalve lock holds the Roto-Cap in place.

The Roto-Cap causes the exhaust valve to slowly rotate as the valve opens and closes. This helps reduce carbon fouling of the exhaust valve and its seat.

Valve tappets
The valve tappets are installed, in the same holes from which theywere removed. Use lots of engine assembly lube on all surfaces thatcontact another metal surface.

The main bearing dowels have not yet been installed.

Camshaft in block
This photo shows the camshaft in place.

Checking end play
Checking the end play of the camshaft. The thrust plate is bolted into position, the spacer washer is placed on the camshaft, the woodruff key is installed and the timing gear is placed on the camshaft. The smooth surface of the spacer washer faces outward. The side of the spacer that is shown in the picture faces the cam.

The timing gear bolt is used to draw the timing gear into place. Don't forget the washer on the bolt. Torque the bolt to 30 to 40ft-lbs (40 to 54 N-m). The end play is .004 to .007 inch (.1 to.18mm). I have been unable to think of an easy way to measure the end play of the camshaft that does not involve the use of a dialindicator.

Valve spring compressed
The installation of the valve spring, keeper and locks. The spring is being compressed so the valve locks can be installed. Engine assembly lube is sticky enough to hold the valve locks in place until the spring compressor can be released.

Spring compressor
This is a wider view of the C-clamp valve spring compressor, whichwill work with valve-in-block or with overhead valve springs, but thecylinder head must be removed first. There are two other types thatwill work with the cylinder head in place on the engine. One only workson valve in block springs and the other only works on overhead valvesprings.

Exhaust valves
The exhaust valves are all installed. -- Eric Lawson

Continue to Page 4: The Crankshaft

Return to the Engine Rebuild Table of Contents.

FacebookVisit CJ3B.info on Facebook.

CJ3B Home | Contents | Search | Links | 3A and 3B Community

Last updated 6 February 1998 by Derek Redmond redmond@cj3b.info
All content not credited and previously copyright, is copyright Derek Redmond