This thin square section push rod tube seal was widely used in various Triumph pre-unit and unit twins at the top position of the push rod tube, where it meets the recess in the cylinder head.
The seal measures .095″ thick and the OD is 1.240″ when fitted to the top of the pushrod. Although intended for the earlier cylinder heads with the shallow recess, the thin seals are helpful when variations in tappet guide blocks, push rod tubes, and head gasket thicknesses are present.
Push rod tube seals are used to seal the joints where the push rod tubes interface with the guide blocks and cylinder heads. If a cylinder head has been machined to correct warpage, often times a thicker head gasket is used to compensate for the material removed during the milling process. Varying thickness seals can be used to achieve the correct “squish” required to provide a good seal without bending the cylinder head when torqued down to the proper specifications.
The push rod tube seal is placed over the top of the pushrod tube against the retaining shoulder. The cylinder head must be removed from the cylinder barrel to access the push rod tubes and seals. Refer to the factory workshop manual for detailed instructions on top end service.