Abstract: A heat exchanger has a plurality of main flow passages 2 for cooling fluid. Each main flow passage has associated with it at least one narrow channel 10 defined by a surface of the main flow passage and an auxiliary surface on a separator plate 8. Relatively hot fluid flows over the separator plate 8 and heats the auxiliary surface such that bubbles formed in the channel are flattened by the surface opposite to the auxiliary surface and pressed against the auxiliary surface. The bubbles eventually pass through holes 12 in the channel 10 into the main flow passage 2 to rejoin the evaporating liquid pool.

Abstract: A guide (28) is provided for retrofitting an existing internal combustion engine block (10) with roller cam followers (24 and 26) in place of conventional barrel-type lifters, without modification of the block itself. The guide includes a guide bar (64), keyed to the upper body (38) of each follower to allow limited rotational freedom thereof and a resilient C-shaped spring clip (70) which simultaneously bears downwardly on the upper surface of the guide bar and upwardly on the lower surface (40) of an engine block boss (18) defining follower receiving bores (20 and 22). Annular spacers (72) are provided, if required, to displace the guide bar upwardly from the upper surface (52) of the boss. An upper leg (76) of the spring clip wraps around the guide bar for retention therewith and a lower leg (78) of the spring clip is necked at a point (86) intermediate adjacent cylindrical portions (30 and 32) of the follower boss for retention therebetween.