Northstar Engines and System Technical Discussion Discussion, Tappets or Rocker Followers - Two Different Head Designs??? in Cadillac Engine Technical Discussion; Flat tappet NS motors use lash caps? Are they solid? They are just a spacer between cam lobe and valve ...
Flat tappet NS motors use lash caps? Are they solid? They are just a spacer between cam lobe and valve stem? I have pulled out a few from junkyard cars where the cams were gone. It looks like a heavy duty cup? I never really inspected them closely or turned them over. It seems solid to me? No hydraulic adjustment?
Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
MD Eastern Shore - Kent Island
Re: Tappets or Rocker Followers - Two Different Head Designs???
They're hydraulic cam followers - a modern version of lash caps. Take a hard look at one - there's one or more oil supply holes drilled in the groove - the bucket rides in the head bore, and full pressure oil is supplied to the bucket by internal oil passages in the head. The follower is actually about 3 pieces - outer bucket, inner hydraulic valve actuator, check valve.
FWIW - In the older, solid cap style of follower there was a hardened steel disc between the follower and cam tip. These discs came in about 20 thicknesses. To set valve lash you warmed up the engine, shut down and removed the cam covers. Then hand-turned the engine, miking the individual valve clearances with a feeler gauge. If a valve was too tight or too loose, you removed the cam(s), miked the disc insert, added or subtracted the necessary lash correction, and inserted a new disc of the proper thickness. (Now do that on a Ferrari V-12.)