Classic car technician Jonn has carried out a diagnosis for number 7 valve clearance that keeps increasing on our 1970 MGB Roadster. He removed the inlet manifold to gain better access to the engine side covers. He then removed the rear side cover.
Jonn slackened the tappets for number 7 and removed the push rod. He was unable to remove the cam follower from the block. He suspected that the follower was worn and “mushroomed”, making it impossible to remove from the top. As a result, Jonn decided to remove the engine to ease the removal of the follower from the underside of the engine. Fluids were drained and the engine was removed and mounted on an engine stand.
The sump was removed and Jonn found small fragments of metal inside. He continued to strip the engine so he was able to remove the camshaft and access the worn follower. He removed the distributor, removed the oil pump and the cam locking plate. The camshaft and number 7 follower were removed and, as Jonn suspected, the cam follower was badly worn and the number 7 cam lobe was also badly worn. New cam and followers are required.
Jonn cleaned parts ready for refitting. Due to the metal fragments in the sump, he thought it prudent to strip the oil pump and clean it. He then inspected the inside for scoring etc. The oil pump looked fine.
The engine was packed with build grease and rebuilt. The block and mating surfaces were cleaned and the cam bearings were inspected. Number 1 cam bearing was showing slight scoring. Jonn will check the tolerance when the new camshaft arrives. In the meantime, Jonn has blown out the oilways and covered the engine until the required parts arrive.
Jonn finished cleaning engine parts in preparation. He also cleaned the engine bay and inner wings/cross member. The gearbox bell housing was cleared out and Jonn visually inspected the thrust bearing, which looked ok.
