A manual is a very good guide, but it can contain errors. A wrong timing instruction can bend valves. Proving the instruction before you act costs minutes.
Steps
- Read the whole job first. Instructions for one task can be split over many pages.
- Test the instruction on the engine. For valve timing, set cylinder one at top dead centre on the compression stroke. Check that the timing marks line up as the manual says. If they do not, stop and find out why. See Record and set cam timing marks.
- Mark before you pull. For a balancer or a counter-rotating shaft, find and note the marks before the crankshaft and gears come out: Check and set counterbalancer timing marks.
- Make your own marks if the cams, gears or sprockets have none. Use a paint pen or a scribe and take a photo.
- Check pictures. A picture may show the wrong part. Compare it with the real part and its name.
- Check clearances with your own measurements, not only the figure in the manual: Choose and use calipers and micrometers.
- Mark parts that look the same. Push rods can have different lengths. Mark each one with its position: Keep parts in order during a strip-down.
Tappets that need time
- Engines with hydraulic tappets can have no compression or run badly after assembly. The tappets pump up and take time to bleed down to the right clearance. Wait, and check again before taking the engine apart: Rebuilt engine will not start or has no compression.
Check your work
- Marks line up before and after the job, and every doubtful instruction has been checked on the engine.