Inspired by the Toyota 4 cylinder engine found here http://www.thingiverse.com/thing:644933 I thought it'd be cool to have more different kinds of these available for download. So.
This model is based on 8-valve cylinder head found from Volvo's 2.0 - 2.3l "Redblock" engines (B200-B230). It uses singular overhead camshaft operating the valves without rockers. Volvo has made these with various configurations, different camshafts etc as it's standard head found in both turbocharged and non-turbo redblocks. These heads don't have bearings for camshaft either, it's simply locked in place with the collars and constantly lubricated with oil channels running around the cam mounts. Super simple.
This isn't meant to be an exact replica: measurements were taken using non-digital caliper so some of them are pretty surely off, intake/exhaust channels are very basic (straight to the valves) and coolant channels are completely missing.
However all the mechanical stuff works and it provides good view of OHC head operation. Files marked as SCALED are ready to print, 40% scale and checked with netfabb.
SCALED files also include some features for easier assembly: places for 4mm x 2mm disc magnets to attach rocker cover and, possibly in the future, the head to the block. Tolerances have been checked for easier assembly, but some can still be pretty tight and require sanding/drilling (depending on printing quality). Like the Toyota engine, this isn't an easy assembly to complete either and does challenge your printer and nerves.
List of parts needed to print:
- Head x 1
- Rocker cover x 1
- Oil cap x 1
- 1st shaft collar x 1
- 2-4 shaft collar x 3
- 5th shaft collar x 1
- Camshaft x 1 (or camshaft split 1 and 2)
- Valve intake x 4
- Valve exhaust x 4
- Cam sprocket x 1
- Valve cap x 8
- Valve spring retainer x 8
- Retainer holder x 8
I had to rotate camshaft to wrong way in the video due to my drill being broken :p the real engine rotates cam in clockwise direction.
Firing order is 1-3-4-2, with 1 closest to the timing belt sprocket.
Wiring order for distribution cap is therefore 4-3-1-2 (left to right, looking from front)
NOTE: If you are printing, make sure you pick the SCALED files, the original ones are in REAL SIZE.
Update 24th Nov 2015: Replaced head_SCALED.stl, rocker_cover_SCALED.stl and valve_cap_SCALED.stl to fix some tolerance issues found after test print. Removed "Work in progress" stamp as the test print turned out pretty good.