Qualcast/Suffolk camshaft replacement?

That's basically correct, but over complicated. For a mower engine, pull out cam so gears are JUST out of mesh, set piston to TDC, rotate cam so BOTH valves are just off their seat, and mesh the gears. Job done. This works for ANY 4-stroke engine with valve overlap (basically anything built after 1920 ish), including multi-cylinder engines. Just pick a cylinder, and time it. All the cylinders that share that cam have to be correct.

If the engine has a distributor (IE car engine), after timing as above, rotate engine one complete turn and time the ignition. Magneto engine spark every revolution, so this is not necessary.

phil_saunders(a)bigfoot.com

Phil Saunders
September 2012

There will be marks. camshaft hole might align with the camshaft cover, have a look there. then on gears etc, might be just a pin indent. if nothing, FOR 4 stroke engines. set the camshaft so valves closed. NO drive to canshaft. there are only a few positions. piston at top dead centre is the start point, just after that, does the plug spark, if so you are the approching exhaust cycle, so next thing, after the piston reaches bottom, the exhaust valve needs to be opening. Then after TDC again, the inlet valve needs to open, to allow fuel mix in. then compression stroke at the top of which, the spark would ignite the fuel driving the piston down to exhaust again. SO once you know the sequence, check with piston at bottom. turning the camshaft to correct sequence position, either inlet just closing, or outlet opening. you might then be able to see the alignment points, as you will not be far out of position. If still no points, set at position and slowly turn over to check, that nothing is going to bang together. then try to start. might be rough, so adjust one way or other until running smooth

SD
September 2012