My Tractor Forum banner

L cam/crankshaft timing

3K views 3 replies 3 participants last post by  beaner2u 
#1 ·
Had to change a broken exhaust camshaft. I see the process in the manual for setting the timing of the camshafts to the idle gear, but is there a set procedure or aligning mark for timing them with the crankshaft. The manual mentions about when the valves should start to open in location to tdc, but mine seems a hair off and I dont want to run it without it being dead on.
 
#4 · (Edited)
We know you have your cases seperated in order to change a cam. Marking sure things go together without a struggle is a good check; can you fit the rear case onto the timing pinion shaft without major effort? The rear bearing can be a bear to get back on sometimes, clean and polish the timing pinion shaft.

When you hold the flywheel assembly as in the photos of the manual, mark the 'high spot' of the rear flywheel(timing pinion side) with a majic marker. The video shows how to time the gears and make sure the timing mark on the idler gear is pointing straight up in the cylinder opening of the rear case, make a majic marker mark above the ider gear near the top inside of the case which aligns to the timing mark or the idler gear. Now when you mesh the flywheel assembly timing pinion shaft gear, with the idler gear you know its correct. You can roll the flywheel a 'little' side to side, you cannot roll it over, but when you bring you rear flywheel timing mark back up to the high marks, you should be able to see the timing marks still aligned on the cam gears and idler gear.

The reason you cannot roll the flywheel completely over after meshing is the way a four-cycle engine works, those cams do not come back in time for many revolutions... I forgot which top stroke timing of the of the cams occurs on.

The video above shows installing a flywheel assembly in a rear case first, I have not tried it that way, and then pull the front case down onto the drive pinion bushing, might try that on my next rebuild. I usually simiply pull cases together with the flywheel assembly in the front half.

Roger,
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top