couple of questions about cam timing

[Guest Anonymous]

im not sure what mark has to be pointing up for the cam to be at TDC? where would the dowel that sticks into the sprocket be pointing? down? what would the very front valves be doing?

also, its quite hard to turn the cam over manually? (i have the head off at the moment). how do you guys do this?

cheers and holiday goodwill to all

ozgeorge

[Guest Anonymous]

The notch on the camshaft flange (facing upwards)should be in line with the center of the oil dispersion tube. This essentially puts the dowel pin down, but is easier to see. I would expect the cam to be hard to turn because of valve spring pressure on the lobes. I would put the timing chain sprocket back on and try to turn it with a rag (both hands) while someone else holds the head down. You'll probably need to let the front of the head overlap your workbench to do this. The head will be at TDC for #1, on the compression stroke, so both #1 valves will be closed.

This is an interference engine, meaning if a valve is down and a piston is up, they will make contact and bend things. Make sure the engine is at TDC, and all of the slack is out of the timing chain on the side opposite the tensioner when both cam and crank are at TDC. This may take some trial and error. When you are satisfied that you have everything right turn it over by hand (wrench on crankshaft nut)a few revolutions and check alignment again. If you encounter significant resistance, stop and check things out. Remember that the crank turns twice for every revolution of the cam (piston at top for compression-intake/exhaust closed and exhaust-exhaust open strokes. Good luck and BE CAREFUL!

Sam

[Guest Anonymous]

Insert 2 long bolts in the front cam hub (where the sprocket usually bolts). Use them to lock a wrench or a screwdriver and turn the cam....

[Guest Anonymous]

(nt)

[Guest Anonymous]

to create some clearance. The valves are can

bend easily if the weight of the head rests on them.

I know...