setting valves with advance key

[brian400ex]

When i go to line my timing mark up where do i line it up at?

Thanks


Also do people still like the advance key or are they taking them back out? mine seems to run fine with it

[81 clark racing]

i love mine the best 20 bucks i ever spent. i plan on taking mine out when i bore my motor

[GPracer2500]

Well, with the Sparks key your TDC mark will be 6 degrees of crank rotation to the left (when facing the left side of the engine) of where it was before. So just turn the crank past the TDC mark just a little and you should be good.

You could also remove the spark plug and find the exact TDC by sticking a dowel rod into the spark plug hole. Make contact with the top of the piston and when the rod reaches it's highest point, that's TDC. Then look at where the TDC mark is on the flywheel in relation to the mark on the case cover and you'll know exactly how far off the TDC mark is.

Bear in mind you don't need to be precisely at TDC. As long as all the valves are closed and the rockers are still on the base circle of the cam (the part of the cam opposite the lobe peaks) then you're good. You've got a little bit of leeway one way and the other.

[wilkin250r]

Originally posted by GPracer2500
Bear in mind you don't need to be precisely at TDC. As long as all the valves are closed and the rockers are still on the base circle of the cam (the part of the cam opposite the lobe peaks) then you're good. You've got a little bit of leeway one way and the other.

I would take it one step further and say go ahead and adjust while dead-on the timing mark. The "little bit of leeway" is going to be at least 20 degrees in either direction, so 6 degrees is certainly safe.