Miketaylor
New member
While installing ?the timing chain in a 1970 170ci. i found when i rotate the cam sprocket to line up the dot with the crank pully, the number one exhaust valve opens. Anyone have have any thoughts on why this would happen?
All Small Six Timing
- Thread starter Miketaylor
- Start date
This relates to all small sixes
You want the timing marks lined up with the dist. rotor pointing at the #1 plug wire otherwise you are 180 out.. The crank turns twice for one cam revolution. You have the dots pointing at each other right?
Does this help? if not keep asking questions.
Does this help? if not keep asking questions.
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Miketaylor
New member
Thanks drag-200stang. The number one piston is at TDC . Rotor is pointing to number one on the distributor cap. Crank sprocket timing dot is in about 2 o'clock pointing at the cam sprocket. To line up the cam sprocket timing dot, i had to turn the cam. with the timing dots lined up that is when number one exhaust valve opens. and the intake valve is closed. with both valves closed on number one, the cam sprocket timing dot is 180 off. At time time will the two timing dots line up and have both valves closed on number one. I have never seen this before and i am lost for any explanation.
Ok, see if the mark on the crank sprocket is at the crank keyway and it should be at the tooth and then see if the mark on the cam sprocket is lined up with the keyway of the sprocket and that should be between two teeth. And again, the marks with the chain on should point to each other. If they are not, sounds like they are made wrong. Can you put up a pic
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should look like this.
What did you find out?
Miketaylor
New member
Purchased a comp cams timing chain set. Found the set I was having problems with has the cam sprocket timing dot about 40 degrees away from the key slot. installed the comp cams put it all back together and it fired and ran well.
Good thing you were smart enough to question it. It is not uncommon to has the timing off about 13 degrees, but I have never seen it off that far. Thats why we say to always degree it especially with aftermarket cams.
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