Have I got the wrong harmonic balancer to go with the timing chain cover (or the wrong timing chain cover to go with the balancer, depending on how you look at it)? Just bought this 305 a while back and put a new double roller timing set in before trying to run it. #1 piston is at TDC with both valves closed. The dots are aligned on the timing chain sprockets. However the mark on the balancer (highlighted with white paint so you can see it) is nowhere close to the 0 degree mark on the tab, for that matter nowhere close to the tab. This is the balancer and cover that was on the engine when I got it.
You use to be able to buy a marker that bolts on with some timing cover bolts . Judging by the holder ( roung tube ) its for a later engine and your balancer is for an earlier .
Make a new mark on the balancer get a new timing pointer buy the correct balancer I like the make a new mark on the balancer , it’s free and the easiest to do
buy a new timing pointer. Might do a search first, too...this has been covered here https://www.jalopyjournal.com/forum/threads/timing-305.1054916/#post-11966616
Time for a new balancer, the outer ring has spun. You need to replace the balancer now before you run the motor, the outer ring can do some big damage if it comes off.
I doubt it on a 305. Depending on the exact year, TDC puts the mark in a very different position than any previous SBC. It migrated up to nearly the 12 o'clock position, and a full 30º counter-clockwise from before 1969. It looks like he has a late 305 cover, but a timing mark that is about 10º off of that. That would be consistent with a 1969-early 1980's damper.
A quick check is to see if the key slot for the key for the damper hub on the crank snout lines up with the groove on the outer ring. If it does, you just have the wrong timing cover/tab. You can just stick a proper tab on it, or make one.
You also have to make sure that you have number 1 on TDC. According to this with the cam gear mark at 6 and the crank gear mark at 12 # 6 piston is set to fire. Crank Gear/Cam Gear Timing Marks. - Chevy Message Forum - Restoration and Repair Help (chevytalk.org) In all my years I have never set a distributor in without bringing the engine up on compression on number one or cranking it over by hand and watching the intake valve open and close and looking in the spark plug hole to check the piston.
I am probably in the minority,,,,,,but I always degree my balancer mark when I degree the rest at TDC . More times than not,,,they are dead on,,,,,or within a degree or so . It is obvious from the pic he provided,,,,,that balancer does not go with that timing cover . I understand that the outer ring can slip,,,and it is possible . But,,,, shouldn’t it slip in the opposite direction of rotation ? I could be wrong,,,,every time I think I know what I am seeing,,,,,I’m not,,,,LoL . Tommy
I bolt a longer than spark plug stop into the correct spark plug hole (the piston that is all the way up in the cylinder at TDC mark area). Roll the engine around till the piston stops against the installed stop, draw a mark on balancer at the pointer. Roll engine over in the opposite direction, till it stops again, draw another mark on balancer. Measure the short distance between marks, divide by two to get the center mark between the previous two marks. That is top dead center. Then grind, or hacksaw a new TDC mark if needed.
I believe that he's ate TDC now. Even if it is not on the compression stroke, up is up. The distributor and cam decide which of the two TDC visits is the beginning of the power stroke, of the four in the cycle. As long as he (and he said he did) lined up the dots on the timing set, the only thing left in the equation is the distributor. He can just put a dot on the cover where the groove on the damper is. The unused tab next to it will provide the necessary measurements for more dots on the cover, on degree intervals, for timing purposes. If he's using a shot water pump, it makes it hard to see the 12:05 position timing tab, if it is marked to read there. One paint marker, no waiting. I did not even own a timing light until I was 23.
I think my dad realized the value of my interest in cars, he bought me these when I was a teenager. He never had to pay for a tune up after that.
Yes, - gimpyshotrods - is right about not being able to see the existing timing tab. Pretend that the existing timing tab does not even exist. Do what - squirrel - said to do in an earlier post....buy a new timing pointer. Then re-mark the balancer for the new positioned timing pointer. This procedure is actually easy and fun to do.
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