hey guys,

i just had my dad in town and we started on my '68 project car- SBC 350. i bought the car running, rough,but running. my dad and i put a timing light on it, and the timing mark was at the 11/12 o'clock area, not even close to the 1/2 o'clock area, where it should be. over the next 2 weeks, we pull the motor, rebuild the trans, new ignition, freshen up all motor gaskets, new intake/carb, ext. in the process we find top dead center, reassemble and.... same problem. we had to turn the distributor almost a 1/4 turn Counter clockwise to get it running. put a timing light on it and the harmonic balancer mark is at the same spot, 11/12 oclock.

any idea what is going on? could the previous owner have installed a harmonic balancer from a different vehicle?

any and all help is greatly appreciated!

thanks
bobby

 

Hi Bob,

This might be far out there, and I haven't experienced myself, but I know some that have. Is this the factory harmonic balancer?

If so, here is what I was told. The balancer is made up of two parts, there is an inner hub and an outer ring. Between the two is a rubber insolator. This insolator can get worn down and cause the outer ring to shift and when this happens, your timing mark will change.

I'm not saying this is the problem, but it's something to look at.

I would like to say, that on Chevy's, the notch/ key in the hub should all be the same (big block and small block) and the difference would be in the size/ weight of the balancer, but would a different motor divison (Ford, Chrysler) be able to fit on a Chevy motor, I'm not sure about that one, if that's what your asking.

 

TDC on my timing tab is between the 1 and 2 o'clock position. Some SBC's used dampeners with the timing notch in different clocked positions, so it sounds like yours may be the wrong one, and/or you have the wrong timing tab. Best thing to do, for your own peace of mind, is to pick up a piston stop (threads in place of the #1 spark plug) and find your true TDC. Put a new mark on the dampener and ignore the other one. Also, make reference marks on the inner hub and outer ring of your dampener to make sure it isn't walking on you.

 

thanks for the input guys. i have been forum hopping and it seems this is a rare issue, and most, if not all the similar threads i have found, have no resolution. the dampener inner/outer hub spinning is a common suggestion. also, there have been references to chevy moving the timing tab and dampener notch to the 12 oclock position for a few years (late 70's early 80's i believe)

i am going to find TDC, the way you have described, camaro '69. i should have done that to begin with.

to complicate things, i bought a new timing light to rule out my original is faulty and because the new one has a tach. when i hooked up the timing mark was on the drivers side, but was very erratic - all over the 1-3 oclock spectrum.

in addition to finding TDC again, im gonna freshen up the balance of the electrical components that i havent already replaced. hopefully this will give me some kind of clue to what is going on.

thanks again and any other suggestions are greatly appreciated

bob