timing question on a '68 318.
 

if my timing marks on my cam sprocket and crank sprocket are lined up why is the timing mark on my harmonic balancer not lining up with the 0 timing mark when im at TDC on my #1 cylinder? there is only one way to line up the timing marks on the cam and crank sprockets right? the drivers side front cylinder is the #1 cylinder right? sorry for such a novice question...please help!

left front cylinder is #1, you are timing the cam and not the ignition, the timing on the harmonic balancer happens after the valves are closed, that is why the mark is off

Welcome. Dot on bottom of cam sprocket, dot on top of crank sprocket in a straight line with center of crank and camshaft. To find true TDC with the heads on a piston stop that screws in the spark plug hole can be purchased or made from an old plug. Stop the piston BTDC and mark balancer, turn the other way until piston stops ATDC and mark balancer, center between the two marks is TDC.
How much are you off?

Sorry NOT TRUE

If the cam dots are truely aligned, THIS WILL BE TDC

(A side note: When the dots are aligned as in the manual, I.E. top sprocket at 6PM and bottom at 12 o clock, THIS IS NO6 ready to fire, not no1. This means that if aligned at 6 and 12 as "in the book" you must either install the distributor pointing to no6, or rotate the crank 1 turn before installing the dist. for no1)

IF YOU ARE CERTAIN that the dots are actually lined up and not one tooth off, then your balancer has slipped the outer ring, which is mounted in rubber

Coronet is correct, but his answer is a little "fast" if you are not experienced.

Buy, get, make a piston stop similar to this:

http://www.jerrybramlett.net/images/...stallation.jpg

You can make one from an old plug--cut around the crimp, drive out the ceramic, and tap the hole for an appropriate bolt. Drill out a nut or two so it will fit down in the old shell, and you can then put a nut "on the back" for jam. You must lock it securely

Pull the no1 plug, make sure the piston is "down a ways" and remove battery ground.

Install the stop. First time you use it, you may have to adjust it. Wrench the engine around until it stops on the device. Make a temporary mark on the balancer exactly under TDC.

Now rotate the engine counter clockwise, until it again stops, and make a second mark.

Now you will have TWO marks some distance apart. True TDC will be halfway in between, and if the old mark is correct, that is where it will be


NOTE When using the stop, you are NOT trying to get the piston to stop at TDC, but at some point before and after. This is because as the piston comes closer and closer to over center, it "slows down" and reading become inaccurate, true even if using a dial indicator on a short block. You therefore measure with the piston "down somewhat" while the "rate of change" is still large.


I WOULD consider, was your balancer "apparently" correct earlier?

Is it possible you have mismatched parts, as in, out of a motor home?

Are you ABSOLUTELY certain that the cam drive is aligned?

Is it "one of those" cam drive setups with multiple marks for advance / retard, and you make have made a mistake there?

Make sure you have two circles lined up...not a triangle and circle and not a square and circle...the square and triangles will put you 5 degrees before or 5 degrees after....that is a novice mistake..done it myself. :doh: