why is my timing mark off?

[olblue2]

ok guys a lil help here, getting the new engine in my 1977 k-20 running and have a question, when taking out the #1 plug and bringing up engine to top compression, i notice my mark on my harmonic balancer is not near the timing scale?  could the balancer be off?   i tried aligning the mark with zero on the scale but then the piston is not at top its on way down??   whats goin on?

[zieg85]

Wrong timing chain cover comes to mind for the harmonic balancer that is on the engine.

[DnStClr]

When you bring the #1 piston to tdc, there should be enough pressure coming out of the plug hole to feel it pretty good. Best way to do it is to have an assistant crank the engine slowly and STOP when your finger is blown off the plug hole. Remove the battery positive cable. Move the engine(breaker bar and 5/8 socket on the crankshaft bolt) til the timing mark on the harmonic balancer is aligned with the pointer. It doesn't matter which way you have to turn the engine. Just align the two marks.
Now remove the distributor cap, but 1st make a mark on the engine where the #1 plug wire hooks up when the cap is on. When the distrib cap is off the rotor button should  be pointing toward the mark you just made on the engine. Approximately 6 or 7 oclock. If it's not, you must remove the distributor and realign it so the rotor button points to your mark, or as close as it can be..
Let us know how it goes. A lot of guys on here can walk you thru your engine setup.

[1980c10]

your distributor could be off a tooth. I had this happened on my '82 k10. this is the way i bought. I tuned it up and put a timing light on it and the mark showed up no where near the mark but ran fine. I pulled the distributor up and moved it a tooth and put it right on the money. made the engine run like new again. I wonder how many years it had been run this way. I would try a timing light and see where the mark shows up if the engine runs.

[78 Chevyrado]

If you have a 350 0r 305  it could be that the outer ring on the balancer has slipped on the inner hub a bit.  Had one do that on my old 77 c10.  It won't make it unbalanced, only throw off the timing mark.  I'd check the other suggestions above though first.

It won't make it unbalanced on a 350 or 305 (internally balanced), but only on a 400 (externally balanced).  so if you have a 400 and it's slipped, it will be a problem. 

[DnStClr]

1980c10- read his post. He said he's trying to get the engine running. Can't use timing light yet..

[Donut]

Which ever is the problem, first thing is to find TDC then you can go from there.

I just changed my balancer.  I found TDC (both valves closed, piston at top) then got the correct balancer for the timing tab.

Sometimes balancers can have the outer ring slip, the timing cover could have been changed, or they could have the wrong balancer for the year.  Some were set up for the TDC mark at 12:00 some at 2:00, (there may be more, this is what I found when I ordered mine.)

If the ring has slipped, I'd replace it.  (My balancer was 60.00 at NAPA).  If it is the wrong one (timing cover or balancer) and it's still good you can re-mark it.  file, hacksaw blade, paint stick, whatever.

This is on the assumption it's a 305 or 350. (like 78 Chevyrado mentioned)

[joesgarage71]

 Who built the engine?
Try another balancer.