I have the drivers side valve cover off. What will be the orientation of the rockers? This is for the compression stroke.

 

both valves closed, you'd need to feel the air at the spark plug hole to know compression. if you're only looking at #1 the dampner mark and timing tab would help you out

 

Stick a straw in and hold it with your fingers, pushing a little bit to make sure it remains in contact with the piston. When the straw starts sliding out, check to see what the rocker position is. Both closed = comprssion stroke, one open one closed = exhaust stroke. Then use the timing mark on the balancer to get it exactly at TDC..

 

could the mark on the dampner be off? My car is an 83 Z so it isnt exactly new anymore haha. But the mark is like 1/4 past the timing tab when I am at TDC. Both valves are in the the closed position and after the next thing that happens is the exhaust valve starts to open so I would think I am at the right place. I went around a couple times to make sure.

 

Yes, the mark on the damper could be off. The entire outer ring of the damper may have slipped, or the timing tab may not be in the correct position, especially if it is one of those aftermarket chromed units. Finding TDC via the "straw" method is usually close enough to determine if the timing marks are off by a significant amount.

If you really want to get down to degrees, you'll have to measure crankshaft rotation (via a degree wheel) from a known stopping point in both directions, then divide the two measured points to find BDC. With that known BDC position, you can turn the crank 180° as inidcated by the degree wheel. This is usually done with a piston stop installed through a spark plug hole (just like degreeing a cam).

Another, slightly less accurate method is to measure the relationship between the crankshaft snout keyway and groove in the balancer ring. The typical SBC has a timing mark that is retarded about 7° from the broached keyway in the crankshaft hub.

 

And my wife calls me a nerd.


It may help to know why you are trying to find TDC, then you can get more precise advice.

 

The timing tab is stock. The straw method is what I used. Im gonna recheck it again tommorow but I think its off. I am trying to find TDC because I am trying to re-install my distributor from scratch.

 

Ah. The straw method with the vc off will do fine. Get in the approximate area and then you can play with the dizzy to finalize it.

 

Ok cool. Just to make sure, I will be pretty close to TDC once the straw stops moving up right? Im about to go work on it some more later today.

 

and dont forget to watch your intake rocker,after it closes you know youll be coming up on tdc of the compression stroke

 

You guys freakin :yourock: I finally was able to get my car started today! I have been working on it since Friday so I was going nuts trying to get my car to run again! It turns out the mark on the balancer is off. I found TDC and the mark was almost 1/4 past the tab. That damn mark has been throwing me off all weekend. I put the dizzy back and it fired right up. Im so happy Now I need a way to accurately set the timing. The car runs good now but Im sure the timing is a little off. Thanks again for the help

 

I've set it by ear, but by no means when I started out. Mr. Nerd's er... Vader's suggestion would work very well. It's roughly how to degree a cam so you may want to research that to get a better understanding of what he is having you do and how to properly do it.

If you research long enough you may even come by a few ways (or may realize yourself how) to make a 'poor man's degree wheel' rather than buy one. Would work acceptably in your situation. I'm cheap and lazy too.