Timing question

[GrantD]

I've got another pretty newbie question, but the easier the question the easier it is to answer. This one is about timing.

I was trying to time out my 1980 200 I6 and I had to retard the light to about 25* or so to get the mark to show in the teeth. I suspect that the damper has slipped as is common on these motors. Before I go through that though i wanted to make sure that I'm timing it right.

Set the timing light to 12*btdc, set inductor over first spark plug wire (which i assume is the one closest to the radiator), then hook up the power cables to the battery. I took off the vacuum advance attached to the distributor and plugged the now open vacuum line to the carb. Is there anything i'm missing? Is there another advance that needs to be overridden?

Thanks again guys.
-Grant

 

[addo]

That should be it. What figure do you get with zero dialback on the light?

 

[GrantD]

I'm sorry I'm not sure what kind of a figure you're talking about, and by zero dialback do you mean to put the dial on the back of of the light to 0*?

Thanks,
- Grant

 

[addo]

Yes, set the light to zero, and what gradation on the scale can you see aligning with the pointer?

Do you know the "dead stop" method for verifying TDC?

 

[GrantD]

i don't know the dead stop method but i'd be curious to know.

 

[addo]

Dead stop method of finding TDC:

You get a bolt with the same metric thread as your sparkplug (see an engineering supplies for this).

Remove all spark plugs and disconnect the battery. Turn the motor until the rotor arm points towards # plug terminal on the cap, and the timing notch on the damper lines up with the scale on your timing cover.

Now thread the bolt in gently, until it touches the piston. Turn the motor backwards a touch (few degrees only), and give the bolt an extra half rotation. Now turn the motor forwards again until you have made snug contact between the piston top and the bolt tip. Mark this point on your damper, aligned with the zero on your timing scale.

Next, rotate the motor in reverse direction until the piston again touches the bolt tip. Mark the damper where it aligns with the zero scale point, again. There should be a small distance between this mark and the first one you made.

Measure this distance exactly, and clearly mark the midpoint. This is true TDC for all intents and porpoises. Set your timing light on zero.

Now, with the motor running again (you DID remove the bolt, right? ) look at where the timing scale reads against the centre mark you just made. That's your real timing.

Regards, Adam.

 

[GrantD]

I guess I had seen that before I didn't know it by name. I heard it a little different though. I don't understand the need for this step though
"Turn the motor backwards a touch (few degrees only), and give the bolt an extra half rotation. Now turn the motor forwards again until you have made snug contact between the piston top and the bolt tip" It would seem that if the max height is set by the bolt in one direction of rotation that it would be the same spot on the other one and you could find the midpoint between the two just the same. If there is further explaination of your method I'd love to hear it I just like to know the exact reason I do things. Thanks a Bunch Now that I know that i'm timing it right. I'll eventually tackle setting the new mark. Thanks guys.

- Grant

 

[addo]

That's it; you're on top of the method. Thread is M18×1.5

 

[GrantD]

Thanks I appreciate it.