I just replaced my distributor on my 87 GT 2.8 V6. I took pictures before the swap and I will take a few after, but there is one thing that is bothering me. I rotated the engine so that the rotor was pointing at the number one cylinder position, and took note of the position of the base relative to the intake vacuum lines. When the the new distributor was placed into the motor and seated, I noticed that the position of the rotor was a little off. It was not more than one tooth off, just slightly off - maybe. But as a sanity check, I went to check the timing mark on the crank pulley, and it wasn't were I thought it would be. Please keep in mind, that I did not check to see where the mark was prior to putting the new distributor in.



As you can see, the timing mark is a little off from the zero mark. Is this because I just didn't really get the cylinder to TDC?

My thought process is telling me to just rotate the crank back a little, until the mark on the crank lines up with the zero mark. It will be a while before I can fire it up, as I am still waiting for some exhaust parts, so my goal here is just to get it close enough so it will start once I get everything back together from my recent clutch job on it.

Thoughts? Recommendations? Opinions?

Thanks

quote Originally posted by computer_engineer: My thought process is telling me to just rotate the crank back a little...

You need to set #1 piston at the top of its compression stroke (by using a probe sticking into the spark plug hole). If the correct/wide timing mark doesn't line up at 0°, it's possible the outer ring of your harmonic balancer has spun. Not much of a surprise if it's the original balancer.

Sometimes the outside ring comes loose from the inside hub of the balancer and that can make the mark be off.

https://www.fiero.nl/forum/Forum2/HTML/131761.html

Okay,

I found a way to determine TDC on these things when you are the only one working on the car. If there are two, then some of these tasks get a lot easier or even become possible.

I took an inspection camera and stuck into the spark plug hole for the #1 cylinder.



Since the distributor rotor was close to the #1 cylinder, I figured that it must be close to TDC.



Photo with the cap off.



Then when I looked at the timing mark on the crank pulley, it was very VERY close the zero degree mark, if not right on it. It was kinda tough to get it just the top and it falling down a little when pushed CW or CCW.



Does this seem right to you guys? Seems close enough to me...it should at least start so I can set timing once the car is back together.

Is #1 piston at the top of its compression stroke? The top of its exhaust stroke won't get you anywhere.

Is the groove we see in the image the wide one? There are three grooves on that ring. Using either one of the two narrower ones... won't get you anywhere.

If you haven't seen it (I'd be surprised if I haven't brought this to your attention previously), look at This. Setting the static ignition timing isn't complicated.

[This message has been edited by Patrick (edited 12-28-2017).]

That does look right. Always bring the engine to TDC by rotating it in the normal clockwise direction. If you overshoot the top, turn it backward, well past TDC then bring it back to TDC. The reason for this is to allow for the wear of the timing chain and gears.

Fiero Fool is correct. Timing chains do stretch and you can calculate the degrees of error by turning the crank back & forth. If the slack is excessive I would suggest replacing the chain.

ps: In case your wondering, "No".. you can't just knock out a link like a bicycle chain.

Spoon

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