Unable to set timing 3.0 L

[kwc98]

Greetings,

I am looking for advice on more things that I can try. I have just installed a donor engine into my 82SC. It has tbitz EFI, MSD 6al, if that matters. I have the stock SC distrib for 82.

The engine starts, but when I go to set the timing, I would say that it is at least 30 deg advanced, when I try to retard, the engine really suffers, putters, dies. So the one way that it will run is about that advanced. This is what I have done:

Checked plug wires, firing order is correct
swapped the green, purple wires from the MSD, no real difference
tried to move the distrib a tooth, could not start
check for vacuum leak, but not sure that would cause these symptoms.

When the distributor is in, the rotor hits the mark perfectly, there is room to adjust +/-

I can rev the engine, but it usually stumbles, then revs up, once up to 2-3000 RPM seems to be running great. This is just by hand, I am not actually driving the car.

Any help appreciated, thanks,
Ken

[James Brown]

don't use the vacuum advance or retard. what does the EFI map look like on a laptop? What is the A/F mixture? lots of things going on with this setup. Is the timing light on #1 plug wire? It shouldn't start with 30˚ advance so that might be a mis-reading.

[kwc98]

thanks James,

My understanding is that I need to get the timing right before I worry about anything else. I have the light on #1. I think at this point I can only hope for the distrib being one tooth off. Previous experiments in this area were fruitless, but I am going to try again.

anyone else have a 30deg theory for me? thanks,
Ken

[Flat6pac]

He s off a tooth on the distri[B]utor, remember the SC turns CCW and the forward tip of the rotor needs to be set for #1 plug
Bruce

[Walter_Middie]

Being off a tooth on the distributor would not effect the timing. That only changes how far you can advance - not the advance itself.

Are you sure you have not mixed up something with the counterclockwise distributor? You have the correct drive gear on the distributor and your plug wires run in the correct order?

[Walter_Middie]

[Eagledriver]

If you are reversing the green and purple wires and not getting a difference you are doing something wrong with your measurement. The correct connection is green to green and purple to the wire shielding. One way catches a sharp pulse as the magnetic rotor passes the stator. The other way catches a shallow ramp well away from the rotor pass. These events are about 30 degrees apart.

I did connect mine wrong when I first built my engine and it did start and run well at idle with the 30 degrees advance from the wrong connection. Your EFI might be set with too low of airflow and/or fuel at idle to run with a "normal" ignition advance.

Get the connection on the MSD correct. (green to green) Then get the thing running even if you have to advance to 30 degrees to make it run. Then gradually reduce the timing while adjusting your EFI to keep it running. Eventually you should be able to get to 10 degrees advance or so. This should be a good setting for now. The stock 82 dizzy will not give enough advance to get you to max power without a recurve.

Make sure you know how to use your timing light. Many of them have a dialed in delay that will distort the reading. I haven't used one like that so I can't tell you how to use it.

-Andy

[Walter_Middie]

Isn't there a way to swap a couple of wires on the MSD that have a large effect on timing? Is this a new MSD installation? Is it set up for 6 cyl not 8?

[kwc98]

You guys are correct, I swapped the wires and I can now get the timing down to at 10 deg, so I am set with the timing, now I just need to get the EFI setup.

thanks,
-Ken