Timing question 200 I6

[franko66]

I read on a few post some conflicting timing settings for the 200 I6. One post said to set the timing at 6 Degrees BTC and the other said that the specs were to be set at 12 dgrees BTC. I set it at 6 first and it ran good. I then readjusted it to 12 degrees and it ran even better. Is 12 degrees too much ? could the 12 degree setting damage any valves? also I read the idle spec to be at 475 to 500 RPM,s . I tried to adjust the idle down to 500 rpms and it just seemed to barely run. I adjusted it back up to 650 to 700 rpms. It would idle better. When I drive around and come to a stop . There is a slight shudder that is steady. Is it because the idle is a little too high? I have a pertronix set up coming soon. I hope that it helps.

 

[ludwig]

Twelve* is fine. You won't hurt anything. Set the idle in DRIVE at about 750 RPM. You will have to advance the timing even more when you get the Pertronix.

Now use a vacuum gauge plugged into the manifold port and time (turn) the distributor until you get max vacuum. It should be anywhere north of 18*. Leave it there.

You can then adjust the idle mix. With the vacuum gauge still plugged in, turn the idle mix screw in until it just starts to stumble. Then back it off until you hit max vacuum, somewhere over 18* and then just a quarter turn more. Now reset the idle to +/- 750 in DRIVE.

Once this is all set, take it out for a drive. Warm it up and accelerate on a grade and if you get knocking, back the distributor off just a touch until it doesn't knock under load. Now you are good.

You will probably have to do this all over again when you get the P-tx. But for the trouble, the car will run much better. The people here who like the Pertronix prefer the Pertronix I. It seems to have fewer failures.

 

[CZLN6]

Howdy Franko:

Welcome to the adventure. The difference in initial advance settings depends on what year engine package you are working with and which transmission your vehicle has. Typically, a car with an auto trans, from the '60s will spec around 12 degrees inital while a stick car will require 6 degrees. Both settings are conservative. In a reasonably clean engine better mileage and performance can be achieved with a few degrees more.

There is little danger to your valves, but Knock, or pre-ignition can be harmful to your engine. If you go too far you will hear it when lugging the engine. If you do simply reduce the initial setting until the knock disappears.

It would help us to help you by knowing what year engine, carb and distributor you're working with as well as trans type.

Ludwig has given you a good plan to optimize your engine. The only thing I'd add is to run a good upper engine cleaner through your gas tank to help to minimize pre-ignition.

I prefer the slowest idle possible, but that will depend on many variables, so somewhere between 500 and 750 rpms will likely be your engines sweet spot.

Hope that is the kind of info you wanted.

Adios, David