2.8 v6 distributor timing

[sotlm2]

I have a 1992 chevy s10 with tbi 2.8. The truck has 185k miles and runs really well. I have gone round and round on where i like the engine timing and wanted to get some tips from someone who has experience with the distributor timing on a 2.8. The engine is all original and apart from gaskets, there have been no engine related changes since new. The timing was set at 12 degrees, but when i changed my oxygen sensor and thermostat, i decided to set it at 10 (which is the factory setting). Its a real pain in the neck to get it exact but i finally did. Now that its there, i have noticed no real performance drop off but my idle is down some and i am not crazy about that. it is the original timing chain and gears, and i want to know what real world experience people have had with adjusting it some. Is there a gas mileage change etc. thanks.

[geoffinbc]

Factory timing is always the best bet if you run 87 octane. You can also adjust timing with a vacuum guage and find the setting with the highest vacuum. See where that get you. It will bring up the idle a bit aswell.

[sharkey]

ive never had an issue setting timing on my 2.8l, its always been easy. when you are doing it, are you unhooking the refference wire??? if not, it will make it a pain to get right, as well as it would not be set correctly.

from past expiriance, i had my motor at 10 degrees base timing, and plugged in it would idle around 18 degrees when warm. if the refference wire was plugged in when you set it you would end up around 6-10 degrees retarded, wich would make it idle crappy but would likley affect performance.

[sotlm2]

thanks for your reply, i did unplug the wire (that acts as a vacuum advance) when i set my timing. It runs perfectly with the minor exception of the idle. I can tell that its down some which occassionally causes it to be 'lumpy'. i think i will bring it up to 11 degrees and see how that works. thanks.