Timing Question

[Wrcampbell]

Ok have alittle question. Ok my 70 C-10 has a 307 2barrel man brake man steering and points. Ok here is the question, Ok the motor has 69k mileage on and holds great compression. So i tune to 2 Degrees BTC and set points to 31 Degrees. Should try a different tune for the age and quality of the gasoline nowadays? any suggestions? Thanks!!!

[Wrenchbender Ret]

Yes. Try about 6-8 degrees timing. It will run much better. If it pings on a hard pull or kicks back when you start it, set it back a little. I dought if it will.

[imjeff]

Make sure you set the dwell before the timing. Each degree of dwell changes the timing two degrees. Advance a couple degrees at a time until you get knock under load, then back it off a couple degrees past when the knock stops.

[Wrcampbell]

Thanks guys!! I am gonna give it a try Thanks Again!!

[hugger6933]

That little change can feel like a motor swap in some cases. I know the later model big block trucks say 88-95 were so choked down that if you put dual pipes on them[witch I'm growing to dislike every day I grow older, at least on daily driven stuff] and then crank up some timing that old rat would wake up quite a bit and change the whole outlook on thing the way it acted. I had sold several of those to farmers and then cranked the timing up some to make it run better and they would come back asking what I did to their truck cause it didn't act like the same one I had sold them. Jim

[Wrcampbell]

Ok adjusted timing to 6BTC and tweeked on points....must say wow what a change! That little 307 is back to life thanks

[imjeff]

Great! Glad you got it figured out!

[geezer#99]

Originally Posted by Wrcampbell

Ok adjusted timing to 6BTC and tweeked on points....must say wow what a change! That little 307 is back to life thanks

You want to feel a real change, bump it up to 12 degrees.

[tinlid]

I will jump in here with further question or two. I also have a 1970 307 with 81,000 miles. Carb rebuilt about 6 months ago. Just put in new plugs, points, cap, rotor, condenser, plug wires and a new vac distributor can. Set dwell at 29. Timing was showing 2 atc so I changed it to 5 btc and did final dwell adjustment to 29. Vac line was plugged when doing this. Now I had to turn in idle adjustment a full turn to get it to idle and it wants to diesel a little when shut off. Also it seems to surge a bit on steady throttle. Hard to notice but not steady like it was. Next step or idea?

[tinlid]

Maybe I should have started a new thread but I figured WRCambell had gotten to where I am and he is running great where as I am not. I also looked at this thread when I started so I pretty much used this info to set mine.

[geezer#99]

Did you know the 'A' on your timing tab means advanced and not 'after' tdc.
Advanced means btdc. You where at 2 degrees btdc. You retarded your timing instead of advancing it more. Start at 10 btdc. Each mark on your tab is 2 degrees. If you look at the tab you need to look to the left side of zero.
Then turn your idle down and it should stop desieling.

[tinlid]

I guess I didn't or old age (70) is catching up and I didn't remember. Anyway, thanks! Guess it should run great as soon as I move it.