I have just went out and bought everything I need to tune-up my engine this weekend. Including an engine analyzer and a timing light. As I have never tried this by myself and I have been jacking around with the carb and distributor blindly for the last couple of years, I know everything must be out of whack. Plus this car has not been driven much, for a while. I plan on changing all of the fluids, plugs, points, filters exct. So what I really need to know is, in what order do I check everything and make adjustments for points, dwell, RPMs, timing, exct. Won't adjusting one thing effect the others? How will I dial everything in just right? Any advice is appreciated. By the way, thanks to 1972 Grabber for posting the link to the Spec sheet. I was looking for that! I have a 302 with a 4bbl carb, and the old breaker points (for now). :16suspect
set the points just above the bottom end of the gap. then check the dwell, try to get that near the lower end of the range but still not at the bottom because they tend to close over time due to wear.I would always go a size above the bottom, i.e. for a 17 gap i would use an 18. make sure the screws are tight when they are set then recheck the dwell. now set your rpm to around 1k and do an initial timing set. once the timing is around 5 or 6 BTDC, set your idle closer to correct. also you dont say what type of 4 barrel. if it is edelbrock, close both needles and turn them back out a half turn then set your idle. if holley (this is off memory though) close both idle jet screws and open them 2 1/2 turns back out i think. EDIT:WITH EITHER CARB once you get all the settings about right turn one idle screw in about a 1/4 turn at a time till the idle starts to sound a little rough. when you hit that point open that screw back to where it was smooth and do the same with the other jet. now check your timing and idle just to make sure they didnt move too much, then drive it around the block to see how it is doing. also, depending on your set up you may have to idle it a little higher than stock so when it is in gear with the high beams on at a light it doesnt die. hope that helps
Your points dwell time will affect your overall timing so you need to set that before setting initial timing at the distributor. As mentioned above, I used to set the points gap at .018" (in a pinch a dollar bill folded in two will get you close). You can fine tune the dwell with your analyzer, 28* if I remember right. As the points rubbing block wears your dwell will increase so start at the low end of the range. Maybe consider stepping up to a Pertronix someday, then you never have to set points again. Most small block Fords like initial timing in the area of 12* - 14* even though specs call for around 6* or 8*. Adds some low rpm torque. If your carb is a Holley or Autolite carefully turn in the idle mixture screws until they lightly bottom out then back them out 2 turns as an initial setting to get the motor running. The best way to adjust the idle mixture is to obtain maximum manifold vacuum while the engine is idling at the normal operating temperature. You have to move back and forth from side to side a few times moving the mixture screws SLOWLY to get max vacuum. If you don't have a vacuum gauge you can use your tach and set for max rpm. You will probably need to readjust idle rpm screw once or twice, too, because that will change as you adjust the mixture.
Thanks for the help. I have an Edelbrock carb. It always seems to me to run a little bit rich. I was thinking of getting plugs a step hotter. I would also like to know if there are any benefits to advancing the timing. This car will mostly be on the street. So is there any advantage to either of these ideas?
edelbrock runs rich stock. turn the idle screws in all the way and out a half turn on that one. also try going one stage lighter on the rod springs. i had to rejet, but i live at 5k feet. no need to alter the plugs. as for timing, i again have to alter for altitude. if your not running the stock cam your cam should have given you a max time BTDC. with this cam and alti i couldnt get mine to run well beyond about 10, i used to run the stock cam at 6 for best results at sea level. but if you can get it to run good towards the 12+ go for it.
I know it's not a stock cam. I'm not the one who put it in so I don't have any specs on it. Is it important to know? How would I find out? The rebuild on my engine was done by someone else years before I bought it.
well if it is runing where it is at, what you can do is get the timing before you make any changes and only go a degree at a time either way. if you are too far one way or the other it will start to pop or rattle the valves under load. i would bet though if it is a mild cam your talking between 5 and 10
