302 Timing Driving me Nuts! (Long Post)

gfw1985 · #1 (**permalink**) 05-14-2008, 12:09 PM

"76" 302 Automatic. Timing is way off. With #1 at TDC rotor points to #1, TDC mark on dampener is right on the money. Starts fine and idles. Vacuum line disconnected and plugged. Timing light shows it way off, probably 35 degrees. Connect vacuum line and unable to give it gas. I have correct vac port, zero vac at idle, manifold vac is 17. Will run fine with vac advance unhooked, rev's fine. While all this is driving me nuts and could live with it, soon as you put it in gear it kills engine. Only thing I can see that has been changed is carb to 4 bbl. Stock ignition. Thats all the info I can think of. Any suggestions?

BaronVonAutomatc · #2 (**permalink**) 05-14-2008, 04:36 PM

So you're turning the engine manually until it's at TDC on #1 (passenger-side front cylinder) to check the dizzy/balancer alignment, then at idle you're showing 35* advance? Where is your timing pointer located? Does the timing advance as rpm increases? What's your idle rpm?

The manifold vacuum reading is a bit low - i.e. late ignition timing. Try advancing the timing until you pull 20" of vacuum and see if it drives.

Run a piece of hose to the vacuum advance (and plug the carb port) then apply vacuum to the advance. It should hold vacuum and the timing should advance ~10 degrees.

Or you may be a tooth off on the rotor.

gfw1985 · #3 (**permalink**) 05-14-2008, 06:27 PM

1) Correct
2) Pointer is on drivers side, about 45 degrees from top
3) Idle is around 850
Will try the rest tomorrow, thanks for the ideas.

gfw1985 · #4 (**permalink**) 05-15-2008, 10:01 AM

Getting closer. Clocked dizzy, does give me more room for vacuum can. Idle down to 800 rpm, timing at 20 degrees BTDC. Adjusted carb idle mix screws per instructions for max manifold vac, up to 19". Still won't rev with vac. line connected. With vac. meter to carb port it is not a progresive advance, vacuum kicks in all at one time. Vacuum can seems to work properly. Thinking carb may be a lot of the problems I have left. Some PO slapped the 4bbl on a 2bbl intake. Kickdown and electric choke were not connected. Still open for suggestions.

gfw1985 · #5 (**permalink**) 05-26-2008, 04:03 PM

Just an update: Pulled carb and had 4bbl. intake. Pulled all casting #'s and it's a "65" 289HP. 600cfm Holley, 10.5:1 comp. Carb gaskets wrong and leaking. Fixed all vacuum leaks, initial timed 10 degrees, w/ 30 degrees cent. advance. 5 gals of premium and running great. Vac. advance plugged and it starts, runs, driving around yard. Won't drive with vac advance hooked up, too much advance. Will have to check into that a bit, ordered recurve kit. Tagging it this week so will see what it does out on the road. But it will scald the tires. Amazing what another 100+hp and extra 200 ft. lbs. torque will do.

BaronVonAutomatc · #6 (**permalink**) 05-26-2008, 04:16 PM

Good deal. Some vacuum advance canisters have a small hex-head screw inside that allow you to adjust the amount of advance. How much does the timing advance when you apply vacuum to the canister? Should only be ~10*.

When you say 30* centrifugal advance you mean 10* initial + 20* mechanical = 30* total, correct?

gfw1985 · #7 (**permalink**) 05-27-2008, 08:57 AM

Quote:

Originally Posted by BaronVonAutomatc

Good deal. Some vacuum advance canisters have a small hex-head screw inside that allow you to adjust the amount of advance. How much does the timing advance when you apply vacuum to the canister? Should only be ~10*.

When you say 30* centrifugal advance you mean 10* initial + 20* mechanical = 30* total, correct?

Correct: I have the vac can adjusted all the way out to slow when it kicks in, but any more advance at all is too much. It's a "76" Bronco with Duraspark ignition and will have to wait till I get my good timing light back from warranty repair before I tweak the dizzy. I'm just tickled it will finally drive.