Timing

[Mopar Trac]

Took our car to track sat night and had problems with engine not taking gas like it should tried the usual things and found some problems but still had the high rpm sputters and bog. On a whim loosened the distributor and start playing with it and low and behold engine settled down and liked it so put on the timming light and had 45 degress of timing! Raced the feature car ran 170 degrees and ran great! Now my question is this seems to be way to much for this engine! Has anyone else seen this before?
The engine is in a street stock 360 +.030 stock intake, thermoquad, KB flattop pistons, 11.5 compression, MP 450/455 cam centerlined at 102 degrees, and externally balanced.
Thanks for the help!

[sanborn]

The purpose of ignition timing is to ignite the compressed mixture at the optimum cylinder pressure. We usually advance the timing before top dead center in order to give the spark flame time to reach its optimum pressure. Optimum pressure sends the piston down the bore with maximum force.

Each engine is different in its optimum ignition advance. 45 degrees sounds very high! Usually 36-38 for a stock type head(flat top piston) seems to work best. Running more advance than that can be due to several reasons; very erratic flame travel in the combustion chamber(usually due to domed pistons), poor ignition condition(a weak spark takes longer to expand through the chamber), or timing marks not correctly marked(or a combination of machining errors leading to a top dead center mark being way off). Forgot another reason, using race gas with too high an octane rating for the application.

45 degrees is about what you would want using methanol fuel(some of you fellas using it correct me if I am wrong). One other thing, could your outer ring have slipped on your harmonic balancer?

Anybody got other opinions?

[Mopar Trac]

Forgot to mention that had corrected TDC and the reading is right. The only thing I had done different on this engine was to back up the centerline setting on the cam from 110 to 102 to increase the torque pulling a 3400# car.
Also we are running a chrome box and have changed the springs in the stock distributor.
Again Thanks

[sanborn]

I admit, I'm stumped. Admittedly my experience with this type of engine is very limited in recent years. Anybody out there got any ideas?

[RonsDirt]

Run about the same engine, except using AFB, 34 to 36 is all it can stand, BUT I tend to run jetting right on lean end. If you are way over jetted this could cause you to need more timing. Check # 6 cly and see if the timing is the same(Might have a bent reluctor in dist). In my late model with 13.5 comp and alcohol I run 32 as alcohol tends to burn faster and am using a longer Rod which causes TDC dwell time to increace.

[355 racer]

We always ran 38-41 deg timing ,9.4:1CR ,2 barrel,alcohol on the 358 chevy. Our R-3 Dodge motor is knocked down to 30-32 deg.,same carb on alcohol ,but 6 1/8" rods. A real torque machine.
Harry