Mustang_Slayer

Hi, I'll keep this as short but as informative as possible...

I own a 1987 Pontiac Trans-Am, 5.0 Liter V8 Carbureted Engine, everything is stock with the exception of a mild cam, edelbrock intake, edelbrock 600 performer carb, Accel Super Coil and Accel Performance Distributor, Cap, and Button, along with Accel 8mm Super Stock Wireset & Plugs and 14" breather. Standard 700R4 Automatic transmission, etc... etc...

I recently did a little work to the top end (carb related) and decided to address a long needed timing issue, the engine rough idles at times and tends to spit back through the carb after being run for a while. It as well used to load up during acceleration (but this was carb related).

My question is to what degree should I set my timing? The numbers etched on the freaking marker above the harmonic balancer are so filthy I can not tell 2 from 4, but after research and knowing these engines as well as I do I fortunately don't need to visually see the numbers to know where the mark is.

I have typically set my engines at 0 Degrees but I have seen several forums that suggest anywhere from 4 some 6 and even 12 Degrees!? Most of these I found are TBI rather than Carbureted or 79 or older engines so this may just be me being paranoid.

Any advice is much appreciated!

vetteoz

iTrader: (13)

No idea why you would set no spark advance on the dizzy?
The whole idea of spark advance is to have the spark start ( allows time for spark propagation across the top of the piston ) BEFORE the piston is at TDC ; not after.

Proven old skool way of setting the advance on a carb engine is to progressively raise the advance , go for a drive and load the engine up ( like up a hill in 4th without shifting down ) and see if the engine pings.
When you finally get pinging, back the advance off a tad and that is the max advance your engine can handle

https://www.thirdgen.org/forums/tbi/...time-tbid.html

sofakingdom

iTrader: (1)

There are 2 major problems with setting the timing to some "spec":

1. The measurement methods are notoriously inaccurate; and
2. The "spec" must serve many masters, including emissions, high & low altitude behavior, the fuel that was available 30 years ago, temperature ranges from -30° to +110°, and so forth; none of which may apply to YOU

I VASTLY prefer the method vetteoz described. THE ENGINE knows what timing it will run the best at, MUCH better than some "spec" does. GIVE THE ENGINE WHAT IT WANTS.

To paraphrase one of The Great Ones in an unrelated field:

"If it RUNS good, it IS good".

Nothing about carb, TBI, computer control, or ANY of that, makes THE SLIGHTEST difference. The engine will run the best when the spark occurs at THE RIGHT time, ALWAYS. All you have to do, is find that spot. And you won't find it in a "book".