Setting timing on 4.3

[C&C Chevy]

Need to know what the timing marks on a 1986 4.3 with carb are supposed to read. Trying to adjust timing to 0 then go from there, but i can barely see the timing teeth with all the crap in the way. I can see the jagged teeth. There are 3 teeth.

\/\/\/ <--- looking foward towards engine.

What are the timing degrees for the marks?

[C-10 simplex]

Is one of the teeth shorter or longer than the other 2?

[jhngardner367]

Each point,and each valley represents 2 degrees.
Looking at the front of the engine,anything LEFT of 0,is before top-dead-center,and RIGHT is AFTER TDC.I believe,on that year,you must also disconnect the brown/black wire to the DST connector,to get a true reading.

[bilfman]

If you have access to a timing light with a degree wheel on it, you dont even need those marks. All you do is use the dial and keep the line on the "big V" tab or 0 degrees. So for example if you have the engine running and you turn the dial on the light to 12 to the the line on the big v, you are at 12 degrees. These lights are very handy when setting total advance because the stamped tabs only go so high.

[C&C Chevy]

The shortest or longest tooth is "0"?

I just played with dizzy until it idle and sounded good and moved on. lol I dont have a degree wheel on timing light. I borrowed one from buddy at work. One problem is I can just barely see the teeth and white line at the same time because of PS pump, A/C and water pump are in the way... I'll probably try and get a wire brush down in there to get the teeth cleaner?

I went ahead and took carb off to remove idle mixture caps on carb so i can adjust A/F mix with a vacuum gauge. Replaced fuel filter while I was at it. I'll work on timing some more when I get the carb back in.

[bilfman]

The deep v is 0.

I'll tell you how I have timed my vehicles for years and it works like a charm with no light.

You need 2 people for this. 1 in the drivers seat, this person does a "brake torque" the driver seat person sets up to do a burnout. But DO NOT break the rear tires loose. Just load it up as much as you can without turning the tires or moving the vehicle. Just try to keep the revs and torque fairly stable.

While doing this person 2 moves the distributor, move it back and forth until you feel the vehicle producing the most power. At this point stop and lock it down. Sometimes this will be a little too far advanced. Drive the vehicle after this until it is good and warmed up. If you notice no ping, that is good. Shut it off, start it up. If you notice no starter drag then you are good to go. If you experience any ping or starter drag when warm the retard the timing a wee bit. Do this until the ping/or starter drag are gone. Presto you are timed to what your engine likes.

This method is for vehicles that do not have computer controlled ignition timing.

[C&C Chevy]

Ok, thanks!

[jhngardner367]

The 4.3 usually has an ecm controlled distributor. Use a timing light.You can clean off the gunk on the tab,by spraying it with carb cleaner,and reaching in with a bit of cloth on a long rod,or screwdriver tip.

[C&C Chevy]

I have a HEI dizzy. Not sure what kind of ecm stuff is on it? Thanks for the carb sray tip!