Ok I cant seem to find anywhere what my style marks are for timing.

Its an 87 monte ss. Lg4 I believe, cc carb'd 305. Anyway I'm trying to get the timing dialed in because it burps out of the carb when you start it but is good once it gets running. Obviously its to retarded.

My tab has 3 small humps then two large ones. Right now I have the timing set between the two large ones which I believe is 0. This is what I am not sure of. If anyone could tell me what the incriments are so I can get it to 6-8* btdc.

Also I should set it which the vacuum advanced clamped I know that. But should I set it with the parking brake on and the car in drive?

 

The point of the widest and deepest notch is 0 degrees.

 

To the left of the deepest V is advanced (as you look at it from the front of the engine).

Look to the first point to the left and then the bottom of the next V to the left of that. The bottom of that V is 6* advanced.

 

Thank you!

 

A picture is always worth a thousand words... and I know i've gotten good use out of this picture...
https://webdisk.ucalgary.ca/~jmknopp...ming%20tab.jpg

 

Thank you very much guys. I got it set to 6* btdc at idle with the dizzy clamped off.

Next step is to find that damn streetfire chart and adjust my timing so its 32* advance at 3500rpms.

I seem to have lost my stupid chart anyone have a link that shows how many turns on the vacuum on the dizzy is how far to advance?

 

??
You won't be able to get more then about 20* of advance out of a normal can. (mechanical advance).
Which vacuum canister do you have? Turning the allen screw adjusts the rate, you use the little oval limiter to adjust the amount.

Got a great article you may want to read, thanks to Damon;
https://www.thirdgen.org/hei

PS - use timing tape (or an aftermarket balancer...), rev it up to 3500RPM, and set it at 34* or whatever you want. Lock it down. Then let the idle advance be what it is. Reset the idle screws for the idle speed you want to have.

 

I have an msd streetfire dizzy. I thought that the second part of the curve was controlled by the vacuum adjustment? Does that article still apply to my dizzy?


Hmmm I'm getting a little confused here. I gave my car about 7* base timing with the vacuum unhooked. I'm thinking I should give it more like 10* but do you think it would detonate on a stock 305 running 87 octane?

I'm assuming then that my MSD is weighted to give me the stock 20*. So with the mechanical advance I'm at 27* so I need to tune in to get another 5-7* from the vacuum then?

 

No, it wants 34 degrees or so of timing when fully advanced with no vacuum advance. Vacuum advance will add additional timing on top of that.

 

Ah, an aftermarket mechanical HEI? You want to use more than the stock 6* settting of the original computer controlled distributor in that case. Probably more like about 12* initial timing. That would be the tip of the 3rd point to the left of the big V, by the way.

Set your initial timing with the vacuum advance DISCONNECTED and with it idling as low as you can get it (so the mechanical advance isn't kicking in a little bit and giving you a false base timing reading).

 

Alright thank you very much. I also posted up about the car bogging down at idle in drive. It almost wants to die. Any chance this is related to the timing?

And if I'm 12* advance at idle I'll still be good with 87octane?

 

Yea, that could cause the bog. Not enough 'power' at idle basically.
Timing has virtually nothing to do with your octane level needed. Set up the car to run right, then use the lowest octane level you can live with. Don't put the cart before the horse eh?

 

Sir I'm following your lead 12* advance when I get home from school it is. Thank you for the input I'll let ya know how it goes.

 

What kind of carb are you running?

 

O my god. I gave it that 12* initial and the car came to life like noones business! Thank you for the advice. I'm still having odd idling problems. I believe the culprit would be running to rich as it pops out the exhaust a little now.

I'm running a mechanical quadrajet. Its the same exact looking as the stock cc one just mechanical. Not sure what it came off of. I'm trying to figure out other than the idle air bleed valves what I can adjust for the mixture. It doesnt seem like theres anything else.

My idle problem has changed in description though. Instead of bogging down very low it will now idle. If I stay sitting for a minute or two it will start to come down, and down until it dies. It definately feels like its drowning out.

Right now theres no choke on the car. I need to tranfer my old electric choke over.