I’ve read a lot of the threads on degrees to set it at, initial, and total advance... still not quite understanding 100%. Bought a nice timing light and getting ready to dive in.

could someone help me with step by step here?

I have a 454 with and MSD ignition - 6420 6AL.

im assuming the vac advance is the vacuum line on the distributor itself?

if I understand correctly what I should do is start the car with that unplugged then get initial timing set to a certain degree. Then plug it back in and I can set my gun to whatever advanced timing I want it to be and it should land somewhere at 38-40?

am I missing any steps? Having trouble finding exact degrees it should be set at for my setup....

 

If you are running points, you have to set them 1st. dwell meter is the most accurate. Once you have that done then check the timing. Unplug the vac line to dist and PLUG it or you will have a big vac leak. You can check initial timiing if you want (at idle), I don't bother. Run the engine up approx 3000 rpm to get total timing @ 34 to 36 degs MAX. Idle it back down then plug your vac line back in and reset idle. Try that. My cars are very happy that way.

 

Dwell gauge. No? Set points to .016 gap. make sure points are fully open on dist cam lobe. So best done with clamp loose so you can turn the distributor. Try gap on several cam lobes. Distributor has 8 lobes. Likelihood of one being worn more than others is slim. But check anyway. Read. http://www.superchevy.com/how-to/add...on-a-corvette/

 

Now, you read the article you got your points set right. Now hook the timing light up turn the distributor back to where you marked it before you loosened the clamp and started spinning the distributor around start the car. Paint a white out mark on balancer at 0 or TDC mark. With vacuum still connected turn the distributor to UC about 20 degrees advanced should be right barely off the top of the timing pointer scale. Now, unhook the vacuum stick a bulb or something into the end of the hose or a cap and see what your timing is sitting at. Should be someplace around 10 degrees. Sounds like you have a dial backlight. Play with the dial and watch that timing mark go to zero. And see if the degrees on the dial back agrees with what the timing pointer was saying previously. Now, rev the motor up until it stops advancing with no vacuum hooked up to the distributor. You watch the timing pointer go right off the timing scale? Good. Now set 36 degrees on the dial back on the light. Rev it up until it stops advancing turn the distributor until it's sitting at zero. You notice i didn't say rev it up to 3,000 RPMs. Cuz you don't know that it stops advancing at 3000. And if you set this 36 degrees and it has another four or five degrees in advance in it you're going to start burning Pistons with too much Advance at Full Throttle. Sure you can play with weights and play with springs and get it to finish advancing by 3000 and you should. But in the meantime you have to be sure you don't have too much advance. So you got your full advantage set at 36 degrees. Pull up back down to idle crank the dial back down to zero and see what it reads on the timing pointer and then turn the dial back until it goes to zero and see what the dial says and see if they agree again. You're probably going to be in the 16 to 18 degrees cranking advance. Because you only have so much mechanical advance. They tell you to set it at 6 and they want 36 but they sure as hell don't give you 30 degrees of mechanical advance. And then go back and hook up the vacuum and see if you got 10 or 12 more degrees with the vacuum hooked up at idle and also at very light throttle. You can have a lot of Advance when you're barely stepping on the gas. It's when you're at 4500 RPMs full throttle and if you have too much Advance your engine will start burning Pistons because it doesn't have enough gasoline.

 

Thank God for voice to text. I could never type that much.

 

Why don't you just e-mail me for my paper on how to set the timing.
Lars
V8FastCars@msn.com

 

To do this process correctly you need this kit https://www.summitracing.com/parts/m...SAAEgIzAPD_BwE
The combination of one black and one silver spring is a good place to start.
The bushing in the kit is to replace the original factory nylon bushing which may or may not be still in one piece.
To install the bushing you have to remove the distributor and the bottom gear.
Try first with just the springs or just email Lars in the post above this one..

 

i actually read your paper in a different thread, just not sure I truly understand a lot of this... I have never worked on anything with a carb or distributor so I have never had to do any of this haha.

I took my vette to my friends shop and they played with it (ran fine before going there but smoked a lot one day [thinking Valves]) so I just asked them to look over the car and give it an oil change. I got it back and it started up better when cold but then after warming up driving around town every time I park it and It’s not easy to start and wants to stall... if I can get it running enough to just move and drive it then it seems to idle fine and not stall... very odd.

 

Guess you have to be more specific as to what they played with at the shop?
Sounds like they may have done something to carburetor idle set up but you need to know what they did.

 

If you do not understand the paper then none of us here are going to be able to tell you any plainer unfortunately. You may want to consider finding a qualified speed shop or old school type Vette and or Musclecar mechanic to work on it.

Jebby

 

Take it a step at a time and ask questions as you get confused. How else are you going to learn? If the answer you get back doesn't solve the confusion, ask again. We all started out not knowing stuff and all have varying degrees of knowledge and ability to explain. Keep at it!

Do your friends really know and understand mechanical timing and carburetion? Hasn't been a thing on most mainstream cars for 30 years or so. If not, then they're experimenting and learning on your car -- might as well do that yourself and be ahead of the game.

 

I set timing by just driving it. I put the fuel in I am always going to run and then keep advancing the timing until it knocks on full throttle then I back it off until it doesn't knock anymore.. Last thing is to make sure that when the car is hot it cranks correctly. If it has a problem cranking, I retard the timing, a smidge.. Haven't taken a light to my car in years. Obviously make sure your point dwell is correct as mentioned above.

 

A low-compression engine like the 454 will be massively and grossly over-advanced if you advance the timing until it knocks, and you will see a severe power loss at that setting. Really bad advice to set the timing "by ear." You won't get it anywhere close to best power.

 

That is just fine for driving. But not for high throttle use. Of course most of these cars rarely see full throttle, but should be sure you are not too advanced.

 

I Have been doing this way for years on SB and BB. Maybe I have a trained ear. I am extremely good at setting timing by ear.

 

If you follow @lars' instructions, you should be all set. They do require a small amount of knowledge of how an engine, carburetor, and distributor work. You can easily get that from Youtube, or a friend who tinkers with cars.

I like this video for how to use a timing light. Did you buy one with dialback advance, or do you need to add the MSD tape (as shown in the video)? If the later, order that now from Amazon.