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thunderbolt · 12-31-2002, 09:58 AM

Herk, you got some great questions for a beginner. I am sure more will chime in on this.

Regarding Rev's timing recomendations, you have some minor modifications to your engine which will change the optimal timing of the car. Second, the number the factory gives you is a very safe number that shouldn't cause detonation. However, more power can be gained by changing the timing to what Rev has recomended, excpeically with your modifications.

When you check this timing it should be at idle with the vacuum disconnected from the distributor. What you are checking is called the initial timing advance and in older cars is controled by the postion of the distributor. What you won't be checking with this method is the "advance curve" or how the engine advance changes with rpm. Inside the distributor are two weights that move further and further out as the engine revs faster. These weights are connected to a cam inside the distributor which changes the advance with changing engine rpm. So your total advance will be the initial advance plus advance from the mechanical advance. Finally, most distributors also have a vacuum canister attached to change the timing based on engine vacuum. This is usually for gas milage and most proformance distributors don't have vacuum advance. All three of these work together for engine advance.

I think Rev's recomendation is right on. I have seen as high as 16, but it is going to depend on your engine. If your timing marks only go to 6 you have a couple of options. 1. Get a timing tape and attach it to the ballancer, this will give you a wider range. 2. Get a dial back timing light. These are more expensive (paid 70 for mine) and will allow you to set the timing advance into the light.

You won't need a vacuum guage for timing, but this is the best way to set the idle screws on your carb, assuming they are adjustable. With the car ideling, adjust the screws until the maximum vacuum is reached. Readjust the idle speed to where you want it and then go after the idle screws again. It only takes a few minutes.

Once again, to set your initial timing you will want the car at an idle. If you want to plot out your advance curve you can take readings at different rpms, say every 500 up to 3500. You should have all your advance in by 3500. A distributor tech (or you can learn it yourself) can then adjust your advance curve for more power while the engine rpm's are changing.

Good luck, sounds like fun.

12-31-2002, 09:58 AM	#4
thunderbolt Registered Member Join Date: Oct 1998 Location: Houston, TX, USA Posts: 380	Herk, you got some great questions for a beginner. I am sure more will chime in on this. Regarding Rev's timing recomendations, you have some minor modifications to your engine which will change the optimal timing of the car. Second, the number the factory gives you is a very safe number that shouldn't cause detonation. However, more power can be gained by changing the timing to what Rev has recomended, excpeically with your modifications. When you check this timing it should be at idle with the vacuum disconnected from the distributor. What you are checking is called the initial timing advance and in older cars is controled by the postion of the distributor. What you won't be checking with this method is the "advance curve" or how the engine advance changes with rpm. Inside the distributor are two weights that move further and further out as the engine revs faster. These weights are connected to a cam inside the distributor which changes the advance with changing engine rpm. So your total advance will be the initial advance plus advance from the mechanical advance. Finally, most distributors also have a vacuum canister attached to change the timing based on engine vacuum. This is usually for gas milage and most proformance distributors don't have vacuum advance. All three of these work together for engine advance. I think Rev's recomendation is right on. I have seen as high as 16, but it is going to depend on your engine. If your timing marks only go to 6 you have a couple of options. 1. Get a timing tape and attach it to the ballancer, this will give you a wider range. 2. Get a dial back timing light. These are more expensive (paid 70 for mine) and will allow you to set the timing advance into the light. You won't need a vacuum guage for timing, but this is the best way to set the idle screws on your carb, assuming they are adjustable. With the car ideling, adjust the screws until the maximum vacuum is reached. Readjust the idle speed to where you want it and then go after the idle screws again. It only takes a few minutes. Once again, to set your initial timing you will want the car at an idle. If you want to plot out your advance curve you can take readings at different rpms, say every 500 up to 3500. You should have all your advance in by 3500. A distributor tech (or you can learn it yourself) can then adjust your advance curve for more power while the engine rpm's are changing. Good luck, sounds like fun.