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Initial (idle) timing is not very important. The main reason that you set timing at idle is simply so you don't have to rev the engine with your face 3" from the fan to set timing.
Distributors give X degrees of advance, and the important factors are degrees of total advance and when it comes in. As has been discussed, you want about 36-38 degrees total, and you want it to be all in by 3000 rpm. So, initial advance is simply a reference point you can use. If the total is 36 and you have it set to 10 degrees before TDC at idle, then its safe to assume that your distributor is adding 26 degrees. In 90% of the combinations, total timing doesn't change. 36-38 is pretty true for any small block regardless of tune. The question is, how much initial do you need. In a stock engine, 10 degrees initial is fine, but if you go with a cam, intake, headers, and other things, 10 might not be enough to get a decent idle. So, I agree with Greg T - it doesn't matter where your initial timing is for the sake of idle. But if you need or want more timing at idle you can have it by changing the amount of total advance the distributor offers. Lets say your engine idles and starts well at 20 degrees. You simply advance it 10 more degrees and then modify the advance weights so that it only offers an additional 16-18 degrees so you can still get the total around the right mark. Put it this way; I had a mild cam in a low compression 454. It was very tolerant of ignition lead, so I was able to lock the mechanical advance, set initial to 36, and I was done. I hooked up to ported vacuum that added more advance at cruise, but dont' get hung up on initial settings. Find the sweet spot for easy idle and starting, then modify the advance to give the balance of the advance. |
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If you did not, then the mechanical timing was not being set to the 36 degrees. Dis-connect the vacuum advance hose from the vacuum advance cannister and plug it. Fire the engine up and get it to operating temps. Now do the same check and adjustment you previously did. After making the adjustment, re-connect the vacuum advance and road test. |
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http://www.chevytech.com/2c44.html http://www.chevytech.com/2c44o1.html http://www.chevytech.com/2c44o4.html |
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The instructions for my MSD distributor tell you to remove the cannister and lock the vacuum advance.
Which you canīt do with an HEI. What model of Holley carb do you have ? |
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I have a 355as well and Iīm using a 6.5" balancer, a Summit piece good enough for low rpmīs on the street, I hardly ever exceed 4000.
I looked at the Proform baseplates and I see two vacuum ports, why hasīnt yours got them ? The rearmost is the one to use for your timing. |
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I personally always use full manifold vacuum. Use whichever works best for you. |
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I did tell you how to check if it showed TDC with the rotor at number one but you just ignored it and go on repeating the same old stuff. Iīm outta here. |
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What im saying is im done with the old balancers! I would like to buy a new one and was wondering which size to get and what timing tab to use. Im not waisting my time with a 30 year old balancer. I cant time the engine so something is wrong with one of the two, balancer/timing tab.
Last edited by scapegoat; 07-10-2008 at 08:12 PM. |
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