o_rod Posted October 24, 2017 Share Posted October 24, 2017 Well after playing with a few distributors and timing over the summer I've finally found the best one for me. One thing I noticed though is that my crank timing mark, when set at 0 degrees TDC, is for cylinder 6? It runs great when I set my timing this way, but why isn't my timing mark showing TDC on cylinder 1? This always confused me and I got quite the fire works when I set it at cylinder 1 the first time I switched distros, any insight? Quote Link to comment Share on other sites More sharing options...
monte70car Posted October 24, 2017 Share Posted October 24, 2017 Was the motor every taken apart and redone? I know when I added gear drive to my car years back the instructions gave you two ways to line the dots up. So maybe someone line the dots up so it is set to fire on 6 instead of 1 just a though. Quote Link to comment Share on other sites More sharing options...
o_rod Posted October 24, 2017 Author Share Posted October 24, 2017 I was told it was rebuilt. To what degree and what was done is unknown, is it possible the crank balancer is off? Quote Link to comment Share on other sites More sharing options...
dejh22 Posted October 24, 2017 Share Posted October 24, 2017 The firing order is 1 8 4 3 6 5 7 2. Are saying that number one wire is at the number 6 position on the cap? If that is the case you can have the number one wire start anywhere on the cap. That is as long as the rotor is pointing at the number one wire wherever it is on the cap as long as number one cylinder is TDC. Quote Link to comment Share on other sites More sharing options...
o_rod Posted October 25, 2017 Author Share Posted October 25, 2017 No, I understand how timing works. The firing order is correct, cylinder 1 spark plug wire is where it should be. When my timing mark on the balancer is at 0 degrees on the timing mark, #6 cylinder is at TDC not #1. It runs fine like this, I just rotate the distributor 180 degrees so it fires #6 first. What I'm curious about is why and when I'm using my timing light should I put the pickup on the 6th cylinder spark plug wire instead of 1? Quote Link to comment Share on other sites More sharing options...
dejh22 Posted October 25, 2017 Share Posted October 25, 2017 That's sounds strange. So when the timing mark is at 0, is the rotor pointing at number 6? I know nothing about timing lights. I always time by vacuum gauge. Most people think I'm nuts but I have done it that way for 30 yrs. I disconnect the power to the distributor pull number one plug. Then I take a paper towel bunch it up and push it into the spark plug hole bump the starter until the paper towel pops out. Check the distributer to see where the rotor is pointing. If it is not pointing at number one I pull up the distributor and turn it till the rotor is pointing at number 1. It may not drop down all the way but that is ok. I put the paper towel back in the speak plug hole and bump it around again until I hear it pop out again. Check the rotor and sure enough it is pointing at number one and distributer is all the way in. Then play with the distributer until I can get it to stay running. I then advance the timing until I get the highest reading and back it off an inch. I also use a vacuum gauge to set the carb. Most the time it is really close. If I get a little spark knock I will back off the timing a little. I just built a 396 for our 71 Monte SS clone. First start was done as described above. It has a larger cam and max vacuum was 16 inches after the carb was dialed in. I backed the timing to 15 inches. It runs great there. It starts fine, accelerates great no spark knock. I also dialed in my soon to be son inlaw's 70 Monte with a 355 we rebuilt for it. It also has a larger cam. I also have a 71 Monte (my profile pic) with a 383 I built about 10 yrs ago. It is dialed in the same way. My son's 72 Monte with a 355 with a mild cam, he dial it in using the same method. 1 Quote Link to comment Share on other sites More sharing options...
overdrive Posted October 25, 2017 Share Posted October 25, 2017 It's not 180 out. You must keep in mind that each piston reaches TDC twice in a 4 cycle [4 stroke] motor. Once at the end of the compression stroke and again at the end of the exhaust stroke. 1 and 6 are both always at TDC at the same time, but they're at the end of different cycles. 8 and 5 are always at TDC at the same time, but they're at the end of different cycles. Same with 4 and 7, 3 and 2. When 6 is at TDC and firing at the end of the compression stroke, 1 is at TDC at the end of the exhaust stroke. If you removed your distributor with the rotor pointing at #6 wire and then realigned the rotor with #1 on the cap, then it would be 180 degrees out. Think about this, if you have both at TDC [0 on the balancer] and #6 is firing, while watching the rotor, simply rotate the crank 1 full turn and you'll then be lined up to fire #1. You'll fire a different cylinder with every 90 degrees of rotation of the crankshaft and the crank turns two full turns to one of the cam. Dan 1 Quote Link to comment Share on other sites More sharing options...
72MC Posted October 25, 2017 Share Posted October 25, 2017 If your engine is 180 degrees out,...you would hear a noise like a shotgun going off as soon as you turned it over. It takes two full revolutions of the crank to complete one complete firing sequences on all 8 cylinders. You're not 180 out. - Dave 1 Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted October 25, 2017 Share Posted October 25, 2017 You can have/set number one spark plug wherever you want on the distributor as long as the “firing order” is correct. Most common I have seen is the 180 out compared to factory specs. As long as you put the pick up from the timing light on the number 1 spark plug wire, no matter where it is on the distributor, you can time the engine “normally”. 1 Quote Link to comment Share on other sites More sharing options...
o_rod Posted October 28, 2017 Author Share Posted October 28, 2017 Wow, thanks for all the info fellas! I'm in the garage right now with the distributor pulled. I'm putting in my Mallory locked unit for the last time. I could not get a proper timing curve with my GM unit. Anyways, I'll use the paper towel trick to see when exactly #1 is at TDC on the compression stroke and how that relates to the timing mark. I lined up my timing mark on the balancer at 0 and I was at the compression TDC on 6 as per usual. Quote Link to comment Share on other sites More sharing options...
overdrive Posted October 31, 2017 Share Posted October 31, 2017 It'll take one full turn of the crank to bring #1 piston to TDC on the compression stroke and you'll get a half turn of the distributor. Perfectly normal and expected. Dan 2 Quote Link to comment Share on other sites More sharing options...
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