Hello, I would like to start by saying that I got a lot of great info by researching old threads. I thought I had it pretty figured out. I set my base time(vacuum advance disconnected at idle) to 12*, but the total without the vacuum was less than 30*. I tried different combos of curve kits including using the lightest springs. I also even made a restrictor plate for the vacuum like Ignitionman taught us, limiting it to about 10*. With this set up I still didn't idle well my vacuum was less than 14inches. things seemed to tune in much nicer with more advance. So I gradually moved the base time up and took it out and ran it hard to listen for pinging... none till I got all the way to 30*! still nothing even 50*!. And it ran strong. At this point I stopped thinking my timing mark must be way off, even though the motor was just rebuilt and I saw for myself that the mark was set perfect. I checked it and from seeing the piston came up to top dead perfectly or at leat less than 10* off. Is this normal? Could the pinging be so faint that I can't hear it? You should know I just rebuilt a quatrajet from a 455 and put it on, thanks to you guys I got rid of the Holley. The carb probibly is not tunned perfectly but should be close enough(idle screws 3 turns out). I have an HEI distributor. I took off the Accel coil and module, and am using new stock ones to eliminate possible problems. The wires, cap , rotor, and plugs are all new. I am using 91 octane gas with some octane booster. I have the high compression pistons (10.2). T/A intake and a nice cam. Any help would be great. I am at such a loss. Thanks, Steve
Steve, Which springs are you using? I have looked at some of the so called advance kits offered, and wondered, what are they thinking. For a strong street car, you want the advance in before 2500 RPM. If you look at the paperwork supplied with the Mr. Gasket spring set, non of the springs will get the advance in that early. The springs supplied with the Crane adjustable vacuum advance cannister, are the best I've seen. You may think your advance is all in with your current springs, but it may not be. Also, the HEI is not the best ignition system to use on our cars. The stock spark curve may not be optimal for our engines. The coil in cap isn't the greatest thing either. Your distributor may not have enough centifugal advance in it, which means you need to have it taken apart and recurved. How are you determining your total advance? Dialback light or 2nd mark on the crank? Which light are you using? Sending a stock distributor to the ignitionman, and letting him curve it and convert it is the way to go IMHO.
Thanks Larry, You might be on to something. The problem is probbibly the mechanical(centifugal) advance, it is only giving me 12* more at the most. Shouldn't it be closer to 20*. And it does seem to come in slow, although I am using the very, very tiny gold springs. The kit I got was just a generic one, infact although I have tried many combos I have the original weights in. The seem much heavier so I thought they would pull out much faster. The weights are 139 and the center piece is 469. And the piece underneith says 26 or mabey 126 hard to tell. When you say recurved do you mean swapping out these parts. If so do you know a set that works better for our engines. I really don't want to send the distributor away if I can avoid it, I don't have time or much money not to mention after al this time i have already put into it. I can look into doing an out of cap coil conversion later, just want it runnig smooth for now. I thought the HEI would be at least as good if not better than the old points. Should I swap it back? By the way I am using an advance light. Do you think that is a problem too? I have checked it with my standard light and it seems percice, at leat up to 12*. Thanks again for your help, Steve
Steve, The best springs I have seen, come with the Crane adjustable vacuum advance. They allow you to bring your advance all in as early as 1800 RPM and as late as 3200, and everything in between. I would suggest you purchase that for the HEI, Summit part # CRN-99600-1. Then limit it the way the ignitionman suggests, not the way Cranes does. I have pictures that Dave sent me awhile back. If you want them send me your e-mail address, and I'll send them to you. You can recurve the distributor by changing weights/springs, but that will not increase the mechanical advance degrees that you have in that HEI. If all it has is 12*, you'll have to run 20* initial to get your 32 total. That's not a bad thing if you can do that and not have trouble cranking the motor when it is hot. Run about 8* of vacuum advance off a manifold source, and that engine should be very responsive because you'll have 28* at idle. First get the Crane kit, so you will be able to get your advance in quicker. It's only 23.00. Don't know which advance light you have, Sears are among the best. Good luck.
real 0 is important! Some of them Hei:s have weary little built in mechanical advance (and weary much vacuum advance in stead, not the hp giving set up you want) In an earlier tread Ignition man actually put on print what weights and center parts to use. If I were you and had the $ I send the points distributor (as Larry70GS was recommending you earlier in this tread) or the hei to I-man to have it fixed. The rest Larry70GS writes is also the way to go.. But 50* and no ping, if you had been using a pertronix we all had the answer by now. (bad pertronix unit) :Brow: I'm concerned that hei of yours is on the road to electrical brake down..... But first thing first, get borrow or make a piston stop and verify your timing marks. Put the stop in cyl. No 1, turn the crank (by hand) to stop and make a mark on the harmonic (use the 0 on the front cower as reference, turn the other way to stop, now make a new mark on the harmonic. Measure the distance between the marks divide by two, and there, in the middle between those marks make the real 0 (zero) mark. Close to (+- 10*) as you write, is not good enough! Lars
