Kimson, The HEI is a little different than the points distributors. The kits come with bushings that are meant for the weights. They fit inside the pivot holes on the weights. Like Nick said, there are 2 slots and pins on the HEI. To see them, you must remove the weights, springs, and center piece. Here's a picture of the slots and pins on an HEI. Notice how big they are. Remember, the distributor turns at half the speed of the crank, so 1* of distributor rotation = 2* of crank rotation. If you can fashion some bushings to fit on these pins(difficult), you may be able to limit the advance. I think you may end up binding up the distributor, and it may not work correctly. Remember, everything must be smooth. When the weights move out against the spring tension, they must be free to return, as engine speed returns to idle. The right way to do this is to disassemble the distributor, weld the slots to reduce their size, and file them to the correct size for the amount of advance you want. You may be able to do this with some JB Weld, I've never tried it, and I'm not sure what dimensions = what amount of degrees. Guess it will have to be trial and error. I'd start by reducing the slot size by half, and go from there.
This is getting to be more then I would know how to fix, but it's been like that for a while now so why not. How imprtant is the balance of this thing when it spins? you'd think that if you start messing with it, it could easily lose it's balance and wear out quite quickly, or break? Is this kind of what is needed to be done?
Is there any other way I could compensate for the built in advance without fiddling with this pin? I don't know what is underneath this thing, but maybe just drill a smalll hole and stick a little screw down next to the pin? If it doesn't work, I'll just take it out and make sure the hole is smooth.
Balance shouldn't be a big deal I would think. Whatever you try, just make sure nothing binds up the advance mechanism, or interferes with moving parts. Your trying to reduce the mechanical advance dso you can run more initial timing.
Kimson Yes, your photos all show viable ways to do it. However, I don't think I would try JB Weld; I would be woried about it breaking off and being loose inside the distributor. I still vote for doing it the way Andy did it in Post #28 at the top of this page. I did it that way, but I only used one screw. I don't think that is a problem.
I'm not sure I get it 100%. First the plate was welded up to limit the available space for the pins to move in, when that didn't work out because of too much trial to get it right he made two adjustable stops out of machine screws? - - - Machine screws? Was the plate still welded, or was it made back into it's original state first, and then the screws came into play? How was the two holes made that became adjustable? - - - "I put the nuts on the screws and held them with vise grips and used a bench grinder to make the head into a cam shape. I used nylock nuts on the screws so they didn't losen up. I'm pretty sure I used holes that were factory. I did have to grind off a tiny part of the under part of the rotor to clear the screw heads. Now total advance is easily adjustable with the rotor off." - - - Made the head of the screw into a cam shape? Used holes that were factory? - - - I'm sorry, I just can't picture it what it looks like? Hope someone can fill in here.. Many thanks for your help.
Kimson, Very simple really. look at the rotor mounting screw holes. Inboard of each hole is a factory hole not being used. He simply used a screw and nut(nylon locking). Then he ground the screw head so that it would stop the rotor from advancing past a certain point. It should work. Again, some trial and error involved.
Looks smart, they might be a bit different though, I'll have to stick my nose in mine to see what the deal is.
Looks like we're in business on this one. On the second picture where the hole is just about to slide under the plate, you could fit the bolt and nut. The pin is pretty much exactly halfway down its hole then. The head of the bolt would sit just a little outside of the hole like in the pic. Sweeeeeet
Kimson, I just got tired of taking the distributor in and out and welding and filing. You won't need to do any of that. Just make the screw head into a cam shape on the grinder or with a file so you can adjust the limit. I used two screws because I didn't want to get anything out of balance but if Nick says his works with one then I guess the second one is optional! Don't forget the clearance the rotor for the screw(s).
I put the screws in there.. Depending on how much I file the heads, I can get different values. Right now it's about half. I've since tried to go down Larry's list, and I'm alreay stuck. This is what has happened, and what is not happening..?? 1. I set the sliding plate as seen in the above posts to half of the pin travel in comparison to stock. This done with the screws I put in. 2. I installed the new crane vacuum canister, fully screwed it in as said in cran manual. There's a little blac plate left over, I'm not sure what to do with this? 3. I installed the yellow springs as recommended by Larry, so I wouldn't have to rev the engine so high to see where my total advance was located. 4. I filed the rotor cap so it wouldn't interfear with the screws I just put in to block the pin sliding. 5. I plugged the vaccum line from the carb for setting the timing. 6. I checked the timing when the engine was just idling, it read 12???, so I set that down to 4. 7. I chalked a mark 1 3/4 clockwise from original mark on pulley, for setting total. 8. Now the progress stops.. I had my gf slowly increase the engine speed so I could see at what rpm the new timing mark would stop moving. The thing was that it never moved??? We went up to 2000 rpm, and nothing happened, we we're always at 4 with the original one..? So now it's time for chicken, and I need to get this thing set up for Saturday, when we're due back at the track. Since none of you want to see a buick do no good at the track, I need your help here... ???
Take the distributor cap off and try to twist the rotor by hand. It should easily rotate about 15 degrees clockwise against the slight tension of the yellow springs. If it will not move, you probably have binding between the bottom of your rotor and the new advance limit screw.
I tried that before I put the cap on it. It moves fine, with a bit of spring tension in it. I filed the rotor enough to make sure it had clearence too.. ?
Try switching springs and trying again. The light springs may already be at full advance. I always run it with my stiffest springs first after any curve work, and do that to ball park the initial setting. Then I try it with my lightest springs (or sometimes even no springs) to set the total. Then, finally, I play with springs to get the total coming in at the rpm of choice.
Good idea, when the lightest (yellow) are on it, it has very little resistance, and the rotor doesn't go back all the way when you check it for tension. I thought I'd give it a try behind the house, and it happily squeeled a tire as soon as you touched the pedal, I guess that's good. I'll have to wait for my gf to come back home so she can do the pedaling, while I check for changes... Many thanks
Well, if the vacuum line is connected it's at 4, id it's plugged it's 6 at idle. I changed the springs to the stiffest, and we reved it to 2000. It didn't move at all, it was stuck at 6 the whole time. Is there anything else I can try here? I've listed everything I've done, and I need to get this thing sorted tonight so it's ready for the track tomorow. Any help is much appreciated.
Kimson, I've been in Florida all week visiting the folks, or I would have seen this. The advance mechanism is binding somewhere. It isn't allowing the mechanical advance to operate. Either the screws you used are too big, or they are somehow binding up the rotor. The rotor should move in relation to the advance plate. It isn't. Try removing the rotor, then pull the weights out to full travel. There should be some movement(limited by your installed screws). The yellow springs will allow most of your advance in at idle. You should still see some additional advance(30* mark moving up), as you rev the motor to 2000 RPM. The vacuum advance must be limited to 8-10* Use the black metal cam to limit the amount the pull pin can travel.(.086" = 8*, .104 = 10*) This involves drilling and tapping an additional hole. (like in the picture). This is different than the way Crane recommends, it's a much better way. All the allen key does is control the spring pressure opposing the vacuum advance, it DOESN'T LIMIT THE ADVANCE. The spring tension affects the rate of vacuum advance.
I kind of had it figured out last night, I had it set up and it was up and running. It didn't run perfect so this morning at 6:30 I put it back in stock condition and headed for the track. As I get more comfortable with understanding more how it works and just fiddling with it, I'm sure all pieces will fall into place. At least I managed to get my time down from 18:43@74.20 to 17:21@78.42, so that felt good. If I then can get the HEI dialed in, I'm sure we can shave off some more. I hate whe you get a really good start and you're ahead for the first hundred yards, cause the other peson has been sleeping at the light, and then they just motor past you... Many thanks for the help, I'll be back in on this thread in a day or two.
I read this thread and just wanted to make sure before i get to carried away that the total timing of 30 t0 36 is also good for a 364. thanks.
