: Shaky Idle

09-26-04, 03:41 PM
Today i loosened up the distributor and tried to get the shakiness out of my 472. I dont have a light, nor know how to use one, so i was twisting the distributor and eyeballing how shaky the engine was. I know for sure that the distributor is on the right tooth, but i couldnt completley eliminate the shakiness.

When i bought the car, i told the guy to give it a tuneup so he went out and bought the cheapest plugs he could find, and replaced all of them except the one on the pass side closest to the firewall (too hard for him to get to). He left the same wires on...same rotor and cap. This is still has the point ignition on it. So is it safe to say that once this thing is completley tuned up, and with a HEI distributor on there, it will be close to perfectly smooth?

Im gonna borrow my friends light and try to figure out how to use it, that may help some too! :rolleyes2

I mean... i drive the car 120+ miles a week, she still gets me like 10-15 mpg. Im about to bed it down for the winter, and try to save up enough money to do all this ignition work to it.

Gimme some input, thanks! :coolgleam

barge master
09-26-04, 11:50 PM
What led you to believe the timing was the cause of the problem to begin with? Make sure you have no vacuum leaks for starters. If you are trying to make the points system work for the time being, you need to set the dwell with a dwell meter, because dwell affects the timing. The shaft of the distributor might have some wear in it too. The HEI makes a huge improvement in any car. You're gonna need different wires anyway so those will help if your tune up parts are getting old.

09-26-04, 11:55 PM
Using a timing light's easy. Hook up the positive connection to the battery, the ground to an engine ground (I use an alternator bolt), and the induction coil to the plug wire going to the #1 cyl (passenger side, front of engine). Pull the vacuum advance line and plug it. Aim the gun at the timing marks and you should see a mark in the crank balancer, where you see it is how advanced the timing is. Having the timing set properly will help with smoothness, but other problems could be affecting it too.

09-27-04, 12:09 AM
What led you to believe the timing was the cause of the problem to begin with? Make sure you have no vacuum leaks for starters. If you are trying to make the points system work for the time being, you need to set the dwell with a dwell meter, because dwell affects the timing. The shaft of the distributor might have some wear in it too. The HEI makes a huge improvement in any car. You're gonna need different wires anyway so those will help if your tune up parts are getting old.

Well i knew the timing wasnt perfect, because i had a friend slap the distributor back on when i replaced my timing set, so i finally decided to play around with it. I didnt hurt nothin. Now whats the dwell? And whats that little allen bolt for, that you can access on the side of the distrib?

barge master
09-27-04, 07:41 AM
That's the dwell adjustment, through the little door. They made a special allen on a flex handle for those. The dwell is the amount of time the points stay closed. All it is is an adjustment of the point gap in a degree value, the smaller the gap, the less dwell. You can usually stick a matchbook cover in there to set the point gap enough to make it run, but setting the dwell is more exact than even a feeler gauge will give you. You hook up the dwell meter, and while it's running, you turn that allen screw to adjust it.

09-29-04, 09:30 PM
Ok this is a little weird.

My friend came over today with the light, we hooked it up, loosened up the distrib and checked it out. At first we didnt even see the groove on the crank pulley, i had to twist the distrib all the way it could go to the right and then the goove came into view. At its closest the groove is about 1 inch away from the timing mark plate. And the engine runs kinda bumpy, the best i can do is eyeball the thing to keep it how i like it.

Now i talked with my father on it and all he wanted to do was blame it on my lead foot. He says that the timing chain skipped a tooth or whatever. I have to disagree seeing as how i changed the sprockets and the chain like 1500 miles ago, and i doubt the car would be able to run as good as it does with the valve train off like that, and thats what he eventually concluded as well. I really have no idea. I know that pulley only goes on one certain way as well as the marker plate, and the light was on the number one.

Im really confused!!! Its about time to put this baby down to rest, and put the 9C1 on the road, but i want to fix this! Thanks! :thumbsup:

09-29-04, 10:13 PM
Are you sure you pulled the vacuum advance line? If not the timing mark is going to be about 20* more advanced.

09-29-04, 10:29 PM
I put a piece of duct tape over it, it was no different when i took the duct tape off so maybe the air was really getting by. Would the vaccuum advance, not being plugged, really cause that much of a difference as im saying????

68' Big Body
09-30-04, 12:31 AM
Sound like your off by at leat one tooth on the distributor. Glad to hear that you've learned to use the timingh light though, so your going in the right direction. Here's what I would do next.

First, crawl under the front of the car and mark the timing notch on the crank pulley so that it's easy to see, some folks use white-out for this but any bright color paint will work, just spary it on a Q-tip and then mark it. While you in there make sure you clean the timing plate really good with a tooth brush or whatever, or just a brillo pad.

Next, mark the distributors base and note the location in which the coil inside is facing. Then simply removed the distributor, look down into the whole and with a large flat screwdriver insert it so that you catches the oil pump pickup, turn that in the direction you need the adjustment range added, so if you turned the distributor toward the fire wall for example and the timing mark still didn't come within the adjustment range on the plate, then you get more range by moving the distributor ONE TOOTH to the rear or just re-insert the distributor one tooth more to the right. from there you can have a friend press down on the distributor while you start the car (they have to keep pressure on it or it will jump back out cause it's not bolted back down just yet). with their spare arm (left) they can hold the light and turn the distributor there holding with their right hand to see if they can get the mark within it's range. If the mark is closer than before then the car should sound smoother and have a better idle. If however the mark is further way than before you'll instantly know that you moved the distributor to the RIGHT when you needed to reinsert it on tooth to the LEFT instead. so at that point you'd shut the car down and, R and R the distributor accordingly and then check again. the tricky part is getting the oil pump pickup (inside the whole) to line up with the notch on the bottom of the distributor shaft. Those notches determine where the distributor will seat, so trying to reinsert the distributor without adjusting the oil pickup will force the distributor to seat in it's original place. simple really... just turn that oil pick up notch either left or right, about 1/4 turn to get the distributor to seat in a new location.

See Ya,

09-30-04, 07:07 PM
So is turning the actual shaft that the rotor is on different from just twisting the housing around? Im assuming thats because the spinning shaft controls the points...correct? Turning the distrib by hand IS different than moving a tooth or two on the cam???

If this IS true, when i shown the timing light on the pulley, the mark on the pulley was off to the side of the marker plate closest to under the water pump...to the left. So which way should i turn the shaft? Clockwise or counter?

And can someone explain to me how this car would run with the timing so off?

68' Big Body
10-01-04, 11:42 AM
Yes that's correct, simply turning the housing as if you were setting the timing and watching the mark move IS DIFFERENT than moving the entire unit itself. You see, turning the housing as you've been doing does adjust the timing, but there's a limited range of movement. So in your case with your mark being to the left of the timing plate, I'd say that you're timing is far advanced, so your engine should be running fast right, sounds like some one is pressing the peddle even though they aren't. I think that were you are, you'll want to removed the distributor and reposition it one tooth towards the REAR or to the RIGHT, or CLOCKWISE. Again, when you take it out of the whole, look down in there at the oil pickup notch and insert a long flat screwdriver in there and also turn it to ther right about 1/4 turn. then put the distributor back in in it's new location. If you find that the distributor want to seat in it's original position, then you kno wyou needed to turn the oil pickup notch just a little further. Like wise if the distriubtor seats back in and it's like 180 from where it was removed, then you have moved it too far. so it can take about a dozen tries before you get it to seat in the correct position. Again, you clued it yourself, since you turned the distributor all the way to the right and the mark came closer to the timing mark but not within the correct range and you couldn't turn the distributor any further, means in order to get the mark within the correct range you have to remove the distributor and turn it to the RIGHT one tooth, then the closest you were before will now be your new far left position and you be able to turn the distributor to the right again as you did before only now it will go into the timings correct range and be able to past through it to the far right.

Your off by one tooth, move it to the right by one tooth, then recheck the timing with light, it will be good..........

See Ya,

10-01-04, 01:58 PM
Just wanted to ask if you are sure that the cylinder which has the old spark plug is getting spark, because that could be the cause. Might be a good idea to bite the bullet and replace that plug.

When i bought the car, i told the guy to give it a tuneup so he went out and bought the cheapest plugs he could find, and replaced all of them except the one on the pass side closest to the firewall (too hard for him to get to). He left the same wires on...same rotor and cap.

10-02-04, 11:43 PM
Ok ive been messing around with it for about 4 hours and im done now... I got it to the left mark on the plate, seems to run best there, that in itself took a ton of time, because i kept having to change to different teeth, prolly about a total of 8 tries with that.... had a few plugs come undone when i was twisting the distrib, and had a full revolution of electrocution, my friend thought that was pretty funny :o Then i was messing with the dwell (bad idea doing it by ear) and i got electrocuted about 5 times doing that.

The dwell....when i first messed with it, i went to go and drive the car and it would putter and stutter under any load, so i kept messing with the dwell, and i got it so i could floor the car under load without any problem. Does that mean its fine or should i get my hands on a dwell meter pretty soon to tune it finely?

This is my daily driver, should i worry about that dwell being off at all? Thanks.

68' Big Body
10-03-04, 12:41 AM
Glad to hear your having some success and that yuo've figured out how to mes with your distributor. It's simple really and what I like most is that I can always go back to square one and set (insert) the distributor back in the whole lined up with cylinder # ONE at it's Top Dead Center position. WHat will really bake your noodle though is knowing that this is the first V-8 automobile I've own in my 33 yrs on this earth, and I've only owned it sinceearly August but I like cars and have built smaller engines before, so I know mechanics. What I know so far tells me that V-8's are the easiest (and cheapest) engines to build / modify.

I don't know CRAP about the Dwell business, still waiuting on my 1968 Cadillac Manual to get here. I don't have points anylonger anyhow, wasn't gonna even try messing with that carp. Caught wind that the HEI swap was the way to go and and make the change 2 weeks after I got the car, or 3 weeks ago. It's about $200 to convert so you need to consider that as well. For me though, anything that can/will make life a little easier down the road is worth it.

See Ya,

10-03-04, 08:04 AM
I really appreciate your help Big Body and everyone elses. BTW, Big Body, i read your post about the HEI swap. This is what i plan on doing over the winter, you said all you had to do was crimp that smog line? The actual distributor fit in there right? Because i know there is an issue with the dual belts to the compressor. If i can just pop one of these in with only having to push that stupid smog line out of the way im going to be pretty happy :D

As far as V8's shes my first and i just bought my Caprice 9C1 with the 350. I never plan on owning anything less than a V8, all my classmates enjoy the Ricer category with the 4 bangers, not me, i like having real power under the hood and a bit of steel wrapped around me! :lildevil:

Still would like to learn more about the dwell if anyone could explain it to me, thanks!

10-03-04, 12:09 PM
Points are actually very easy to adjust. After you do it a few times it's a piece of cake. When I first started messin with cars there was no such thing as electronic ignition on a stock vehicle.

There are a few things to keep in mind with a standard point ignition system.
First, you need to replace the points often, every 3 to 6 thousand miles. If the points contact surfaces are burned, pitted or not smooth, it's time for a change. Second, this type of system has a somewhat lower voltage to the spark plugs. Therefore, always change your plugs every 6000 miles or so. If you don't know the milage on the plugs, change them. You often hear people say that spark plugs last longer with electronic ignition. This is not completely correct. Spark plugs can be used longer with electronic ignition because electronic ignition has the ability to fire a BAD plug. Conventional ignition systems will not tolerate a bad plug. Third, your ignition wires, distributor cap and rotor need to be in great shape, if in doubt replace. In the old days these items were replaced as part of a tune-up.

I recommend you purchase or borrow a dwell meter, the correct point adjustment is 30 degrees plus or minus 2 degrees. Dwell is simply the number of degrees the points remain closed. Dwell will affect ignition timing. It is standard procedure to replace points, set dwell and then set timing (in that order). If you do not have a dwell meter you can set the points using the gap method. Crank engine until distributor cam lobe is at its highest point (maximum point gap opening) and adjust using feeler gauge. The correct gap is .017" for cadillacs of that vintage. Be sure to use that cam lube that came with the new set of points, just smear a little on the distributor cam.

As to setting the timing, I use the old fashioned way. use as much advance possible without knocking under normal driving conditions. A little (very little) knocking under extreme conditions (hard acceleration) is ok. Some will retard the timing 1 degree at this point. This setting gives you maximum power and fuel economy.

As to converting a conventional ignition to electronic, that's your choice. I would be perfectly happy with conventional. While I have worked on both types of systems, I like the simplicity of points, less parts, easy to diagnose, cheap to repair.

Good luck, let us know how it goes.

10-03-04, 07:26 PM
I notice since ive adjusted the timing, at idle, it sounds much more throaty, but it sounds consistent whereas before i could hear it sputter once and a while, and the sound wasnt as deep, this may have something to do with the dwell tho, im borrowing a meter within the next few days, how do these things hook up? Its my friends but he just discovered it himself and doesnt know how to use it. Last night we were gauging the dwell by how many feet of rubber i could lay :burn: ....haha we were actually just having some fun. :yup:

68' Big Body
10-04-04, 12:11 AM
Yeah the distributor is the same, it's just the top portion that works differently even though they look similar. With the swap you'd also remove the small canister shaped ignition coil, cause HEI's have the coil built into the cap...like your Chevy should have. The HEI's are usually LARGER in size, so that's why they rub against the belts. Regarding those belts, I didn't need the remove the rear most belt becasue mine didn't rub against the distributor cap like I had been told it would. There was only a hair worth of room between them, like 1/8 in so I kept an eye on it. However this week when I installed the Edelbrock Intake Manifold (that doesn't work with the stock A/C Compressor, so all the A/C stuff was pulled) both of those belts were pulled and now there is just ONE belt that runs from the crank pulley up to the power steering, so the rubbing issue is NO ISSUE. By the way if you ever decide to pull the A/C from your car, the belt that you need to go between the crank pulley and power steering pulley is 47.5 in long. That smog liine that runs under there, I just smashed it down with some vice-grips, so the line is flat in one spot about 2" long, because the distributor would not seat all the way down since it was being stopped by this line.When the line was flattened though, it did go all the way down like it should. I didn't touch anything else with the smog pump, just flattened the line in that one spot. I guess I'm still emissions legal then huh :D ? Or yo0u could remove the line, and perhaps the entire system but then you'd need to get some freeze plugs to patch the hole you'd have in both cylinder heads, and you might have problems with emissions. Of course you could just add some cheap asses CAT CONVERTERS when you go Dual Exhaust? Nah, that's more money and weight, just smash the line.

See Ya,

10-04-04, 07:29 AM
Ok so it sounds like im in the clear for the HEI, im thinking aobut just completley removing the smog system, i dont get the car inspected anyway, just hand over 10 bucks and my friend thumbs a safety sticker for me off the roll and im on my way :canttalk: