How to set timing with no timing marks.

I’ve got a 68 Charger with a 383, Mopar electronic ignition. I’ve had some trouble with the car dying at idle at temperature. I had posted this problem in another thread and people suggested adjusting the timing. Cool. Oh, wait there’s no timing marks on the harmonic balancer. I am probably going to use a vacuum gauge off the manifold to set timing but I’ve never done it before and I’m not super confident. As I understand it you advance the distributor until you get maximum vacuum and then back off 1-2 degrees to prevent engine ping. Am I in the ball park here? Any other suggested methods for setting timing?

There's no notch on the damper ? Anyway, you should ascertain true TDC, then apply a timing tape on the balancer once you know actual TDC, then adjust from there.

Is the balancer a after market one or a Chrysler factory one ?
If its a factory 383 balancer its possible the small grove/line is full of crud and someone has painted right over it, seen that once on a brand X engine.

You might want to look harder for a slot in the dampner. Here's how to find actual top dead center on your dampner useing a home made piston stop. You can buy them also.

https://www.forbbodiesonly.com/mopa...ade-tools-lets-see-them.56433/#post-910446556

The slot on the damper is easily visible but there are no numbers on the dampener to indicate its position relative to the gauge on the timing gear cover. If popping on a timing tape will solve this issue then great, I’ll give it a shot.

Btw, here is the link I was using to find info on timing using a vacuum gauge. Seems to be oversimplified but since I’ve never done it before I don’t know.

http://automotivemileposts.com/garage/v2n8.html

Do you have this tab on your timing chain cover?

First off you need a piston stop. Thread it into #1 cylinder and then turn the engine by hand until the engine stops moving, mark your balancer at zero against the cover. Go the opposite direction(almost 360 degrees) and then again when the engine stops, mark your balancer at zero. Measure the distance between your two new marks(with a fabric tape) and divide by 2, mark your balancer. That is exact TDC and your correct zero on the balancer. This also helps to identify if an old balancer has slipped. You should land on some kind of groove or slot on the balancer.

You will need a dial back timing light. Get a good bright white mark on the balancer at TDC and then when you dial in your timing light to whatever timing you wan and run the engine, the white mark will line up at the 0 advance line on the cover. So you dial it into lets say 12 degrees, hit it with the light and then turn your dist until your new white mark is at the 0 on the cover, that means your at 12 degrees advance. Then to check overall advance, rev the engine up and dial in the light until that white mark is again at 0 on the cover, you can then read the timing light dial and know your overall total timing advance.

Hope this makes sense!

Disconnect fuel. Pop cylinder 1s spark plugs place your thumb over the hole, jump the started till compression blows your thumb off tHe hole pop you distributed cap. Wherever the rotor is becomes where the wire for cylinder one goes. Then follow the firing order. That’s the super simple, get me in the ballpark method.

You need to mark TDC.

Once you set it by advancing to highest vacuum reading, you effectively raise the total timing. Once you go past 37 -38 degrees of total timing you stand a good chance of detonation. Total can be limited with a plate in the distributor or welding up the stock slots. But, you need to know where you are and how many degrees advanced it it set.

Dial-back timing light. If no actual zero mark, find TDC and make a reference mark, then use dial-back timing light.

khryslerkid said:

Do you have this tab on your timing chain cover?

View attachment 627163

Click to expand...

Are you referring to the tab being missing on the cover? If so, you need to replace it so you know where you're at but using a vacuum gauge will tell you what your engine likes, if you advance to obtain the highest reading, you will be close. Tighten the hold down bolt and see if she starts easily there, if not then back it off a notch. I use a digital hand held tach too because you can see instant changes. Engines are different, one want's an initial of 14 btdc and another likes 18, this is where the vacuum gauge comes in. In all cases, disconnect the vacuum advance before setting initial. You still need to know for sure how much timing you are running though because as already mentioned, if you have more than 34-36 all in then you are flirting with disaster......detonation

On these mopars, there are no numbers on the balancer. There is a notch / line in the balancer. That’s the top dead center mark. You should have the timing tab on your timing cover... passenger side.. as kryslerkid posted.

Here’s what I’d do:

1) find the mark on the balancer, clean it off real good and mark it with a dot of whiteout.

2) Clean the timing tab real good and mark the 0, +10 and -10 with white out. Your timing tab should have a line for 0* clearly labeled (some also have a hole on the zero line). There should be two or three lines in each direction, these are in 5° increments. Most timing tabs have the +10 in -10 clearly labeled.

3) mark the base of your distributor and make a corresponding mark on the engine block - so you can always return to your initial setting

4) loosen your distributor - not dead loose - just loose enough that you can twist the distributor with a little force.

5) start the car and check timing - should be in the neighborhood of 12 - 14 degrees advanced at idle. If it isn’t, twist the distributor until it is, then lock her down.

Don’t set your timing with vacuum. Doesn’t work in my humble opinion and will have you way way advanced.

———— Edit:

Here’s a pic of an aftermarket timing cover I have - timing marks are a little different - I think these are the 70’s timing marks.. your 68 should just have -10 through +15 I think.

wish I had my old 383 damper, but “she gone”. I’d have shown you how it all works together...

But once you find the marks l, even I can do it.

Agree with HT413 and I'll add-

I have 99.99% success setting timing by advancing until it pings under load (find a lightly traveled road) and then backing off until it stops.

I've found this method MUCH more reliable than book specs.

The only times that doesn't work is if something is wrong inside the distributor.

Any updates?