Rules of setting timing (without a light)

[Dan66]

Thanks once again to everyone that responded to my "car won't start" posts. If you haven't heard - it was the red wire to the coil... It had broken/rusted apart way up in the original harness taping. The break was pretty well hidden from view. Anyhow...

Gotta reset my timing. Been needing to for a while now. And I know the basic guidelines. (At least this is how I've done it for years): Block the wheels and have a buddy bring the RPMs up to 2000 or 3000 with the car in gear. Then - with the air cleaner in place and the vacuum line disconnected and plugged - twist the distributor to find the smoothest running position. Done.

My questions are, why do we do some of these things...
1. Why must the car be in gear?
2. Why must the vacuum be disconnected and plugged?
3. Why must the air cleaner be in place?

I usually get pretty good results from this technique; but I've never bothered to find out the reasons behind everything. ::

[HoosierBuddy]

If you aren't going to shell out the 30 bucks for a timing light at Walmart...and you're too far away from me to come get mine...cause you're MORE than welcome to borrow it anytime....then.

1. There's absolutely no reason to have your vacuum line disconnected. Leave it on.
2. There is LITTLE reason to have your air cleaner on. It's in the way. Take it off.
3. You don't need a buddy. Make small adjustments clockwise to increase timing or counterclockwise to retard and find the spot at which you can get a nice steady idle once the car is warmed up and the choke is off.
4. If you shut it off and it doesn't want to start retard the timing.
5. If you take it on a drive and it want's to ping, retard the timing.
6. If the idle is rough or it wants to surge at idle...try increasing the timing.

Before you start...double check your wires are all going to the right sparkplugs.

Good luck.

Phil

[Dan66]

If you aren't going to shell out the 30 bucks for a timing light at Walmart...

It's not that I refuse to drop $30 on a light; it's that I've been told (and read) numerous times to not use a light on our older cars. Something about the rubber parts of the harmonic balancer will have shrunk to the point that the marks are no longer useful... In other words - you'll get closer going by ear. But I s'pose if you're willing to make the drive down to Austin, Phil - I'll be here most of the day!

[Richelieu]

This goes against Hoosier here and I haven't run my engine yet so my comments are only based on what I was told... by multiple people...

The vacuum line you speak of... is that going to the dizzy, or the carb? if you're talking the dizzy line, so you take that off and plug it so the vacuum advance will not affect the setting of the initial timing. You're trying to get a baseline at that point, and any little RPM will create a small amount of vacuum, which will make the dizzy advance....

Now if we're talkin' vacuum at the carb, or a mech dizzy... all bets are off, but I know for vacuum advance dizzy, as mine is, that's what I have to do.

[Gene_J]

1. Why must the car be in gear?
A) Because when you are driving you are usually in gear. If the car idles quite nicely in Park this does not mean it will idle nicely when the RPMs drop at a stop light in Drive.

2. Why must the vacuum be disconnected and plugged?
A) There will be a small amount of advance if you don't. You are setting the base mechanical timing. There will be more advance later because of the vacuum advance. If you do not plug it you will get a vacuum leak and it will not run well!

3. Why must the air cleaner be in place?
A) It should not make that much difference. Certainly not as much as the vacuum leak when you didn't plug the vacuum advance!

Most manuals also specify that you set timing and idle with the lights on also just for an additional load on the engine! A few suggest having the air conditioning on.

[66CoupeNW]

Lemme get this straight ... your supposed to put the car in gear, rev it up to 3000 RPM, then stand in front of it tweaking the distributor! :: :: Man, that sounds like something I'd read in a Darwin award nomination!

I used to time by ear, but then I bought some timing tape from Summit, found exact TDC on cylinder 1 with a caliper through the spark plug hole, then marked the balancer with the tape. She runs beautiful when I time her exactly per spec.

[65HiPo]

Hey Dan,
Bring your car over to my place this weekend (I'm in Round Rock) and I'll help you out. I've got a badass timing light and an old style engine analyzer for checking point dwell and the like. I adjusted mine yesterday and she purrs like a newborn kitten. Shoot me an e-mail at raley65@sbcglobal.net

Gerald

[Dan66]

Lemme get this straight ... your supposed to put the car in gear, rev it up to 3000 RPM, then stand in front of it tweaking the distributor...

My car has an "R" that makes it go backwards! I was pretty sure this would keep me from being squished in the garage!

[HoosierBuddy]

Richleau...you are completely correct...if he was using a timing light to set the inital advance...it should be done with the vacuum advance disconnected and pluged (so there isn't any vacuum leak).

However...he has no way to measure the inital timing without a light...because he's going to do it by ear...so he should leave the vacuum advance hooked up the whole time.

As far as the harmonic balancer shifting theory...I too have read that. I'm not sure how common or uncomman it is. If my balancer had slipped I would want to know that so I could replace it. It can't be doing much of a damping job if the rubber is so shot that it has slipped.

Verifying TDC and using timing tape would be way better still.

Phil

[dailydriver]

First of all, leave the air cleaner on. When jacking around with the timing, you are prone to get a backfire through the carb. So, unless you want fire extinguisher material down the carb, leave it on!

Advanced timing is good, unless it pings, then it's bad.

Retarded timing is bad, period. I once helped a young mustanger time his car, and it was set about 35 deg slower than it should have been. He had proudly related to me how he had timed it by "ear". He had spent a lot of money trying to cure his heating problem. Retiming it fixed the heating problem. :p

So, here's how I do it:

Adjust the timing to where it idles well, but usually not nearly at maximum RPM. Then, stick a 1/2" wrench in your pocket and go for a ride. If you can get it to ping at all, you need to retard the timing. If you can't get it to ping under a load at 50-60 mph, advance it until it does... this is for a reference point -- Otherwise, you may have it too far retarded and settle for that if it otherwise runs OK. To summarize advance it until it pings, then back off until you can't make it ping. No guesswork, nothing to remember. That's the way I do it. Have Fun!

[63BGT66]

I thought the vacuum was ported..so there shouldn't be any advance at idle.

[SUZIE68]

Lemme get this straight ... your supposed to put the car in gear, rev it up to 3000 RPM, then stand in front of it tweaking the distributor! Man, that sounds like something I'd read in a Darwin award nomination!

Hehehehe too funny ::

Jon

[dailydriver]

I'm not sure what you're saying. We were talking about timing by "ear", turning the distributor while it's idling. You can retard, or advance the timing as much as you have room to turn the distributor while idling. Does that clear it up?

[63BGT66]

The vacuum advance should not be funtioning at idle with ported vacuum is what I was refering to. I can see no reason to plug the line in this case since it would have no impact on the initial setting, but I see Dan is trying to do it another way..off idle.

[jcsshane]

Ken! The tried and true power tuning method ~ I agree, bring it to ping and back it off till it stops. Seems to work for me everytime - Jc