Timing Question

[Tommy21]

Hello all, I have a 1977 that passes California smog with flying colors (or did 1 year ago). Now retesting, the smog tech said the timing is not at 8 advanced as it needs to be to pass smog.

It starts right up, runs smooth and has tons of power so I assume the timing is on, or very close. He disconnected the vacuum advance line (did not plug either dist or hose) and said the light was hitting to the right of 0 on the indicator.

Is it possible the harmonic balancer spun the outer ring?

 

[joshd1971bronco]

I'd take it to a reputable shop or friend with a timing light and get it checked. That guy may not have accurately read the timing.
'to the right of 0' would still be a little advanced I think, which is what you want. 8-10 degrees initial timing without the vacuum advance is considered target (depending on your motor, fuel, etc).
How many miles/how old is the motor? Timing chain and gears?
Engines can 'jump time' but I think it's a statistical anomaly. And I doubt your balancer moved.
Clean up the balancer at the timing marks and mark it real good with a paint pen or something very visible.

Sent from my Pixel 3 using Tapatalk

 

[pipeline010]

good advice. I would go onto craigslist and find a shady tree mechanic to come out and help you set the timing.

ordinarily that can be a real crap shoot, but for something as simple as setting timing it's not a big deal. real value = make him show you how to do what he's doing. that's what I did and never needed another mechanic (for timing anyway).

local shops don't want to teach you anything..they just want to do it and get you the f out of there for the next customer. not criticizing...it's a business.

 

[Slowleak]

The outer ring on my 77 was slipping. The Bronco ran fine but when I checked the timing it appeared to be way off.

If you have the original balancer you really need to check it. I would suggest you clean it and paint a line on it across both rings so you can see if it slips. Check the rubber ring for cracks and deterioration. Make sure the outer ring is not slipping back towards the engine also. If it looks bad replace it before it turns loose. They can cause all kinds of damage when they go....

 

[matts460]

Wow pulled vacuum hose off and didn't plug it!? theres your sign! Anybody can read a repair manual for checking timing on these old trucks and first thing it says is to unplug vacuum advance hose PLUG IT and check initial timing. Initial timing and idle setting will be different for A/C equipped, manual trans, and automatic trans cars/trucks. Oh and Duh the timing should be to the right of 0 mark if standing at the front of truck facing firewall, that's your before top dead center (advance) Sounds to me like its is in time and if the light was flashing to the right of 0 about a half inch its probably dead on 8deg you need. You need to find new mechanic that knows what timing does/is and how to read a timing light.

 

[Tommy21]

Great advice, thank you all. I'm going to check the timing as I suspect he was reading incorrectly. The balancer doesn't look very old so hopefully it didn't slip the outer ring. I'm going to clean the balancer, paint the marks and get a better idea of what's actually going on. Thanks!

 

[kylakekevin]

Also make sure the guy doesn't have the timing light that you can adjust when it flashes or if he does make sure it is zeroed. Ask me how I know this.

 

[blubuckaroo]

The harmonic balancer ring can slip, and can come off.
I had one come loose while on the way home from a camping trip. Fortunately, it slid forward and was caught on the crank pulley. It made one hell of a noise!
I pulled the belts and pulley to get the ring off, on the side of the road. We made the trip home without the balancer ring. I didn't even notice a difference without it.

The problem now is, to find "exact" top dead center without pulling the timing cover off.
I've done it by using a piston stop, marking the balancer in both directions. Top dead center will be half way between the two marks.

 

[tirewater]

Smog tests are every two years, unless your truck was labelled a gross polluter in prior tests. If you had it smogged last year, are you sure you have to do it this year?

As for the reading, sounds like you're on it.

 

[DirtDonk]

And the guy is looking for factory spec by default, because it's a test. So if it's set to, for example 10 degrees, it might run perfectly fine but is not within spec so he can't pass it.
The engine has lots of timing leeway. The test does not.

Paul

 

[SHX669]

I would also suspect the " tester " -- if he says you're timing doesn't meet specs but he doesn't know what your initial timing actually is - ??

 

[DirtDonk]

In his defense (but just barely) you can leave the hoses uncorked and not be doing it "wrong" for his end. If he was just verifying the timing, and not caring about how it ran, then it's perfectly viable to just unplug the hose(s) and leave them that way while checking.
And being a '77 there may not have been a vacuum signal at either hose anyway. Whether the single or the double diaphragm, much of the vacuum signal for the distributor is routed through timed and temperature valves and there may not have been any chance in how it was idling when the hoses were unplugged.

Depending on the type of shop you were testing at too (perhaps a "test only" station?) they're not allowed usually to adjust the timing for you in order to get it passed.
I don't remember why they did that, but it was probably to keep people from getting gouged by unscrupulous shops that would charge you extra to set timing or turn a screw on a carburetor.
Of course, on a '77 and especially if it had aftermarket air conditioning, it might have been a $50 job to find and turn the clamp bolt! Which they may not have had the proper tools for anyway, if it was just a testing station.

If the guy was not the boss, he might have been going by the book so as not to lose his job if the customer turned out to be an inspector, or the boss was watching over his shoulder.

Paul

 

[blubuckaroo]

And the guy is looking for factory spec by default, because it's a test. So if it's set to, for example 10 degrees, it might run perfectly fine but is not within spec so he can't pass it.
The engine has lots of timing leeway. The test does not.

Paul

This is right.^
I'd just set it to spec, and have it retested.
The actual "tailpipe" part of the test has a lot of leeway on these old cars too.

A funny story...
Our '77 Bronco had passed the CA emission test, but the car had a bad rattling sound from the muffler, when running it up to speed on the dyno roller.
So, after leaving the smog shop, I stopped at the muffler shop to have the muffler replaced. The guy called me out and asked me to look into the catalytic converter. The honeycomb material was completely gone, and was now in the muffler. So, the guy wanted to sell me a new catalytic converter too. I asked him "why?" He said so it can pass the emission test. I told him, it just passed as is. Why would I put a new one in?
The car passed again two years later as is.

 

[laserfish]

Like Blu, I had one come apart the same way a couple of months ago. Sure makes a racket jangling against the crank pulley. Purchased my replacement from Summit here in town.
Sure am glad I do not have to deal with the smog police here in TX!

 

[tirewater]

The allowable emissions for older cars in CA is pretty high relative to new cars. A well tuned car could pass without a working cat.

In addition, the tech at my last test said there was +/- factor of 2 degrees for timing. The timing range was between 6-10 (basing off 8 degree stock timing).

 

[Allen_69]

I'd fix it with this.

 

[TDubya]

but the car had a bad rattling sound from the muffler

Ahh, bad muffler bearing. Been there...

 

[SHX669]

but the car had a bad rattling sound from the muffler

Ahh, bad muffler bearing. Been there...

Did you ever fix that ? I thought that was giving you some problems 3-4 years ago on the Covered Bridge tour/ excursion/ run - LOL -- getting harder to find those OEM Parts .

 

[TDubya]

Yah, I traded a guy some headlight fluid for a brand new, in the box muffler bearing. Good to go!

 

[SHX669]

Yah, I traded a guy some headlight fluid for a brand new, in the box muffler bearing. Good to go!

Awesome - glad it worked out