Need timing help

[Dr_Snooz]

I just finished putting the new Edelbrock carb and Edelbrock intake on my truck. I'm ready to get it smogged, but I have a problem with the timing. If I set the timing by ear and/or a vacuum gauge, it runs great. However, when I check it with the light, it's shows that it's way advanced. So advanced that it's way off the timing tab. I estimate that it's firing at 50* BTDC according to the timing tab. If I retard it down to 12* BTDC the idle slows down and becomes rough and the engine starts making a strange plinking sound. It seems to run well at 50* BTDC and from my reading, it seems that most people time big blocks by ear, so I'm comfortable with where it's set.

However, I seem to recall that part of the CA smog check involves checking timing. If so, then I don't see it passing being so far advanced. What are my options for fixing this?



In other news, I forgot to reconnect the coil wires before I tried to start it up. When I reconnected them and tried again, I lit all the residual gas vapor in the exhaust and blew out the back of my muffler.    The upshot is that the truck sounds AWESOME now! It rumbles like an old '70s muscle car. I LOVE it!

Thanks for the help.

[topp]

What year?
Is it TBI?

[78 Chevyrado]

Sounds like the harmonic balancer may have slipped and the timing mark is off.

[topp]

Or if it's TBI he didn't unplug the Override to base time it.

[78 Chevyrado]

I just thought of a cheat that may work....   forget the old timing mark and put you some timing tape on the balancer and make where it runs the best read what the truck should be set at....  it might work???  

[HIGHPLAINSDRIFTER]

Custom exhaust always up's the resale value!

[Dr_Snooz]

Thanks 78 Chevyrado. Those are both good suggestions. I never knew that the balancer could slip and I'll bet that's what happened. I think the timing tape is a great idea. I'll try a straight smog check today. If they shoot me down, I'll be back with some timing tape (assuming they don't shoot me down for the Edelbrock carb first).

Thanks guys!

[Lt.Del]

is this your '86?  i assume it is carbed?
do you have vacuum advance?  I don't know if 86 had those or not but if so, was the vacuum line removed from distr. advance and plugged? 
I think 87 began tbi, so I don't think there is brown wire by the master cylinder that needs to be unplugged prior to timing.

[slammed79]

You should be fine as long as you put an egr valve and your vacuum is still mostly right let us know how you fare.

[Dr_Snooz]

This is my '86. No TBI. I tried timing without the vacuum line, but it didn't change anything. The line doesn't seem to have any vacuum at idle.

I took it today for the smog check and failed by miles. It's so far over on HCs that it earned the dreaded "gross polluter" designation. I hope I can fix that with some simple carb tinkering. I might have to buy an air fuel ratio gauge to get it right. They're expensive, but probably cheaper than back to back to back smog checks. I'll do a compression check and leak down test too just to rule those out.

As I suspected, they squawked about the timing. I think I'm just going to repaint the mark and be done with it.

I'll keep you posted.

[1980c10]

your distributor could be a tooth off that would put your timing mark out of place as well.