318 Harmonic Balancer

[markbob]

Hi all

My 69 Coronet with a 318 V8 seems to be off a bit

I tried timing it and it appears the timing is very advanced
I have the flame thrower coil and electronic ignition installed.

Can a harmonic balancer shift on the crank and therefore mess up my timing light adjustments?

I have the car running smooth at idle and seems to be starting, idling and running fine.... But the timing marks are all messed up

Thx

MB

 

[69roadr]

i would look at the distributor and related parts first.

 

[threewood]

It absolutely can. Only way to be sure is use a top dead center tool in the #1 spark plug hole. On compression stroke, back it off 30 degrees or so, insert the tool and rotate until it stops. Mark the damper at 0. Rotate the other way until it stops, Mark the damper at 0. Half way between these 2 marks is tdc.

I had mine slip about 15 degrees and couldn't see the mark when timing it. When I get home, I'll post pics and the Summit damper I bought to replace it.

What rpms are you turning at idle? If it is too fast the mechanical advance could be raising the advance = raising idle = Making your timing mark erratic.

Check tdc first.

 

[SgtLee511]

Mine was so far off my 340 it was pointed at the distributor,

 

[markbob]

Thanks for the replies...
Not sure why it would slip.... Maybe it wasn't torqued down enough.
All I know is you can't time it properly with the favor way off.
I just rotated it until it smoothly idled.
That will have to be good enough until I can tear it apart and fix it
The idle is about 650 or so in park....

 

[threewood]

Thinking about the question more. If the balancer slips, it will not affect the idle one bit. But you will not be able to accurately time it. If you are experiencing the faster idle after install of the Ignitor II, it does advance it about 10 degrees or so from points if you left the distributor where it was. Happened when I installed mine, fired right up though but was running about 22* initial.

 

[Cranky]

It's the inertia ring that slips on the hub of the balancer.....there's just rubber between the center and the ring. If it's an original balancer, the rubber is probably good and dry by now.

 

[KarNut46]

Cranky's right. Outer ring connected to hub by a strip of rubber (or neoprene). Vulcanized (think glued). I've used both Summit brand and Professional products and both are adequate for small block street use. Only gripe is the location of the timing marks. They put them on the front of the balancer. Timing tab on most small block timing chain covers is near the back of the balancer.