Harmonic balancer and timing question

[565bbchevy]

Yeah the mechanic said the idle advance was 22 degrees. It starts up fairly easy, no big troubles when it's warm

So do you mean "initial advance" which would be the base timing before mechanical or vacuum advance is added?

 

[mobileaudio25]

So do you mean "initial advance" which would be the base timing before mechanical or vacuum advance is added?

Yes thats what I meant. Sorry my knowledge on timing isnt all the way there. I'm thinking he forgot to take the vacuum advance off the distributor ..

 

[mobileaudio25]

If the balancer is a stock unit it is possible the outer ring spun on the hub which will throw off your timing reading if this is the case I would buy a nice aftermarket one that has the timing marks already on them and if you plan on going to the track get one that is SFI approved, there are plenty of affordable ones out there.

I don't plan on taking it to the track other than maybe a time or two to see what it does. I think it is stock I was looking into one of these. Do you think and 8in balancer would be better for my application?

https://m.summitracing.com/parts/sum-161358

 

[lilbowtie]

My advice would be to re-check your timing W/O the vac advance @ idle and total and go from there.

 

[Texas82GP]

Can someone speak to the pros/cons of the 6" balancer versus the 8" balancer to answer the OP's question, in case he decides to buy one?

To the OP: if you are using an old original balancer, I would suggest replacing it. The elastomer ring between the inner 'hub' and the outer ring of the balancer can dry rot and allow the outer ring to slip relative to the inner hub, which will throw of the position of the timing mark. Worse than that, the balancer can come apart when run hard. A new balancer is cheap insurance.

 

[pontiacgp]

Can someone speak to the pros/cons of the 6" balancer versus the 8" balancer to answer the OP's question, in case he decides to buy one?.

some people think there is less rotating mass with a 6" so the engine will speed up and slow down quicker....but harmonic balancers are tuned for a frequency of harmonic vibrations so 6" or 8" is really not the important question. What you need to find out is what rpm are they dampening vibrations and for what type of crank. A steel crank needs a different balancer than a cast iron crank

 

[mobileaudio25]

Can someone speak to the pros/cons of the 6" balancer versus the 8" balancer to answer the OP's question, in case he decides to buy one?

To the OP: if you are using an old original balancer, I would suggest replacing it. The elastomer ring between the inner 'hub' and the outer ring of the balancer can dry rot and allow the outer ring to slip relative to the inner hub, which will throw of the position of the timing mark. Worse than that, the balancer can come apart when run hard. A new balancer is cheap insurance.

I've read online from a few resources that an 8in heavier balancer actually made more power than a smaller 6.75 in balancer. I like everything to be new the lower control arms and harmonic balancer are the only original parts on the car...

I wanted to just replace the balancer and make sure everything is set up correctly... I still think the vacuum advance was left on when checking the timing

 

[565bbchevy]

For the stock style replacement balancers you are looking at the 8" will do a better job of controlling harmonics but once you get into SFI race style balancers they tend to average around 7" or so, my ATI on my BBC is 7.25" and does an excellent job.